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  19. </a></div> <!----></nav>  <ul class="sidebar-links"><li><section class="sidebar-group depth-0"><p class="sidebar-heading open"><span>Mini-Redis教程</span> <!----></p> <ul class="sidebar-links sidebar-group-items"><li><a href="/rust_camp_tutorial/Rust%E6%96%87%E6%A1%A3/Mini-Redis%E6%95%99%E7%A8%8B.html#准备工作" class="sidebar-link">准备工作</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header"><a href="/rust_camp_tutorial/Rust%E6%96%87%E6%A1%A3/Mini-Redis%E6%95%99%E7%A8%8B.html#获取代码" class="sidebar-link">获取代码</a></li><li class="sidebar-sub-header"><a href="/rust_camp_tutorial/Rust%E6%96%87%E6%A1%A3/Mini-Redis%E6%95%99%E7%A8%8B.html#运行项目" class="sidebar-link">运行项目</a></li></ul></li><li><a href="/rust_camp_tutorial/Rust%E6%96%87%E6%A1%A3/Mini-Redis%E6%95%99%E7%A8%8B.html#module" class="sidebar-link">Module</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header"><a href="/rust_camp_tutorial/Rust%E6%96%87%E6%A1%A3/Mini-Redis%E6%95%99%E7%A8%8B.html#client" class="sidebar-link">client</a></li><li class="sidebar-sub-header"><a href="/rust_camp_tutorial/Rust%E6%96%87%E6%A1%A3/Mini-Redis%E6%95%99%E7%A8%8B.html#blocking-client" class="sidebar-link">blocking_client</a></li><li class="sidebar-sub-header"><a href="/rust_camp_tutorial/Rust%E6%96%87%E6%A1%A3/Mini-Redis%E6%95%99%E7%A8%8B.html#cmd" class="sidebar-link">cmd</a></li><li class="sidebar-sub-header"><a href="/rust_camp_tutorial/Rust%E6%96%87%E6%A1%A3/Mini-Redis%E6%95%99%E7%A8%8B.html#frame" class="sidebar-link">frame</a></li><li class="sidebar-sub-header"><a href="/rust_camp_tutorial/Rust%E6%96%87%E6%A1%A3/Mini-Redis%E6%95%99%E7%A8%8B.html#sever" class="sidebar-link">sever</a></li></ul></li><li><a href="/rust_camp_tutorial/Rust%E6%96%87%E6%A1%A3/Mini-Redis%E6%95%99%E7%A8%8B.html#function-2" class="sidebar-link">Function</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header"><a href="/rust_camp_tutorial/Rust%E6%96%87%E6%A1%A3/Mini-Redis%E6%95%99%E7%A8%8B.html#fn-buffer" class="sidebar-link">Fn Buffer</a></li></ul></li><li><a href="/rust_camp_tutorial/Rust%E6%96%87%E6%A1%A3/Mini-Redis%E6%95%99%E7%A8%8B.html#struct-16" class="sidebar-link">Struct</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header"><a href="/rust_camp_tutorial/Rust%E6%96%87%E6%A1%A3/Mini-Redis%E6%95%99%E7%A8%8B.html#buffer" class="sidebar-link">Buffer</a></li><li class="sidebar-sub-header"><a href="/rust_camp_tutorial/Rust%E6%96%87%E6%A1%A3/Mini-Redis%E6%95%99%E7%A8%8B.html#connection" class="sidebar-link">Connection</a></li></ul></li></ul></section></li></ul> </aside> <main class="page"> <div class="theme-default-content content__default"><h1 id="mini-redis教程"><a href="#mini-redis教程" class="header-anchor">#</a> Mini-Redis教程</h1> <h2 id="准备工作"><a href="#准备工作" class="header-anchor">#</a> 准备工作</h2> <h3 id="获取代码"><a href="#获取代码" class="header-anchor">#</a> 获取代码</h3> <div class="language-shell extra-class"><pre class="language-shell"><code><span class="token function">git</span> clone <span class="token parameter variable">--recursive</span> https://github.com/DragonOS-Community/rust_camp_code.git
    20. 

  20. </code></pre></div><p>教程版请切换curse-mini-redis分支</p> <h3 id="运行项目"><a href="#运行项目" class="header-anchor">#</a> 运行项目</h3> <h4 id="运行服务端"><a href="#运行服务端" class="header-anchor">#</a> 运行服务端</h4> <div class="language-shell extra-class"><pre class="language-shell"><code><span class="token assign-left variable">RUST_LOG</span><span class="token operator">=</span>debug <span class="token function">cargo</span> run <span class="token parameter variable">--bin</span> mini-redis-server
    21. 

  21. </code></pre></div><p>运行服务端之后，就可以运行redis操作的代码和redis的命令了。详情请参考example文件夹下的代码和redis的命令。</p> <h4 id="运行example的代码"><a href="#运行example的代码" class="header-anchor">#</a> 运行example的代码</h4> <div class="language-shell extra-class"><pre class="language-shell"><code><span class="token function">cargo</span> run <span class="token parameter variable">--example</span> hello_world
    22. 

  22. </code></pre></div><h4 id="运行redis命令"><a href="#运行redis命令" class="header-anchor">#</a> 运行redis命令</h4> <div class="language-shell extra-class"><pre class="language-shell"><code><span class="token function">cargo</span> run <span class="token parameter variable">--bin</span> mini-redis-cli <span class="token builtin class-name">set</span> foo bar
    23. 

  23. 

  24. <span class="token function">cargo</span> run <span class="token parameter variable">--bin</span> mini-redis-cli get foo
    25. 

  25. </code></pre></div><h2 id="module"><a href="#module" class="header-anchor">#</a> Module</h2> <h3 id="client"><a href="#client" class="header-anchor">#</a> client</h3> <blockquote><p>最小的redis会话。为所支持的命令提供异步连接。</p></blockquote> <p>代码位于src/clients/client.rs</p> <h4 id="client-2"><a href="#client-2" class="header-anchor">#</a> Client</h4> <h5 id="struct"><a href="#struct" class="header-anchor">#</a> Struct</h5> <p>用于建立和存储客户端连接</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">pub</span> <span class="token keyword">struct</span> <span class="token type-definition class-name">Client</span><span class="token punctuation">{</span>
    26. 

  26.     <span class="token comment">/// 客户端连接</span>
    27. 

  27.     connection<span class="token punctuation">:</span><span class="token class-name">Connection</span><span class="token punctuation">,</span>
    28. 

  28. <span class="token punctuation">}</span>
    29. 

  29. </code></pre></div><h5 id="implementation"><a href="#implementation" class="header-anchor">#</a> Implementation</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">Client</span><span class="token punctuation">{</span>
    30. 

  30.     <span class="token comment">/// 建立连接</span>
    31. 

  31.     <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">connect</span><span class="token operator">&lt;</span><span class="token class-name">T</span><span class="token punctuation">:</span> <span class="token class-name">ToSocketAddrs</span><span class="token operator">&gt;</span><span class="token punctuation">(</span>addr<span class="token punctuation">:</span> <span class="token class-name">T</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Client</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    32. 

  32.         <span class="token comment">// 与addr建立tcp连接并获取套接字</span>
    33. 

  33.         <span class="token keyword">let</span> socket <span class="token operator">=</span> <span class="token class-name">TcpStream</span><span class="token punctuation">::</span><span class="token function">connect</span><span class="token punctuation">(</span>addr<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    34. 

  34.         <span class="token comment">// 使用套接字建立连接</span>
    35. 

  35.         <span class="token keyword">let</span> connection <span class="token operator">=</span> <span class="token class-name">Connection</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span>socket<span class="token punctuation">)</span><span class="token punctuation">;</span>
    36. 

  36.         <span class="token comment">// 返回客户端</span>
    37. 

  37.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">Client</span> <span class="token punctuation">{</span> connection <span class="token punctuation">}</span><span class="token punctuation">)</span>
    38. 

  38.     <span class="token punctuation">}</span>
    39. 

  39. 

  40.     <span class="token comment">/// ping客户端</span>
    41. 

  41.     <span class="token attribute attr-name">#[instrument(skip(self))]</span>
    42. 

  42.     <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">ping</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> msg<span class="token punctuation">:</span> <span class="token class-name">Option</span><span class="token operator">&lt;</span><span class="token class-name">Bytes</span><span class="token operator">&gt;</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Bytes</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    43. 

  43.         <span class="token comment">// 构建ping消息</span>
    44. 

  44.         <span class="token keyword">let</span> frame <span class="token operator">=</span> <span class="token class-name">Ping</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span>msg<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">into_frame</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    45. 

  45.         <span class="token comment">// 日志记录ping</span>
    46. 

  46.         <span class="token macro property">debug!</span><span class="token punctuation">(</span>request <span class="token operator">=</span> <span class="token operator">?</span>frame<span class="token punctuation">)</span><span class="token punctuation">;</span>
    47. 

  47.         <span class="token comment">// 发送ping消息</span>
    48. 

  48.         <span class="token keyword">self</span><span class="token punctuation">.</span>connection<span class="token punctuation">.</span><span class="token function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>frame<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    49. 

  49.         <span class="token comment">// 读取响应，对Frame::Simple、Frame::Bulk、error类型进行处理</span>
    50. 

  50.         <span class="token keyword">match</span> <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">read_response</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span> <span class="token punctuation">{</span>
    51. 

  51.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Simple</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span>value<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    52. 

  52.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Bulk</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span><span class="token punctuation">,</span>
    53. 

  53.             frame <span class="token operator">=&gt;</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>frame<span class="token punctuation">.</span><span class="token function">to_error</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    54. 

  54.         <span class="token punctuation">}</span>
    55. 

  55.     <span class="token punctuation">}</span>
    56. 

  56. 

  57.     <span class="token comment">/// 获取key对应的value</span>
    58. 

  58.     <span class="token attribute attr-name">#[instrument(skip(self))]</span>
    59. 

  59.     <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">get</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>key<span class="token punctuation">:</span><span class="token operator">&amp;</span><span class="token keyword">str</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Option</span><span class="token operator">&lt;</span><span class="token class-name">Bytes</span><span class="token operator">&gt;&gt;</span> <span class="token punctuation">{</span>
    60. 

  60.         <span class="token comment">// 创建获取'key'的值的'Get'命令,并将其转换成frame格式</span>
    61. 

  61.         <span class="token keyword">let</span> frame <span class="token operator">=</span> <span class="token class-name">Get</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span>key<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">into_frame</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    62. 

  62.         <span class="token comment">// 日志记录frme</span>
    63. 

  63.         <span class="token macro property">debug!</span><span class="token punctuation">(</span>request <span class="token operator">=</span> <span class="token operator">?</span>frame<span class="token punctuation">)</span><span class="token punctuation">;</span>
    64. 

  64. 

  65.         <span class="token comment">// 将frame通过连接异步写给套接字</span>
    66. 

  66.         <span class="token keyword">self</span><span class="token punctuation">.</span>connection<span class="token punctuation">.</span><span class="token function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>frame<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    67. 

  67. 

  68.         <span class="token comment">// 异步读响应,并匹配Simple、Bulk、NUll的情况</span>
    69. 

  69.         <span class="token keyword">match</span> <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">read_response</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span> <span class="token punctuation">{</span>
    70. 

  70.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Simple</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">Some</span><span class="token punctuation">(</span>value<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    71. 

  71.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Bulk</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">Some</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    72. 

  72.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Null</span> <span class="token operator">=&gt;</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">None</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    73. 

  73.             frame <span class="token operator">=&gt;</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>frame<span class="token punctuation">.</span><span class="token function">to_error</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    74. 

  74.         <span class="token punctuation">}</span>
    75. 

  75.     <span class="token punctuation">}</span>
    76. 

  76. 

  77.     <span class="token comment">/// 设置key对应的value</span>
    78. 

  78.     <span class="token attribute attr-name">#[instrument(skip(self))]</span>
    79. 

  79.     <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">set</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> key<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">str</span><span class="token punctuation">,</span> value<span class="token punctuation">:</span> <span class="token class-name">Bytes</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    80. 

  80.         <span class="token comment">// 通过set_cmd异步创建过期时间为None的Set命令</span>
    81. 

  81.         <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">set_cmd</span><span class="token punctuation">(</span><span class="token class-name">Set</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span>key<span class="token punctuation">,</span> value<span class="token punctuation">,</span> <span class="token class-name">None</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span>
    82. 

  82.     <span class="token punctuation">}</span>
    83. 

  83. 

  84.     <span class="token comment">/// 设置key对应的value，value在expiration后过期</span>
    85. 

  85.     <span class="token attribute attr-name">#[instrument(skip(self))]</span>
    86. 

  86.     <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">set_expires</span><span class="token punctuation">(</span>
    87. 

  87.         <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
    88. 

  88.         key<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">str</span><span class="token punctuation">,</span>
    89. 

  89.         value<span class="token punctuation">:</span> <span class="token class-name">Bytes</span><span class="token punctuation">,</span>
    90. 

  90.         expiration<span class="token punctuation">:</span> <span class="token class-name">Duration</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span><span class="token punctuation">{</span>
    91. 

  91.         <span class="token comment">// 通过set_cmd异步创建过期时间为expiration的Set命令</span>
    92. 

  92.         <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">set_cmd</span><span class="token punctuation">(</span><span class="token class-name">Set</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span>key<span class="token punctuation">,</span> value<span class="token punctuation">,</span> <span class="token class-name">Some</span><span class="token punctuation">(</span>expiration<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span>
    93. 

  93.     <span class="token punctuation">}</span>
    94. 

  94. 

  95.     <span class="token comment">/// Set命令的主要逻辑</span>
    96. 

  96.     <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">set_cmd</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> cmd<span class="token punctuation">:</span> <span class="token class-name">Set</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    97. 

  97.         <span class="token comment">// 将cmd转化为frame的形式</span>
    98. 

  98.         <span class="token keyword">let</span> frame <span class="token operator">=</span> cmd<span class="token punctuation">.</span><span class="token function">into_frame</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    99. 

  99.         <span class="token comment">// 将frame写入连接</span>
    100. 

  100.         <span class="token keyword">self</span><span class="token punctuation">.</span>connection<span class="token punctuation">.</span><span class="token function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>frame<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    101. 

  101.         <span class="token comment">// 读取对frame的响应，并匹配响应状态</span>
    102. 

  102.         <span class="token comment">// 执行成功响应为&quot;OK&quot;</span>
    103. 

  103.         <span class="token comment">// 其他响应均为失败</span>
    104. 

  104.         <span class="token keyword">match</span> <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">read_response</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span> <span class="token punctuation">{</span>
    105. 

  105.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Simple</span><span class="token punctuation">(</span>response<span class="token punctuation">)</span> <span class="token keyword">if</span> response <span class="token operator">==</span> <span class="token string">&quot;OK&quot;</span> <span class="token operator">=&gt;</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    106. 

  106.             frame <span class="token operator">=&gt;</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>frame<span class="token punctuation">.</span><span class="token function">to_error</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    107. 

  107.         <span class="token punctuation">}</span>    
    108. 

  108.     <span class="token punctuation">}</span>
    109. 

  109. 

  110.     <span class="token comment">/// 将信息推送给指定的频道</span>
    111. 

  111.     <span class="token attribute attr-name">#[instrument(skip(self))]</span>
    112. 

  112.     <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">publish</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> channel<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">str</span><span class="token punctuation">,</span> message<span class="token punctuation">:</span> <span class="token class-name">Bytes</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token keyword">u64</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    113. 

  113.         <span class="token comment">// 将Publish命令转成frame的格式</span>
    114. 

  114.         <span class="token keyword">let</span> frame <span class="token operator">=</span> <span class="token class-name">Publish</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span>channel<span class="token punctuation">,</span> message<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">into_frame</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    115. 

  115. 

  116.         <span class="token comment">// 日志记录frme</span>
    117. 

  117.         <span class="token macro property">debug!</span><span class="token punctuation">(</span>request <span class="token operator">=</span> <span class="token operator">?</span>frame<span class="token punctuation">)</span><span class="token punctuation">;</span>
    118. 

  118. 

  119.         <span class="token comment">// 将frame通过连接异步写给套接字</span>
    120. 

  120.         <span class="token keyword">self</span><span class="token punctuation">.</span>connection<span class="token punctuation">.</span><span class="token function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>frame<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    121. 

  121. 

  122.         <span class="token comment">// 异步读请求，并匹配请求类型</span>
    123. 

  123.         <span class="token comment">// 如果是整数帧，则返回OK(response)</span>
    124. 

  124.         <span class="token comment">// 否则返回错误</span>
    125. 

  125.         <span class="token keyword">match</span> <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">read_response</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span> <span class="token punctuation">{</span>
    126. 

  126.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Integer</span><span class="token punctuation">(</span>response<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span>response<span class="token punctuation">)</span><span class="token punctuation">,</span>
    127. 

  127.             frame <span class="token operator">=&gt;</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>frame<span class="token punctuation">.</span><span class="token function">to_error</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    128. 

  128.         <span class="token punctuation">}</span>
    129. 

  129.     <span class="token punctuation">}</span>
    130. 

  130. 

  131.     <span class="token comment">/// SUBSCRIBE的主要逻辑</span>
    132. 

  132.     <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">subscribe_cmd</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> channels<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token punctuation">[</span><span class="token class-name">String</span><span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    133. 

  133.         <span class="token comment">// 将Subscribe命令转成frame的格式</span>
    134. 

  134.         <span class="token keyword">let</span> frame <span class="token operator">=</span> <span class="token class-name">Subscribe</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span>channels<span class="token punctuation">.</span><span class="token function">to_vec</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">into_frame</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    135. 

  135. 

  136.         <span class="token comment">// 日志记录frme</span>
    137. 

  137.         <span class="token macro property">debug!</span><span class="token punctuation">(</span>request <span class="token operator">=</span> <span class="token operator">?</span>frame<span class="token punctuation">)</span><span class="token punctuation">;</span>
    138. 

  138. 

  139.         <span class="token comment">// 将frame通过连接异步写给套接字</span>
    140. 

  140.         <span class="token keyword">self</span><span class="token punctuation">.</span>connection<span class="token punctuation">.</span><span class="token function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>frame<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    141. 

  141. 

  142.         <span class="token comment">// 遍历channels，服务端通过响应确认订阅每个频道</span>
    143. 

  143.         <span class="token keyword">for</span> channel <span class="token keyword">in</span> channels <span class="token punctuation">{</span>
    144. 

  144.             <span class="token comment">// 获取响应</span>
    145. 

  145.             <span class="token keyword">let</span> response <span class="token operator">=</span> <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">read_response</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    146. 

  146. 

  147.             <span class="token comment">// 分析不同情况的响应</span>
    148. 

  148.             <span class="token keyword">match</span> response <span class="token punctuation">{</span>
    149. 

  149.                 <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Array</span><span class="token punctuation">(</span><span class="token keyword">ref</span> frame<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token keyword">match</span> frame<span class="token punctuation">.</span><span class="token function">as_slice</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    150. 

  150.                     <span class="token punctuation">[</span>subscribe<span class="token punctuation">,</span> schannel<span class="token punctuation">,</span> <span class="token punctuation">..</span><span class="token punctuation">]</span>
    151. 

  151.                         <span class="token keyword">if</span> <span class="token operator">*</span>subscribe <span class="token operator">==</span> <span class="token string">&quot;subscribe&quot;</span> <span class="token operator">&amp;&amp;</span> <span class="token operator">*</span>schannel <span class="token operator">==</span> channel <span class="token operator">=&gt;</span> <span class="token punctuation">{</span><span class="token punctuation">}</span>
    152. 

  152.                     _ <span class="token operator">=&gt;</span> <span class="token keyword">return</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>response<span class="token punctuation">.</span><span class="token function">to_error</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    153. 

  153.                 <span class="token punctuation">}</span><span class="token punctuation">,</span>
    154. 

  154.                 frame <span class="token operator">=&gt;</span> <span class="token keyword">return</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>frame<span class="token punctuation">.</span><span class="token function">to_error</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    155. 

  155.             <span class="token punctuation">}</span><span class="token punctuation">;</span>
    156. 

  156.         <span class="token punctuation">}</span>
    157. 

  157. 

  158.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    159. 

  159.     <span class="token punctuation">}</span>
    160. 

  160. 

  161.     <span class="token comment">/// 监听若干个指定的频道</span>
    162. 

  162.     <span class="token attribute attr-name">#[instrument(skip(self))]</span>
    163. 

  163.     <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">subscribe</span><span class="token punctuation">(</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> channels<span class="token punctuation">:</span> <span class="token class-name">Vec</span><span class="token operator">&lt;</span><span class="token class-name">String</span><span class="token operator">&gt;</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Subscriber</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    164. 

  164.         <span class="token comment">// 异步调用subscribe_cmd，客户端状态将会转为subscriber</span>
    165. 

  165.         <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">subscribe_cmd</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>channels<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    166. 

  166. 

  167.         <span class="token comment">// 返回Subscriber类型对象</span>
    168. 

  168.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">Subscriber</span> <span class="token punctuation">{</span>
    169. 

  169.             client<span class="token punctuation">:</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
    170. 

  170.             subscribed_channels<span class="token punctuation">:</span> channels<span class="token punctuation">,</span>
    171. 

  171.         <span class="token punctuation">}</span><span class="token punctuation">)</span>
    172. 

  172.     <span class="token punctuation">}</span>
    173. 

  173. 

  174.     <span class="token comment">/// 读取响应</span>
    175. 

  175.     <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">read_response</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Frame</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    176. 

  176.         <span class="token comment">// 异步读取连接的frame</span>
    177. 

  177.         <span class="token keyword">let</span> response <span class="token operator">=</span> <span class="token keyword">self</span><span class="token punctuation">.</span>connection<span class="token punctuation">.</span><span class="token function">read_frame</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    178. 

  178.         <span class="token comment">// 日志记录读取信息</span>
    179. 

  179.         <span class="token macro property">debug!</span><span class="token punctuation">(</span><span class="token operator">?</span>response<span class="token punctuation">)</span><span class="token punctuation">;</span>
    180. 

  180. 

  181.         <span class="token comment">// 解析响应，判断响应的类型</span>
    182. 

  182.         <span class="token comment">// Some(Frame::Error(msg))</span>
    183. 

  183.         <span class="token comment">// Some(frame)</span>
    184. 

  184.         <span class="token comment">// None：响应为None意味着服务端关闭</span>
    185. 

  185.         <span class="token keyword">match</span> response <span class="token punctuation">{</span>
    186. 

  186.             <span class="token comment">// Error frames are converted to `Err`</span>
    187. 

  187.             <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Error</span><span class="token punctuation">(</span>msg<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>msg<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    188. 

  188.             <span class="token class-name">Some</span><span class="token punctuation">(</span>frame<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span>frame<span class="token punctuation">)</span><span class="token punctuation">,</span>
    189. 

  189.             <span class="token class-name">None</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    190. 

  190.                 <span class="token comment">// Receiving `None` here indicates the server has closed the</span>
    191. 

  191.                 <span class="token comment">// connection without sending a frame. This is unexpected and is</span>
    192. 

  192.                 <span class="token comment">// represented as a &quot;connection reset by peer&quot; error.</span>
    193. 

  193.                 <span class="token keyword">let</span> err <span class="token operator">=</span> <span class="token class-name">Error</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span><span class="token class-name">ErrorKind</span><span class="token punctuation">::</span><span class="token class-name">ConnectionReset</span><span class="token punctuation">,</span> <span class="token string">&quot;connection reset by server&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    194. 

  194. 

  195.                 <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    196. 

  196.             <span class="token punctuation">}</span>
    197. 

  197.         <span class="token punctuation">}</span>
    198. 

  198. 

  199.     <span class="token punctuation">}</span>
    200. 

  200. <span class="token punctuation">}</span>
    201. 

  201. </code></pre></div><h4 id="message"><a href="#message" class="header-anchor">#</a> Message</h4> <h5 id="struct-2"><a href="#struct-2" class="header-anchor">#</a> Struct</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">/// A message received on a subscribed channel.</span>
    202. 

  202. <span class="token attribute attr-name">#[derive(Debug, Clone)]</span>
    203. 

  203. <span class="token keyword">pub</span> <span class="token keyword">struct</span> <span class="token type-definition class-name">Message</span> <span class="token punctuation">{</span>
    204. 

  204.     <span class="token keyword">pub</span> channel<span class="token punctuation">:</span> <span class="token class-name">String</span><span class="token punctuation">,</span>
    205. 

  205.     <span class="token keyword">pub</span> content<span class="token punctuation">:</span> <span class="token class-name">Bytes</span><span class="token punctuation">,</span>
    206. 

  206. <span class="token punctuation">}</span>
    207. 

  207. </code></pre></div><h4 id="subscriber"><a href="#subscriber" class="header-anchor">#</a> Subscriber</h4> <blockquote><p>订阅者类型，在客户端订阅若干频道后会转变成订阅者，此时只能执行publish/subscribe相关的命令</p></blockquote> <p>代码位置：src/clients/client.rs</p> <h5 id="struct-3"><a href="#struct-3" class="header-anchor">#</a> Struct</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">pub</span> <span class="token keyword">struct</span> <span class="token type-definition class-name">Subscriber</span> <span class="token punctuation">{</span>
    208. 

  208.     <span class="token comment">/// 客户端</span>
    209. 

  209.     client<span class="token punctuation">:</span> <span class="token class-name">Client</span><span class="token punctuation">,</span>
    210. 

  210.     <span class="token comment">/// 所订阅的频道集合</span>
    211. 

  211.     subscribed_channels<span class="token punctuation">:</span> <span class="token class-name">Vec</span><span class="token operator">&lt;</span><span class="token class-name">String</span><span class="token operator">&gt;</span><span class="token punctuation">,</span>
    212. 

  212. <span class="token punctuation">}</span>
    213. 

  213. </code></pre></div><h5 id="implementation-2"><a href="#implementation-2" class="header-anchor">#</a> Implementation</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">Subscriber</span><span class="token punctuation">{</span>
    214. 

  214.     <span class="token comment">/// 获取订阅的频道集合</span>
    215. 

  215.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">get_subscribed</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token operator">&amp;</span><span class="token punctuation">[</span><span class="token class-name">String</span><span class="token punctuation">]</span> <span class="token punctuation">{</span>
    216. 

  216.         <span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">.</span>subscribed_channels
    217. 

  217.     <span class="token punctuation">}</span>
    218. 

  218. 

  219.     <span class="token comment">/// 获取客户端收到的下一条消息（可能需要等待）</span>
    220. 

  220.     <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">next_message</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Option</span><span class="token operator">&lt;</span><span class="token class-name">Message</span><span class="token operator">&gt;&gt;</span> <span class="token punctuation">{</span>
    221. 

  221.         <span class="token keyword">match</span> <span class="token keyword">self</span><span class="token punctuation">.</span>client<span class="token punctuation">.</span>connection<span class="token punctuation">.</span><span class="token function">read_frame</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span> <span class="token punctuation">{</span>
    222. 

  222.             <span class="token class-name">Some</span><span class="token punctuation">(</span>mframe<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    223. 

  223.                 <span class="token comment">// 使用日志记录mframe</span>
    224. 

  224.                 <span class="token macro property">debug!</span><span class="token punctuation">(</span><span class="token operator">?</span>mframe<span class="token punctuation">)</span><span class="token punctuation">;</span>
    225. 

  225.                 <span class="token keyword">match</span> mframe <span class="token punctuation">{</span>
    226. 

  226.                     <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Array</span><span class="token punctuation">(</span><span class="token keyword">ref</span> frame<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token keyword">match</span> frame<span class="token punctuation">.</span><span class="token function">as_slice</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    227. 

  227.                       <span class="token comment">// frame分片后格式为[message,channel,content]</span>
    228. 

  228.                       <span class="token comment">// 当接收到信息时，message == 'message'</span>
    229. 

  229.                       <span class="token comment">// 成立则将信息转化为Message的形式返回</span>
    230. 

  230.                       <span class="token comment">// 否则返回错误</span>
    231. 

  231.                       <span class="token punctuation">[</span>message<span class="token punctuation">,</span> channel<span class="token punctuation">,</span> content<span class="token punctuation">]</span> <span class="token keyword">if</span> <span class="token operator">*</span>message <span class="token operator">==</span> <span class="token string">&quot;message&quot;</span> <span class="token operator">=&gt;</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token class-name">Message</span> <span class="token punctuation">{</span>
    232. 

  232.                             channel<span class="token punctuation">:</span> channel<span class="token punctuation">.</span><span class="token function">to_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    233. 

  233.                             content<span class="token punctuation">:</span> <span class="token class-name">Bytes</span><span class="token punctuation">::</span><span class="token function">from</span><span class="token punctuation">(</span>content<span class="token punctuation">.</span><span class="token function">to_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    234. 

  234.                         <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    235. 

  235.                         _ <span class="token operator">=&gt;</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>mframe<span class="token punctuation">.</span><span class="token function">to_error</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    236. 

  236.                     <span class="token punctuation">}</span><span class="token punctuation">,</span>
    237. 

  237.                     frame <span class="token operator">=&gt;</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>frame<span class="token punctuation">.</span><span class="token function">to_error</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    238. 

  238.                 <span class="token punctuation">}</span>
    239. 

  239.             <span class="token punctuation">}</span>
    240. 

  240.             <span class="token class-name">None</span> <span class="token operator">=&gt;</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">None</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    241. 

  241.         <span class="token punctuation">}</span>
    242. 

  242.     <span class="token punctuation">}</span>
    243. 

  243. 

  244.     <span class="token comment">/// 将收到的message转换成stream形式</span>
    245. 

  245.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">into_stream</span><span class="token punctuation">(</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">impl</span> <span class="token class-name">Stream</span><span class="token operator">&lt;</span><span class="token class-name">Item</span> <span class="token operator">=</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Message</span><span class="token operator">&gt;&gt;</span> <span class="token punctuation">{</span>
    246. 

  246.         <span class="token macro property">try_stream!</span> <span class="token punctuation">{</span>
    247. 

  247.             <span class="token keyword">while</span> <span class="token keyword">let</span> <span class="token class-name">Some</span><span class="token punctuation">(</span>message<span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">next_message</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span> <span class="token punctuation">{</span>
    248. 

  248.                 <span class="token keyword">yield</span> message<span class="token punctuation">;</span>
    249. 

  249.             <span class="token punctuation">}</span>
    250. 

  250.         <span class="token punctuation">}</span>
    251. 

  251.     <span class="token punctuation">}</span>
    252. 

  252. 

  253.     <span class="token comment">/// 订阅新的频道集合</span>
    254. 

  254.     <span class="token attribute attr-name">#[instrument(skip(self))]</span>
    255. 

  255.     <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">subscribe</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> channels<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token punctuation">[</span><span class="token class-name">String</span><span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    256. 

  256.         <span class="token comment">// 调用subscribe_cmd，订阅新的频道集合</span>
    257. 

  257.         <span class="token keyword">self</span><span class="token punctuation">.</span>client<span class="token punctuation">.</span><span class="token function">subscribe_cmd</span><span class="token punctuation">(</span>channels<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    258. 

  258. 

  259.         <span class="token comment">// 更新当前的已订阅频道</span>
    260. 

  260.         <span class="token keyword">self</span><span class="token punctuation">.</span>subscribed_channels
    261. 

  261.             <span class="token punctuation">.</span><span class="token function">extend</span><span class="token punctuation">(</span>channels<span class="token punctuation">.</span><span class="token function">iter</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">map</span><span class="token punctuation">(</span><span class="token class-name">Clone</span><span class="token punctuation">::</span>clone<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    262. 

  262. 

  263.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    264. 

  264.     <span class="token punctuation">}</span>
    265. 

  265. 

  266.     <span class="token comment">/// 取消订阅指定的频道</span>
    267. 

  267.     <span class="token attribute attr-name">#[instrument(skip(self))]</span>
    268. 

  268.     <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">unsubscribe</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> channels<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token punctuation">[</span><span class="token class-name">String</span><span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    269. 

  269.         <span class="token comment">// 创建Unsubcribe命令，并转为frame形式</span>
    270. 

  270.         <span class="token keyword">let</span> frame <span class="token operator">=</span> <span class="token class-name">Unsubscribe</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span>channels<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">into_frame</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    271. 

  271.         <span class="token comment">// 日志记录请求</span>
    272. 

  272.         <span class="token macro property">debug!</span><span class="token punctuation">(</span>request <span class="token operator">=</span> <span class="token operator">?</span>frame<span class="token punctuation">)</span><span class="token punctuation">;</span>
    273. 

  273. 

  274.         <span class="token comment">// 将请求写入连接</span>
    275. 

  275.         <span class="token keyword">self</span><span class="token punctuation">.</span>client<span class="token punctuation">.</span>connection<span class="token punctuation">.</span><span class="token function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>frame<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    276. 

  276. 

  277.         <span class="token comment">// 如果channels为空，那么取消订阅所有频道</span>
    278. 

  278.         <span class="token comment">// 否则只取消channels中指定的频道</span>
    279. 

  279.         <span class="token keyword">let</span> num <span class="token operator">=</span> <span class="token keyword">if</span> channels<span class="token punctuation">.</span><span class="token function">is_empty</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    280. 

  280.             <span class="token keyword">self</span><span class="token punctuation">.</span>subscribed_channels<span class="token punctuation">.</span><span class="token function">len</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
    281. 

  281.         <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
    282. 

  282.             channels<span class="token punctuation">.</span><span class="token function">len</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
    283. 

  283.         <span class="token punctuation">}</span><span class="token punctuation">;</span>
    284. 

  284. 

  285.         <span class="token comment">// 解析响应</span>
    286. 

  286.         <span class="token keyword">for</span> _ <span class="token keyword">in</span> <span class="token number">0</span><span class="token punctuation">..</span>num <span class="token punctuation">{</span>
    287. 

  287.             <span class="token comment">// 读取响应</span>
    288. 

  288.             <span class="token macro property">todo!</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    289. 

  289.             <span class="token comment">// 判断响应类型</span>
    290. 

  290.             <span class="token keyword">match</span> response <span class="token punctuation">{</span>
    291. 

  291.                 <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Array</span><span class="token punctuation">(</span><span class="token keyword">ref</span> frame<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token keyword">match</span> frame<span class="token punctuation">.</span><span class="token function">as_slice</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    292. 

  292.                     <span class="token comment">// frame分片后格式为['unsubscribe',channel,..]</span>
    293. 

  293.                     <span class="token comment">// 判断是否取消订阅</span>
    294. 

  294.                     <span class="token punctuation">[</span>unsubscribe<span class="token punctuation">,</span> channel<span class="token punctuation">,</span> <span class="token punctuation">..</span><span class="token punctuation">]</span> <span class="token keyword">if</span> <span class="token operator">*</span>unsubscribe <span class="token operator">==</span> <span class="token string">&quot;unsubscribe&quot;</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    295. 

  295.                        <span class="token comment">// 获取当前订阅数组的长度</span>
    296. 

  296.                         <span class="token keyword">let</span> len <span class="token operator">=</span> <span class="token keyword">self</span><span class="token punctuation">.</span>subscribed_channels<span class="token punctuation">.</span><span class="token function">len</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    297. 

  297.                         <span class="token comment">// 长度为0，返回错误</span>
    298. 

  298.                         <span class="token keyword">if</span> len <span class="token operator">==</span> <span class="token number">0</span> <span class="token punctuation">{</span>
    299. 

  299.                             <span class="token comment">// There must be at least one channel</span>
    300. 

  300.                             <span class="token keyword">return</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>response<span class="token punctuation">.</span><span class="token function">to_error</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    301. 

  301.                         <span class="token punctuation">}</span>
    302. 

  302.                         <span class="token comment">// 当channel存在于subscribed_channels时将其删除</span>
    303. 

  303.                         <span class="token keyword">self</span><span class="token punctuation">.</span>subscribed_channels<span class="token punctuation">.</span><span class="token function">retain</span><span class="token punctuation">(</span><span class="token closure-params"><span class="token closure-punctuation punctuation">|</span>c<span class="token closure-punctuation punctuation">|</span></span> <span class="token operator">*</span>channel <span class="token operator">!=</span> <span class="token operator">&amp;</span>c<span class="token punctuation">[</span><span class="token punctuation">..</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    304. 

  304. 

  305.                         <span class="token comment">// 删除数大于1则返回错误</span>
    306. 

  306.                         <span class="token keyword">if</span> <span class="token keyword">self</span><span class="token punctuation">.</span>subscribed_channels<span class="token punctuation">.</span><span class="token function">len</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">!=</span> len <span class="token operator">-</span> <span class="token number">1</span> <span class="token punctuation">{</span>
    307. 

  307.                             <span class="token keyword">return</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>response<span class="token punctuation">.</span><span class="token function">to_error</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    308. 

  308.                         <span class="token punctuation">}</span>                    <span class="token punctuation">}</span>
    309. 

  309.                     _ <span class="token operator">=&gt;</span> <span class="token keyword">return</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>response<span class="token punctuation">.</span><span class="token function">to_error</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    310. 

  310.                 <span class="token punctuation">}</span><span class="token punctuation">,</span>
    311. 

  311.                 frame <span class="token operator">=&gt;</span> <span class="token keyword">return</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>frame<span class="token punctuation">.</span><span class="token function">to_error</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    312. 

  312.             <span class="token punctuation">}</span><span class="token punctuation">;</span>
    313. 

  313.         <span class="token punctuation">}</span>
    314. 

  314. 

  315.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    316. 

  316.     <span class="token punctuation">}</span>   
    317. 

  317. <span class="token punctuation">}</span>
    318. 

  318. </code></pre></div><h3 id="blocking-client"><a href="#blocking-client" class="header-anchor">#</a> blocking_client</h3> <blockquote><p>最小的阻塞性Redis客户端</p></blockquote> <p>代码位置：src/clients/blocking_client.rs</p> <h4 id="blockingclient"><a href="#blockingclient" class="header-anchor">#</a> BlockingClient</h4> <h5 id="struct-4"><a href="#struct-4" class="header-anchor">#</a> Struct</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">pub</span> <span class="token keyword">struct</span> <span class="token type-definition class-name">BlockingClient</span><span class="token punctuation">{</span>
    319. 

  319.      <span class="token comment">/// 异步的客户端</span>
    320. 

  320.      inner<span class="token punctuation">:</span> <span class="token keyword">crate</span><span class="token module-declaration namespace"><span class="token punctuation">::</span>clients<span class="token punctuation">::</span></span><span class="token class-name">Client</span><span class="token punctuation">,</span>
    321. 

  321.      <span class="token comment">/// 运行时环境，负责调度和管理异步任务的执行</span>
    322. 

  322.      rt<span class="token punctuation">:</span> <span class="token class-name">Runtime</span><span class="token punctuation">,</span>
    323. 

  323. <span class="token punctuation">}</span>
    324. 

  324. </code></pre></div><h5 id="implementation-3"><a href="#implementation-3" class="header-anchor">#</a> Implementation</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">BlockingClient</span><span class="token punctuation">{</span>
    325. 

  325.     <span class="token comment">/// 建立连接</span>
    326. 

  326.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">connect</span><span class="token operator">&lt;</span><span class="token class-name">T</span><span class="token punctuation">:</span> <span class="token class-name">ToSocketAddrs</span><span class="token operator">&gt;</span><span class="token punctuation">(</span>addr<span class="token punctuation">:</span> <span class="token class-name">T</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">BlockingClient</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    327. 

  327.         <span class="token keyword">let</span> rt <span class="token operator">=</span> <span class="token namespace">tokio<span class="token punctuation">::</span>runtime<span class="token punctuation">::</span></span><span class="token class-name">Builder</span><span class="token punctuation">::</span><span class="token function">new_current_thread</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
    328. 

  328.             <span class="token punctuation">.</span><span class="token function">enable_all</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
    329. 

  329.             <span class="token punctuation">.</span><span class="token function">build</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">?</span><span class="token punctuation">;</span>
    330. 

  330. 

  331.         <span class="token keyword">let</span> inner <span class="token operator">=</span> rt<span class="token punctuation">.</span><span class="token function">block_on</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token module-declaration namespace"><span class="token punctuation">::</span>clients<span class="token punctuation">::</span></span><span class="token class-name">Client</span><span class="token punctuation">::</span><span class="token function">connect</span><span class="token punctuation">(</span>addr<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token operator">?</span><span class="token punctuation">;</span>
    332. 

  332. 

  333.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">BlockingClient</span> <span class="token punctuation">{</span> inner<span class="token punctuation">,</span> rt <span class="token punctuation">}</span><span class="token punctuation">)</span>
    334. 

  334.     <span class="token punctuation">}</span>    
    335. 

  335. 

  336.     <span class="token comment">/// 异步获取指定值</span>
    337. 

  337.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">get</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> key<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">str</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Option</span><span class="token operator">&lt;</span><span class="token class-name">Bytes</span><span class="token operator">&gt;&gt;</span> <span class="token punctuation">{</span>
    338. 

  338.         <span class="token comment">// 异步调用get获取key对应的值</span>
    339. 

  339.         <span class="token keyword">self</span><span class="token punctuation">.</span>rt<span class="token punctuation">.</span><span class="token function">block_on</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>inner<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span>key<span class="token punctuation">)</span><span class="token punctuation">)</span>
    340. 

  340.     <span class="token punctuation">}</span>
    341. 

  341. 

  342.     <span class="token comment">/// 异步给key赋值</span>
    343. 

  343.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">set</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> key<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">str</span><span class="token punctuation">,</span> value<span class="token punctuation">:</span> <span class="token class-name">Bytes</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    344. 

  344.         <span class="token comment">// 异步调用set给key赋值</span>
    345. 

  345.         <span class="token keyword">self</span><span class="token punctuation">.</span>rt<span class="token punctuation">.</span><span class="token function">block_on</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>inner<span class="token punctuation">.</span><span class="token function">set</span><span class="token punctuation">(</span>key<span class="token punctuation">,</span> value<span class="token punctuation">)</span><span class="token punctuation">)</span>
    346. 

  346.     <span class="token punctuation">}</span>    
    347. 

  347. 

  348.    <span class="token comment">/// 异步给key赋值，并指定过期时间</span>
    349. 

  349.        <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">set_expires</span><span class="token punctuation">(</span>
    350. 

  350.         <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
    351. 

  351.         key<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">str</span><span class="token punctuation">,</span>
    352. 

  352.         value<span class="token punctuation">:</span> <span class="token class-name">Bytes</span><span class="token punctuation">,</span>
    353. 

  353.         expiration<span class="token punctuation">:</span> <span class="token class-name">Duration</span><span class="token punctuation">,</span>
    354. 

  354.     <span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    355. 

  355.         <span class="token comment">// 异步调用set_expires给key赋值</span>
    356. 

  356.         <span class="token keyword">self</span><span class="token punctuation">.</span>rt
    357. 

  357.             <span class="token punctuation">.</span><span class="token function">block_on</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>inner<span class="token punctuation">.</span><span class="token function">set_expires</span><span class="token punctuation">(</span>key<span class="token punctuation">,</span> value<span class="token punctuation">,</span> expiration<span class="token punctuation">)</span><span class="token punctuation">)</span>    <span class="token punctuation">}</span>
    358. 

  358. 

  359.     <span class="token comment">/// 异步推送消息</span>
    360. 

  360.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">publish</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> channel<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">str</span><span class="token punctuation">,</span> message<span class="token punctuation">:</span> <span class="token class-name">Bytes</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token keyword">u64</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    361. 

  361.         <span class="token comment">// 异步调用publish给指定channel推送消息</span>
    362. 

  362.         <span class="token keyword">self</span><span class="token punctuation">.</span>rt<span class="token punctuation">.</span><span class="token function">block_on</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>inner<span class="token punctuation">.</span><span class="token function">publish</span><span class="token punctuation">(</span>channel<span class="token punctuation">,</span> message<span class="token punctuation">)</span><span class="token punctuation">)</span>
    363. 

  363.     <span class="token punctuation">}</span>
    364. 

  364. 

  365.     <span class="token comment">/// 异步执行订阅指定频道操作，并将Client转换为BlockingSubcriber状态</span>
    366. 

  366.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">subscribe</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">,</span> channels<span class="token punctuation">:</span> <span class="token class-name">Vec</span><span class="token operator">&lt;</span><span class="token class-name">String</span><span class="token operator">&gt;</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">BlockingSubscriber</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    367. 

  367.         <span class="token comment">// 异步调用subscribe函数，转换client状态</span>
    368. 

  368.         <span class="token keyword">let</span> subscriber <span class="token operator">=</span> <span class="token keyword">self</span><span class="token punctuation">.</span>rt<span class="token punctuation">.</span><span class="token function">block_on</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>inner<span class="token punctuation">.</span><span class="token function">subscribe</span><span class="token punctuation">(</span>channels<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token operator">?</span><span class="token punctuation">;</span>
    369. 

  369.         <span class="token comment">// 返回BlockingSubscriber</span>
    370. 

  370.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">BlockingSubscriber</span> <span class="token punctuation">{</span>
    371. 

  371.             inner<span class="token punctuation">:</span> subscriber<span class="token punctuation">,</span>
    372. 

  372.             rt<span class="token punctuation">:</span> <span class="token keyword">self</span><span class="token punctuation">.</span>rt<span class="token punctuation">,</span>
    373. 

  373.         <span class="token punctuation">}</span><span class="token punctuation">)</span>
    374. 

  374.     <span class="token punctuation">}</span>    
    375. 

  375. <span class="token punctuation">}</span>
    376. 

  376. </code></pre></div><h4 id="blockingsubscriber"><a href="#blockingsubscriber" class="header-anchor">#</a> BlockingSubscriber</h4> <h5 id="struct-5"><a href="#struct-5" class="header-anchor">#</a> Struct</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">pub</span> <span class="token keyword">struct</span> <span class="token type-definition class-name">BlockingSubscriber</span> <span class="token punctuation">{</span>
    377. 

  377.     <span class="token comment">/// 异步的订阅者</span>
    378. 

  378.     inner<span class="token punctuation">:</span> <span class="token keyword">crate</span><span class="token module-declaration namespace"><span class="token punctuation">::</span>clients<span class="token punctuation">::</span></span><span class="token class-name">Subscriber</span><span class="token punctuation">,</span>
    379. 

  379.     <span class="token comment">/// 运行时环境，负责调度和管理异步任务的执行</span>
    380. 

  380.     rt<span class="token punctuation">:</span> <span class="token class-name">Runtime</span><span class="token punctuation">,</span>
    381. 

  381. <span class="token punctuation">}</span>
    382. 

  382. </code></pre></div><h5 id="implementation-4"><a href="#implementation-4" class="header-anchor">#</a> Implementation</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">BlockingSubscriber</span><span class="token punctuation">{</span>
    383. 

  383.     <span class="token comment">/// 获取订阅的channel集合</span>
    384. 

  384.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">get_subscribed</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token operator">&amp;</span><span class="token punctuation">[</span><span class="token class-name">String</span><span class="token punctuation">]</span> <span class="token punctuation">{</span>
    385. 

  385.         <span class="token comment">// 获取订阅的channel集合，并返回</span>
    386. 

  386.         <span class="token keyword">self</span><span class="token punctuation">.</span>inner<span class="token punctuation">.</span><span class="token function">get_subscribed</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
    387. 

  387.     <span class="token punctuation">}</span>
    388. 

  388. 

  389.        <span class="token comment">/// 异步接收下一条信息</span>
    390. 

  390.        <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">next_message</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Option</span><span class="token operator">&lt;</span><span class="token class-name">Message</span><span class="token operator">&gt;&gt;</span> <span class="token punctuation">{</span>
    391. 

  391.         <span class="token comment">// 异步执行获取下一条信息的操作</span>
    392. 

  392.         <span class="token keyword">self</span><span class="token punctuation">.</span>rt<span class="token punctuation">.</span><span class="token function">block_on</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>inner<span class="token punctuation">.</span><span class="token function">next_message</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    393. 

  393.     <span class="token punctuation">}</span>
    394. 

  394. 

  395.     <span class="token comment">/// 异步订阅新的频道集合</span>
    396. 

  396.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">subscribe</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> channels<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token punctuation">[</span><span class="token class-name">String</span><span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    397. 

  397.         <span class="token comment">// 异步订阅新的频道集合</span>
    398. 

  398.         <span class="token keyword">self</span><span class="token punctuation">.</span>rt<span class="token punctuation">.</span><span class="token function">block_on</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>inner<span class="token punctuation">.</span><span class="token function">subscribe</span><span class="token punctuation">(</span>channels<span class="token punctuation">)</span><span class="token punctuation">)</span>
    399. 

  399.     <span class="token punctuation">}</span>
    400. 

  400. 

  401.     <span class="token comment">/// 异步执行取消订阅指定频道集操作</span>
    402. 

  402.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">unsubscribe</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> channels<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token punctuation">[</span><span class="token class-name">String</span><span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    403. 

  403.         <span class="token comment">// 异步执行取消订阅指定频道集操作</span>
    404. 

  404.         <span class="token keyword">self</span><span class="token punctuation">.</span>rt<span class="token punctuation">.</span><span class="token function">block_on</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>inner<span class="token punctuation">.</span><span class="token function">unsubscribe</span><span class="token punctuation">(</span>channels<span class="token punctuation">)</span><span class="token punctuation">)</span>
    405. 

  405.     <span class="token punctuation">}</span>
    406. 

  406. 

  407.     <span class="token comment">/// 获取BlockingSubscriber的迭代器</span>
    408. 

  408.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">into_iter</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">impl</span> <span class="token class-name">Iterator</span><span class="token operator">&lt;</span><span class="token class-name">Item</span> <span class="token operator">=</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Message</span><span class="token operator">&gt;&gt;</span> <span class="token punctuation">{</span>
    409. 

  409.         <span class="token class-name">SubscriberIterator</span> <span class="token punctuation">{</span>
    410. 

  410.             inner<span class="token punctuation">:</span> <span class="token keyword">self</span><span class="token punctuation">.</span>inner<span class="token punctuation">,</span>
    411. 

  411.             rt<span class="token punctuation">:</span> <span class="token keyword">self</span><span class="token punctuation">.</span>rt<span class="token punctuation">,</span>
    412. 

  412.         <span class="token punctuation">}</span>
    413. 

  413.     <span class="token punctuation">}</span>
    414. 

  414. <span class="token punctuation">}</span>
    415. 

  415. </code></pre></div><h4 id="subscriberiterator"><a href="#subscriberiterator" class="header-anchor">#</a> SubscriberIterator</h4> <h5 id="struct-6"><a href="#struct-6" class="header-anchor">#</a> Struct</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">/// BlockingSubscriber的迭代器</span>
    416. 

  416. <span class="token comment">/// 通过`Subscriber::into_iter`可以获取</span>
    417. 

  417. <span class="token keyword">struct</span> <span class="token type-definition class-name">SubscriberIterator</span> <span class="token punctuation">{</span>
    418. 

  418.     <span class="token comment">/// BlockingSubscriber中的Subscriber</span>
    419. 

  419.     inner<span class="token punctuation">:</span> <span class="token keyword">crate</span><span class="token module-declaration namespace"><span class="token punctuation">::</span>clients<span class="token punctuation">::</span></span><span class="token class-name">Subscriber</span><span class="token punctuation">,</span>
    420. 

  420. 

  421.     <span class="token comment">/// BlockingSubscriber中的Runtime</span>
    422. 

  422.     rt<span class="token punctuation">:</span> <span class="token class-name">Runtime</span><span class="token punctuation">,</span>
    423. 

  423. <span class="token punctuation">}</span>
    424. 

  424. </code></pre></div><h5 id="implementation-5"><a href="#implementation-5" class="header-anchor">#</a> Implementation</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">Iterator</span> <span class="token keyword">for</span> <span class="token class-name">SubscriberIterator</span> <span class="token punctuation">{</span>
    425. 

  425.     <span class="token comment">/// 定义迭代器的元素类型</span>
    426. 

  426.     <span class="token keyword">type</span> <span class="token type-definition class-name">Item</span> <span class="token operator">=</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Message</span><span class="token operator">&gt;</span><span class="token punctuation">;</span>
    427. 

  427. 

  428.     <span class="token comment">/// 获取迭代器的下一个元素</span>
    429. 

  429.     <span class="token comment">/// 返回Some(Ok(message)) 表示存在下一个元素</span>
    430. 

  430.     <span class="token comment">/// 返回Some(Err(error)) 表示获取下一个元素出错</span>
    431. 

  431.     <span class="token comment">/// 返回None 表示没有下一个元素</span>
    432. 

  432.     <span class="token keyword">fn</span> <span class="token function-definition function">next</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Option</span><span class="token operator">&lt;</span><span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Message</span><span class="token operator">&gt;&gt;</span>
    433. 

  433.     <span class="token punctuation">{</span>
    434. 

  434.         <span class="token keyword">self</span><span class="token punctuation">.</span>rt<span class="token punctuation">.</span><span class="token function">block_on</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>inner<span class="token punctuation">.</span><span class="token function">next_message</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">transpose</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
    435. 

  435.     <span class="token punctuation">}</span>
    436. 

  436. <span class="token punctuation">}</span>
    437. 

  437. </code></pre></div><h3 id="cmd"><a href="#cmd" class="header-anchor">#</a> cmd</h3> <h4 id="get"><a href="#get" class="header-anchor">#</a> Get</h4> <blockquote><p>获取key对应的value</p></blockquote> <ul><li>如果key不存在，返回nil</li> <li>如果value不是string类型，返回error</li></ul> <p>代码位置：src/cmd/get.rs</p> <h5 id="struct-7"><a href="#struct-7" class="header-anchor">#</a> Struct</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token attribute attr-name">#[derive(Debug)]</span>
    438. 

  438. <span class="token keyword">pub</span> <span class="token keyword">struct</span> <span class="token type-definition class-name">Get</span> <span class="token punctuation">{</span>
    439. 

  439.     <span class="token comment">/// Name of the key to get</span>
    440. 

  440.     key<span class="token punctuation">:</span> <span class="token class-name">String</span><span class="token punctuation">,</span>
    441. 

  441. <span class="token punctuation">}</span>
    442. 

  442. </code></pre></div><h5 id="implementation-6"><a href="#implementation-6" class="header-anchor">#</a> Implementation</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">Get</span><span class="token punctuation">{</span>
    443. 

  443.     <span class="token comment">/// 创建一个Get命令对象</span>
    444. 

  444.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">new</span><span class="token punctuation">(</span>key<span class="token punctuation">:</span> <span class="token keyword">impl</span> <span class="token class-name">ToString</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Get</span> <span class="token punctuation">{</span>
    445. 

  445.         <span class="token class-name">Get</span> <span class="token punctuation">{</span>
    446. 

  446.             key<span class="token punctuation">:</span> key<span class="token punctuation">.</span><span class="token function">to_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    447. 

  447.         <span class="token punctuation">}</span>
    448. 

  448.     <span class="token punctuation">}</span>
    449. 

  449. 

  450.     <span class="token comment">/// Get the key</span>
    451. 

  451.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">key</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token operator">&amp;</span><span class="token keyword">str</span> <span class="token punctuation">{</span>
    452. 

  452.         <span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">.</span>key
    453. 

  453.     <span class="token punctuation">}</span>
    454. 

  454. 

  455.     <span class="token comment">/// 解析frame，并获取对应Get命令</span>
    456. 

  456.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">parse_frames</span><span class="token punctuation">(</span>parse<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Parse</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Get</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    457. 

  457.         <span class="token keyword">let</span> key <span class="token operator">=</span> parse<span class="token punctuation">.</span><span class="token function">next_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">?</span><span class="token punctuation">;</span>
    458. 

  458.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">Get</span> <span class="token punctuation">{</span> key <span class="token punctuation">}</span><span class="token punctuation">)</span>
    459. 

  459.     <span class="token punctuation">}</span>
    460. 

  460. 

  461.     <span class="token comment">/// 对数据库执行Get命令</span>
    462. 

  462.     <span class="token attribute attr-name">#[instrument(skip(self, db, dst))]</span>
    463. 

  463.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">apply</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">,</span> db<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token class-name">Db</span><span class="token punctuation">,</span> dst<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Connection</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    464. 

  464.         <span class="token comment">// 从数据库中获取value</span>
    465. 

  465.         <span class="token comment">// 如果值存在，则将其转成Frame::Bulk形式</span>
    466. 

  466.         <span class="token comment">// 否则转成Frame::Null</span>
    467. 

  467.         <span class="token keyword">let</span> response <span class="token operator">=</span> <span class="token keyword">if</span> <span class="token keyword">let</span> <span class="token class-name">Some</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span> <span class="token operator">=</span> db<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">.</span>key<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    468. 

  468.             <span class="token comment">// If a value is present, it is written to the client in &quot;bulk&quot;</span>
    469. 

  469.             <span class="token comment">// format.</span>
    470. 

  470.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Bulk</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span>
    471. 

  471.         <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
    472. 

  472.             <span class="token comment">// If there is no value, `Null` is written.</span>
    473. 

  473.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Null</span>
    474. 

  474.         <span class="token punctuation">}</span><span class="token punctuation">;</span>
    475. 

  475. 

  476.         <span class="token comment">// 日志记录响应</span>
    477. 

  477.         <span class="token macro property">debug!</span><span class="token punctuation">(</span><span class="token operator">?</span>response<span class="token punctuation">)</span><span class="token punctuation">;</span>
    478. 

  478. 

  479.         <span class="token comment">// 将响应写入连接</span>
    480. 

  480.         dst<span class="token punctuation">.</span><span class="token function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>response<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    481. 

  481. 

  482.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    483. 

  483.     <span class="token punctuation">}</span>
    484. 

  484. 

  485.     <span class="token comment">/// 将命令转成Frame格式，在客户端将格式化的Get</span>
    486. 

  486.     <span class="token comment">///命令发给服务端时会调用。</span>
    487. 

  487.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">into_frame</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Frame</span> <span class="token punctuation">{</span>
    488. 

  488.         <span class="token keyword">let</span> <span class="token keyword">mut</span> frame <span class="token operator">=</span> <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token function">array</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    489. 

  489.         <span class="token comment">/// 将命令以[&quot;get&quot;,key]的形式放入frame。注意每个元素都要转成字节形式</span>
    490. 

  490.         <span class="token macro property">todo!</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    491. 

  491.         frame
    492. 

  492.     <span class="token punctuation">}</span>
    493. 

  493. <span class="token punctuation">}</span>
    494. 

  494. </code></pre></div><h4 id="publish"><a href="#publish" class="header-anchor">#</a> Publish</h4> <p>代码位置：src/cmd/publish.rs</p> <h5 id="struct-8"><a href="#struct-8" class="header-anchor">#</a> Struct</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">/// 向指定频道推送消息</span>
    495. 

  495. <span class="token attribute attr-name">#[derive(Debug)]</span>
    496. 

  496. <span class="token keyword">pub</span> <span class="token keyword">struct</span> <span class="token type-definition class-name">Publish</span> <span class="token punctuation">{</span>
    497. 

  497.     <span class="token comment">/// 频道名</span>
    498. 

  498.     channel<span class="token punctuation">:</span> <span class="token class-name">String</span><span class="token punctuation">,</span>
    499. 

  499. 

  500.     <span class="token comment">/// 要发送的消息</span>
    501. 

  501.     message<span class="token punctuation">:</span> <span class="token class-name">Bytes</span><span class="token punctuation">,</span>
    502. 

  502. <span class="token punctuation">}</span>
    503. 

  503. </code></pre></div><h5 id="implementation-7"><a href="#implementation-7" class="header-anchor">#</a> Implementation</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">Publish</span><span class="token punctuation">{</span>
    504. 

  504.     <span class="token comment">/// 创建Publish命令</span>
    505. 

  505.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">new</span><span class="token punctuation">(</span>channel<span class="token punctuation">:</span> <span class="token keyword">impl</span> <span class="token class-name">ToString</span><span class="token punctuation">,</span> message<span class="token punctuation">:</span> <span class="token class-name">Bytes</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Publish</span> <span class="token punctuation">{</span>
    506. 

  506.         <span class="token class-name">Publish</span> <span class="token punctuation">{</span>
    507. 

  507.             channel<span class="token punctuation">:</span> channel<span class="token punctuation">.</span><span class="token function">to_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    508. 

  508.             message<span class="token punctuation">,</span>
    509. 

  509.         <span class="token punctuation">}</span>
    510. 

  510.     <span class="token punctuation">}</span>
    511. 

  511. 

  512.     <span class="token comment">/// 解析frame，并获取对应Publish命令</span>
    513. 

  513.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">parse_frames</span><span class="token punctuation">(</span>parse<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Parse</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Publish</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    514. 

  514.         <span class="token comment">// 获取string形式的channel</span>
    515. 

  515.         <span class="token keyword">let</span> channel <span class="token operator">=</span> parse<span class="token punctuation">.</span><span class="token function">next_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">?</span><span class="token punctuation">;</span>
    516. 

  516. 

  517.         <span class="token comment">// 获取字节形式的message</span>
    518. 

  518.         <span class="token keyword">let</span> message <span class="token operator">=</span> parse<span class="token punctuation">.</span><span class="token function">next_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">?</span><span class="token punctuation">;</span>
    519. 

  519. 

  520.         <span class="token comment">// 返回对应Publish</span>
    521. 

  521.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">Publish</span> <span class="token punctuation">{</span> channel<span class="token punctuation">,</span> message <span class="token punctuation">}</span><span class="token punctuation">)</span>
    522. 

  522.     <span class="token punctuation">}</span>
    523. 

  523. 

  524.     <span class="token comment">/// 对数据库执行publish命令</span>
    525. 

  525.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">apply</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">,</span> db<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token class-name">Db</span><span class="token punctuation">,</span> dst<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Connection</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span><span class="token punctuation">{</span>
    526. 

  526.         <span class="token comment">// 向数据库连接执行publish操作，并获取到订阅channel的subscriber的数量</span>
    527. 

  527.         <span class="token keyword">let</span> num_subscribers <span class="token operator">=</span> db<span class="token punctuation">.</span><span class="token function">publish</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">.</span>channel<span class="token punctuation">,</span> <span class="token keyword">self</span><span class="token punctuation">.</span>message<span class="token punctuation">)</span><span class="token punctuation">;</span>
    528. 

  528. 

  529.         <span class="token comment">// 将subscriber_num转换成整数帧，并将其写入连接</span>
    530. 

  530.         <span class="token keyword">let</span> response <span class="token operator">=</span> <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Integer</span><span class="token punctuation">(</span>num_subscribers <span class="token keyword">as</span> <span class="token keyword">u64</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    531. 

  531.         dst<span class="token punctuation">.</span><span class="token function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>response<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    532. 

  532. 

  533.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    534. 

  534.     <span class="token punctuation">}</span>
    535. 

  535. 

  536.     <span class="token comment">/// 将publish命令转成frame的形式</span>
    537. 

  537.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">into_frame</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Frame</span> <span class="token punctuation">{</span>
    538. 

  538.         <span class="token keyword">let</span> <span class="token keyword">mut</span> frame <span class="token operator">=</span> <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token function">array</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    539. 

  539.         <span class="token comment">// 将publish命令以[&quot;publish&quot;,channel,message]的形式写入数组。注意每个元素都要转成字节形式</span>
    540. 

  540.         frame<span class="token punctuation">.</span><span class="token function">push_bulk</span><span class="token punctuation">(</span><span class="token class-name">Bytes</span><span class="token punctuation">::</span><span class="token function">from</span><span class="token punctuation">(</span><span class="token string">&quot;publish&quot;</span><span class="token punctuation">.</span><span class="token function">as_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    541. 

  541.         frame<span class="token punctuation">.</span><span class="token function">push_bulk</span><span class="token punctuation">(</span><span class="token class-name">Bytes</span><span class="token punctuation">::</span><span class="token function">from</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>channel<span class="token punctuation">.</span><span class="token function">into_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    542. 

  542.         frame<span class="token punctuation">.</span><span class="token function">push_bulk</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>message<span class="token punctuation">)</span><span class="token punctuation">;</span>
    543. 

  543. 

  544.         frame
    545. 

  545.     <span class="token punctuation">}</span>
    546. 

  546. <span class="token punctuation">}</span>
    547. 

  547. </code></pre></div><h4 id="set"><a href="#set" class="header-anchor">#</a> Set</h4> <p>代码位置：src/cmd/set.rs</p> <h5 id="struct-9"><a href="#struct-9" class="header-anchor">#</a> Struct</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">/// 设置key的值</span>
    548. 

  548. <span class="token attribute attr-name">#[derive(Debug)]</span>
    549. 

  549. <span class="token keyword">pub</span> <span class="token keyword">struct</span> <span class="token type-definition class-name">Set</span> <span class="token punctuation">{</span>
    550. 

  550.     <span class="token comment">/// the lookup key</span>
    551. 

  551.     key<span class="token punctuation">:</span> <span class="token class-name">String</span><span class="token punctuation">,</span>
    552. 

  552. 

  553.     <span class="token comment">/// the value to be stored</span>
    554. 

  554.     value<span class="token punctuation">:</span> <span class="token class-name">Bytes</span><span class="token punctuation">,</span>
    555. 

  555. 

  556.     <span class="token comment">/// When to expire the key</span>
    557. 

  557.     expire<span class="token punctuation">:</span> <span class="token class-name">Option</span><span class="token operator">&lt;</span><span class="token class-name">Duration</span><span class="token operator">&gt;</span><span class="token punctuation">,</span>
    558. 

  558. <span class="token punctuation">}</span>
    559. 

  559. </code></pre></div><h5 id="implementation-8"><a href="#implementation-8" class="header-anchor">#</a> Implementation</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">Set</span><span class="token punctuation">{</span>
    560. 

  560.     <span class="token comment">/// 创建一个set命令</span>
    561. 

  561.     <span class="token comment">/// </span>
    562. 

  562.     <span class="token comment">/// 如果不需要过期时间则expire为None</span>
    563. 

  563.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">new</span><span class="token punctuation">(</span>key<span class="token punctuation">:</span> <span class="token keyword">impl</span> <span class="token class-name">ToString</span><span class="token punctuation">,</span> value<span class="token punctuation">:</span> <span class="token class-name">Bytes</span><span class="token punctuation">,</span> expire<span class="token punctuation">:</span> <span class="token class-name">Option</span><span class="token operator">&lt;</span><span class="token class-name">Duration</span><span class="token operator">&gt;</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Set</span> <span class="token punctuation">{</span>
    564. 

  564.         <span class="token class-name">Set</span> <span class="token punctuation">{</span>
    565. 

  565.             key<span class="token punctuation">:</span> key<span class="token punctuation">.</span><span class="token function">to_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    566. 

  566.             value<span class="token punctuation">,</span>
    567. 

  567.             expire<span class="token punctuation">,</span>
    568. 

  568.         <span class="token punctuation">}</span>
    569. 

  569.     <span class="token punctuation">}</span>
    570. 

  570. 

  571.     <span class="token comment">/// Get the key</span>
    572. 

  572.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">key</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token operator">&amp;</span><span class="token keyword">str</span> <span class="token punctuation">{</span>
    573. 

  573.         <span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">.</span>key
    574. 

  574.     <span class="token punctuation">}</span>
    575. 

  575. 

  576.     <span class="token comment">/// Get the value</span>
    577. 

  577.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">value</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token operator">&amp;</span><span class="token class-name">Bytes</span> <span class="token punctuation">{</span>
    578. 

  578.         <span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">.</span>value
    579. 

  579.     <span class="token punctuation">}</span>
    580. 

  580. 

  581.     <span class="token comment">/// Get the expire</span>
    582. 

  582.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">expire</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Option</span><span class="token operator">&lt;</span><span class="token class-name">Duration</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    583. 

  583.         <span class="token keyword">self</span><span class="token punctuation">.</span>expire
    584. 

  584.     <span class="token punctuation">}</span>
    585. 

  585. 

  586.     <span class="token comment">/// 解析frame</span>
    587. 

  587.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">parse_frames</span><span class="token punctuation">(</span>parse<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Parse</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Set</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    588. 

  588.         <span class="token keyword">use</span> <span class="token class-name">ParseError</span><span class="token punctuation">::</span><span class="token class-name">EndOfStream</span><span class="token punctuation">;</span>
    589. 

  589. 

  590.         <span class="token comment">// 使用 parse.next_string() 方法读取下一个字符串字段作为键（key）。</span>
    591. 

  591.         <span class="token keyword">let</span> key <span class="token operator">=</span> parse<span class="token punctuation">.</span><span class="token function">next_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">?</span><span class="token punctuation">;</span>
    592. 

  592. 

  593.         <span class="token comment">// 使用 parse.next_bytes() 方法读取下一个字节字段作为值（value）。</span>
    594. 

  594.         <span class="token keyword">let</span> value <span class="token operator">=</span> parse<span class="token punctuation">.</span><span class="token function">next_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">?</span><span class="token punctuation">;</span>
    595. 

  595. 

  596.         <span class="token comment">// 创建一个mut expire，用于存储过期时间。初始值为 None。</span>
    597. 

  597.         <span class="token keyword">let</span> <span class="token keyword">mut</span> expire <span class="token operator">=</span> <span class="token class-name">None</span><span class="token punctuation">;</span>
    598. 

  598. 

  599.         <span class="token comment">// 分析其他情况的帧</span>
    600. 

  600.         <span class="token keyword">match</span> parse<span class="token punctuation">.</span><span class="token function">next_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    601. 

  601.             <span class="token class-name">Ok</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span> <span class="token keyword">if</span> s<span class="token punctuation">.</span><span class="token function">to_uppercase</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">==</span> <span class="token string">&quot;EX&quot;</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    602. 

  602.                 <span class="token comment">// 如果下一个字符串字段是 &quot;EX&quot;（不区分大小写），则表示设置了过期时间且单位是secs</span>
    603. 

  603.                 <span class="token comment">// 下一个值应该是一个整数，并转成Duration类型。</span>
    604. 

  604.                 <span class="token keyword">let</span> secs <span class="token operator">=</span> parse<span class="token punctuation">.</span><span class="token function">next_int</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">?</span><span class="token punctuation">;</span>
    605. 

  605.                 expire <span class="token operator">=</span> <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token class-name">Duration</span><span class="token punctuation">::</span><span class="token function">from_secs</span><span class="token punctuation">(</span>secs<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    606. 

  606.             <span class="token punctuation">}</span>
    607. 

  607.             <span class="token class-name">Ok</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span> <span class="token keyword">if</span> s<span class="token punctuation">.</span><span class="token function">to_uppercase</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">==</span> <span class="token string">&quot;PX&quot;</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    608. 

  608.                 <span class="token comment">// 如果下一个字符串字段是 &quot;PX&quot;（不区分大小写），则表示设置了过期时间且单位是millis</span>
    609. 

  609.                 <span class="token comment">// 下一个值应该是一个整数，并转成Duration类型。</span>
    610. 

  610.                 <span class="token keyword">let</span> ms <span class="token operator">=</span> parse<span class="token punctuation">.</span><span class="token function">next_int</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">?</span><span class="token punctuation">;</span>
    611. 

  611.                 expire <span class="token operator">=</span> <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token class-name">Duration</span><span class="token punctuation">::</span><span class="token function">from_millis</span><span class="token punctuation">(</span>ms<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    612. 

  612.             <span class="token punctuation">}</span>
    613. 

  613.             <span class="token comment">// 如果下一个字符串字段不是 &quot;EX&quot; 或 &quot;PX&quot;，则表示设置了不支持的选项，将返回一个错误，指示 SET 目前仅支持过期时间选项。</span>
    614. 

  614.             <span class="token class-name">Ok</span><span class="token punctuation">(</span>_<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token keyword">return</span> <span class="token class-name">Err</span><span class="token punctuation">(</span><span class="token string">&quot;currently `SET` only supports the expiration option&quot;</span><span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    615. 

  615.             <span class="token comment">// 如果解析到达流的末尾，表示没有进一步的数据需要解析，这是正常的运行时情况，表示没有指定 SET 的选项。</span>
    616. 

  616.             <span class="token class-name">Err</span><span class="token punctuation">(</span><span class="token class-name">EndOfStream</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span><span class="token punctuation">}</span>
    617. 

  617.             <span class="token comment">// 其他所有错误都会返回一个错误，导致连接被终止。</span>
    618. 

  618.             <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token keyword">return</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    619. 

  619.         <span class="token punctuation">}</span>
    620. 

  620. 

  621.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">Set</span> <span class="token punctuation">{</span> key<span class="token punctuation">,</span> value<span class="token punctuation">,</span> expire <span class="token punctuation">}</span><span class="token punctuation">)</span>
    622. 

  622.     <span class="token punctuation">}</span>
    623. 

  623. 

  624.     <span class="token comment">/// 对数据库连接执行set命令</span>
    625. 

  625.     <span class="token attribute attr-name">#[instrument(skip(self, db, dst))]</span>
    626. 

  626.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">apply</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">,</span> db<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token class-name">Db</span><span class="token punctuation">,</span> dst<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Connection</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    627. 

  627.         <span class="token comment">// 执行set</span>
    628. 

  628.         db<span class="token punctuation">.</span><span class="token function">set</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>key<span class="token punctuation">,</span> <span class="token keyword">self</span><span class="token punctuation">.</span>value<span class="token punctuation">,</span> <span class="token keyword">self</span><span class="token punctuation">.</span>expire<span class="token punctuation">)</span><span class="token punctuation">;</span>
    629. 

  629. 

  630.         <span class="token comment">// 创建执行成功响应，并写给连接</span>
    631. 

  631.         <span class="token keyword">let</span> response <span class="token operator">=</span> <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Simple</span><span class="token punctuation">(</span><span class="token string">&quot;OK&quot;</span><span class="token punctuation">.</span><span class="token function">to_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    632. 

  632.         <span class="token macro property">debug!</span><span class="token punctuation">(</span><span class="token operator">?</span>response<span class="token punctuation">)</span><span class="token punctuation">;</span>
    633. 

  633.         dst<span class="token punctuation">.</span><span class="token function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>response<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    634. 

  634. 

  635.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    636. 

  636.     <span class="token punctuation">}</span>
    637. 

  637. 

  638.     <span class="token comment">/// 将set命令转成frame形式</span>
    639. 

  639.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">into_frame</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Frame</span> <span class="token punctuation">{</span>
    640. 

  640.         <span class="token keyword">let</span> <span class="token keyword">mut</span> frame <span class="token operator">=</span> <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token function">array</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    641. 

  641.         <span class="token comment">// 将命令以[&quot;set&quot;,key,value]的形式写入frame</span>
    642. 

  642.         frame<span class="token punctuation">.</span><span class="token function">push_bulk</span><span class="token punctuation">(</span><span class="token class-name">Bytes</span><span class="token punctuation">::</span><span class="token function">from</span><span class="token punctuation">(</span><span class="token string">&quot;set&quot;</span><span class="token punctuation">.</span><span class="token function">as_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    643. 

  643.         frame<span class="token punctuation">.</span><span class="token function">push_bulk</span><span class="token punctuation">(</span><span class="token class-name">Bytes</span><span class="token punctuation">::</span><span class="token function">from</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>key<span class="token punctuation">.</span><span class="token function">into_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    644. 

  644.         frame<span class="token punctuation">.</span><span class="token function">push_bulk</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>value<span class="token punctuation">)</span><span class="token punctuation">;</span>
    645. 

  645.         <span class="token comment">// 判断是否有过期时间，如果有过期时间以[&quot;px&quot;,ms]的格式写入frame</span>
    646. 

  646.         <span class="token keyword">if</span> <span class="token keyword">let</span> <span class="token class-name">Some</span><span class="token punctuation">(</span>ms<span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token keyword">self</span><span class="token punctuation">.</span>expire <span class="token punctuation">{</span>
    647. 

  647.             <span class="token comment">// 可以用以下两种方式设置过期时间，在这里使用第二种，因为精度更高</span>
    648. 

  648.             <span class="token comment">// 1. SET key value EX seconds</span>
    649. 

  649.             <span class="token comment">// 2. SET key value PX milliseconds</span>
    650. 

  650.             frame<span class="token punctuation">.</span><span class="token function">push_bulk</span><span class="token punctuation">(</span><span class="token class-name">Bytes</span><span class="token punctuation">::</span><span class="token function">from</span><span class="token punctuation">(</span><span class="token string">&quot;px&quot;</span><span class="token punctuation">.</span><span class="token function">as_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    651. 

  651.             frame<span class="token punctuation">.</span><span class="token function">push_int</span><span class="token punctuation">(</span>ms<span class="token punctuation">.</span><span class="token function">as_millis</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">as</span> <span class="token keyword">u64</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    652. 

  652.         <span class="token punctuation">}</span>
    653. 

  653.         frame
    654. 

  654.     <span class="token punctuation">}</span>
    655. 

  655. <span class="token punctuation">}</span>
    656. 

  656. </code></pre></div><h4 id="subscribe-message"><a href="#subscribe-message" class="header-anchor">#</a> Subscribe+Message</h4> <p>代码位置：src/cmd/subscribe.rs</p> <h5 id="struct-10"><a href="#struct-10" class="header-anchor">#</a> Struct</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">/// 订阅命令</span>
    657. 

  657. <span class="token comment">/// </span>
    658. 

  658. <span class="token comment">/// 一旦客户端进入订阅状态，它只能提出 </span>
    659. 

  659. <span class="token comment">/// SUBSCRIBE, PSUBSCRIBE, UNSUBSCRIBE,</span>
    660. 

  660. <span class="token comment">/// PUNSUBSCRIBE, PING 和 QUIT命令</span>
    661. 

  661. <span class="token attribute attr-name">#[derive(Debug)]</span>
    662. 

  662. <span class="token keyword">pub</span> <span class="token keyword">struct</span> <span class="token type-definition class-name">Subscribe</span> <span class="token punctuation">{</span>
    663. 

  663.     channels<span class="token punctuation">:</span> <span class="token class-name">Vec</span><span class="token operator">&lt;</span><span class="token class-name">String</span><span class="token operator">&gt;</span><span class="token punctuation">,</span>
    664. 

  664. <span class="token punctuation">}</span>
    665. 

  665. 

  666. <span class="token comment">/// 信息流</span>
    667. 

  667. <span class="token keyword">type</span> <span class="token type-definition class-name">Messages</span> <span class="token operator">=</span> <span class="token class-name">Pin</span><span class="token operator">&lt;</span><span class="token class-name">Box</span><span class="token operator">&lt;</span><span class="token keyword">dyn</span> <span class="token class-name">Stream</span><span class="token operator">&lt;</span><span class="token class-name">Item</span> <span class="token operator">=</span> <span class="token class-name">Bytes</span><span class="token operator">&gt;</span> <span class="token operator">+</span> <span class="token class-name">Send</span><span class="token operator">&gt;&gt;</span><span class="token punctuation">;</span>
    668. 

  668. </code></pre></div><h5 id="implementation-9"><a href="#implementation-9" class="header-anchor">#</a> Implementation</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">Subscribe</span><span class="token punctuation">{</span>
    669. 

  669.     <span class="token comment">/// 创建一个新的订阅者以监听频道</span>
    670. 

  670.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">new</span><span class="token punctuation">(</span>channels<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token punctuation">[</span><span class="token class-name">String</span><span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Subscribe</span> <span class="token punctuation">{</span>
    671. 

  671.         <span class="token class-name">Subscribe</span> <span class="token punctuation">{</span>
    672. 

  672.             channels<span class="token punctuation">:</span> channels<span class="token punctuation">.</span><span class="token function">to_vec</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    673. 

  673.         <span class="token punctuation">}</span>
    674. 

  674.     <span class="token punctuation">}</span>
    675. 

  675.      <span class="token comment">/// 解析subscribe帧</span>
    676. 

  676.      <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">parse_frames</span><span class="token punctuation">(</span>parse<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Parse</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Subscribe</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    677. 

  677.         <span class="token keyword">use</span> <span class="token class-name">ParseError</span><span class="token punctuation">::</span><span class="token class-name">EndOfStream</span><span class="token punctuation">;</span>
    678. 

  678.         <span class="token comment">// 获取第一个channel，并判断是否为none，不为none则写入数组</span>
    679. 

  679.         <span class="token keyword">let</span> <span class="token keyword">mut</span> channels <span class="token operator">=</span> <span class="token macro property">vec!</span><span class="token punctuation">[</span>parse<span class="token punctuation">.</span><span class="token function">next_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">?</span><span class="token punctuation">]</span><span class="token punctuation">;</span>
    680. 

  680.         <span class="token comment">// 循环解析剩下的channel，并将其写入数组</span>
    681. 

  681.         <span class="token keyword">loop</span> <span class="token punctuation">{</span>
    682. 

  682.             <span class="token keyword">match</span> parse<span class="token punctuation">.</span><span class="token function">next_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    683. 

  683.                 <span class="token comment">// 推送消息给频道</span>
    684. 

  684.                 <span class="token class-name">Ok</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> channels<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">,</span>
    685. 

  685.                 <span class="token comment">// EndOfStream说明不会再有消息了</span>
    686. 

  686.                 <span class="token class-name">Err</span><span class="token punctuation">(</span><span class="token class-name">EndOfStream</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token keyword">break</span><span class="token punctuation">,</span>
    687. 

  687.                 <span class="token comment">// 错误报告</span>
    688. 

  688.                 <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token keyword">return</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    689. 

  689.             <span class="token punctuation">}</span>
    690. 

  690.         <span class="token punctuation">}</span>
    691. 

  691.         <span class="token comment">// 返回结果</span>
    692. 

  692.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">Subscribe</span> <span class="token punctuation">{</span> channels <span class="token punctuation">}</span><span class="token punctuation">)</span>
    693. 

  693.     <span class="token punctuation">}</span>
    694. 

  694. 

  695.     <span class="token comment">/// 数据库执行subscribe命令</span>
    696. 

  696.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">apply</span><span class="token punctuation">(</span>
    697. 

  697.         <span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
    698. 

  698.         db<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token class-name">Db</span><span class="token punctuation">,</span>
    699. 

  699.         dst<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Connection</span><span class="token punctuation">,</span>
    700. 

  700.         shutdown<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Shutdown</span><span class="token punctuation">,</span>
    701. 

  701.     <span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    702. 

  702.         <span class="token comment">// 创建一个 StreamMap 对象，用于跟踪活动的订阅。使用map可以防止订阅重复</span>
    703. 

  703.         <span class="token keyword">let</span> <span class="token keyword">mut</span> subscriptions <span class="token operator">=</span> <span class="token class-name">StreamMap</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    704. 

  704. 

  705.         <span class="token keyword">loop</span> <span class="token punctuation">{</span>
    706. 

  706.             <span class="token comment">// 遍历channels，drain(..)会将管道从channels中移除</span>
    707. 

  707.             <span class="token comment">// subscribe_to_channel会订阅传入的管道</span>
    708. 

  708.             <span class="token comment">// await等待管道订阅成功</span>
    709. 

  709.             <span class="token keyword">for</span> channel_name <span class="token keyword">in</span> <span class="token keyword">self</span><span class="token punctuation">.</span>channels<span class="token punctuation">.</span><span class="token function">drain</span><span class="token punctuation">(</span><span class="token punctuation">..</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    710. 

  710.                 <span class="token function">subscribe_to_channel</span><span class="token punctuation">(</span>channel_name<span class="token punctuation">,</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> subscriptions<span class="token punctuation">,</span> db<span class="token punctuation">,</span> dst<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    711. 

  711.             <span class="token punctuation">}</span>
    712. 

  712. 

  713.             <span class="token comment">// 使用 select! 宏等待以下几种情况中的任何一种发生：</span>
    714. 

  714.             <span class="token comment">// 1. 从已订阅的通道接收到消息。</span>
    715. 

  715.             <span class="token comment">// 2. 从客户端接收到订阅或取消订阅命令。</span>
    716. 

  716.             <span class="token comment">// 3. 收到服务器关闭信号。</span>
    717. 

  717.             <span class="token macro property">select!</span> <span class="token punctuation">{</span>
    718. 

  718.                 <span class="token comment">// 接收来自已订阅通道的消息。</span>
    719. 

  719.                 <span class="token comment">// subscriptions.next() 返回一个异步迭代器</span>
    720. 

  720.                 <span class="token comment">// 当有新的消息到达时，会返回 Some((channel_name, msg))</span>
    721. 

  721.                 <span class="token comment">// 其中 channel_name 是通道名称，msg 是消息内容。</span>
    722. 

  722.                 <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token punctuation">(</span>channel_name<span class="token punctuation">,</span> msg<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token operator">=</span> subscriptions<span class="token punctuation">.</span><span class="token function">next</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    723. 

  723.                     <span class="token comment">// 将收到的消息构造成消息帧写给客户端</span>
    724. 

  724.                     dst<span class="token punctuation">.</span><span class="token function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token function">make_message_frame</span><span class="token punctuation">(</span>channel_name<span class="token punctuation">,</span> msg<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    725. 

  725.                 <span class="token punctuation">}</span>
    726. 

  726.                 <span class="token comment">// dst.read_frame() 返回一个异步操作结果，</span>
    727. 

  727.                 <span class="token comment">//当有新的帧可用时，会返回 Some(frame)，其中 frame 是读取到的帧。如果客户端断开连接，会返回 None。</span>
    728. 

  728.                 res <span class="token operator">=</span> dst<span class="token punctuation">.</span><span class="token function">read_frame</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    729. 

  729.                     <span class="token keyword">let</span> frame <span class="token operator">=</span> <span class="token keyword">match</span> res<span class="token operator">?</span> <span class="token punctuation">{</span>
    730. 

  730.                         <span class="token class-name">Some</span><span class="token punctuation">(</span>frame<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> frame<span class="token punctuation">,</span>
    731. 

  731.                         <span class="token comment">// This happens if the remote client has disconnected.</span>
    732. 

  732.                         <span class="token class-name">None</span> <span class="token operator">=&gt;</span> <span class="token keyword">return</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    733. 

  733.                     <span class="token punctuation">}</span><span class="token punctuation">;</span>
    734. 

  734.                     <span class="token comment">// 处理从客户端接收到的命令帧</span>
    735. 

  735.                     <span class="token function">handle_command</span><span class="token punctuation">(</span>
    736. 

  736.                         frame<span class="token punctuation">,</span>
    737. 

  737.                         <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">.</span>channels<span class="token punctuation">,</span>
    738. 

  738.                         <span class="token operator">&amp;</span><span class="token keyword">mut</span> subscriptions<span class="token punctuation">,</span>
    739. 

  739.                         dst<span class="token punctuation">,</span>
    740. 

  740.                     <span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    741. 

  741.                 <span class="token punctuation">}</span>
    742. 

  742.                 <span class="token comment">// 接收服务器关闭信号。</span>
    743. 

  743.                 _ <span class="token operator">=</span> shutdown<span class="token punctuation">.</span><span class="token function">recv</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    744. 

  744.                     <span class="token keyword">return</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    745. 

  745.                 <span class="token punctuation">}</span>
    746. 

  746.             <span class="token punctuation">}</span><span class="token punctuation">;</span>
    747. 

  747.         <span class="token punctuation">}</span>
    748. 

  748.     <span class="token punctuation">}</span>
    749. 

  749. 

  750.     <span class="token comment">/// 将命令转为frame类型</span>
    751. 

  751.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">into_frame</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Frame</span> <span class="token punctuation">{</span>
    752. 

  752.         <span class="token keyword">let</span> <span class="token keyword">mut</span> frame <span class="token operator">=</span> <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token function">array</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    753. 

  753.         <span class="token comment">// 将命令以[&quot;subscribe&quot;,channel1,channel2...]的形</span>
    754. 

  754.         <span class="token comment">//式放入数组</span>
    755. 

  755.         frame<span class="token punctuation">.</span><span class="token function">push_bulk</span><span class="token punctuation">(</span><span class="token class-name">Bytes</span><span class="token punctuation">::</span><span class="token function">from</span><span class="token punctuation">(</span><span class="token string">&quot;unsubscribe&quot;</span><span class="token punctuation">.</span><span class="token function">as_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    756. 

  756.         <span class="token keyword">for</span> channel <span class="token keyword">in</span> <span class="token keyword">self</span><span class="token punctuation">.</span>channels <span class="token punctuation">{</span>
    757. 

  757.             frame<span class="token punctuation">.</span><span class="token function">push_bulk</span><span class="token punctuation">(</span><span class="token class-name">Bytes</span><span class="token punctuation">::</span><span class="token function">from</span><span class="token punctuation">(</span>channel<span class="token punctuation">.</span><span class="token function">into_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    758. 

  758.         <span class="token punctuation">}</span>
    759. 

  759.         frame
    760. 

  760.     <span class="token punctuation">}</span>
    761. 

  761. 

  762. 

  763. 

  764. <span class="token punctuation">}</span>
    765. 

  765. </code></pre></div><h5 id="function"><a href="#function" class="header-anchor">#</a> Function</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">subscribe_to_channel</span><span class="token punctuation">(</span>
    766. 

  766.     channel_name<span class="token punctuation">:</span> <span class="token class-name">String</span><span class="token punctuation">,</span>
    767. 

  767.     subscriptions<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">StreamMap</span><span class="token operator">&lt;</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">Messages</span><span class="token operator">&gt;</span><span class="token punctuation">,</span>
    768. 

  768.     db<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token class-name">Db</span><span class="token punctuation">,</span>
    769. 

  769.     dst<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Connection</span><span class="token punctuation">,</span>
    770. 

  770. <span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    771. 

  771.     <span class="token comment">// 向数据发送订阅请求</span>
    772. 

  772.     <span class="token keyword">let</span> <span class="token keyword">mut</span> rx <span class="token operator">=</span> db<span class="token punctuation">.</span><span class="token function">subscribe</span><span class="token punctuation">(</span>channel_name<span class="token punctuation">.</span><span class="token function">clone</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    773. 

  773. 

  774.     <span class="token comment">// 接受订阅回复</span>
    775. 

  775.     <span class="token keyword">let</span> rx <span class="token operator">=</span> <span class="token class-name">Box</span><span class="token punctuation">::</span><span class="token function">pin</span><span class="token punctuation">(</span><span class="token namespace">async_stream<span class="token punctuation">::</span></span><span class="token macro property">stream!</span> <span class="token punctuation">{</span>
    776. 

  776.         <span class="token keyword">loop</span> <span class="token punctuation">{</span>
    777. 

  777.             <span class="token keyword">match</span> rx<span class="token punctuation">.</span><span class="token function">recv</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span> <span class="token punctuation">{</span>
    778. 

  778.                 <span class="token class-name">Ok</span><span class="token punctuation">(</span>msg<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token keyword">yield</span> msg<span class="token punctuation">,</span>
    779. 

  779.                 <span class="token comment">// If we lagged in consuming messages, just resume.</span>
    780. 

  780.                 <span class="token class-name">Err</span><span class="token punctuation">(</span><span class="token namespace">broadcast<span class="token punctuation">::</span>error<span class="token punctuation">::</span></span><span class="token class-name">RecvError</span><span class="token punctuation">::</span><span class="token class-name">Lagged</span><span class="token punctuation">(</span>_<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span><span class="token punctuation">}</span>
    781. 

  781.                 <span class="token class-name">Err</span><span class="token punctuation">(</span>_<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token keyword">break</span><span class="token punctuation">,</span>
    782. 

  782.             <span class="token punctuation">}</span>
    783. 

  783.         <span class="token punctuation">}</span>
    784. 

  784.     <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    785. 

  785. 

  786.     <span class="token comment">// 将订阅成功的管道加入到订阅map中</span>
    787. 

  787.     subscriptions<span class="token punctuation">.</span><span class="token function">insert</span><span class="token punctuation">(</span>channel_name<span class="token punctuation">.</span><span class="token function">clone</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> rx<span class="token punctuation">)</span><span class="token punctuation">;</span>
    788. 

  788. 

  789.     <span class="token comment">// 响应成功订阅报文</span>
    790. 

  790.     <span class="token keyword">let</span> response <span class="token operator">=</span> <span class="token function">make_subscribe_frame</span><span class="token punctuation">(</span>channel_name<span class="token punctuation">,</span> subscriptions<span class="token punctuation">.</span><span class="token function">len</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    791. 

  791.     dst<span class="token punctuation">.</span><span class="token function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>response<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    792. 

  792. 

  793.     <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    794. 

  794. <span class="token punctuation">}</span>
    795. 

  795. 

  796. <span class="token comment">/// 处理subscribe和unsubscibe的逻辑</span>
    797. 

  797. <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">handle_command</span><span class="token punctuation">(</span>
    798. 

  798.     frame<span class="token punctuation">:</span> <span class="token class-name">Frame</span><span class="token punctuation">,</span>
    799. 

  799.     subscribe_to<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Vec</span><span class="token operator">&lt;</span><span class="token class-name">String</span><span class="token operator">&gt;</span><span class="token punctuation">,</span>
    800. 

  800.     subscriptions<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">StreamMap</span><span class="token operator">&lt;</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">Messages</span><span class="token operator">&gt;</span><span class="token punctuation">,</span>
    801. 

  801.     dst<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Connection</span><span class="token punctuation">,</span>
    802. 

  802. <span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    803. 

  803.     <span class="token comment">// 匹配命令，判断要执行的操作</span>
    804. 

  804.     <span class="token keyword">match</span> <span class="token class-name">Command</span><span class="token punctuation">::</span><span class="token function">from_frame</span><span class="token punctuation">(</span>frame<span class="token punctuation">)</span><span class="token operator">?</span> <span class="token punctuation">{</span>
    805. 

  805.         <span class="token class-name">Command</span><span class="token punctuation">::</span><span class="token class-name">Subscribe</span><span class="token punctuation">(</span>subscribe<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    806. 

  806.         <span class="token comment">// 将要订阅的频道加入到订阅map          </span>
    807. 

  807.             subscribe_to<span class="token punctuation">.</span><span class="token function">extend</span><span class="token punctuation">(</span>subscribe<span class="token punctuation">.</span>channels<span class="token punctuation">.</span><span class="token function">into_iter</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    808. 

  808.         <span class="token punctuation">}</span>
    809. 

  809.         <span class="token class-name">Command</span><span class="token punctuation">::</span><span class="token class-name">Unsubscribe</span><span class="token punctuation">(</span><span class="token keyword">mut</span> unsubscribe<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    810. 

  810.             <span class="token comment">// 判断是否指定了要取消订阅的频道</span>
    811. 

  811.             <span class="token comment">// 如果没有则需要订阅所有channels</span>
    812. 

  812.             <span class="token keyword">if</span> unsubscribe<span class="token punctuation">.</span>channels<span class="token punctuation">.</span><span class="token function">is_empty</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    813. 

  813.                 unsubscribe<span class="token punctuation">.</span>channels <span class="token operator">=</span> subscriptions
    814. 

  814.                     <span class="token punctuation">.</span><span class="token function">keys</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
    815. 

  815.                     <span class="token punctuation">.</span><span class="token function">map</span><span class="token punctuation">(</span><span class="token closure-params"><span class="token closure-punctuation punctuation">|</span>channel_name<span class="token closure-punctuation punctuation">|</span></span> channel_name<span class="token punctuation">.</span><span class="token function">to_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    816. 

  816.                     <span class="token punctuation">.</span><span class="token function">collect</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    817. 

  817.             <span class="token punctuation">}</span>
    818. 

  818.             <span class="token comment">// 将需要取消订阅的频道从map中移除</span>
    819. 

  819.             <span class="token keyword">for</span> channel_name <span class="token keyword">in</span> unsubscribe<span class="token punctuation">.</span>channels <span class="token punctuation">{</span>
    820. 

  820.                   subscriptions<span class="token punctuation">.</span><span class="token function">remove</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>channel_name<span class="token punctuation">)</span><span class="token punctuation">;</span>
    821. 

  821.                   <span class="token comment">// 生成unsubscribe响应</span>
    822. 

  822.                   <span class="token keyword">let</span> response <span class="token operator">=</span> <span class="token function">make_unsubscribe_frame</span><span class="token punctuation">(</span>channel_name<span class="token punctuation">,</span> subscriptions<span class="token punctuation">.</span><span class="token function">len</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    823. 

  823.                   <span class="token comment">// 写入unsubscribe响应</span>
    824. 

  824.                   dst<span class="token punctuation">.</span><span class="token function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>response<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    825. 

  825.             <span class="token punctuation">}</span>
    826. 

  826.         <span class="token punctuation">}</span>
    827. 

  827.         command <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    828. 

  828.             <span class="token comment">// 其他命令都看作是unknown命令</span>
    829. 

  829.             <span class="token keyword">let</span> cmd <span class="token operator">=</span> <span class="token class-name">Unknown</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span>command<span class="token punctuation">.</span><span class="token function">get_name</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    830. 

  830.             cmd<span class="token punctuation">.</span><span class="token function">apply</span><span class="token punctuation">(</span>dst<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    831. 

  831.         <span class="token punctuation">}</span>
    832. 

  832.     <span class="token punctuation">}</span>
    833. 

  833.     <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    834. 

  834. <span class="token punctuation">}</span>
    835. 

  835. </code></pre></div><h4 id="unsubscribe"><a href="#unsubscribe" class="header-anchor">#</a> Unsubscribe</h4> <p>代码位置：src/cmd/subcribe.rs</p> <h5 id="struct-11"><a href="#struct-11" class="header-anchor">#</a> Struct</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">/// 取消订阅命令</span>
    836. 

  836. <span class="token comment">///</span>
    837. 

  837. <span class="token comment">/// 如果channels为空，则取消订阅所有频道</span>
    838. 

  838. <span class="token attribute attr-name">#[derive(Clone, Debug)]</span>
    839. 

  839. <span class="token keyword">pub</span> <span class="token keyword">struct</span> <span class="token type-definition class-name">Unsubscribe</span> <span class="token punctuation">{</span>
    840. 

  840.     channels<span class="token punctuation">:</span> <span class="token class-name">Vec</span><span class="token operator">&lt;</span><span class="token class-name">String</span><span class="token operator">&gt;</span><span class="token punctuation">,</span>
    841. 

  841. <span class="token punctuation">}</span>
    842. 

  842. </code></pre></div><h5 id="implementation-10"><a href="#implementation-10" class="header-anchor">#</a> Implementation</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">Unsubscribe</span><span class="token punctuation">{</span>
    843. 

  843.      <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">new</span><span class="token punctuation">(</span>channels<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token punctuation">[</span><span class="token class-name">String</span><span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Unsubscribe</span> <span class="token punctuation">{</span>
    844. 

  844.         <span class="token class-name">Unsubscribe</span> <span class="token punctuation">{</span>
    845. 

  845.             channels<span class="token punctuation">:</span> channels<span class="token punctuation">.</span><span class="token function">to_vec</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    846. 

  846.         <span class="token punctuation">}</span>
    847. 

  847.     <span class="token punctuation">}</span>
    848. 

  848.     <span class="token comment">/// 解析unsubscribe帧</span>
    849. 

  849.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">parse_frames</span><span class="token punctuation">(</span>parse<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Parse</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Unsubscribe</span><span class="token punctuation">,</span> <span class="token class-name">ParseError</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    850. 

  850.         <span class="token keyword">use</span> <span class="token class-name">ParseError</span><span class="token punctuation">::</span><span class="token class-name">EndOfStream</span><span class="token punctuation">;</span>
    851. 

  851. 

  852.         <span class="token comment">// 创建数组，用于存储channels</span>
    853. 

  853.         <span class="token keyword">let</span> <span class="token keyword">mut</span> channels <span class="token operator">=</span> <span class="token macro property">vec!</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">;</span>
    854. 

  854. 

  855.         <span class="token comment">// 循环解析数据，将channel放入数组</span>
    856. 

  856.         <span class="token keyword">loop</span> <span class="token punctuation">{</span>
    857. 

  857.             <span class="token keyword">match</span> parse<span class="token punctuation">.</span><span class="token function">next_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    858. 

  858.                 <span class="token comment">// 将数据推送到要取消订阅的频道列表</span>
    859. 

  859.                 <span class="token class-name">Ok</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> channels<span class="token punctuation">.</span><span class="token function">push</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">,</span>
    860. 

  860.                 <span class="token comment">// EndOfStream代表数据解析完成</span>
    861. 

  861.                 <span class="token class-name">Err</span><span class="token punctuation">(</span><span class="token class-name">EndOfStream</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token keyword">break</span><span class="token punctuation">,</span>
    862. 

  862.                 <span class="token comment">// 其他错误</span>
    863. 

  863.                 <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token keyword">return</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">)</span><span class="token punctuation">,</span>
    864. 

  864.             <span class="token punctuation">}</span>
    865. 

  865.         <span class="token punctuation">}</span>
    866. 

  866. 

  867.         <span class="token comment">// 返回命令</span>
    868. 

  868.     <span class="token punctuation">}</span>
    869. 

  869.     <span class="token comment">/// 将unsubscribe命令转成帧</span>
    870. 

  870.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">into_frame</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Frame</span> <span class="token punctuation">{</span>
    871. 

  871.         <span class="token keyword">let</span> <span class="token keyword">mut</span> frame <span class="token operator">=</span> <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token function">array</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    872. 

  872.         <span class="token comment">// 将命令以[&quot;unsubscribe&quot;,channel1,channel2...]形</span>
    873. 

  873.         <span class="token comment">// 式放入数组</span>
    874. 

  874.         frame<span class="token punctuation">.</span><span class="token function">push_bulk</span><span class="token punctuation">(</span><span class="token class-name">Bytes</span><span class="token punctuation">::</span><span class="token function">from</span><span class="token punctuation">(</span><span class="token string">&quot;unsubscribe&quot;</span><span class="token punctuation">.</span><span class="token function">as_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    875. 

  875. 

  876.         <span class="token keyword">for</span> channel <span class="token keyword">in</span> <span class="token keyword">self</span><span class="token punctuation">.</span>channels <span class="token punctuation">{</span>
    877. 

  877.             frame<span class="token punctuation">.</span><span class="token function">push_bulk</span><span class="token punctuation">(</span><span class="token class-name">Bytes</span><span class="token punctuation">::</span><span class="token function">from</span><span class="token punctuation">(</span>channel<span class="token punctuation">.</span><span class="token function">into_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    878. 

  878.         <span class="token punctuation">}</span>
    879. 

  879.         frame
    880. 

  880.     <span class="token punctuation">}</span>
    881. 

  881. <span class="token punctuation">}</span>
    882. 

  882. </code></pre></div><h4 id="unknown"><a href="#unknown" class="header-anchor">#</a> Unknown</h4> <h5 id="struct-12"><a href="#struct-12" class="header-anchor">#</a> Struct</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token attribute attr-name">#[derive(Debug)]</span>
    883. 

  883. <span class="token keyword">pub</span> <span class="token keyword">struct</span> <span class="token type-definition class-name">Unknown</span> <span class="token punctuation">{</span>
    884. 

  884.     command_name<span class="token punctuation">:</span> <span class="token class-name">String</span><span class="token punctuation">,</span>
    885. 

  885. <span class="token punctuation">}</span>
    886. 

  886. </code></pre></div><h5 id="implementation-11"><a href="#implementation-11" class="header-anchor">#</a> Implementation</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">Unknown</span><span class="token punctuation">{</span>
    887. 

  887.     <span class="token comment">/// 创建unknown命令</span>
    888. 

  888.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">new</span><span class="token punctuation">(</span>key<span class="token punctuation">:</span> <span class="token keyword">impl</span> <span class="token class-name">ToString</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Unknown</span> <span class="token punctuation">{</span>
    889. 

  889.         <span class="token class-name">Unknown</span> <span class="token punctuation">{</span>
    890. 

  890.             command_name<span class="token punctuation">:</span> key<span class="token punctuation">.</span><span class="token function">to_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    891. 

  891.         <span class="token punctuation">}</span>
    892. 

  892.     <span class="token punctuation">}</span>
    893. 

  893. 

  894.     <span class="token comment">/// 获取命令名</span>
    895. 

  895.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">get_name</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token operator">&amp;</span><span class="token keyword">str</span> <span class="token punctuation">{</span>
    896. 

  896.         <span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">.</span>command_name
    897. 

  897.     <span class="token punctuation">}</span>
    898. 

  898. 

  899.     <span class="token comment">/// 回应客户端不支持当前命令</span>
    900. 

  900.     <span class="token attribute attr-name">#[instrument(skip(self, dst))]</span>
    901. 

  901.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">apply</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">,</span> dst<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Connection</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    902. 

  902.         <span class="token comment">// 生成错误帧响应</span>
    903. 

  903.         <span class="token keyword">let</span> response <span class="token operator">=</span> <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Error</span><span class="token punctuation">(</span><span class="token macro property">format!</span><span class="token punctuation">(</span><span class="token string">&quot;ERR unknown command '{}'&quot;</span><span class="token punctuation">,</span> <span class="token keyword">self</span><span class="token punctuation">.</span>command_name<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    904. 

  904.         <span class="token comment">// 日志记录响应</span>
    905. 

  905.         <span class="token macro property">debug!</span><span class="token punctuation">(</span><span class="token operator">?</span>response<span class="token punctuation">)</span><span class="token punctuation">;</span>
    906. 

  906.         <span class="token comment">// 将帧写入连接</span>
    907. 

  907.         dst<span class="token punctuation">.</span><span class="token function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>response<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    908. 

  908.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    909. 

  909.     <span class="token punctuation">}</span>
    910. 

  910. <span class="token punctuation">}</span>
    911. 

  911. </code></pre></div><h4 id="ping"><a href="#ping" class="header-anchor">#</a> Ping</h4> <h5 id="struct-13"><a href="#struct-13" class="header-anchor">#</a> Struct</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token attribute attr-name">#[derive(Debug, Default)]</span>
    912. 

  912. <span class="token keyword">pub</span> <span class="token keyword">struct</span> <span class="token type-definition class-name">Ping</span> <span class="token punctuation">{</span>
    913. 

  913.     <span class="token comment">/// 自定义消息返回</span>
    914. 

  914.     msg<span class="token punctuation">:</span> <span class="token class-name">Option</span><span class="token operator">&lt;</span><span class="token class-name">Bytes</span><span class="token operator">&gt;</span><span class="token punctuation">,</span>
    915. 

  915. <span class="token punctuation">}</span>
    916. 

  916. </code></pre></div><h5 id="implement"><a href="#implement" class="header-anchor">#</a> Implement</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">Ping</span> <span class="token punctuation">{</span>
    917. 

  917.     <span class="token comment">/// 创建一个新的携带自定信息的Ping命令</span>
    918. 

  918.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">new</span><span class="token punctuation">(</span>msg<span class="token punctuation">:</span> <span class="token class-name">Option</span><span class="token operator">&lt;</span><span class="token class-name">Bytes</span><span class="token operator">&gt;</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Ping</span> <span class="token punctuation">{</span>
    919. 

  919.         <span class="token class-name">Ping</span> <span class="token punctuation">{</span> msg <span class="token punctuation">}</span>
    920. 

  920.     <span class="token punctuation">}</span>
    921. 

  921. 

  922.     <span class="token comment">/// 解析ping命令</span>
    923. 

  923.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">parse_frames</span><span class="token punctuation">(</span>parse<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Parse</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Ping</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    924. 

  924.         <span class="token keyword">match</span> parse<span class="token punctuation">.</span><span class="token function">next_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    925. 

  925.             <span class="token class-name">Ok</span><span class="token punctuation">(</span>msg<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">Ping</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span><span class="token class-name">Some</span><span class="token punctuation">(</span>msg<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    926. 

  926.             <span class="token class-name">Err</span><span class="token punctuation">(</span><span class="token class-name">ParseError</span><span class="token punctuation">::</span><span class="token class-name">EndOfStream</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">Ping</span><span class="token punctuation">::</span><span class="token function">default</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    927. 

  927.             <span class="token class-name">Err</span><span class="token punctuation">(</span>e<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>e<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    928. 

  928.         <span class="token punctuation">}</span>
    929. 

  929.     <span class="token punctuation">}</span>
    930. 

  930. 

  931.     <span class="token comment">/// ping命令执行逻辑</span>
    932. 

  932.     <span class="token comment">///</span>
    933. 

  933.     <span class="token comment">/// 响应会被写入dst。</span>
    934. 

  934.     <span class="token comment">/// 服务端受到命令并执行时会执行。</span>
    935. 

  935.     <span class="token attribute attr-name">#[instrument(skip(self, dst))]</span>
    936. 

  936.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">apply</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">,</span> dst<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token class-name">Connection</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    937. 

  937.         <span class="token keyword">let</span> response <span class="token operator">=</span> <span class="token keyword">match</span> <span class="token keyword">self</span><span class="token punctuation">.</span>msg <span class="token punctuation">{</span>
    938. 

  938.             <span class="token class-name">None</span> <span class="token operator">=&gt;</span> <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Simple</span><span class="token punctuation">(</span><span class="token string">&quot;PONG&quot;</span><span class="token punctuation">.</span><span class="token function">to_string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    939. 

  939.             <span class="token class-name">Some</span><span class="token punctuation">(</span>msg<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Bulk</span><span class="token punctuation">(</span>msg<span class="token punctuation">)</span><span class="token punctuation">,</span>
    940. 

  940.         <span class="token punctuation">}</span><span class="token punctuation">;</span>
    941. 

  941. 

  942.         <span class="token macro property">debug!</span><span class="token punctuation">(</span><span class="token operator">?</span>response<span class="token punctuation">)</span><span class="token punctuation">;</span>
    943. 

  943. 

  944.         dst<span class="token punctuation">.</span><span class="token function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>response<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    945. 

  945. 

  946.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    947. 

  947.     <span class="token punctuation">}</span>
    948. 

  948. 

  949.     <span class="token comment">/// 将命令转换成frame</span>
    950. 

  950.     <span class="token comment">///This is called by the client when encoding a `Ping` command to send</span>
    951. 

  951.     <span class="token comment">/// to the server.</span>
    952. 

  952.     <span class="token comment">/// 当客户端需要发送ping命令给服务端时会被调用</span>
    953. 

  953.     <span class="token keyword">pub</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">)</span> <span class="token keyword">fn</span> <span class="token function-definition function">into_frame</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Frame</span> <span class="token punctuation">{</span>
    954. 

  954.         <span class="token keyword">let</span> <span class="token keyword">mut</span> frame <span class="token operator">=</span> <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token function">array</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    955. 

  955.         frame<span class="token punctuation">.</span><span class="token function">push_bulk</span><span class="token punctuation">(</span><span class="token class-name">Bytes</span><span class="token punctuation">::</span><span class="token function">from</span><span class="token punctuation">(</span><span class="token string">&quot;ping&quot;</span><span class="token punctuation">.</span><span class="token function">as_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    956. 

  956.         <span class="token keyword">if</span> <span class="token keyword">let</span> <span class="token class-name">Some</span><span class="token punctuation">(</span>msg<span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token keyword">self</span><span class="token punctuation">.</span>msg <span class="token punctuation">{</span>
    957. 

  957.             frame<span class="token punctuation">.</span><span class="token function">push_bulk</span><span class="token punctuation">(</span>msg<span class="token punctuation">)</span><span class="token punctuation">;</span>
    958. 

  958.         <span class="token punctuation">}</span>
    959. 

  959.         frame
    960. 

  960.     <span class="token punctuation">}</span>
    961. 

  961. <span class="token punctuation">}</span>
    962. 

  962. </code></pre></div><h3 id="frame"><a href="#frame" class="header-anchor">#</a> frame</h3> <blockquote><p>redis协议帧</p></blockquote> <h4 id="enum"><a href="#enum" class="header-anchor">#</a> enum</h4> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">/// A frame in the Redis protocol.</span>
    963. 

  963. <span class="token attribute attr-name">#[derive(Clone, Debug)]</span>
    964. 

  964. <span class="token keyword">pub</span> <span class="token keyword">enum</span> <span class="token type-definition class-name">Frame</span> <span class="token punctuation">{</span>
    965. 

  965.     <span class="token class-name">Simple</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    966. 

  966.     <span class="token class-name">Error</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    967. 

  967.     <span class="token class-name">Integer</span><span class="token punctuation">(</span><span class="token keyword">u64</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    968. 

  968.     <span class="token class-name">Bulk</span><span class="token punctuation">(</span><span class="token class-name">Bytes</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    969. 

  969.     <span class="token class-name">Null</span><span class="token punctuation">,</span>
    970. 

  970.     <span class="token class-name">Array</span><span class="token punctuation">(</span><span class="token class-name">Vec</span><span class="token operator">&lt;</span><span class="token class-name">Frame</span><span class="token operator">&gt;</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    971. 

  971. <span class="token punctuation">}</span>
    972. 

  972. 

  973. <span class="token attribute attr-name">#[derive(Debug)]</span>
    974. 

  974. <span class="token keyword">pub</span> <span class="token keyword">enum</span> <span class="token type-definition class-name">Error</span> <span class="token punctuation">{</span>
    975. 

  975.     <span class="token comment">/// Not enough data is available to parse a message</span>
    976. 

  976.     <span class="token class-name">Incomplete</span><span class="token punctuation">,</span>
    977. 

  977. 

  978.     <span class="token comment">/// Invalid message encoding</span>
    979. 

  979.     <span class="token class-name">Other</span><span class="token punctuation">(</span><span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Error</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    980. 

  980. <span class="token punctuation">}</span>
    981. 

  981. </code></pre></div><h3 id="sever"><a href="#sever" class="header-anchor">#</a> sever</h3> <blockquote><p>mini-redis的服务端。提供了一个异步的<code>run</code>函数，用于监听连接，并为每个连接生成一个任务</p></blockquote> <h4 id="listener"><a href="#listener" class="header-anchor">#</a> Listener</h4> <h5 id="struct-14"><a href="#struct-14" class="header-anchor">#</a> Struct</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">/// 服务端用于监听的连接</span>
    982. 

  982. <span class="token attribute attr-name">#[derive(Debug)]</span>
    983. 

  983. <span class="token keyword">struct</span> <span class="token type-definition class-name">Listener</span> <span class="token punctuation">{</span>
    984. 

  984.     <span class="token comment">/// 可共享的数据库连接句柄（Arc形式）</span>
    985. 

  985.     db_holder<span class="token punctuation">:</span> <span class="token class-name">DbDropGuard</span><span class="token punctuation">,</span>
    986. 

  986. 

  987.     <span class="token comment">/// TCP监听类，由run函数提供</span>
    988. 

  988.     listener<span class="token punctuation">:</span> <span class="token class-name">TcpListener</span><span class="token punctuation">,</span>
    989. 

  989. 

  990.     <span class="token comment">/// 信号量，用于限制连接数</span>
    991. 

  991.     limit_connections<span class="token punctuation">:</span> <span class="token class-name">Arc</span><span class="token operator">&lt;</span><span class="token class-name">Semaphore</span><span class="token operator">&gt;</span><span class="token punctuation">,</span>
    992. 

  992. 

  993.     <span class="token comment">/// 用于广播shutdown信号</span>
    994. 

  994.     notify_shutdown<span class="token punctuation">:</span> <span class="token namespace">broadcast<span class="token punctuation">::</span></span><span class="token class-name">Sender</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span><span class="token punctuation">,</span>
    995. 

  995. 

  996.     <span class="token comment">/// 用于在客户端完成所有任务后安全关闭连接。</span>
    997. 

  997.     <span class="token comment">/// 当一个连接被初始化，它会保存‵shutdown_complete_tx‵的clone，被关闭时回收</span>
    998. 

  998.     <span class="token comment">/// 当所有listener的连接都被关闭后，sender也会被释放</span>
    999. 

  999.     <span class="token comment">/// 所有任务被完成后，`shutdown_complete_rx.recv()`会返回`None`</span>
    1000. 

  1000.     shutdown_complete_tx<span class="token punctuation">:</span> <span class="token namespace">mpsc<span class="token punctuation">::</span></span><span class="token class-name">Sender</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span><span class="token punctuation">,</span>
    1001. 

  1001. <span class="token punctuation">}</span>
    1002. 

  1002. </code></pre></div><h5 id="implementation-12"><a href="#implementation-12" class="header-anchor">#</a> Implementation</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">Listener</span> <span class="token punctuation">{</span>
    1003. 

  1003.     <span class="token comment">/// 启动server监听服务</span>
    1004. 

  1004.     <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">run</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    1005. 

  1005.         <span class="token macro property">info!</span><span class="token punctuation">(</span><span class="token string">&quot;accepting inbound connections&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1006. 

  1006. 

  1007.         <span class="token keyword">loop</span> <span class="token punctuation">{</span>
    1008. 

  1008.             <span class="token comment">// 等待有名额创建连接</span>
    1009. 

  1009.             <span class="token keyword">let</span> permit <span class="token operator">=</span> <span class="token keyword">self</span>
    1010. 

  1010.                 <span class="token punctuation">.</span>limit_connections
    1011. 

  1011.                 <span class="token punctuation">.</span><span class="token function">clone</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
    1012. 

  1012.                 <span class="token punctuation">.</span><span class="token function">acquire_owned</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
    1013. 

  1013.                 <span class="token punctuation">.</span><span class="token keyword">await</span>
    1014. 

  1014.                 <span class="token punctuation">.</span><span class="token function">unwrap</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1015. 

  1015. 

  1016.             <span class="token comment">// 建立tcp连接，获取套接字</span>
    1017. 

  1017.             <span class="token keyword">let</span> socket <span class="token operator">=</span> <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">accept</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1018. 

  1018. 

  1019.             <span class="token comment">// 存储连接状态</span>
    1020. 

  1020.             <span class="token keyword">let</span> <span class="token keyword">mut</span> handler <span class="token operator">=</span> <span class="token class-name">Handler</span> <span class="token punctuation">{</span>
    1021. 

  1021.                 <span class="token comment">// 获取数据库连接</span>
    1022. 

  1022.                 db<span class="token punctuation">:</span> <span class="token keyword">self</span><span class="token punctuation">.</span>db_holder<span class="token punctuation">.</span><span class="token function">db</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    1023. 

  1023. 

  1024.                 <span class="token comment">// 新建连接</span>
    1025. 

  1025.                 connection<span class="token punctuation">:</span> <span class="token class-name">Connection</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span>socket<span class="token punctuation">)</span><span class="token punctuation">,</span>
    1026. 

  1026. 

  1027.                 <span class="token comment">// 用于接受shutdown信号</span>
    1028. 

  1028.                 shutdown<span class="token punctuation">:</span> <span class="token class-name">Shutdown</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>notify_shutdown<span class="token punctuation">.</span><span class="token function">subscribe</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    1029. 

  1029. 

  1030.                 <span class="token comment">// 一旦所有的clone被释放，会通过此成员来通知</span>
    1031. 

  1031.                 _shutdown_complete<span class="token punctuation">:</span> <span class="token keyword">self</span><span class="token punctuation">.</span>shutdown_complete_tx<span class="token punctuation">.</span><span class="token function">clone</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    1032. 

  1032.             <span class="token punctuation">}</span><span class="token punctuation">;</span>
    1033. 

  1033. 

  1034.                 <span class="token comment">// 创建一个异步的任务执行连接要做的操作</span>
    1035. 

  1035.                 <span class="token namespace">tokio<span class="token punctuation">::</span></span><span class="token function">spawn</span><span class="token punctuation">(</span><span class="token keyword">async</span> <span class="token keyword">move</span> <span class="token punctuation">{</span>
    1036. 

  1036.                 <span class="token comment">// 执行连接，并记录错误</span>
    1037. 

  1037.                 <span class="token keyword">if</span> <span class="token keyword">let</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token operator">=</span> handler<span class="token punctuation">.</span><span class="token function">run</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span> <span class="token punctuation">{</span>
    1038. 

  1038.                     <span class="token macro property">error!</span><span class="token punctuation">(</span>cause <span class="token operator">=</span> <span class="token operator">?</span>err<span class="token punctuation">,</span> <span class="token string">&quot;connection error&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1039. 

  1039.                 <span class="token punctuation">}</span>
    1040. 

  1040.                 <span class="token comment">// 归还连接名额</span>
    1041. 

  1041.                 <span class="token function">drop</span><span class="token punctuation">(</span>permit<span class="token punctuation">)</span><span class="token punctuation">;</span>
    1042. 

  1042.             <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1043. 

  1043.         <span class="token punctuation">}</span>
    1044. 

  1044.     <span class="token punctuation">}</span>
    1045. 

  1045. 

  1046.     <span class="token comment">/// 建立tcp连接，获取套接字</span>
    1047. 

  1047.     <span class="token comment">/// 如果发生错误，最大重连次数为6，最后一次等待时间为64s。重连流程参考tcp超时重发机制。</span>
    1048. 

  1048.     <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">accept</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">TcpStream</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    1049. 

  1049.         <span class="token keyword">let</span> <span class="token keyword">mut</span> backoff <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">;</span>
    1050. 

  1050. 

  1051.         <span class="token comment">// 尝试接受连接</span>
    1052. 

  1052.         <span class="token keyword">loop</span> <span class="token punctuation">{</span>
    1053. 

  1053.             <span class="token comment">// 成功直接返回tcp连接 失败返回错误信息</span>
    1054. 

  1054.             <span class="token keyword">match</span> <span class="token keyword">self</span><span class="token punctuation">.</span>listener<span class="token punctuation">.</span><span class="token function">accept</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span> <span class="token punctuation">{</span>
    1055. 

  1055.                 <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span>socket<span class="token punctuation">,</span> _<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token keyword">return</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span>socket<span class="token punctuation">)</span><span class="token punctuation">,</span>
    1056. 

  1056.                 <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    1057. 

  1057.                     <span class="token keyword">if</span> backoff <span class="token operator">&gt;</span> <span class="token number">64</span> <span class="token punctuation">{</span>
    1058. 

  1058.                         <span class="token comment">// 等待时间过长，返回错误</span>
    1059. 

  1059.                         <span class="token keyword">return</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1060. 

  1060.                     <span class="token punctuation">}</span>
    1061. 

  1061.                 <span class="token punctuation">}</span>
    1062. 

  1062.             <span class="token punctuation">}</span>
    1063. 

  1063. 

  1064.             <span class="token comment">// 睡眠</span>
    1065. 

  1065.             <span class="token namespace">time<span class="token punctuation">::</span></span><span class="token function">sleep</span><span class="token punctuation">(</span><span class="token class-name">Duration</span><span class="token punctuation">::</span><span class="token function">from_secs</span><span class="token punctuation">(</span>backoff<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token punctuation">;</span>
    1066. 

  1066. 

  1067.             <span class="token comment">// 指数增长等待时间</span>
    1068. 

  1068.             backoff <span class="token operator">*=</span> <span class="token number">2</span><span class="token punctuation">;</span>
    1069. 

  1069.         <span class="token punctuation">}</span>
    1070. 

  1070.     <span class="token punctuation">}</span>
    1071. 

  1071. <span class="token punctuation">}</span>
    1072. 

  1072. </code></pre></div><h4 id="handler"><a href="#handler" class="header-anchor">#</a> Handler</h4> <h5 id="struct-15"><a href="#struct-15" class="header-anchor">#</a> Struct</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">/// 服务端的具体连接</span>
    1073. 

  1073. <span class="token attribute attr-name">#[derive(Debug)]</span>
    1074. 

  1074. <span class="token keyword">struct</span> <span class="token type-definition class-name">Handler</span> <span class="token punctuation">{</span>
    1075. 

  1075.     <span class="token comment">/// 数据库连接</span>
    1076. 

  1076.     db<span class="token punctuation">:</span> <span class="token class-name">Db</span><span class="token punctuation">,</span>
    1077. 

  1077. 

  1078.     <span class="token comment">/// tcp连接</span>
    1079. 

  1079.     connection<span class="token punctuation">:</span> <span class="token class-name">Connection</span><span class="token punctuation">,</span>
    1080. 

  1080. 

  1081.     <span class="token comment">/// 监听shutdown信号</span>
    1082. 

  1082.     shutdown<span class="token punctuation">:</span> <span class="token class-name">Shutdown</span><span class="token punctuation">,</span>
    1083. 

  1083. 

  1084.     <span class="token comment">/// 不直接使用，用来判断当前类对象是否被释放</span>
    1085. 

  1085.     _shutdown_complete<span class="token punctuation">:</span> <span class="token namespace">mpsc<span class="token punctuation">::</span></span><span class="token class-name">Sender</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span><span class="token punctuation">,</span>
    1086. 

  1086. <span class="token punctuation">}</span>
    1087. 

  1087. </code></pre></div><h5 id="implementation-13"><a href="#implementation-13" class="header-anchor">#</a> Implementation</h5> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">Handler</span> <span class="token punctuation">{</span>
    1088. 

  1088.     <span class="token comment">/// 处理单个连接</span>
    1089. 

  1089.     <span class="token comment">/// </span>
    1090. 

  1090.     <span class="token comment">/// 当接收到shutdown信号时，等到该连接处于安全状态时，连接会断开</span>
    1091. 

  1091.     <span class="token attribute attr-name">#[instrument(skip(self))]</span>
    1092. 

  1092.     <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">run</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    1093. 

  1093.         <span class="token comment">// 循环处理帧</span>
    1094. 

  1094.         <span class="token keyword">while</span> <span class="token operator">!</span><span class="token keyword">self</span><span class="token punctuation">.</span>shutdown<span class="token punctuation">.</span><span class="token function">s_shutdown</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    1095. 

  1095.             <span class="token keyword">let</span> maybe_frame <span class="token operator">=</span> <span class="token namespace">tokio<span class="token punctuation">::</span></span><span class="token macro property">select!</span> <span class="token punctuation">{</span>
    1096. 

  1096.                 res <span class="token operator">=</span> <span class="token keyword">self</span><span class="token punctuation">.</span>connection<span class="token punctuation">.</span><span class="token function">read_frame</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> res<span class="token operator">?</span><span class="token punctuation">,</span>
    1097. 

  1097.                 _ <span class="token operator">=</span> <span class="token keyword">self</span><span class="token punctuation">.</span>shutdown<span class="token punctuation">.</span><span class="token function">recv</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    1098. 

  1098.                     <span class="token comment">// 接收到shutdown信号，退出run函数会使任务结束</span>
    1099. 

  1099.                     <span class="token keyword">return</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1100. 

  1100.                 <span class="token punctuation">}</span>
    1101. 

  1101.             <span class="token punctuation">}</span><span class="token punctuation">;</span>
    1102. 

  1102. 

  1103.             <span class="token comment">// 判断从远端收到的帧（maybe_frame）是否有内容，收到‵None`时说明远端关闭</span>
    1104. 

  1104.             <span class="token keyword">let</span> frame <span class="token operator">=</span> <span class="token keyword">match</span> maybe_frame <span class="token punctuation">{</span>
    1105. 

  1105.                 <span class="token class-name">Some</span><span class="token punctuation">(</span>frame<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> frame<span class="token punctuation">,</span>
    1106. 

  1106.                 <span class="token class-name">None</span> <span class="token operator">=&gt;</span> <span class="token keyword">return</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    1107. 

  1107.             <span class="token punctuation">}</span><span class="token punctuation">;</span>
    1108. 

  1108. 

  1109.             <span class="token comment">// 将frame转为命令形式</span>
    1110. 

  1110.             <span class="token keyword">let</span> cmd <span class="token operator">=</span> <span class="token class-name">Command</span><span class="token punctuation">::</span><span class="token function">from_frame</span><span class="token punctuation">(</span>frame<span class="token punctuation">)</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1111. 

  1111. 

  1112.             <span class="token comment">// 日志记录接收到的命令</span>
    1113. 

  1113.             <span class="token macro property">debug!</span><span class="token punctuation">(</span><span class="token operator">?</span>cmd<span class="token punctuation">)</span><span class="token punctuation">;</span>
    1114. 

  1114. 

  1115.             <span class="token comment">// 异步执行命令</span>
    1116. 

  1116.             cmd<span class="token punctuation">.</span><span class="token function">apply</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">.</span>db<span class="token punctuation">,</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">.</span>connection<span class="token punctuation">,</span> <span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">.</span>shutdown<span class="token punctuation">)</span>
    1117. 

  1117.                 <span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1118. 

  1118.         <span class="token punctuation">}</span>
    1119. 

  1119. 

  1120.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    1121. 

  1121.     <span class="token punctuation">}</span>
    1122. 

  1122. <span class="token punctuation">}</span>
    1123. 

  1123. </code></pre></div><h4 id="fn-run"><a href="#fn-run" class="header-anchor">#</a> Fn Run</h4> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">/// mini-redis的服务端启动函数</span>
    1124. 

  1124. <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">run</span><span class="token punctuation">(</span>listener<span class="token punctuation">:</span> <span class="token class-name">TcpListener</span><span class="token punctuation">,</span> shutdown<span class="token punctuation">:</span> <span class="token keyword">impl</span> <span class="token class-name">Future</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    1125. 

  1125.     <span class="token comment">// 初始化shutdown信号广播管道</span>
    1126. 

  1126.     <span class="token keyword">let</span> <span class="token punctuation">(</span>notify_shutdown<span class="token punctuation">,</span> _<span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token namespace">broadcast<span class="token punctuation">::</span></span><span class="token function">channel</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1127. 

  1127.     <span class="token comment">// 初始化shutdown关闭机制</span>
    1128. 

  1128.     <span class="token keyword">let</span> <span class="token punctuation">(</span>shutdown_complete_tx<span class="token punctuation">,</span> <span class="token keyword">mut</span> shutdown_complete_rx<span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token namespace">mpsc<span class="token punctuation">::</span></span><span class="token function">channel</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1129. 

  1129. 

  1130.     <span class="token comment">// 初始化监听连接</span>
    1131. 

  1131.     <span class="token keyword">let</span> <span class="token keyword">mut</span> server <span class="token operator">=</span> <span class="token class-name">Listener</span> <span class="token punctuation">{</span>
    1132. 

  1132.         listener<span class="token punctuation">,</span>
    1133. 

  1133.         db_holder<span class="token punctuation">:</span> <span class="token class-name">DbDropGuard</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    1134. 

  1134.         limit_connections<span class="token punctuation">:</span> <span class="token class-name">Arc</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span><span class="token class-name">Semaphore</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span><span class="token constant">MAX_CONNECTIONS</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    1135. 

  1135.         notify_shutdown<span class="token punctuation">,</span>
    1136. 

  1136.         shutdown_complete_tx<span class="token punctuation">,</span>
    1137. 

  1137.     <span class="token punctuation">}</span><span class="token punctuation">;</span>
    1138. 

  1138. 

  1139.     <span class="token comment">// 监听是否有连接到达</span>
    1140. 

  1140.     <span class="token namespace">tokio<span class="token punctuation">::</span></span><span class="token macro property">select!</span> <span class="token punctuation">{</span>
    1141. 

  1141.         res <span class="token operator">=</span> server<span class="token punctuation">.</span><span class="token function">run</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    1142. 

  1142.             <span class="token comment">// 处理连接失败的情况</span>
    1143. 

  1143.             <span class="token keyword">if</span> <span class="token keyword">let</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token operator">=</span> res <span class="token punctuation">{</span>
    1144. 

  1144.                 <span class="token macro property">error!</span><span class="token punctuation">(</span>cause <span class="token operator">=</span> <span class="token operator">%</span>err<span class="token punctuation">,</span> <span class="token string">&quot;failed to accept&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1145. 

  1145.             <span class="token punctuation">}</span>
    1146. 

  1146.         <span class="token punctuation">}</span>
    1147. 

  1147.         _ <span class="token operator">=</span> shutdown <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    1148. 

  1148.             <span class="token macro property">info!</span><span class="token punctuation">(</span><span class="token string">&quot;shutting down&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1149. 

  1149.         <span class="token punctuation">}</span>
    1150. 

  1150.     <span class="token punctuation">}</span>
    1151. 

  1151. 

  1152.     <span class="token keyword">let</span> <span class="token class-name">Listener</span> <span class="token punctuation">{</span>
    1153. 

  1153.         shutdown_complete_tx<span class="token punctuation">,</span>
    1154. 

  1154.         notify_shutdown<span class="token punctuation">,</span>
    1155. 

  1155.         <span class="token punctuation">..</span>
    1156. 

  1156.     <span class="token punctuation">}</span> <span class="token operator">=</span> server<span class="token punctuation">;</span>
    1157. 

  1157. 

  1158.     <span class="token comment">// 所有的处在subscribe状态的任务会接收到shutdown信号并且退出</span>
    1159. 

  1159.     <span class="token function">drop</span><span class="token punctuation">(</span>notify_shutdown<span class="token punctuation">)</span><span class="token punctuation">;</span>
    1160. 

  1160.     <span class="token comment">// 回收监听者的shutdown_complete_tx，意味着只有其他连接持有shutdown_complete_tx了</span>
    1161. 

  1161.     <span class="token function">drop</span><span class="token punctuation">(</span>shutdown_complete_tx<span class="token punctuation">)</span><span class="token punctuation">;</span>
    1162. 

  1162. 

  1163.     <span class="token comment">// 等待所有活跃连接完成其任务</span>
    1164. 

  1164.     <span class="token comment">// 当所有shutdown_complete_tx都被释放，说明所有连接都断开了</span>
    1165. 

  1165.     <span class="token comment">// 此时`recv()`会返回`None`并且`mpsc`管道会被关闭</span>
    1166. 

  1166.     <span class="token keyword">let</span> _ <span class="token operator">=</span> shutdown_complete_rx<span class="token punctuation">.</span><span class="token function">recv</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token punctuation">;</span>
    1167. 

  1167. <span class="token punctuation">}</span>
    1168. 

  1168. </code></pre></div><h2 id="function-2"><a href="#function-2" class="header-anchor">#</a> Function</h2> <h3 id="fn-buffer"><a href="#fn-buffer" class="header-anchor">#</a> Fn Buffer</h3> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">/// 创建一个请求缓冲区</span>
    1169. 

  1169. <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">buffer</span><span class="token punctuation">(</span>client<span class="token punctuation">:</span> <span class="token class-name">Client</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Buffer</span> <span class="token punctuation">{</span>
    1170. 

  1170.     <span class="token comment">// 创建一个容量为32的异步通道。tx为发送端，rx为接收端</span>
    1171. 

  1171.     <span class="token keyword">let</span> <span class="token punctuation">(</span>tx<span class="token punctuation">,</span> rx<span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token function">channel</span><span class="token punctuation">(</span><span class="token number">32</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1172. 

  1172. 

  1173.     <span class="token comment">// 使用 tokio::spawn 函数创建一个异步任务（task）</span>
    1174. 

  1174.     <span class="token comment">// run 函数接受 client 和 rx（接收端）作为参数</span>
    1175. 

  1175.     <span class="token comment">// 并在 await 关键字处暂停执行，直到接收端接收到消息。</span>
    1176. 

  1176.     <span class="token namespace">tokio<span class="token punctuation">::</span></span><span class="token function">spawn</span><span class="token punctuation">(</span><span class="token keyword">async</span> <span class="token keyword">move</span> <span class="token punctuation">{</span> <span class="token function">run</span><span class="token punctuation">(</span>client<span class="token punctuation">,</span> rx<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1177. 

  1177. 

  1178.     <span class="token comment">// 返回缓冲区</span>
    1179. 

  1179.     <span class="token class-name">Buffer</span> <span class="token punctuation">{</span> tx <span class="token punctuation">}</span>
    1180. 

  1180. <span class="token punctuation">}</span>
    1181. 

  1181. </code></pre></div><h2 id="struct-16"><a href="#struct-16" class="header-anchor">#</a> Struct</h2> <h3 id="buffer"><a href="#buffer" class="header-anchor">#</a> Buffer</h3> <h4 id="struct-17"><a href="#struct-17" class="header-anchor">#</a> struct</h4> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">/// 客户端的请求窗口</span>
    1182. 

  1182. <span class="token attribute attr-name">#[derive(Clone)]</span>
    1183. 

  1183. <span class="token keyword">pub</span> <span class="token keyword">struct</span> <span class="token type-definition class-name">Buffer</span> <span class="token punctuation">{</span>
    1184. 

  1184.     tx<span class="token punctuation">:</span> <span class="token class-name">Sender</span><span class="token operator">&lt;</span><span class="token class-name">Message</span><span class="token operator">&gt;</span><span class="token punctuation">,</span>
    1185. 

  1185. <span class="token punctuation">}</span>
    1186. 

  1186. </code></pre></div><h4 id="implementation-14"><a href="#implementation-14" class="header-anchor">#</a> Implementation</h4> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">Buffer</span><span class="token punctuation">{</span>
    1187. 

  1187.     <span class="token comment">/// 获取key的值。请求会被缓存直到连接能够发送请求</span>
    1188. 

  1188.         <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">get</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> key<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">str</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Option</span><span class="token operator">&lt;</span><span class="token class-name">Bytes</span><span class="token operator">&gt;&gt;</span> <span class="token punctuation">{</span>
    1189. 

  1189.         <span class="token comment">// 初始化一个get命令</span>
    1190. 

  1190.         <span class="token keyword">let</span> get <span class="token operator">=</span> <span class="token class-name">Command</span><span class="token punctuation">::</span><span class="token class-name">Get</span><span class="token punctuation">(</span>key<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1191. 

  1191. 

  1192.         <span class="token comment">// 初始化一次性的管道以接收连接的回应</span>
    1193. 

  1193.         <span class="token keyword">let</span> <span class="token punctuation">(</span>tx<span class="token punctuation">,</span> rx<span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token namespace">oneshot<span class="token punctuation">::</span></span><span class="token function">channel</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1194. 

  1194. 

  1195.         <span class="token comment">// 发送请求</span>
    1196. 

  1196.         <span class="token keyword">self</span><span class="token punctuation">.</span>tx<span class="token punctuation">.</span><span class="token function">send</span><span class="token punctuation">(</span><span class="token punctuation">(</span>get<span class="token punctuation">,</span> tx<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1197. 

  1197. 

  1198.         <span class="token comment">// 等待回应，并返回结果</span>
    1199. 

  1199.         <span class="token keyword">match</span> rx<span class="token punctuation">.</span><span class="token keyword">await</span> <span class="token punctuation">{</span>
    1200. 

  1200.             <span class="token class-name">Ok</span><span class="token punctuation">(</span>res<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> res<span class="token punctuation">,</span>
    1201. 

  1201.             <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    1202. 

  1202.       <span class="token punctuation">}</span>
    1203. 

  1203.     <span class="token punctuation">}</span>
    1204. 

  1204. 

  1205.     <span class="token comment">/// 设置key的值</span>
    1206. 

  1206.     <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">set</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> key<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token keyword">str</span><span class="token punctuation">,</span> value<span class="token punctuation">:</span> <span class="token class-name">Bytes</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    1207. 

  1207.         <span class="token comment">// 初始化一个set命令</span>
    1208. 

  1208.         <span class="token keyword">let</span> set <span class="token operator">=</span> <span class="token class-name">Command</span><span class="token punctuation">::</span><span class="token class-name">Set</span><span class="token punctuation">(</span>key<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> value<span class="token punctuation">)</span><span class="token punctuation">;</span>
    1209. 

  1209. 

  1210.         <span class="token comment">// 初始化一次性的管道以接收连接的回应</span>
    1211. 

  1211.         <span class="token keyword">let</span> <span class="token punctuation">(</span>tx<span class="token punctuation">,</span> rx<span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token namespace">oneshot<span class="token punctuation">::</span></span><span class="token function">channel</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1212. 

  1212. 

  1213.         <span class="token comment">// 发送请求</span>
    1214. 

  1214.         <span class="token keyword">self</span><span class="token punctuation">.</span>tx<span class="token punctuation">.</span><span class="token function">send</span><span class="token punctuation">(</span><span class="token punctuation">(</span>set<span class="token punctuation">,</span> tx<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1215. 

  1215. 

  1216.         <span class="token comment">// 等待回应，并返回结果</span>
    1217. 

  1217.         <span class="token keyword">match</span> rx<span class="token punctuation">.</span><span class="token keyword">await</span> <span class="token punctuation">{</span>
    1218. 

  1218.             <span class="token class-name">Ok</span><span class="token punctuation">(</span>res<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> res<span class="token punctuation">.</span><span class="token function">map</span><span class="token punctuation">(</span><span class="token closure-params"><span class="token closure-punctuation punctuation">|</span>_<span class="token closure-punctuation punctuation">|</span></span> <span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    1219. 

  1219.             <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>err<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    1220. 

  1220.         <span class="token punctuation">}</span>
    1221. 

  1221.     <span class="token punctuation">}</span>           
    1222. 

  1222. <span class="token punctuation">}</span>
    1223. 

  1223. </code></pre></div><h3 id="connection"><a href="#connection" class="header-anchor">#</a> Connection</h3> <h4 id="struct-18"><a href="#struct-18" class="header-anchor">#</a> struct</h4> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">/// 发送和接收来自远端的帧</span>
    1224. 

  1224. <span class="token attribute attr-name">#[derive(Debug)]</span>
    1225. 

  1225. <span class="token keyword">pub</span> <span class="token keyword">struct</span> <span class="token type-definition class-name">Connection</span> <span class="token punctuation">{</span>
    1226. 

  1226.     <span class="token comment">// 带有写入缓冲区的tcp流</span>
    1227. 

  1227.     stream<span class="token punctuation">:</span> <span class="token class-name">BufWriter</span><span class="token operator">&lt;</span><span class="token class-name">TcpStream</span><span class="token operator">&gt;</span><span class="token punctuation">,</span>
    1228. 

  1228. 

  1229.     <span class="token comment">// 帧读缓冲区</span>
    1230. 

  1230.     buffer<span class="token punctuation">:</span> <span class="token class-name">BytesMut</span><span class="token punctuation">,</span>
    1231. 

  1231. <span class="token punctuation">}</span>
    1232. 

  1232. </code></pre></div><h4 id="implementation-15"><a href="#implementation-15" class="header-anchor">#</a> Implementation</h4> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">Connection</span><span class="token punctuation">{</span>
    1233. 

  1233.     <span class="token comment">/// 创建新的连接并返回socket，同时初始化缓冲区</span>
    1234. 

  1234.     <span class="token keyword">pub</span> <span class="token keyword">fn</span> <span class="token function-definition function">new</span><span class="token punctuation">(</span>socket<span class="token punctuation">:</span> <span class="token class-name">TcpStream</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token class-name">Connection</span> <span class="token punctuation">{</span>
    1235. 

  1235.         <span class="token class-name">Connection</span> <span class="token punctuation">{</span>
    1236. 

  1236.             stream<span class="token punctuation">:</span> <span class="token class-name">BufWriter</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span>socket<span class="token punctuation">)</span><span class="token punctuation">,</span>
    1237. 

  1237.             buffer<span class="token punctuation">:</span> <span class="token class-name">BytesMut</span><span class="token punctuation">::</span><span class="token function">with_capacity</span><span class="token punctuation">(</span><span class="token number">4</span> <span class="token operator">*</span> <span class="token number">1024</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    1238. 

  1238.         <span class="token punctuation">}</span>
    1239. 

  1239.     <span class="token punctuation">}</span>
    1240. 

  1240. 

  1241.     <span class="token comment">/// 从tcp流中读取一个帧</span>
    1242. 

  1242.     <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">read_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Option</span><span class="token operator">&lt;</span><span class="token class-name">Frame</span><span class="token operator">&gt;&gt;</span> <span class="token punctuation">{</span>
    1243. 

  1243.         <span class="token keyword">loop</span> <span class="token punctuation">{</span>
    1244. 

  1244.             <span class="token comment">// 解析并获取帧</span>
    1245. 

  1245.             <span class="token keyword">if</span> <span class="token keyword">let</span> <span class="token class-name">Some</span><span class="token punctuation">(</span>frame<span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">parse_frame</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">?</span> <span class="token punctuation">{</span>
    1246. 

  1246.                 <span class="token keyword">return</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">Some</span><span class="token punctuation">(</span>frame<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1247. 

  1247.             <span class="token punctuation">}</span>
    1248. 

  1248.             <span class="token comment">// 尝试从socket中读取更多的数据，如果读到的字节数为0，说明流被关闭</span>
    1249. 

  1249.             <span class="token keyword">if</span> <span class="token number">0</span> <span class="token operator">==</span> <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">read_buf</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">.</span>buffer<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span> <span class="token punctuation">{</span>
    1250. 

  1250.                 <span class="token comment">// 如果缓冲区为空说明远端正常关闭，否则为远端发送rst保温</span>
    1251. 

  1251.                 <span class="token keyword">if</span> <span class="token keyword">self</span><span class="token punctuation">.</span>buffer<span class="token punctuation">.</span><span class="token function">is_empty</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    1252. 

  1252.                     <span class="token keyword">return</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">None</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1253. 

  1253.                 <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
    1254. 

  1254.                     <span class="token keyword">return</span> <span class="token class-name">Err</span><span class="token punctuation">(</span><span class="token string">&quot;connection reset by peer&quot;</span><span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1255. 

  1255.                 <span class="token punctuation">}</span>
    1256. 

  1256.             <span class="token punctuation">}</span>
    1257. 

  1257.         <span class="token punctuation">}</span>
    1258. 

  1258.     <span class="token punctuation">}</span>
    1259. 

  1259. 

  1260.     <span class="token comment">/// 解析并获取frame。</span>
    1261. 

  1261.     <span class="token comment">/// 如果数据不够则返回 `Ok(None)`</span>
    1262. 

  1262.     <span class="token comment">/// 如果数据不合理则返回Err</span>
    1263. 

  1263.     <span class="token keyword">fn</span> <span class="token function-definition function">parse_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token keyword">crate</span><span class="token punctuation">::</span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token class-name">Option</span><span class="token operator">&lt;</span><span class="token class-name">Frame</span><span class="token operator">&gt;&gt;</span> <span class="token punctuation">{</span>
    1264. 

  1264.         <span class="token keyword">use</span> <span class="token namespace">frame<span class="token punctuation">::</span></span><span class="token class-name">Error</span><span class="token punctuation">::</span><span class="token class-name">Incomplete</span><span class="token punctuation">;</span>
    1265. 

  1265. 

  1266.         <span class="token comment">// 创建cursor用于追踪buffer中的数据位置</span>
    1267. 

  1267.         <span class="token keyword">let</span> <span class="token keyword">mut</span> buf <span class="token operator">=</span> <span class="token class-name">Cursor</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">self</span><span class="token punctuation">.</span>buffer<span class="token punctuation">[</span><span class="token punctuation">..</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1268. 

  1268. 

  1269.         <span class="token comment">// 检查缓冲区中是否有足够的数据</span>
    1270. 

  1270.         <span class="token keyword">match</span> <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token function">check</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> buf<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    1271. 

  1271.             <span class="token class-name">Ok</span><span class="token punctuation">(</span>_<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    1272. 

  1272.                 <span class="token comment">// 由于Frame::check()开始时会定位到缓冲区的末尾，所以可以获取到缓冲区的数据长度</span>
    1273. 

  1273.                 <span class="token keyword">let</span> len <span class="token operator">=</span> buf<span class="token punctuation">.</span><span class="token function">position</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">as</span> <span class="token keyword">usize</span><span class="token punctuation">;</span>
    1274. 

  1274. 

  1275.                 <span class="token comment">// 重置cursor位置</span>
    1276. 

  1276.                 buf<span class="token punctuation">.</span><span class="token function">set_position</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1277. 

  1277. 

  1278.                 <span class="token comment">// 解析frame</span>
    1279. 

  1279.                 <span class="token keyword">let</span> frame <span class="token operator">=</span> <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token function">parse</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> buf<span class="token punctuation">)</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1280. 

  1280. 

  1281.                 <span class="token comment">// 从buffer中删除所有数据（因为已经被解析了）</span>
    1282. 

  1282.                 <span class="token keyword">self</span><span class="token punctuation">.</span>buffer<span class="token punctuation">.</span><span class="token function">advance</span><span class="token punctuation">(</span>len<span class="token punctuation">)</span><span class="token punctuation">;</span>
    1283. 

  1283. 

  1284.                 <span class="token comment">// 返回frame</span>
    1285. 

  1285.                 <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">Some</span><span class="token punctuation">(</span>frame<span class="token punctuation">)</span><span class="token punctuation">)</span>
    1286. 

  1286.             <span class="token punctuation">}</span>
    1287. 

  1287.             <span class="token comment">// 数据不足以解析成单独的帧，返回None，说明需要继续等待</span>
    1288. 

  1288.             <span class="token class-name">Err</span><span class="token punctuation">(</span><span class="token class-name">Incomplete</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token class-name">None</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    1289. 

  1289.             <span class="token comment">// 返回错误</span>
    1290. 

  1290.             <span class="token class-name">Err</span><span class="token punctuation">(</span>e<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token class-name">Err</span><span class="token punctuation">(</span>e<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    1291. 

  1291.         <span class="token punctuation">}</span>
    1292. 

  1292.     <span class="token punctuation">}</span>
    1293. 

  1293. 

  1294.     <span class="token comment">/// 向TCP流中写数据</span>
    1295. 

  1295.     <span class="token keyword">pub</span> <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">write_frame</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> frame<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token class-name">Frame</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token namespace">io<span class="token punctuation">::</span></span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    1296. 

  1296.         <span class="token keyword">match</span> frame <span class="token punctuation">{</span>
    1297. 

  1297.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Array</span><span class="token punctuation">(</span>val<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    1298. 

  1298.                 <span class="token comment">// 对帧类型前缀进行编码。对于数组，它是“*”。</span>
    1299. 

  1299.                 <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">write_u8</span><span class="token punctuation">(</span><span class="token char">b'*'</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1300. 

  1300. 

  1301.                 <span class="token comment">// 写入数组长度</span>
    1302. 

  1302.                 <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">write_decimal</span><span class="token punctuation">(</span>val<span class="token punctuation">.</span><span class="token function">len</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">as</span> <span class="token keyword">u64</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1303. 

  1303. 

  1304.                 <span class="token comment">// 遍历并写入数组中每个元素</span>
    1305. 

  1305.                 <span class="token keyword">for</span> entry <span class="token keyword">in</span> <span class="token operator">&amp;</span><span class="token operator">*</span><span class="token operator">*</span>val <span class="token punctuation">{</span>
    1306. 

  1306.                     <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">write_value</span><span class="token punctuation">(</span>entry<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1307. 

  1307.                 <span class="token punctuation">}</span>
    1308. 

  1308.             <span class="token punctuation">}</span>
    1309. 

  1309.             <span class="token comment">// 直接写入整个帧</span>
    1310. 

  1310.             _ <span class="token operator">=&gt;</span> <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">write_value</span><span class="token punctuation">(</span>frame<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">,</span>
    1311. 

  1311.         <span class="token punctuation">}</span>
    1312. 

  1312. 

  1313.         <span class="token comment">// 保证缓冲区都被写入套接字</span>
    1314. 

  1314.         <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">flush</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span>
    1315. 

  1315.     <span class="token punctuation">}</span>
    1316. 

  1316. 

  1317.     <span class="token comment">/// 将帧文字写入流</span>
    1318. 

  1318.     <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">write_value</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> frame<span class="token punctuation">:</span> <span class="token operator">&amp;</span><span class="token class-name">Frame</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token namespace">io<span class="token punctuation">::</span></span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    1319. 

  1319.             <span class="token comment">// 判断帧的类型，将不同的帧按照格式写入流</span>
    1320. 

  1320.             <span class="token keyword">match</span> frame <span class="token punctuation">{</span>
    1321. 

  1321.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Simple</span><span class="token punctuation">(</span>val<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    1322. 

  1322.                 <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">write_u8</span><span class="token punctuation">(</span><span class="token char">b'+'</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1323. 

  1323.                 <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">write_all</span><span class="token punctuation">(</span>val<span class="token punctuation">.</span><span class="token function">as_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1324. 

  1324.                 <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">write_all</span><span class="token punctuation">(</span><span class="token string">b&quot;\r\n&quot;</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1325. 

  1325.             <span class="token punctuation">}</span>
    1326. 

  1326.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Error</span><span class="token punctuation">(</span>val<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    1327. 

  1327.                 <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">write_u8</span><span class="token punctuation">(</span><span class="token char">b'-'</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1328. 

  1328.                 <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">write_all</span><span class="token punctuation">(</span>val<span class="token punctuation">.</span><span class="token function">as_bytes</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1329. 

  1329.                 <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">write_all</span><span class="token punctuation">(</span><span class="token string">b&quot;\r\n&quot;</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1330. 

  1330.             <span class="token punctuation">}</span>
    1331. 

  1331.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Integer</span><span class="token punctuation">(</span>val<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    1332. 

  1332.                 <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">write_u8</span><span class="token punctuation">(</span><span class="token char">b':'</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1333. 

  1333.                 <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">write_decimal</span><span class="token punctuation">(</span><span class="token operator">*</span>val<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1334. 

  1334.             <span class="token punctuation">}</span>
    1335. 

  1335.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Null</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    1336. 

  1336.                 <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">write_all</span><span class="token punctuation">(</span><span class="token string">b&quot;$-1\r\n&quot;</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1337. 

  1337.             <span class="token punctuation">}</span>
    1338. 

  1338.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Bulk</span><span class="token punctuation">(</span>val<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    1339. 

  1339.                 <span class="token keyword">let</span> len <span class="token operator">=</span> val<span class="token punctuation">.</span><span class="token function">len</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1340. 

  1340. 

  1341.                 <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">write_u8</span><span class="token punctuation">(</span><span class="token char">b'$'</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1342. 

  1342.                 <span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">write_decimal</span><span class="token punctuation">(</span>len <span class="token keyword">as</span> <span class="token keyword">u64</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1343. 

  1343.                 <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">write_all</span><span class="token punctuation">(</span>val<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1344. 

  1344.                 <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">write_all</span><span class="token punctuation">(</span><span class="token string">b&quot;\r\n&quot;</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1345. 

  1345.             <span class="token punctuation">}</span>
    1346. 

  1346.             <span class="token comment">// 暂时不支持解析数组类型</span>
    1347. 

  1347.             <span class="token class-name">Frame</span><span class="token punctuation">::</span><span class="token class-name">Array</span><span class="token punctuation">(</span>_val<span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token macro property">unreachable!</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    1348. 

  1348.         <span class="token punctuation">}</span>
    1349. 

  1349. 

  1350.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    1351. 

  1351.     <span class="token punctuation">}</span>
    1352. 

  1352. 

  1353.     <span class="token comment">/// 将十进制帧写入流</span>
    1354. 

  1354.     <span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">write_decimal</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> val<span class="token punctuation">:</span> <span class="token keyword">u64</span><span class="token punctuation">)</span> <span class="token punctuation">-&gt;</span> <span class="token namespace">io<span class="token punctuation">::</span></span><span class="token class-name">Result</span><span class="token operator">&lt;</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&gt;</span> <span class="token punctuation">{</span>
    1355. 

  1355.         <span class="token keyword">use</span> <span class="token namespace">std<span class="token punctuation">::</span>io<span class="token punctuation">::</span></span><span class="token class-name">Write</span><span class="token punctuation">;</span>
    1356. 

  1356. 

  1357.         <span class="token comment">// 将数据转换成string</span>
    1358. 

  1358.         <span class="token keyword">let</span> <span class="token keyword">mut</span> buf <span class="token operator">=</span> <span class="token punctuation">[</span><span class="token number">0u8</span><span class="token punctuation">;</span> <span class="token number">20</span><span class="token punctuation">]</span><span class="token punctuation">;</span>
    1359. 

  1359.         <span class="token keyword">let</span> <span class="token keyword">mut</span> buf <span class="token operator">=</span> <span class="token class-name">Cursor</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> buf<span class="token punctuation">[</span><span class="token punctuation">..</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    1360. 

  1360.         <span class="token macro property">write!</span><span class="token punctuation">(</span><span class="token operator">&amp;</span><span class="token keyword">mut</span> buf<span class="token punctuation">,</span> <span class="token string">&quot;{}&quot;</span><span class="token punctuation">,</span> val<span class="token punctuation">)</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1361. 

  1361.         <span class="token comment">// 将数据写入流</span>
    1362. 

  1362.         <span class="token keyword">let</span> pos <span class="token operator">=</span> buf<span class="token punctuation">.</span><span class="token function">position</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">as</span> <span class="token keyword">usize</span><span class="token punctuation">;</span>
    1363. 

  1363.         <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">write_all</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>buf<span class="token punctuation">.</span><span class="token function">get_ref</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">[</span><span class="token punctuation">..</span>pos<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1364. 

  1364.         <span class="token keyword">self</span><span class="token punctuation">.</span>stream<span class="token punctuation">.</span><span class="token function">write_all</span><span class="token punctuation">(</span><span class="token string">b&quot;\r\n&quot;</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token operator">?</span><span class="token punctuation">;</span>
    1365. 

  1365. 

  1366.         <span class="token class-name">Ok</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
    1367. 

  1367.     <span class="token punctuation">}</span>
    1368. 

  1368. <span class="token punctuation">}</span>
    1369. 

  1369. </code></pre></div></div> <footer class="page-edit"><!----> <!----></footer> <!----> </main></div><div class="global-ui"></div></div>
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