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// 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.
use prelude::*;
use comm::{Port, Chan};
use cmp;
use io;
use option::{None, Option, Some};
use super::{Reader, Writer};
use vec::{bytes, CopyableVector, MutableVector, ImmutableVector};
/// Allows reading from a port.
///
/// # Example
///
/// ```
/// let reader = PortReader::new(port);
///
/// let mut buf = ~[0u8, ..100];
/// match reader.read(buf) {
/// Some(nread) => println!("Read {} bytes", nread),
/// None => println!("At the end of the stream!")
/// }
/// ```
pub struct PortReader {
priv buf: Option<~[u8]>, // A buffer of bytes received but not consumed.
priv pos: uint, // How many of the buffered bytes have already be consumed.
priv port: Port<~[u8]>, // The port to pull data from.
priv closed: bool, // Whether the pipe this port connects to has been closed.
}
impl PortReader {
pub fn new(port: Port<~[u8]>) -> PortReader {
PortReader {
buf: None,
pos: 0,
port: port,
closed: false,
}
}
}
impl Reader for PortReader {
fn read(&mut self, buf: &mut [u8]) -> Option<uint> {
let mut num_read = 0;
loop {
match self.buf {
Some(ref prev) => {
let dst = buf.mut_slice_from(num_read);
let src = prev.slice_from(self.pos);
let count = cmp::min(dst.len(), src.len());
bytes::copy_memory(dst, src.slice_to(count));
num_read += count;
self.pos += count;
},
None => (),
};
if num_read == buf.len() || self.closed {
break;
}
self.pos = 0;
self.buf = self.port.recv_opt();
self.closed = self.buf.is_none();
}
if self.closed && num_read == 0 {
io::io_error::cond.raise(io::standard_error(io::EndOfFile));
None
} else {
Some(num_read)
}
}
fn eof(&mut self) -> bool { self.closed }
}
/// Allows writing to a chan.
///
/// # Example
///
/// ```
/// let writer = ChanWriter::new(chan);
/// writer.write("hello, world".as_bytes());
/// ```
pub struct ChanWriter {
chan: Chan<~[u8]>,
}
impl ChanWriter {
pub fn new(chan: Chan<~[u8]>) -> ChanWriter {
ChanWriter { chan: chan }
}
}
impl Writer for ChanWriter {
fn write(&mut self, buf: &[u8]) {
if !self.chan.try_send(buf.to_owned()) {
io::io_error::cond.raise(io::IoError {
kind: io::BrokenPipe,
desc: "Pipe closed",
detail: None
});
}
}
}
#[cfg(test)]
mod test {
use prelude::*;
use super::*;
use io;
use task;
#[test]
fn test_port_reader() {
let (port, chan) = Chan::new();
do task::spawn {
chan.send(~[1u8, 2u8]);
chan.send(~[]);
chan.send(~[3u8, 4u8]);
chan.send(~[5u8, 6u8]);
chan.send(~[7u8, 8u8]);
}
let mut reader = PortReader::new(port);
let mut buf = ~[0u8, ..3];
assert_eq!(false, reader.eof());
assert_eq!(Some(0), reader.read([]));
assert_eq!(false, reader.eof());
assert_eq!(Some(3), reader.read(buf));
assert_eq!(false, reader.eof());
assert_eq!(~[1,2,3], buf);
assert_eq!(Some(3), reader.read(buf));
assert_eq!(false, reader.eof());
assert_eq!(~[4,5,6], buf);
assert_eq!(Some(2), reader.read(buf));
assert_eq!(~[7,8,6], buf);
assert_eq!(true, reader.eof());
let mut err = None;
let result = io::io_error::cond.trap(|io::standard_error(k, _, _)| {
err = Some(k)
}).inside(|| {
reader.read(buf)
});
assert_eq!(Some(io::EndOfFile), err);
assert_eq!(None, result);
assert_eq!(true, reader.eof());
assert_eq!(~[7,8,6], buf);
// Ensure it continues to fail in the same way.
err = None;
let result = io::io_error::cond.trap(|io::standard_error(k, _, _)| {
err = Some(k)
}).inside(|| {
reader.read(buf)
});
assert_eq!(Some(io::EndOfFile), err);
assert_eq!(None, result);
assert_eq!(true, reader.eof());
assert_eq!(~[7,8,6], buf);
}
#[test]
fn test_chan_writer() {
let (port, chan) = Chan::new();
let mut writer = ChanWriter::new(chan);
writer.write_be_u32(42);
let wanted = ~[0u8, 0u8, 0u8, 42u8];
let got = do task::try { port.recv() }.unwrap();
assert_eq!(wanted, got);
let mut err = None;
io::io_error::cond.trap(|io::IoError { kind, .. } | {
err = Some(kind)
}).inside(|| {
writer.write_u8(1)
});
assert_eq!(Some(io::BrokenPipe), err);
}
}
|
