// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

extern crate libc;

use num;
use prelude::*;
use io::{mod, IoResult, IoError};

pub mod fs;
pub mod os;
pub mod c;

pub type sock_t = io::file::fd_t;
pub type wrlen = libc::size_t;
pub unsafe fn close_sock(sock: sock_t) { let _ = libc::close(sock); }

pub fn last_error() -> IoError {
    let errno = os::errno() as i32;
    let mut err = decode_error(errno);
    err.detail = Some(os::error_string(errno));
    err
}

/// Convert an `errno` value into a high-level error variant and description.
pub fn decode_error(errno: i32) -> IoError {
    // FIXME: this should probably be a bit more descriptive...
    let (kind, desc) = match errno {
        libc::EOF => (io::EndOfFile, "end of file"),
        libc::ECONNREFUSED => (io::ConnectionRefused, "connection refused"),
        libc::ECONNRESET => (io::ConnectionReset, "connection reset"),
        libc::EPERM | libc::EACCES =>
            (io::PermissionDenied, "permission denied"),
        libc::EPIPE => (io::BrokenPipe, "broken pipe"),
        libc::ENOTCONN => (io::NotConnected, "not connected"),
        libc::ECONNABORTED => (io::ConnectionAborted, "connection aborted"),
        libc::EADDRNOTAVAIL => (io::ConnectionRefused, "address not available"),
        libc::EADDRINUSE => (io::ConnectionRefused, "address in use"),
        libc::ENOENT => (io::FileNotFound, "no such file or directory"),
        libc::EISDIR => (io::InvalidInput, "illegal operation on a directory"),
        libc::ENOSYS => (io::IoUnavailable, "function not implemented"),
        libc::EINVAL => (io::InvalidInput, "invalid argument"),
        libc::ENOTTY =>
            (io::MismatchedFileTypeForOperation,
             "file descriptor is not a TTY"),
        libc::ETIMEDOUT => (io::TimedOut, "operation timed out"),
        libc::ECANCELED => (io::TimedOut, "operation aborted"),

        // These two constants can have the same value on some systems,
        // but different values on others, so we can't use a match
        // clause
        x if x == libc::EAGAIN || x == libc::EWOULDBLOCK =>
            (io::ResourceUnavailable, "resource temporarily unavailable"),

        _ => (io::OtherIoError, "unknown error")
    };
    IoError { kind: kind, desc: desc, detail: None }
}

#[inline]
pub fn retry<I: PartialEq + num::One + Neg<I>> (f: || -> I) -> I {
    let minus_one = -num::one::<I>();
    loop {
        let n = f();
        if n == minus_one && os::errno() == libc::EINTR as int { }
        else { return n }
    }
}

pub fn ms_to_timeval(ms: u64) -> libc::timeval {
    libc::timeval {
        tv_sec: (ms / 1000) as libc::time_t,
        tv_usec: ((ms % 1000) * 1000) as libc::suseconds_t,
    }
}

pub fn wouldblock() -> bool {
    let err = os::errno();
    err == libc::EWOULDBLOCK as int || err == libc::EAGAIN as int
}

pub fn set_nonblocking(fd: net::sock_t, nb: bool) -> IoResult<()> {
    let set = nb as libc::c_int;
    super::mkerr_libc(retry(|| unsafe { c::ioctl(fd, c::FIONBIO, &set) }))
}