futures-net 0.6.0

use iovec::{unix, IoVec};
use libc;
use std::cmp;
use std::fs::File;
use std::io::{self, Read, Write};
use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};

use crate::driver::sys::event::{Evented, EventedFd, PollOpt, Ready};
use crate::driver::sys::linux::cvt;
use crate::driver::sys::{Poll, Token};

pub fn set_nonblock(fd: libc::c_int) -> io::Result<()> {
    unsafe {
        let flags = libc::fcntl(fd, libc::F_GETFL);
        cvt(libc::fcntl(fd, libc::F_SETFL, flags | libc::O_NONBLOCK)).map(|_| ())
    }
}

pub fn set_cloexec(fd: libc::c_int) -> io::Result<()> {
    unsafe {
        let flags = libc::fcntl(fd, libc::F_GETFD);
        cvt(libc::fcntl(fd, libc::F_SETFD, flags | libc::FD_CLOEXEC)).map(|_| ())
    }
}

/*
 *
 * ===== Basic IO type =====
 *
 */

/// Manages a FD
#[derive(Debug)]
pub struct Io {
    fd: File,
}

impl Io {
    /// Try to clone the FD
    pub fn try_clone(&self) -> io::Result<Io> {
        Ok(Io {
            fd: self.fd.try_clone()?,
        })
    }
}

impl FromRawFd for Io {
    unsafe fn from_raw_fd(fd: RawFd) -> Io {
        Io {
            fd: File::from_raw_fd(fd),
        }
    }
}

impl IntoRawFd for Io {
    fn into_raw_fd(self) -> RawFd {
        self.fd.into_raw_fd()
    }
}

impl AsRawFd for Io {
    fn as_raw_fd(&self) -> RawFd {
        self.fd.as_raw_fd()
    }
}

impl Evented for Io {
    fn register(
        &self,
        poll: &Poll,
        token: Token,
        interest: Ready,
        opts: PollOpt,
    ) -> io::Result<()> {
        EventedFd(&self.as_raw_fd()).register(poll, token, interest, opts)
    }

    fn reregister(
        &self,
        poll: &Poll,
        token: Token,
        interest: Ready,
        opts: PollOpt,
    ) -> io::Result<()> {
        EventedFd(&self.as_raw_fd()).reregister(poll, token, interest, opts)
    }

    fn deregister(&self, poll: &Poll) -> io::Result<()> {
        EventedFd(&self.as_raw_fd()).deregister(poll)
    }
}

impl Read for Io {
    fn read(&mut self, dst: &mut [u8]) -> io::Result<usize> {
        (&self.fd).read(dst)
    }
}

impl<'a> Read for &'a Io {
    fn read(&mut self, dst: &mut [u8]) -> io::Result<usize> {
        (&self.fd).read(dst)
    }
}

impl Write for Io {
    fn write(&mut self, src: &[u8]) -> io::Result<usize> {
        (&self.fd).write(src)
    }

    fn flush(&mut self) -> io::Result<()> {
        (&self.fd).flush()
    }
}

impl<'a> Write for &'a Io {
    fn write(&mut self, src: &[u8]) -> io::Result<usize> {
        (&self.fd).write(src)
    }

    fn flush(&mut self) -> io::Result<()> {
        (&self.fd).flush()
    }
}

pub trait VecIo {
    fn readv(&self, bufs: &mut [&mut IoVec]) -> io::Result<usize>;

    fn writev(&self, bufs: &[&IoVec]) -> io::Result<usize>;
}

impl<T: AsRawFd> VecIo for T {
    fn readv(&self, bufs: &mut [&mut IoVec]) -> io::Result<usize> {
        unsafe {
            let slice = unix::as_os_slice_mut(bufs);
            let len = cmp::min(<libc::c_int>::max_value() as usize, slice.len());
            let rc = libc::readv(self.as_raw_fd(), slice.as_ptr(), len as libc::c_int);
            if rc < 0 {
                Err(io::Error::last_os_error())
            } else {
                Ok(rc as usize)
            }
        }
    }

    fn writev(&self, bufs: &[&IoVec]) -> io::Result<usize> {
        unsafe {
            let slice = unix::as_os_slice(bufs);
            let len = cmp::min(<libc::c_int>::max_value() as usize, slice.len());
            let rc = libc::writev(self.as_raw_fd(), slice.as_ptr(), len as libc::c_int);
            if rc < 0 {
                Err(io::Error::last_os_error())
            } else {
                Ok(rc as usize)
            }
        }
    }
}