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// Copyright © 2017 Mozilla Foundation
//
// This program is made available under an ISC-style license. See the
// accompanying file LICENSE for details
//! Various async helpers modelled after futures-rs and tokio-io.
#[cfg(unix)]
use crate::msg::{RecvMsg, SendMsg};
use bytes::{Buf, BufMut};
#[cfg(unix)]
use futures::Async;
use futures::Poll;
#[cfg(unix)]
use iovec::IoVec;
#[cfg(unix)]
use mio::Ready;
use std::io;
use tokio_io::{AsyncRead, AsyncWrite};
pub trait AsyncRecvMsg: AsyncRead {
/// Pull some bytes from this source into the specified `Buf`, returning
/// how many bytes were read.
///
/// The `buf` provided will have bytes read into it and the internal cursor
/// will be advanced if any bytes were read. Note that this method typically
/// will not reallocate the buffer provided.
fn recv_msg_buf<B>(&mut self, buf: &mut B, cmsg: &mut B) -> Poll<(usize, i32), io::Error>
where
Self: Sized,
B: BufMut;
}
/// A trait for writable objects which operated in an async fashion.
///
/// This trait inherits from `std::io::Write` and indicates that an I/O object is
/// **nonblocking**, meaning that it will return an error instead of blocking
/// when bytes cannot currently be written, but hasn't closed. Specifically
/// this means that the `write` function for types that implement this trait
/// can have a few return values:
///
/// * `Ok(n)` means that `n` bytes of data was immediately written .
/// * `Err(e) if e.kind() == ErrorKind::WouldBlock` means that no data was
/// written from the buffer provided. The I/O object is not currently
/// writable but may become writable in the future.
/// * `Err(e)` for other errors are standard I/O errors coming from the
/// underlying object.
pub trait AsyncSendMsg: AsyncWrite {
/// Write a `Buf` into this value, returning how many bytes were written.
///
/// Note that this method will advance the `buf` provided automatically by
/// the number of bytes written.
fn send_msg_buf<B, C>(&mut self, buf: &mut B, cmsg: &C) -> Poll<usize, io::Error>
where
Self: Sized,
B: Buf,
C: Buf;
}
////////////////////////////////////////////////////////////////////////////////
#[cfg(unix)]
impl AsyncRecvMsg for super::AsyncMessageStream {
fn recv_msg_buf<B>(&mut self, buf: &mut B, cmsg: &mut B) -> Poll<(usize, i32), io::Error>
where
B: BufMut,
{
if let Async::NotReady =
<super::AsyncMessageStream>::poll_read_ready(self, Ready::readable())?
{
return Ok(Async::NotReady);
}
let r = unsafe {
// The `IoVec` type can't have a 0-length size, so we create a bunch
// of dummy versions on the stack with 1 length which we'll quickly
// overwrite.
let b1: &mut [u8] = &mut [0];
let b2: &mut [u8] = &mut [0];
let b3: &mut [u8] = &mut [0];
let b4: &mut [u8] = &mut [0];
let b5: &mut [u8] = &mut [0];
let b6: &mut [u8] = &mut [0];
let b7: &mut [u8] = &mut [0];
let b8: &mut [u8] = &mut [0];
let b9: &mut [u8] = &mut [0];
let b10: &mut [u8] = &mut [0];
let b11: &mut [u8] = &mut [0];
let b12: &mut [u8] = &mut [0];
let b13: &mut [u8] = &mut [0];
let b14: &mut [u8] = &mut [0];
let b15: &mut [u8] = &mut [0];
let b16: &mut [u8] = &mut [0];
let mut bufs: [&mut IoVec; 16] = [
b1.into(),
b2.into(),
b3.into(),
b4.into(),
b5.into(),
b6.into(),
b7.into(),
b8.into(),
b9.into(),
b10.into(),
b11.into(),
b12.into(),
b13.into(),
b14.into(),
b15.into(),
b16.into(),
];
let n = buf.bytes_vec_mut(&mut bufs);
self.recv_msg(&mut bufs[..n], cmsg.bytes_mut())
};
match r {
Ok((n, cmsg_len, flags)) => {
unsafe {
buf.advance_mut(n);
}
unsafe {
cmsg.advance_mut(cmsg_len);
}
Ok((n, flags).into())
}
Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
self.clear_read_ready(mio::Ready::readable())?;
Ok(Async::NotReady)
}
Err(e) => Err(e),
}
}
}
#[cfg(unix)]
impl AsyncSendMsg for super::AsyncMessageStream {
fn send_msg_buf<B, C>(&mut self, buf: &mut B, cmsg: &C) -> Poll<usize, io::Error>
where
B: Buf,
C: Buf,
{
if let Async::NotReady = <super::AsyncMessageStream>::poll_write_ready(self)? {
return Ok(Async::NotReady);
}
let r = {
// The `IoVec` type can't have a zero-length size, so create a dummy
// version from a 1-length slice which we'll overwrite with the
// `bytes_vec` method.
static DUMMY: &[u8] = &[0];
let nom = <&IoVec>::from(DUMMY);
let mut bufs = [
nom, nom, nom, nom, nom, nom, nom, nom, nom, nom, nom, nom, nom, nom, nom, nom,
];
let n = buf.bytes_vec(&mut bufs);
self.send_msg(&bufs[..n], cmsg.bytes())
};
match r {
Ok(n) => {
buf.advance(n);
Ok(Async::Ready(n))
}
Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
self.clear_write_ready()?;
Ok(Async::NotReady)
}
Err(e) => Err(e),
}
}
}
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