xtask: rework command line

    xtask codegen --libbpf-dir <libbpf-dir> [SUBCOMMAND]

If SUBCOMMAND (eg aya or aya-bpf-bindings) is not given, codegen
everything.

xtask/src/codegen/aya.rs

@@ -1,23 +1,16 @@
 use anyhow::anyhow;
 use std::path::PathBuf;
-use structopt::StructOpt;
 
 use aya_gen::{bindgen, write_to_file};
 
-use crate::codegen::Architecture;
+use crate::codegen::{Architecture, Options};
 
-#[derive(StructOpt)]
-pub struct CodegenOptions {
-    #[structopt(long)]
-    libbpf_dir: PathBuf,
+pub fn codegen(opts: &Options) -> Result<(), anyhow::Error> {
+    codegen_internal_btf_bindings(opts)?;
+    codegen_bindings(opts)
 }
 
-pub fn codegen(opts: CodegenOptions) -> Result<(), anyhow::Error> {
-    codegen_internal_btf_bindings(&opts)?;
-    codegen_bindings(&opts)
-}
-
-fn codegen_internal_btf_bindings(opts: &CodegenOptions) -> Result<(), anyhow::Error> {
+fn codegen_internal_btf_bindings(opts: &Options) -> Result<(), anyhow::Error> {
     let dir = PathBuf::from("aya");
     let generated = dir.join("src/generated");
     let mut bindgen = bindgen::user_builder().header(
@@ -46,7 +39,7 @@ fn codegen_internal_btf_bindings(opts: &CodegenOptions) -> Result<(), anyhow::Er
     Ok(())
 }
 
-fn codegen_bindings(opts: &CodegenOptions) -> Result<(), anyhow::Error> {
+fn codegen_bindings(opts: &Options) -> Result<(), anyhow::Error> {
     let types = [
         // BPF
         "BPF_TYPES",

xtask/src/codegen/aya_bpf_bindings.rs

@@ -2,7 +2,6 @@ use anyhow::anyhow;
 use proc_macro2::TokenStream;
 use quote::ToTokens;
 use std::path::PathBuf;
-use structopt::StructOpt;
 
 use aya_gen::{
     bindgen,
@@ -13,16 +12,10 @@ use syn::{parse_str, Item};
 
 use crate::codegen::{
     helpers::{expand_helpers, extract_helpers},
-    Architecture,
+    Architecture, Options,
 };
 
-#[derive(StructOpt)]
-pub struct CodegenOptions {
-    #[structopt(long)]
-    libbpf_dir: PathBuf,
-}
-
-pub fn codegen(opts: CodegenOptions) -> Result<(), anyhow::Error> {
+pub fn codegen(opts: &Options) -> Result<(), anyhow::Error> {
     let dir = PathBuf::from("bpf/aya-bpf-bindings");
 
     let builder = || {

xtask/src/codegen/mod.rs

@@ -2,6 +2,8 @@ mod aya;
 mod aya_bpf_bindings;
 mod helpers;
 
+use std::path::PathBuf;
+
 use structopt::StructOpt;
 
 const SUPPORTED_ARCHS: &'static [Architecture] = &[Architecture::X86_64, Architecture::AArch64];
@@ -41,22 +43,29 @@ impl std::fmt::Display for Architecture {
 
 #[derive(StructOpt)]
 pub struct Options {
+    #[structopt(long)]
+    libbpf_dir: PathBuf,
+
     #[structopt(subcommand)]
-    command: Command,
+    command: Option<Command>,
 }
 
 #[derive(StructOpt)]
 enum Command {
     #[structopt(name = "aya")]
-    Aya(aya::CodegenOptions),
+    Aya,
     #[structopt(name = "aya-bpf-bindings")]
-    AyaBpfBindings(aya_bpf_bindings::CodegenOptions),
+    AyaBpfBindings,
 }
 
 pub fn codegen(opts: Options) -> Result<(), anyhow::Error> {
     use Command::*;
     match opts.command {
-        Aya(opts) => aya::codegen(opts),
-        AyaBpfBindings(opts) => aya_bpf_bindings::codegen(opts),
+        Some(Aya) => aya::codegen(&opts),
+        Some(AyaBpfBindings) => aya_bpf_bindings::codegen(&opts),
+        None => {
+            aya::codegen(&opts)?;
+            aya_bpf_bindings::codegen(&opts)
+        }
     }
 }