//! dlfcn implementation for Redox, following http://pubs.opengroup.org/onlinepubs/7908799/xsh/dlfcn.h.html

use core::sync::atomic::{AtomicUsize, Ordering, ATOMIC_USIZE_INIT};
use core::{ptr, str};

use c_str::CStr;
use platform::types::*;

pub const RTLD_LAZY: c_int = 0x0001;
pub const RTLD_NOW: c_int = 0x0002;
pub const RTLD_GLOBAL: c_int = 0x0100;
pub const RTLD_LOCAL: c_int = 0x0000;

static ERROR_NOT_SUPPORTED: &'static CStr = c_str!("dlfcn not supported");

#[thread_local]
static ERROR: AtomicUsize = ATOMIC_USIZE_INIT;

#[repr(C)]
pub struct Dl_info {
    dli_fname: *const c_char,
    dli_fbase: *mut c_void,
    dli_sname: *const c_char,
    dli_saddr: *mut c_void,
}

#[no_mangle]
pub unsafe extern "C" fn dladdr(addr: *mut c_void, info: *mut Dl_info) -> c_int {
    (*info).dli_fname = ptr::null();
    (*info).dli_fbase = ptr::null_mut();
    (*info).dli_sname = ptr::null();
    (*info).dli_saddr = ptr::null_mut();
    0
}

#[no_mangle]
pub unsafe extern "C" fn dlopen(filename: *const c_char, flags: c_int) -> *mut c_void {
    let filename_opt = if filename.is_null() {
        None
    } else {
        Some(str::from_utf8_unchecked(
            CStr::from_ptr(filename).to_bytes(),
        ))
    };

    eprintln!("dlopen({:?}, {:#>04x})", filename_opt, flags);

    if let Some(filename) = filename_opt {
        ERROR.store(ERROR_NOT_SUPPORTED.as_ptr() as usize, Ordering::SeqCst);
        ptr::null_mut()
    } else {
        1 as *mut c_void
    }
}

#[no_mangle]
pub unsafe extern "C" fn dlsym(handle: *mut c_void, symbol: *const c_char) -> *mut c_void {
    let symbol_opt = if symbol.is_null() {
        None
    } else {
        Some(str::from_utf8_unchecked(CStr::from_ptr(symbol).to_bytes()))
    };

    eprintln!("dlsym({:p}, {:?})", handle, symbol_opt);

    ptr::null_mut()
}

#[no_mangle]
pub extern "C" fn dlclose(handle: *mut c_void) -> c_int {
    0
}

#[no_mangle]
pub extern "C" fn dlerror() -> *mut c_char {
    ERROR.swap(0, Ordering::SeqCst) as *mut c_char
}