rust/src/libstd/io/pipe.rs
2014-01-09 09:27:10 -08:00

103 lines
2.9 KiB
Rust

// Copyright 2013 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.
//! Synchronous, in-memory pipes.
//!
//! Currently these aren't particularly useful, there only exists bindings
//! enough so that pipes can be created to child processes.
use prelude::*;
use io::{io_error, EndOfFile};
use libc;
use rt::rtio::{RtioPipe, LocalIo};
pub struct PipeStream {
priv obj: ~RtioPipe,
}
impl PipeStream {
/// Consumes a file descriptor to return a pipe stream that will have
/// synchronous, but non-blocking reads/writes. This is useful if the file
/// descriptor is acquired via means other than the standard methods.
///
/// This operation consumes ownership of the file descriptor and it will be
/// closed once the object is deallocated.
///
/// # Example
///
/// use std::libc;
/// use std::io::pipe;
///
/// let mut pipe = PipeStream::open(libc::STDERR_FILENO);
/// pipe.write(bytes!("Hello, stderr!"));
///
/// # Failure
///
/// If the pipe cannot be created, an error will be raised on the
/// `io_error` condition.
pub fn open(fd: libc::c_int) -> Option<PipeStream> {
LocalIo::maybe_raise(|io| {
io.pipe_open(fd).map(|obj| PipeStream { obj: obj })
})
}
pub fn new(inner: ~RtioPipe) -> PipeStream {
PipeStream { obj: inner }
}
}
impl Reader for PipeStream {
fn read(&mut self, buf: &mut [u8]) -> Option<uint> {
match self.obj.read(buf) {
Ok(read) => Some(read),
Err(ioerr) => {
// EOF is indicated by returning None
if ioerr.kind != EndOfFile {
io_error::cond.raise(ioerr);
}
return None;
}
}
}
}
impl Writer for PipeStream {
fn write(&mut self, buf: &[u8]) {
match self.obj.write(buf) {
Ok(_) => (),
Err(ioerr) => {
io_error::cond.raise(ioerr);
}
}
}
}
#[cfg(test)]
mod test {
iotest!(fn partial_read() {
use os;
use io::pipe::PipeStream;
let os::Pipe { input, out } = os::pipe();
let out = PipeStream::open(out);
let mut input = PipeStream::open(input);
let (p, c) = Chan::new();
do spawn {
let mut out = out;
out.write([10]);
p.recv(); // don't close the pipe until the other read has finished
}
let mut buf = [0, ..10];
input.read(buf);
c.send(());
})
}