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comm.rs
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comm.rs
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// Copyright 2012-2013 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.
/*!
Higher level communication abstractions.
*/
#[allow(missing_doc)];
use std::comm;
/// An extension of `pipes::stream` that allows both sending and receiving.
pub struct DuplexStream<T, U> {
priv chan: Chan<T>,
priv port: Port<U>,
}
// Allow these methods to be used without import:
impl<T:Send,U:Send> DuplexStream<T, U> {
/// Creates a bidirectional stream.
pub fn new() -> (DuplexStream<T, U>, DuplexStream<U, T>) {
let (p1, c2) = Chan::new();
let (p2, c1) = Chan::new();
(DuplexStream { chan: c1, port: p1 },
DuplexStream { chan: c2, port: p2 })
}
pub fn send(&self, x: T) {
self.chan.send(x)
}
pub fn try_send(&self, x: T) -> bool {
self.chan.try_send(x)
}
pub fn recv(&self) -> U {
self.port.recv()
}
pub fn try_recv(&self) -> comm::TryRecvResult<U> {
self.port.try_recv()
}
pub fn recv_opt(&self) -> Option<U> {
self.port.recv_opt()
}
}
/// An extension of `pipes::stream` that provides synchronous message sending.
pub struct SyncChan<T> { priv duplex_stream: DuplexStream<T, ()> }
/// An extension of `pipes::stream` that acknowledges each message received.
pub struct SyncPort<T> { priv duplex_stream: DuplexStream<(), T> }
impl<T: Send> SyncChan<T> {
pub fn send(&self, val: T) {
assert!(self.try_send(val), "SyncChan.send: receiving port closed");
}
/// Sends a message, or report if the receiver has closed the connection
/// before receiving.
pub fn try_send(&self, val: T) -> bool {
self.duplex_stream.try_send(val) && self.duplex_stream.recv_opt().is_some()
}
}
impl<T: Send> SyncPort<T> {
pub fn recv(&self) -> T {
self.recv_opt().expect("SyncPort.recv: sending channel closed")
}
pub fn recv_opt(&self) -> Option<T> {
self.duplex_stream.recv_opt().map(|val| {
self.duplex_stream.try_send(());
val
})
}
pub fn try_recv(&self) -> comm::TryRecvResult<T> {
match self.duplex_stream.try_recv() {
comm::Data(t) => { self.duplex_stream.try_send(()); comm::Data(t) }
state => state,
}
}
}
/// Creates a stream whose channel, upon sending a message, blocks until the
/// message is received.
pub fn rendezvous<T: Send>() -> (SyncPort<T>, SyncChan<T>) {
let (chan_stream, port_stream) = DuplexStream::new();
(SyncPort { duplex_stream: port_stream },
SyncChan { duplex_stream: chan_stream })
}
#[cfg(test)]
mod test {
use comm::{DuplexStream, rendezvous};
#[test]
pub fn DuplexStream1() {
let (left, right) = DuplexStream::new();
left.send(~"abc");
right.send(123);
assert!(left.recv() == 123);
assert!(right.recv() == ~"abc");
}
#[test]
pub fn basic_rendezvous_test() {
let (port, chan) = rendezvous();
do spawn {
chan.send("abc");
}
assert!(port.recv() == "abc");
}
#[test]
fn recv_a_lot() {
// Rendezvous streams should be able to handle any number of messages being sent
let (port, chan) = rendezvous();
do spawn {
10000.times(|| { chan.send(()) })
}
10000.times(|| { port.recv() })
}
#[test]
fn send_and_fail_and_try_recv() {
let (port, chan) = rendezvous();
do spawn {
chan.duplex_stream.send(()); // Can't access this field outside this module
fail!()
}
port.recv()
}
#[test]
fn try_send_and_recv_then_fail_before_ack() {
let (port, chan) = rendezvous();
do spawn {
port.duplex_stream.recv();
fail!()
}
chan.try_send(());
}
#[test]
#[should_fail]
fn send_and_recv_then_fail_before_ack() {
let (port, chan) = rendezvous();
do spawn {
port.duplex_stream.recv();
fail!()
}
chan.send(());
}
}