2030 lines
64 KiB
Rust
2030 lines
64 KiB
Rust
// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! Communication primitives for concurrent tasks
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//!
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//! Rust makes it very difficult to share data among tasks to prevent race
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//! conditions and to improve parallelism, but there is often a need for
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//! communication between concurrent tasks. The primitives defined in this
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//! module are the building blocks for synchronization in rust.
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//!
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//! This module provides message-based communication over channels, concretely
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//! defined among three types:
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//!
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//! * `Sender`
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//! * `SyncSender`
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//! * `Receiver`
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//!
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//! A `Sender` or `SyncSender` is used to send data to a `Receiver`. Both
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//! senders are clone-able such that many tasks can send simultaneously to one
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//! receiver. These channels are *task blocking*, not *thread blocking*. This
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//! means that if one task is blocked on a channel, other tasks can continue to
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//! make progress.
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//!
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//! Rust channels come in one of two flavors:
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//!
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//! 1. An asynchronous, infinitely buffered channel. The `channel()` function
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//! will return a `(Sender, Receiver)` tuple where all sends will be
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//! **asynchronous** (they never block). The channel conceptually has an
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//! infinite buffer.
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//!
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//! 2. A synchronous, bounded channel. The `sync_channel()` function will return
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//! a `(SyncSender, Receiver)` tuple where the storage for pending messages
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//! is a pre-allocated buffer of a fixed size. All sends will be
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//! **synchronous** by blocking until there is buffer space available. Note
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//! that a bound of 0 is allowed, causing the channel to become a
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//! "rendezvous" channel where each sender atomically hands off a message to
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//! a receiver.
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//!
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//! ## Panic Propagation
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//!
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//! In addition to being a core primitive for communicating in rust, channels
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//! are the points at which panics are propagated among tasks. Whenever the one
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//! half of channel is closed, the other half will have its next operation
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//! `panic!`. The purpose of this is to allow propagation of panics among tasks
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//! that are linked to one another via channels.
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//!
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//! There are methods on both of senders and receivers to perform their
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//! respective operations without panicking, however.
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//!
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//! # Example
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//!
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//! Simple usage:
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//!
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//! ```
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//! use std::thread::Thread;
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//!
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//! // Create a simple streaming channel
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//! let (tx, rx) = channel();
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//! Thread::spawn(move|| {
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//! tx.send(10i);
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//! }).detach();
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//! assert_eq!(rx.recv(), 10i);
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//! ```
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//!
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//! Shared usage:
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//!
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//! ```
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//! use std::thread::Thread;
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//!
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//! // Create a shared channel that can be sent along from many threads
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//! // where tx is the sending half (tx for transmission), and rx is the receiving
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//! // half (rx for receiving).
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//! let (tx, rx) = channel();
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//! for i in range(0i, 10i) {
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//! let tx = tx.clone();
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//! Thread::spawn(move|| {
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//! tx.send(i);
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//! }).detach()
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//! }
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//!
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//! for _ in range(0i, 10i) {
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//! let j = rx.recv();
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//! assert!(0 <= j && j < 10);
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//! }
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//! ```
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//!
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//! Propagating panics:
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//!
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//! ```should_fail
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//! // The call to recv() will panic!() because the channel has already hung
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//! // up (or been deallocated)
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//! let (tx, rx) = channel::<int>();
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//! drop(tx);
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//! rx.recv();
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//! ```
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//!
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//! Synchronous channels:
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//!
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//! ```
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//! use std::thread::Thread;
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//!
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//! let (tx, rx) = sync_channel::<int>(0);
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//! Thread::spawn(move|| {
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//! // This will wait for the parent task to start receiving
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//! tx.send(53);
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//! }).detach();
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//! rx.recv();
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//! ```
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//!
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//! Reading from a channel with a timeout requires to use a Timer together
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//! with the channel. You can use the select! macro to select either and
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//! handle the timeout case. This first example will break out of the loop
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//! after 10 seconds no matter what:
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//!
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//! ```no_run
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//! use std::io::timer::Timer;
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//! use std::time::Duration;
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//!
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//! let (tx, rx) = channel::<int>();
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//! let mut timer = Timer::new().unwrap();
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//! let timeout = timer.oneshot(Duration::seconds(10));
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//!
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//! loop {
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//! select! {
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//! val = rx.recv() => println!("Received {}", val),
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//! () = timeout.recv() => {
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//! println!("timed out, total time was more than 10 seconds");
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//! break;
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//! }
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//! }
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//! }
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//! ```
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//!
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//! This second example is more costly since it allocates a new timer every
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//! time a message is received, but it allows you to timeout after the channel
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//! has been inactive for 5 seconds:
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//!
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//! ```no_run
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//! use std::io::timer::Timer;
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//! use std::time::Duration;
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//!
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//! let (tx, rx) = channel::<int>();
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//! let mut timer = Timer::new().unwrap();
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//!
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//! loop {
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//! let timeout = timer.oneshot(Duration::seconds(5));
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//!
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//! select! {
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//! val = rx.recv() => println!("Received {}", val),
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//! () = timeout.recv() => {
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//! println!("timed out, no message received in 5 seconds");
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//! break;
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//! }
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//! }
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//! }
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//! ```
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// A description of how Rust's channel implementation works
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//
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// Channels are supposed to be the basic building block for all other
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// concurrent primitives that are used in Rust. As a result, the channel type
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// needs to be highly optimized, flexible, and broad enough for use everywhere.
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//
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// The choice of implementation of all channels is to be built on lock-free data
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// structures. The channels themselves are then consequently also lock-free data
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// structures. As always with lock-free code, this is a very "here be dragons"
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// territory, especially because I'm unaware of any academic papers that have
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// gone into great length about channels of these flavors.
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//
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// ## Flavors of channels
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//
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// From the perspective of a consumer of this library, there is only one flavor
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// of channel. This channel can be used as a stream and cloned to allow multiple
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// senders. Under the hood, however, there are actually three flavors of
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// channels in play.
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//
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// * Oneshots - these channels are highly optimized for the one-send use case.
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// They contain as few atomics as possible and involve one and
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// exactly one allocation.
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// * Streams - these channels are optimized for the non-shared use case. They
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// use a different concurrent queue that is more tailored for this
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// use case. The initial allocation of this flavor of channel is not
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// optimized.
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// * Shared - this is the most general form of channel that this module offers,
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// a channel with multiple senders. This type is as optimized as it
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// can be, but the previous two types mentioned are much faster for
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// their use-cases.
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//
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// ## Concurrent queues
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//
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// The basic idea of Rust's Sender/Receiver types is that send() never blocks, but
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// recv() obviously blocks. This means that under the hood there must be some
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// shared and concurrent queue holding all of the actual data.
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//
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// With two flavors of channels, two flavors of queues are also used. We have
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// chosen to use queues from a well-known author that are abbreviated as SPSC
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// and MPSC (single producer, single consumer and multiple producer, single
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// consumer). SPSC queues are used for streams while MPSC queues are used for
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// shared channels.
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//
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// ### SPSC optimizations
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//
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// The SPSC queue found online is essentially a linked list of nodes where one
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// half of the nodes are the "queue of data" and the other half of nodes are a
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// cache of unused nodes. The unused nodes are used such that an allocation is
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// not required on every push() and a free doesn't need to happen on every
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// pop().
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//
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// As found online, however, the cache of nodes is of an infinite size. This
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// means that if a channel at one point in its life had 50k items in the queue,
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// then the queue will always have the capacity for 50k items. I believed that
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// this was an unnecessary limitation of the implementation, so I have altered
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// the queue to optionally have a bound on the cache size.
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//
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// By default, streams will have an unbounded SPSC queue with a small-ish cache
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// size. The hope is that the cache is still large enough to have very fast
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// send() operations while not too large such that millions of channels can
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// coexist at once.
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//
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// ### MPSC optimizations
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//
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// Right now the MPSC queue has not been optimized. Like the SPSC queue, it uses
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// a linked list under the hood to earn its unboundedness, but I have not put
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// forth much effort into having a cache of nodes similar to the SPSC queue.
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//
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// For now, I believe that this is "ok" because shared channels are not the most
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// common type, but soon we may wish to revisit this queue choice and determine
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// another candidate for backend storage of shared channels.
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//
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// ## Overview of the Implementation
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//
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// Now that there's a little background on the concurrent queues used, it's
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// worth going into much more detail about the channels themselves. The basic
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// pseudocode for a send/recv are:
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//
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//
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// send(t) recv()
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// queue.push(t) return if queue.pop()
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// if increment() == -1 deschedule {
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// wakeup() if decrement() > 0
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// cancel_deschedule()
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// }
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// queue.pop()
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//
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// As mentioned before, there are no locks in this implementation, only atomic
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// instructions are used.
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//
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// ### The internal atomic counter
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//
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// Every channel has a shared counter with each half to keep track of the size
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// of the queue. This counter is used to abort descheduling by the receiver and
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// to know when to wake up on the sending side.
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//
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// As seen in the pseudocode, senders will increment this count and receivers
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// will decrement the count. The theory behind this is that if a sender sees a
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// -1 count, it will wake up the receiver, and if the receiver sees a 1+ count,
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// then it doesn't need to block.
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//
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// The recv() method has a beginning call to pop(), and if successful, it needs
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// to decrement the count. It is a crucial implementation detail that this
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// decrement does *not* happen to the shared counter. If this were the case,
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// then it would be possible for the counter to be very negative when there were
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// no receivers waiting, in which case the senders would have to determine when
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// it was actually appropriate to wake up a receiver.
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//
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// Instead, the "steal count" is kept track of separately (not atomically
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// because it's only used by receivers), and then the decrement() call when
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// descheduling will lump in all of the recent steals into one large decrement.
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//
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// The implication of this is that if a sender sees a -1 count, then there's
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// guaranteed to be a waiter waiting!
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//
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// ## Native Implementation
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//
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// A major goal of these channels is to work seamlessly on and off the runtime.
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// All of the previous race conditions have been worded in terms of
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// scheduler-isms (which is obviously not available without the runtime).
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//
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// For now, native usage of channels (off the runtime) will fall back onto
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// mutexes/cond vars for descheduling/atomic decisions. The no-contention path
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// is still entirely lock-free, the "deschedule" blocks above are surrounded by
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// a mutex and the "wakeup" blocks involve grabbing a mutex and signaling on a
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// condition variable.
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//
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// ## Select
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//
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// Being able to support selection over channels has greatly influenced this
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// design, and not only does selection need to work inside the runtime, but also
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// outside the runtime.
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//
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// The implementation is fairly straightforward. The goal of select() is not to
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// return some data, but only to return which channel can receive data without
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// blocking. The implementation is essentially the entire blocking procedure
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// followed by an increment as soon as its woken up. The cancellation procedure
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// involves an increment and swapping out of to_wake to acquire ownership of the
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// task to unblock.
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//
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// Sadly this current implementation requires multiple allocations, so I have
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// seen the throughput of select() be much worse than it should be. I do not
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// believe that there is anything fundamental that needs to change about these
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// channels, however, in order to support a more efficient select().
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//
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// # Conclusion
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//
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// And now that you've seen all the races that I found and attempted to fix,
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// here's the code for you to find some more!
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use core::prelude::*;
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pub use self::TryRecvError::*;
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pub use self::TrySendError::*;
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use self::Flavor::*;
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use alloc::arc::Arc;
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use core::kinds::marker;
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use core::mem;
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use core::cell::UnsafeCell;
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pub use self::select::{Select, Handle};
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use self::select::StartResult;
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use self::select::StartResult::*;
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use self::blocking::SignalToken;
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macro_rules! test {
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{ fn $name:ident() $b:block $(#[$a:meta])*} => (
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mod $name {
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#![allow(unused_imports)]
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use prelude::*;
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use rt;
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use comm::*;
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use super::*;
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use thread::Thread;
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$(#[$a])* #[test] fn f() { $b }
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}
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)
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}
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mod blocking;
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mod oneshot;
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mod select;
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mod shared;
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mod stream;
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mod sync;
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mod mpsc_queue;
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mod spsc_queue;
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/// The receiving-half of Rust's channel type. This half can only be owned by
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/// one task
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#[unstable]
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pub struct Receiver<T> {
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inner: UnsafeCell<Flavor<T>>,
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// can't share in an arc
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_marker: marker::NoSync,
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}
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/// An iterator over messages on a receiver, this iterator will block
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/// whenever `next` is called, waiting for a new message, and `None` will be
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/// returned when the corresponding channel has hung up.
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#[unstable]
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pub struct Messages<'a, T:'a> {
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rx: &'a Receiver<T>
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}
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/// The sending-half of Rust's asynchronous channel type. This half can only be
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/// owned by one task, but it can be cloned to send to other tasks.
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#[unstable]
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pub struct Sender<T> {
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inner: UnsafeCell<Flavor<T>>,
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// can't share in an arc
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_marker: marker::NoSync,
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}
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/// The sending-half of Rust's synchronous channel type. This half can only be
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/// owned by one task, but it can be cloned to send to other tasks.
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#[unstable = "this type may be renamed, but it will always exist"]
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pub struct SyncSender<T> {
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inner: Arc<UnsafeCell<sync::Packet<T>>>,
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// can't share in an arc
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_marker: marker::NoSync,
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}
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/// This enumeration is the list of the possible reasons that try_recv could not
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/// return data when called.
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#[deriving(PartialEq, Clone, Show)]
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#[experimental = "this is likely to be removed in changing try_recv()"]
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pub enum TryRecvError {
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/// This channel is currently empty, but the sender(s) have not yet
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/// disconnected, so data may yet become available.
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Empty,
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/// This channel's sending half has become disconnected, and there will
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/// never be any more data received on this channel
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Disconnected,
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}
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impl Copy for TryRecvError {}
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/// This enumeration is the list of the possible error outcomes for the
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/// `SyncSender::try_send` method.
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#[deriving(PartialEq, Clone, Show)]
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#[experimental = "this is likely to be removed in changing try_send()"]
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pub enum TrySendError<T> {
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/// The data could not be sent on the channel because it would require that
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/// the callee block to send the data.
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///
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/// If this is a buffered channel, then the buffer is full at this time. If
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/// this is not a buffered channel, then there is no receiver available to
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/// acquire the data.
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Full(T),
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/// This channel's receiving half has disconnected, so the data could not be
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/// sent. The data is returned back to the callee in this case.
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RecvDisconnected(T),
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}
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enum Flavor<T> {
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Oneshot(Arc<UnsafeCell<oneshot::Packet<T>>>),
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Stream(Arc<UnsafeCell<stream::Packet<T>>>),
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Shared(Arc<UnsafeCell<shared::Packet<T>>>),
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Sync(Arc<UnsafeCell<sync::Packet<T>>>),
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}
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#[doc(hidden)]
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trait UnsafeFlavor<T> {
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fn inner_unsafe<'a>(&'a self) -> &'a UnsafeCell<Flavor<T>>;
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unsafe fn inner_mut<'a>(&'a self) -> &'a mut Flavor<T> {
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&mut *self.inner_unsafe().get()
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}
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unsafe fn inner<'a>(&'a self) -> &'a Flavor<T> {
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&*self.inner_unsafe().get()
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}
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}
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impl<T> UnsafeFlavor<T> for Sender<T> {
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fn inner_unsafe<'a>(&'a self) -> &'a UnsafeCell<Flavor<T>> {
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&self.inner
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}
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}
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impl<T> UnsafeFlavor<T> for Receiver<T> {
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fn inner_unsafe<'a>(&'a self) -> &'a UnsafeCell<Flavor<T>> {
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&self.inner
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}
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}
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/// Creates a new asynchronous channel, returning the sender/receiver halves.
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///
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/// All data sent on the sender will become available on the receiver, and no
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/// send will block the calling task (this channel has an "infinite buffer").
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///
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/// # Example
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///
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/// ```
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/// use std::thread::Thread;
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///
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/// // tx is is the sending half (tx for transmission), and rx is the receiving
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/// // half (rx for receiving).
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/// let (tx, rx) = channel();
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///
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/// // Spawn off an expensive computation
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/// Thread::spawn(move|| {
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/// # fn expensive_computation() {}
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/// tx.send(expensive_computation());
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/// }).detach();
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///
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/// // Do some useful work for awhile
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///
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/// // Let's see what that answer was
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/// println!("{}", rx.recv());
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/// ```
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#[unstable]
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pub fn channel<T: Send>() -> (Sender<T>, Receiver<T>) {
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let a = Arc::new(UnsafeCell::new(oneshot::Packet::new()));
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(Sender::new(Oneshot(a.clone())), Receiver::new(Oneshot(a)))
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}
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/// Creates a new synchronous, bounded channel.
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///
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/// Like asynchronous channels, the `Receiver` will block until a message
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/// becomes available. These channels differ greatly in the semantics of the
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/// sender from asynchronous channels, however.
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///
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/// This channel has an internal buffer on which messages will be queued. When
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|
/// the internal buffer becomes full, future sends will *block* waiting for the
|
|
/// buffer to open up. Note that a buffer size of 0 is valid, in which case this
|
|
/// becomes "rendezvous channel" where each send will not return until a recv
|
|
/// is paired with it.
|
|
///
|
|
/// As with asynchronous channels, all senders will panic in `send` if the
|
|
/// `Receiver` has been destroyed.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```
|
|
/// use std::thread::Thread;
|
|
///
|
|
/// let (tx, rx) = sync_channel(1);
|
|
///
|
|
/// // this returns immediately
|
|
/// tx.send(1i);
|
|
///
|
|
/// Thread::spawn(move|| {
|
|
/// // this will block until the previous message has been received
|
|
/// tx.send(2i);
|
|
/// }).detach();
|
|
///
|
|
/// assert_eq!(rx.recv(), 1i);
|
|
/// assert_eq!(rx.recv(), 2i);
|
|
/// ```
|
|
#[unstable = "this function may be renamed to more accurately reflect the type \
|
|
of channel that is is creating"]
|
|
pub fn sync_channel<T: Send>(bound: uint) -> (SyncSender<T>, Receiver<T>) {
|
|
let a = Arc::new(UnsafeCell::new(sync::Packet::new(bound)));
|
|
(SyncSender::new(a.clone()), Receiver::new(Sync(a)))
|
|
}
|
|
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
// Sender
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
impl<T: Send> Sender<T> {
|
|
fn new(inner: Flavor<T>) -> Sender<T> {
|
|
Sender {
|
|
inner: UnsafeCell::new(inner),
|
|
_marker: marker::NoSync,
|
|
}
|
|
}
|
|
|
|
/// Sends a value along this channel to be received by the corresponding
|
|
/// receiver.
|
|
///
|
|
/// Rust channels are infinitely buffered so this method will never block.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// This function will panic if the other end of the channel has hung up.
|
|
/// This means that if the corresponding receiver has fallen out of scope,
|
|
/// this function will trigger a panic message saying that a message is
|
|
/// being sent on a closed channel.
|
|
///
|
|
/// Note that if this function does *not* panic, it does not mean that the
|
|
/// data will be successfully received. All sends are placed into a queue,
|
|
/// so it is possible for a send to succeed (the other end is alive), but
|
|
/// then the other end could immediately disconnect.
|
|
///
|
|
/// The purpose of this functionality is to propagate panicks among tasks.
|
|
/// If a panic is not desired, then consider using the `send_opt` method
|
|
#[experimental = "this function is being considered candidate for removal \
|
|
to adhere to the general guidelines of rust"]
|
|
pub fn send(&self, t: T) {
|
|
if self.send_opt(t).is_err() {
|
|
panic!("sending on a closed channel");
|
|
}
|
|
}
|
|
|
|
/// Attempts to send a value on this channel, returning it back if it could
|
|
/// not be sent.
|
|
///
|
|
/// A successful send occurs when it is determined that the other end of
|
|
/// the channel has not hung up already. An unsuccessful send would be one
|
|
/// where the corresponding receiver has already been deallocated. Note
|
|
/// that a return value of `Err` means that the data will never be
|
|
/// received, but a return value of `Ok` does *not* mean that the data
|
|
/// will be received. It is possible for the corresponding receiver to
|
|
/// hang up immediately after this function returns `Ok`.
|
|
///
|
|
/// Like `send`, this method will never block.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// This method will never panic, it will return the message back to the
|
|
/// caller if the other end is disconnected
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```
|
|
/// let (tx, rx) = channel();
|
|
///
|
|
/// // This send is always successful
|
|
/// assert_eq!(tx.send_opt(1i), Ok(()));
|
|
///
|
|
/// // This send will fail because the receiver is gone
|
|
/// drop(rx);
|
|
/// assert_eq!(tx.send_opt(1i), Err(1));
|
|
/// ```
|
|
#[unstable = "this function may be renamed to send() in the future"]
|
|
pub fn send_opt(&self, t: T) -> Result<(), T> {
|
|
let (new_inner, ret) = match *unsafe { self.inner() } {
|
|
Oneshot(ref p) => {
|
|
unsafe {
|
|
let p = p.get();
|
|
if !(*p).sent() {
|
|
return (*p).send(t);
|
|
} else {
|
|
let a = Arc::new(UnsafeCell::new(stream::Packet::new()));
|
|
match (*p).upgrade(Receiver::new(Stream(a.clone()))) {
|
|
oneshot::UpSuccess => {
|
|
let ret = (*a.get()).send(t);
|
|
(a, ret)
|
|
}
|
|
oneshot::UpDisconnected => (a, Err(t)),
|
|
oneshot::UpWoke(token) => {
|
|
// This send cannot panic because the thread is
|
|
// asleep (we're looking at it), so the receiver
|
|
// can't go away.
|
|
(*a.get()).send(t).ok().unwrap();
|
|
token.signal();
|
|
(a, Ok(()))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
Stream(ref p) => return unsafe { (*p.get()).send(t) },
|
|
Shared(ref p) => return unsafe { (*p.get()).send(t) },
|
|
Sync(..) => unreachable!(),
|
|
};
|
|
|
|
unsafe {
|
|
let tmp = Sender::new(Stream(new_inner));
|
|
mem::swap(self.inner_mut(), tmp.inner_mut());
|
|
}
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
#[unstable]
|
|
impl<T: Send> Clone for Sender<T> {
|
|
fn clone(&self) -> Sender<T> {
|
|
let (packet, sleeper, guard) = match *unsafe { self.inner() } {
|
|
Oneshot(ref p) => {
|
|
let a = Arc::new(UnsafeCell::new(shared::Packet::new()));
|
|
unsafe {
|
|
let guard = (*a.get()).postinit_lock();
|
|
match (*p.get()).upgrade(Receiver::new(Shared(a.clone()))) {
|
|
oneshot::UpSuccess |
|
|
oneshot::UpDisconnected => (a, None, guard),
|
|
oneshot::UpWoke(task) => (a, Some(task), guard)
|
|
}
|
|
}
|
|
}
|
|
Stream(ref p) => {
|
|
let a = Arc::new(UnsafeCell::new(shared::Packet::new()));
|
|
unsafe {
|
|
let guard = (*a.get()).postinit_lock();
|
|
match (*p.get()).upgrade(Receiver::new(Shared(a.clone()))) {
|
|
stream::UpSuccess |
|
|
stream::UpDisconnected => (a, None, guard),
|
|
stream::UpWoke(task) => (a, Some(task), guard),
|
|
}
|
|
}
|
|
}
|
|
Shared(ref p) => {
|
|
unsafe { (*p.get()).clone_chan(); }
|
|
return Sender::new(Shared(p.clone()));
|
|
}
|
|
Sync(..) => unreachable!(),
|
|
};
|
|
|
|
unsafe {
|
|
(*packet.get()).inherit_blocker(sleeper, guard);
|
|
|
|
let tmp = Sender::new(Shared(packet.clone()));
|
|
mem::swap(self.inner_mut(), tmp.inner_mut());
|
|
}
|
|
Sender::new(Shared(packet))
|
|
}
|
|
}
|
|
|
|
#[unsafe_destructor]
|
|
impl<T: Send> Drop for Sender<T> {
|
|
fn drop(&mut self) {
|
|
match *unsafe { self.inner_mut() } {
|
|
Oneshot(ref mut p) => unsafe { (*p.get()).drop_chan(); },
|
|
Stream(ref mut p) => unsafe { (*p.get()).drop_chan(); },
|
|
Shared(ref mut p) => unsafe { (*p.get()).drop_chan(); },
|
|
Sync(..) => unreachable!(),
|
|
}
|
|
}
|
|
}
|
|
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
// SyncSender
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
impl<T: Send> SyncSender<T> {
|
|
fn new(inner: Arc<UnsafeCell<sync::Packet<T>>>) -> SyncSender<T> {
|
|
SyncSender { inner: inner, _marker: marker::NoSync }
|
|
}
|
|
|
|
/// Sends a value on this synchronous channel.
|
|
///
|
|
/// This function will *block* until space in the internal buffer becomes
|
|
/// available or a receiver is available to hand off the message to.
|
|
///
|
|
/// Note that a successful send does *not* guarantee that the receiver will
|
|
/// ever see the data if there is a buffer on this channel. Messages may be
|
|
/// enqueued in the internal buffer for the receiver to receive at a later
|
|
/// time. If the buffer size is 0, however, it can be guaranteed that the
|
|
/// receiver has indeed received the data if this function returns success.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Similarly to `Sender::send`, this function will panic if the
|
|
/// corresponding `Receiver` for this channel has disconnected. This
|
|
/// behavior is used to propagate panics among tasks.
|
|
///
|
|
/// If a panic is not desired, you can achieve the same semantics with the
|
|
/// `SyncSender::send_opt` method which will not panic if the receiver
|
|
/// disconnects.
|
|
#[experimental = "this function is being considered candidate for removal \
|
|
to adhere to the general guidelines of rust"]
|
|
pub fn send(&self, t: T) {
|
|
if self.send_opt(t).is_err() {
|
|
panic!("sending on a closed channel");
|
|
}
|
|
}
|
|
|
|
/// Send a value on a channel, returning it back if the receiver
|
|
/// disconnected
|
|
///
|
|
/// This method will *block* to send the value `t` on the channel, but if
|
|
/// the value could not be sent due to the receiver disconnecting, the value
|
|
/// is returned back to the callee. This function is similar to `try_send`,
|
|
/// except that it will block if the channel is currently full.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// This function cannot panic.
|
|
#[unstable = "this function may be renamed to send() in the future"]
|
|
pub fn send_opt(&self, t: T) -> Result<(), T> {
|
|
unsafe { (*self.inner.get()).send(t) }
|
|
}
|
|
|
|
/// Attempts to send a value on this channel without blocking.
|
|
///
|
|
/// This method differs from `send_opt` by returning immediately if the
|
|
/// channel's buffer is full or no receiver is waiting to acquire some
|
|
/// data. Compared with `send_opt`, this function has two failure cases
|
|
/// instead of one (one for disconnection, one for a full buffer).
|
|
///
|
|
/// See `SyncSender::send` for notes about guarantees of whether the
|
|
/// receiver has received the data or not if this function is successful.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// This function cannot panic
|
|
#[unstable = "the return type of this function is candidate for \
|
|
modification"]
|
|
pub fn try_send(&self, t: T) -> Result<(), TrySendError<T>> {
|
|
unsafe { (*self.inner.get()).try_send(t) }
|
|
}
|
|
}
|
|
|
|
#[unstable]
|
|
impl<T: Send> Clone for SyncSender<T> {
|
|
fn clone(&self) -> SyncSender<T> {
|
|
unsafe { (*self.inner.get()).clone_chan(); }
|
|
return SyncSender::new(self.inner.clone());
|
|
}
|
|
}
|
|
|
|
#[unsafe_destructor]
|
|
impl<T: Send> Drop for SyncSender<T> {
|
|
fn drop(&mut self) {
|
|
unsafe { (*self.inner.get()).drop_chan(); }
|
|
}
|
|
}
|
|
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
// Receiver
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
impl<T: Send> Receiver<T> {
|
|
fn new(inner: Flavor<T>) -> Receiver<T> {
|
|
Receiver { inner: UnsafeCell::new(inner), _marker: marker::NoSync }
|
|
}
|
|
|
|
/// Blocks waiting for a value on this receiver
|
|
///
|
|
/// This function will block if necessary to wait for a corresponding send
|
|
/// on the channel from its paired `Sender` structure. This receiver will
|
|
/// be woken up when data is ready, and the data will be returned.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Similar to channels, this method will trigger a task panic if the
|
|
/// other end of the channel has hung up (been deallocated). The purpose of
|
|
/// this is to propagate panicks among tasks.
|
|
///
|
|
/// If a panic is not desired, then there are two options:
|
|
///
|
|
/// * If blocking is still desired, the `recv_opt` method will return `None`
|
|
/// when the other end hangs up
|
|
///
|
|
/// * If blocking is not desired, then the `try_recv` method will attempt to
|
|
/// peek at a value on this receiver.
|
|
#[experimental = "this function is being considered candidate for removal \
|
|
to adhere to the general guidelines of rust"]
|
|
pub fn recv(&self) -> T {
|
|
match self.recv_opt() {
|
|
Ok(t) => t,
|
|
Err(()) => panic!("receiving on a closed channel"),
|
|
}
|
|
}
|
|
|
|
/// Attempts to return a pending value on this receiver without blocking
|
|
///
|
|
/// This method will never block the caller in order to wait for data to
|
|
/// become available. Instead, this will always return immediately with a
|
|
/// possible option of pending data on the channel.
|
|
///
|
|
/// This is useful for a flavor of "optimistic check" before deciding to
|
|
/// block on a receiver.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// This function cannot panic.
|
|
#[unstable = "the return type of this function may be altered"]
|
|
pub fn try_recv(&self) -> Result<T, TryRecvError> {
|
|
loop {
|
|
let new_port = match *unsafe { self.inner() } {
|
|
Oneshot(ref p) => {
|
|
match unsafe { (*p.get()).try_recv() } {
|
|
Ok(t) => return Ok(t),
|
|
Err(oneshot::Empty) => return Err(Empty),
|
|
Err(oneshot::Disconnected) => return Err(Disconnected),
|
|
Err(oneshot::Upgraded(rx)) => rx,
|
|
}
|
|
}
|
|
Stream(ref p) => {
|
|
match unsafe { (*p.get()).try_recv() } {
|
|
Ok(t) => return Ok(t),
|
|
Err(stream::Empty) => return Err(Empty),
|
|
Err(stream::Disconnected) => return Err(Disconnected),
|
|
Err(stream::Upgraded(rx)) => rx,
|
|
}
|
|
}
|
|
Shared(ref p) => {
|
|
match unsafe { (*p.get()).try_recv() } {
|
|
Ok(t) => return Ok(t),
|
|
Err(shared::Empty) => return Err(Empty),
|
|
Err(shared::Disconnected) => return Err(Disconnected),
|
|
}
|
|
}
|
|
Sync(ref p) => {
|
|
match unsafe { (*p.get()).try_recv() } {
|
|
Ok(t) => return Ok(t),
|
|
Err(sync::Empty) => return Err(Empty),
|
|
Err(sync::Disconnected) => return Err(Disconnected),
|
|
}
|
|
}
|
|
};
|
|
unsafe {
|
|
mem::swap(self.inner_mut(),
|
|
new_port.inner_mut());
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Attempt to wait for a value on this receiver, but does not panic if the
|
|
/// corresponding channel has hung up.
|
|
///
|
|
/// This implementation of iterators for ports will always block if there is
|
|
/// not data available on the receiver, but it will not panic in the case
|
|
/// that the channel has been deallocated.
|
|
///
|
|
/// In other words, this function has the same semantics as the `recv`
|
|
/// method except for the panic aspect.
|
|
///
|
|
/// If the channel has hung up, then `Err` is returned. Otherwise `Ok` of
|
|
/// the value found on the receiver is returned.
|
|
#[unstable = "this function may be renamed to recv()"]
|
|
pub fn recv_opt(&self) -> Result<T, ()> {
|
|
loop {
|
|
let new_port = match *unsafe { self.inner() } {
|
|
Oneshot(ref p) => {
|
|
match unsafe { (*p.get()).recv() } {
|
|
Ok(t) => return Ok(t),
|
|
Err(oneshot::Empty) => return unreachable!(),
|
|
Err(oneshot::Disconnected) => return Err(()),
|
|
Err(oneshot::Upgraded(rx)) => rx,
|
|
}
|
|
}
|
|
Stream(ref p) => {
|
|
match unsafe { (*p.get()).recv() } {
|
|
Ok(t) => return Ok(t),
|
|
Err(stream::Empty) => return unreachable!(),
|
|
Err(stream::Disconnected) => return Err(()),
|
|
Err(stream::Upgraded(rx)) => rx,
|
|
}
|
|
}
|
|
Shared(ref p) => {
|
|
match unsafe { (*p.get()).recv() } {
|
|
Ok(t) => return Ok(t),
|
|
Err(shared::Empty) => return unreachable!(),
|
|
Err(shared::Disconnected) => return Err(()),
|
|
}
|
|
}
|
|
Sync(ref p) => return unsafe { (*p.get()).recv() }
|
|
};
|
|
unsafe {
|
|
mem::swap(self.inner_mut(), new_port.inner_mut());
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Returns an iterator that will block waiting for messages, but never
|
|
/// `panic!`. It will return `None` when the channel has hung up.
|
|
#[unstable]
|
|
pub fn iter<'a>(&'a self) -> Messages<'a, T> {
|
|
Messages { rx: self }
|
|
}
|
|
}
|
|
|
|
impl<T: Send> select::Packet for Receiver<T> {
|
|
fn can_recv(&self) -> bool {
|
|
loop {
|
|
let new_port = match *unsafe { self.inner() } {
|
|
Oneshot(ref p) => {
|
|
match unsafe { (*p.get()).can_recv() } {
|
|
Ok(ret) => return ret,
|
|
Err(upgrade) => upgrade,
|
|
}
|
|
}
|
|
Stream(ref p) => {
|
|
match unsafe { (*p.get()).can_recv() } {
|
|
Ok(ret) => return ret,
|
|
Err(upgrade) => upgrade,
|
|
}
|
|
}
|
|
Shared(ref p) => {
|
|
return unsafe { (*p.get()).can_recv() };
|
|
}
|
|
Sync(ref p) => {
|
|
return unsafe { (*p.get()).can_recv() };
|
|
}
|
|
};
|
|
unsafe {
|
|
mem::swap(self.inner_mut(),
|
|
new_port.inner_mut());
|
|
}
|
|
}
|
|
}
|
|
|
|
fn start_selection(&self, mut token: SignalToken) -> StartResult {
|
|
loop {
|
|
let (t, new_port) = match *unsafe { self.inner() } {
|
|
Oneshot(ref p) => {
|
|
match unsafe { (*p.get()).start_selection(token) } {
|
|
oneshot::SelSuccess => return Installed,
|
|
oneshot::SelCanceled => return Abort,
|
|
oneshot::SelUpgraded(t, rx) => (t, rx),
|
|
}
|
|
}
|
|
Stream(ref p) => {
|
|
match unsafe { (*p.get()).start_selection(token) } {
|
|
stream::SelSuccess => return Installed,
|
|
stream::SelCanceled => return Abort,
|
|
stream::SelUpgraded(t, rx) => (t, rx),
|
|
}
|
|
}
|
|
Shared(ref p) => {
|
|
return unsafe { (*p.get()).start_selection(token) };
|
|
}
|
|
Sync(ref p) => {
|
|
return unsafe { (*p.get()).start_selection(token) };
|
|
}
|
|
};
|
|
token = t;
|
|
unsafe {
|
|
mem::swap(self.inner_mut(), new_port.inner_mut());
|
|
}
|
|
}
|
|
}
|
|
|
|
fn abort_selection(&self) -> bool {
|
|
let mut was_upgrade = false;
|
|
loop {
|
|
let result = match *unsafe { self.inner() } {
|
|
Oneshot(ref p) => unsafe { (*p.get()).abort_selection() },
|
|
Stream(ref p) => unsafe {
|
|
(*p.get()).abort_selection(was_upgrade)
|
|
},
|
|
Shared(ref p) => return unsafe {
|
|
(*p.get()).abort_selection(was_upgrade)
|
|
},
|
|
Sync(ref p) => return unsafe {
|
|
(*p.get()).abort_selection()
|
|
},
|
|
};
|
|
let new_port = match result { Ok(b) => return b, Err(p) => p };
|
|
was_upgrade = true;
|
|
unsafe {
|
|
mem::swap(self.inner_mut(),
|
|
new_port.inner_mut());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#[unstable]
|
|
impl<'a, T: Send> Iterator<T> for Messages<'a, T> {
|
|
fn next(&mut self) -> Option<T> { self.rx.recv_opt().ok() }
|
|
}
|
|
|
|
#[unsafe_destructor]
|
|
impl<T: Send> Drop for Receiver<T> {
|
|
fn drop(&mut self) {
|
|
match *unsafe { self.inner_mut() } {
|
|
Oneshot(ref mut p) => unsafe { (*p.get()).drop_port(); },
|
|
Stream(ref mut p) => unsafe { (*p.get()).drop_port(); },
|
|
Shared(ref mut p) => unsafe { (*p.get()).drop_port(); },
|
|
Sync(ref mut p) => unsafe { (*p.get()).drop_port(); },
|
|
}
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod test {
|
|
use prelude::*;
|
|
|
|
use os;
|
|
use super::*;
|
|
|
|
pub fn stress_factor() -> uint {
|
|
match os::getenv("RUST_TEST_STRESS") {
|
|
Some(val) => from_str::<uint>(val.as_slice()).unwrap(),
|
|
None => 1,
|
|
}
|
|
}
|
|
|
|
test! { fn smoke() {
|
|
let (tx, rx) = channel::<int>();
|
|
tx.send(1);
|
|
assert_eq!(rx.recv(), 1);
|
|
} }
|
|
|
|
test! { fn drop_full() {
|
|
let (tx, _rx) = channel();
|
|
tx.send(box 1i);
|
|
} }
|
|
|
|
test! { fn drop_full_shared() {
|
|
let (tx, _rx) = channel();
|
|
drop(tx.clone());
|
|
drop(tx.clone());
|
|
tx.send(box 1i);
|
|
} }
|
|
|
|
test! { fn smoke_shared() {
|
|
let (tx, rx) = channel::<int>();
|
|
tx.send(1);
|
|
assert_eq!(rx.recv(), 1);
|
|
let tx = tx.clone();
|
|
tx.send(1);
|
|
assert_eq!(rx.recv(), 1);
|
|
} }
|
|
|
|
test! { fn smoke_threads() {
|
|
let (tx, rx) = channel::<int>();
|
|
spawn(move|| {
|
|
tx.send(1);
|
|
});
|
|
assert_eq!(rx.recv(), 1);
|
|
} }
|
|
|
|
test! { fn smoke_port_gone() {
|
|
let (tx, rx) = channel::<int>();
|
|
drop(rx);
|
|
tx.send(1);
|
|
} #[should_fail] }
|
|
|
|
test! { fn smoke_shared_port_gone() {
|
|
let (tx, rx) = channel::<int>();
|
|
drop(rx);
|
|
tx.send(1);
|
|
} #[should_fail] }
|
|
|
|
test! { fn smoke_shared_port_gone2() {
|
|
let (tx, rx) = channel::<int>();
|
|
drop(rx);
|
|
let tx2 = tx.clone();
|
|
drop(tx);
|
|
tx2.send(1);
|
|
} #[should_fail] }
|
|
|
|
test! { fn port_gone_concurrent() {
|
|
let (tx, rx) = channel::<int>();
|
|
spawn(move|| {
|
|
rx.recv();
|
|
});
|
|
loop { tx.send(1) }
|
|
} #[should_fail] }
|
|
|
|
test! { fn port_gone_concurrent_shared() {
|
|
let (tx, rx) = channel::<int>();
|
|
let tx2 = tx.clone();
|
|
spawn(move|| {
|
|
rx.recv();
|
|
});
|
|
loop {
|
|
tx.send(1);
|
|
tx2.send(1);
|
|
}
|
|
} #[should_fail] }
|
|
|
|
test! { fn smoke_chan_gone() {
|
|
let (tx, rx) = channel::<int>();
|
|
drop(tx);
|
|
rx.recv();
|
|
} #[should_fail] }
|
|
|
|
test! { fn smoke_chan_gone_shared() {
|
|
let (tx, rx) = channel::<()>();
|
|
let tx2 = tx.clone();
|
|
drop(tx);
|
|
drop(tx2);
|
|
rx.recv();
|
|
} #[should_fail] }
|
|
|
|
test! { fn chan_gone_concurrent() {
|
|
let (tx, rx) = channel::<int>();
|
|
spawn(move|| {
|
|
tx.send(1);
|
|
tx.send(1);
|
|
});
|
|
loop { rx.recv(); }
|
|
} #[should_fail] }
|
|
|
|
test! { fn stress() {
|
|
let (tx, rx) = channel::<int>();
|
|
spawn(move|| {
|
|
for _ in range(0u, 10000) { tx.send(1i); }
|
|
});
|
|
for _ in range(0u, 10000) {
|
|
assert_eq!(rx.recv(), 1);
|
|
}
|
|
} }
|
|
|
|
test! { fn stress_shared() {
|
|
static AMT: uint = 10000;
|
|
static NTHREADS: uint = 8;
|
|
let (tx, rx) = channel::<int>();
|
|
let (dtx, drx) = channel::<()>();
|
|
|
|
spawn(move|| {
|
|
for _ in range(0, AMT * NTHREADS) {
|
|
assert_eq!(rx.recv(), 1);
|
|
}
|
|
match rx.try_recv() {
|
|
Ok(..) => panic!(),
|
|
_ => {}
|
|
}
|
|
dtx.send(());
|
|
});
|
|
|
|
for _ in range(0, NTHREADS) {
|
|
let tx = tx.clone();
|
|
spawn(move|| {
|
|
for _ in range(0, AMT) { tx.send(1); }
|
|
});
|
|
}
|
|
drop(tx);
|
|
drx.recv();
|
|
} }
|
|
|
|
#[test]
|
|
fn send_from_outside_runtime() {
|
|
let (tx1, rx1) = channel::<()>();
|
|
let (tx2, rx2) = channel::<int>();
|
|
let (tx3, rx3) = channel::<()>();
|
|
let tx4 = tx3.clone();
|
|
spawn(move|| {
|
|
tx1.send(());
|
|
for _ in range(0i, 40) {
|
|
assert_eq!(rx2.recv(), 1);
|
|
}
|
|
tx3.send(());
|
|
});
|
|
rx1.recv();
|
|
spawn(move|| {
|
|
for _ in range(0i, 40) {
|
|
tx2.send(1);
|
|
}
|
|
tx4.send(());
|
|
});
|
|
rx3.recv();
|
|
rx3.recv();
|
|
}
|
|
|
|
#[test]
|
|
fn recv_from_outside_runtime() {
|
|
let (tx, rx) = channel::<int>();
|
|
let (dtx, drx) = channel();
|
|
spawn(move|| {
|
|
for _ in range(0i, 40) {
|
|
assert_eq!(rx.recv(), 1);
|
|
}
|
|
dtx.send(());
|
|
});
|
|
for _ in range(0u, 40) {
|
|
tx.send(1);
|
|
}
|
|
drx.recv();
|
|
}
|
|
|
|
#[test]
|
|
fn no_runtime() {
|
|
let (tx1, rx1) = channel::<int>();
|
|
let (tx2, rx2) = channel::<int>();
|
|
let (tx3, rx3) = channel::<()>();
|
|
let tx4 = tx3.clone();
|
|
spawn(move|| {
|
|
assert_eq!(rx1.recv(), 1);
|
|
tx2.send(2);
|
|
tx4.send(());
|
|
});
|
|
spawn(move|| {
|
|
tx1.send(1);
|
|
assert_eq!(rx2.recv(), 2);
|
|
tx3.send(());
|
|
});
|
|
rx3.recv();
|
|
rx3.recv();
|
|
}
|
|
|
|
test! { fn oneshot_single_thread_close_port_first() {
|
|
// Simple test of closing without sending
|
|
let (_tx, rx) = channel::<int>();
|
|
drop(rx);
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_close_chan_first() {
|
|
// Simple test of closing without sending
|
|
let (tx, _rx) = channel::<int>();
|
|
drop(tx);
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_send_port_close() {
|
|
// Testing that the sender cleans up the payload if receiver is closed
|
|
let (tx, rx) = channel::<Box<int>>();
|
|
drop(rx);
|
|
tx.send(box 0);
|
|
} #[should_fail] }
|
|
|
|
test! { fn oneshot_single_thread_recv_chan_close() {
|
|
// Receiving on a closed chan will panic
|
|
let res = Thread::spawn(move|| {
|
|
let (tx, rx) = channel::<int>();
|
|
drop(tx);
|
|
rx.recv();
|
|
}).join();
|
|
// What is our res?
|
|
assert!(res.is_err());
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_send_then_recv() {
|
|
let (tx, rx) = channel::<Box<int>>();
|
|
tx.send(box 10);
|
|
assert!(rx.recv() == box 10);
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_try_send_open() {
|
|
let (tx, rx) = channel::<int>();
|
|
assert!(tx.send_opt(10).is_ok());
|
|
assert!(rx.recv() == 10);
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_try_send_closed() {
|
|
let (tx, rx) = channel::<int>();
|
|
drop(rx);
|
|
assert!(tx.send_opt(10).is_err());
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_try_recv_open() {
|
|
let (tx, rx) = channel::<int>();
|
|
tx.send(10);
|
|
assert!(rx.recv_opt() == Ok(10));
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_try_recv_closed() {
|
|
let (tx, rx) = channel::<int>();
|
|
drop(tx);
|
|
assert!(rx.recv_opt() == Err(()));
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_peek_data() {
|
|
let (tx, rx) = channel::<int>();
|
|
assert_eq!(rx.try_recv(), Err(Empty));
|
|
tx.send(10);
|
|
assert_eq!(rx.try_recv(), Ok(10));
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_peek_close() {
|
|
let (tx, rx) = channel::<int>();
|
|
drop(tx);
|
|
assert_eq!(rx.try_recv(), Err(Disconnected));
|
|
assert_eq!(rx.try_recv(), Err(Disconnected));
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_peek_open() {
|
|
let (_tx, rx) = channel::<int>();
|
|
assert_eq!(rx.try_recv(), Err(Empty));
|
|
} }
|
|
|
|
test! { fn oneshot_multi_task_recv_then_send() {
|
|
let (tx, rx) = channel::<Box<int>>();
|
|
spawn(move|| {
|
|
assert!(rx.recv() == box 10);
|
|
});
|
|
|
|
tx.send(box 10);
|
|
} }
|
|
|
|
test! { fn oneshot_multi_task_recv_then_close() {
|
|
let (tx, rx) = channel::<Box<int>>();
|
|
spawn(move|| {
|
|
drop(tx);
|
|
});
|
|
let res = Thread::spawn(move|| {
|
|
assert!(rx.recv() == box 10);
|
|
}).join();
|
|
assert!(res.is_err());
|
|
} }
|
|
|
|
test! { fn oneshot_multi_thread_close_stress() {
|
|
for _ in range(0, stress_factor()) {
|
|
let (tx, rx) = channel::<int>();
|
|
spawn(move|| {
|
|
drop(rx);
|
|
});
|
|
drop(tx);
|
|
}
|
|
} }
|
|
|
|
test! { fn oneshot_multi_thread_send_close_stress() {
|
|
for _ in range(0, stress_factor()) {
|
|
let (tx, rx) = channel::<int>();
|
|
spawn(move|| {
|
|
drop(rx);
|
|
});
|
|
let _ = Thread::spawn(move|| {
|
|
tx.send(1);
|
|
}).join();
|
|
}
|
|
} }
|
|
|
|
test! { fn oneshot_multi_thread_recv_close_stress() {
|
|
for _ in range(0, stress_factor()) {
|
|
let (tx, rx) = channel::<int>();
|
|
spawn(move|| {
|
|
let res = Thread::spawn(move|| {
|
|
rx.recv();
|
|
}).join();
|
|
assert!(res.is_err());
|
|
});
|
|
spawn(move|| {
|
|
spawn(move|| {
|
|
drop(tx);
|
|
});
|
|
});
|
|
}
|
|
} }
|
|
|
|
test! { fn oneshot_multi_thread_send_recv_stress() {
|
|
for _ in range(0, stress_factor()) {
|
|
let (tx, rx) = channel();
|
|
spawn(move|| {
|
|
tx.send(box 10i);
|
|
});
|
|
spawn(move|| {
|
|
assert!(rx.recv() == box 10i);
|
|
});
|
|
}
|
|
} }
|
|
|
|
test! { fn stream_send_recv_stress() {
|
|
for _ in range(0, stress_factor()) {
|
|
let (tx, rx) = channel();
|
|
|
|
send(tx, 0);
|
|
recv(rx, 0);
|
|
|
|
fn send(tx: Sender<Box<int>>, i: int) {
|
|
if i == 10 { return }
|
|
|
|
spawn(move|| {
|
|
tx.send(box i);
|
|
send(tx, i + 1);
|
|
});
|
|
}
|
|
|
|
fn recv(rx: Receiver<Box<int>>, i: int) {
|
|
if i == 10 { return }
|
|
|
|
spawn(move|| {
|
|
assert!(rx.recv() == box i);
|
|
recv(rx, i + 1);
|
|
});
|
|
}
|
|
}
|
|
} }
|
|
|
|
test! { fn recv_a_lot() {
|
|
// Regression test that we don't run out of stack in scheduler context
|
|
let (tx, rx) = channel();
|
|
for _ in range(0i, 10000) { tx.send(()); }
|
|
for _ in range(0i, 10000) { rx.recv(); }
|
|
} }
|
|
|
|
test! { fn shared_chan_stress() {
|
|
let (tx, rx) = channel();
|
|
let total = stress_factor() + 100;
|
|
for _ in range(0, total) {
|
|
let tx = tx.clone();
|
|
spawn(move|| {
|
|
tx.send(());
|
|
});
|
|
}
|
|
|
|
for _ in range(0, total) {
|
|
rx.recv();
|
|
}
|
|
} }
|
|
|
|
test! { fn test_nested_recv_iter() {
|
|
let (tx, rx) = channel::<int>();
|
|
let (total_tx, total_rx) = channel::<int>();
|
|
|
|
spawn(move|| {
|
|
let mut acc = 0;
|
|
for x in rx.iter() {
|
|
acc += x;
|
|
}
|
|
total_tx.send(acc);
|
|
});
|
|
|
|
tx.send(3);
|
|
tx.send(1);
|
|
tx.send(2);
|
|
drop(tx);
|
|
assert_eq!(total_rx.recv(), 6);
|
|
} }
|
|
|
|
test! { fn test_recv_iter_break() {
|
|
let (tx, rx) = channel::<int>();
|
|
let (count_tx, count_rx) = channel();
|
|
|
|
spawn(move|| {
|
|
let mut count = 0;
|
|
for x in rx.iter() {
|
|
if count >= 3 {
|
|
break;
|
|
} else {
|
|
count += x;
|
|
}
|
|
}
|
|
count_tx.send(count);
|
|
});
|
|
|
|
tx.send(2);
|
|
tx.send(2);
|
|
tx.send(2);
|
|
let _ = tx.send_opt(2);
|
|
drop(tx);
|
|
assert_eq!(count_rx.recv(), 4);
|
|
} }
|
|
|
|
test! { fn try_recv_states() {
|
|
let (tx1, rx1) = channel::<int>();
|
|
let (tx2, rx2) = channel::<()>();
|
|
let (tx3, rx3) = channel::<()>();
|
|
spawn(move|| {
|
|
rx2.recv();
|
|
tx1.send(1);
|
|
tx3.send(());
|
|
rx2.recv();
|
|
drop(tx1);
|
|
tx3.send(());
|
|
});
|
|
|
|
assert_eq!(rx1.try_recv(), Err(Empty));
|
|
tx2.send(());
|
|
rx3.recv();
|
|
assert_eq!(rx1.try_recv(), Ok(1));
|
|
assert_eq!(rx1.try_recv(), Err(Empty));
|
|
tx2.send(());
|
|
rx3.recv();
|
|
assert_eq!(rx1.try_recv(), Err(Disconnected));
|
|
} }
|
|
|
|
// This bug used to end up in a livelock inside of the Receiver destructor
|
|
// because the internal state of the Shared packet was corrupted
|
|
test! { fn destroy_upgraded_shared_port_when_sender_still_active() {
|
|
let (tx, rx) = channel();
|
|
let (tx2, rx2) = channel();
|
|
spawn(move|| {
|
|
rx.recv(); // wait on a oneshot
|
|
drop(rx); // destroy a shared
|
|
tx2.send(());
|
|
});
|
|
// make sure the other task has gone to sleep
|
|
for _ in range(0u, 5000) { Thread::yield_now(); }
|
|
|
|
// upgrade to a shared chan and send a message
|
|
let t = tx.clone();
|
|
drop(tx);
|
|
t.send(());
|
|
|
|
// wait for the child task to exit before we exit
|
|
rx2.recv();
|
|
}}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod sync_tests {
|
|
use prelude::*;
|
|
use os;
|
|
|
|
pub fn stress_factor() -> uint {
|
|
match os::getenv("RUST_TEST_STRESS") {
|
|
Some(val) => from_str::<uint>(val.as_slice()).unwrap(),
|
|
None => 1,
|
|
}
|
|
}
|
|
|
|
test! { fn smoke() {
|
|
let (tx, rx) = sync_channel::<int>(1);
|
|
tx.send(1);
|
|
assert_eq!(rx.recv(), 1);
|
|
} }
|
|
|
|
test! { fn drop_full() {
|
|
let (tx, _rx) = sync_channel(1);
|
|
tx.send(box 1i);
|
|
} }
|
|
|
|
test! { fn smoke_shared() {
|
|
let (tx, rx) = sync_channel::<int>(1);
|
|
tx.send(1);
|
|
assert_eq!(rx.recv(), 1);
|
|
let tx = tx.clone();
|
|
tx.send(1);
|
|
assert_eq!(rx.recv(), 1);
|
|
} }
|
|
|
|
test! { fn smoke_threads() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
spawn(move|| {
|
|
tx.send(1);
|
|
});
|
|
assert_eq!(rx.recv(), 1);
|
|
} }
|
|
|
|
test! { fn smoke_port_gone() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
drop(rx);
|
|
tx.send(1);
|
|
} #[should_fail] }
|
|
|
|
test! { fn smoke_shared_port_gone2() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
drop(rx);
|
|
let tx2 = tx.clone();
|
|
drop(tx);
|
|
tx2.send(1);
|
|
} #[should_fail] }
|
|
|
|
test! { fn port_gone_concurrent() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
spawn(move|| {
|
|
rx.recv();
|
|
});
|
|
loop { tx.send(1) }
|
|
} #[should_fail] }
|
|
|
|
test! { fn port_gone_concurrent_shared() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
let tx2 = tx.clone();
|
|
spawn(move|| {
|
|
rx.recv();
|
|
});
|
|
loop {
|
|
tx.send(1);
|
|
tx2.send(1);
|
|
}
|
|
} #[should_fail] }
|
|
|
|
test! { fn smoke_chan_gone() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
drop(tx);
|
|
rx.recv();
|
|
} #[should_fail] }
|
|
|
|
test! { fn smoke_chan_gone_shared() {
|
|
let (tx, rx) = sync_channel::<()>(0);
|
|
let tx2 = tx.clone();
|
|
drop(tx);
|
|
drop(tx2);
|
|
rx.recv();
|
|
} #[should_fail] }
|
|
|
|
test! { fn chan_gone_concurrent() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
spawn(move|| {
|
|
tx.send(1);
|
|
tx.send(1);
|
|
});
|
|
loop { rx.recv(); }
|
|
} #[should_fail] }
|
|
|
|
test! { fn stress() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
spawn(move|| {
|
|
for _ in range(0u, 10000) { tx.send(1); }
|
|
});
|
|
for _ in range(0u, 10000) {
|
|
assert_eq!(rx.recv(), 1);
|
|
}
|
|
} }
|
|
|
|
test! { fn stress_shared() {
|
|
static AMT: uint = 1000;
|
|
static NTHREADS: uint = 8;
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
let (dtx, drx) = sync_channel::<()>(0);
|
|
|
|
spawn(move|| {
|
|
for _ in range(0, AMT * NTHREADS) {
|
|
assert_eq!(rx.recv(), 1);
|
|
}
|
|
match rx.try_recv() {
|
|
Ok(..) => panic!(),
|
|
_ => {}
|
|
}
|
|
dtx.send(());
|
|
});
|
|
|
|
for _ in range(0, NTHREADS) {
|
|
let tx = tx.clone();
|
|
spawn(move|| {
|
|
for _ in range(0, AMT) { tx.send(1); }
|
|
});
|
|
}
|
|
drop(tx);
|
|
drx.recv();
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_close_port_first() {
|
|
// Simple test of closing without sending
|
|
let (_tx, rx) = sync_channel::<int>(0);
|
|
drop(rx);
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_close_chan_first() {
|
|
// Simple test of closing without sending
|
|
let (tx, _rx) = sync_channel::<int>(0);
|
|
drop(tx);
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_send_port_close() {
|
|
// Testing that the sender cleans up the payload if receiver is closed
|
|
let (tx, rx) = sync_channel::<Box<int>>(0);
|
|
drop(rx);
|
|
tx.send(box 0);
|
|
} #[should_fail] }
|
|
|
|
test! { fn oneshot_single_thread_recv_chan_close() {
|
|
// Receiving on a closed chan will panic
|
|
let res = Thread::spawn(move|| {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
drop(tx);
|
|
rx.recv();
|
|
}).join();
|
|
// What is our res?
|
|
assert!(res.is_err());
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_send_then_recv() {
|
|
let (tx, rx) = sync_channel::<Box<int>>(1);
|
|
tx.send(box 10);
|
|
assert!(rx.recv() == box 10);
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_try_send_open() {
|
|
let (tx, rx) = sync_channel::<int>(1);
|
|
assert_eq!(tx.try_send(10), Ok(()));
|
|
assert!(rx.recv() == 10);
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_try_send_closed() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
drop(rx);
|
|
assert_eq!(tx.try_send(10), Err(RecvDisconnected(10)));
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_try_send_closed2() {
|
|
let (tx, _rx) = sync_channel::<int>(0);
|
|
assert_eq!(tx.try_send(10), Err(Full(10)));
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_try_recv_open() {
|
|
let (tx, rx) = sync_channel::<int>(1);
|
|
tx.send(10);
|
|
assert!(rx.recv_opt() == Ok(10));
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_try_recv_closed() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
drop(tx);
|
|
assert!(rx.recv_opt() == Err(()));
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_peek_data() {
|
|
let (tx, rx) = sync_channel::<int>(1);
|
|
assert_eq!(rx.try_recv(), Err(Empty));
|
|
tx.send(10);
|
|
assert_eq!(rx.try_recv(), Ok(10));
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_peek_close() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
drop(tx);
|
|
assert_eq!(rx.try_recv(), Err(Disconnected));
|
|
assert_eq!(rx.try_recv(), Err(Disconnected));
|
|
} }
|
|
|
|
test! { fn oneshot_single_thread_peek_open() {
|
|
let (_tx, rx) = sync_channel::<int>(0);
|
|
assert_eq!(rx.try_recv(), Err(Empty));
|
|
} }
|
|
|
|
test! { fn oneshot_multi_task_recv_then_send() {
|
|
let (tx, rx) = sync_channel::<Box<int>>(0);
|
|
spawn(move|| {
|
|
assert!(rx.recv() == box 10);
|
|
});
|
|
|
|
tx.send(box 10);
|
|
} }
|
|
|
|
test! { fn oneshot_multi_task_recv_then_close() {
|
|
let (tx, rx) = sync_channel::<Box<int>>(0);
|
|
spawn(move|| {
|
|
drop(tx);
|
|
});
|
|
let res = Thread::spawn(move|| {
|
|
assert!(rx.recv() == box 10);
|
|
}).join();
|
|
assert!(res.is_err());
|
|
} }
|
|
|
|
test! { fn oneshot_multi_thread_close_stress() {
|
|
for _ in range(0, stress_factor()) {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
spawn(move|| {
|
|
drop(rx);
|
|
});
|
|
drop(tx);
|
|
}
|
|
} }
|
|
|
|
test! { fn oneshot_multi_thread_send_close_stress() {
|
|
for _ in range(0, stress_factor()) {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
spawn(move|| {
|
|
drop(rx);
|
|
});
|
|
let _ = Thread::spawn(move || {
|
|
tx.send(1);
|
|
}).join();
|
|
}
|
|
} }
|
|
|
|
test! { fn oneshot_multi_thread_recv_close_stress() {
|
|
for _ in range(0, stress_factor()) {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
spawn(move|| {
|
|
let res = Thread::spawn(move|| {
|
|
rx.recv();
|
|
}).join();
|
|
assert!(res.is_err());
|
|
});
|
|
spawn(move|| {
|
|
spawn(move|| {
|
|
drop(tx);
|
|
});
|
|
});
|
|
}
|
|
} }
|
|
|
|
test! { fn oneshot_multi_thread_send_recv_stress() {
|
|
for _ in range(0, stress_factor()) {
|
|
let (tx, rx) = sync_channel::<Box<int>>(0);
|
|
spawn(move|| {
|
|
tx.send(box 10i);
|
|
});
|
|
spawn(move|| {
|
|
assert!(rx.recv() == box 10i);
|
|
});
|
|
}
|
|
} }
|
|
|
|
test! { fn stream_send_recv_stress() {
|
|
for _ in range(0, stress_factor()) {
|
|
let (tx, rx) = sync_channel::<Box<int>>(0);
|
|
|
|
send(tx, 0);
|
|
recv(rx, 0);
|
|
|
|
fn send(tx: SyncSender<Box<int>>, i: int) {
|
|
if i == 10 { return }
|
|
|
|
spawn(move|| {
|
|
tx.send(box i);
|
|
send(tx, i + 1);
|
|
});
|
|
}
|
|
|
|
fn recv(rx: Receiver<Box<int>>, i: int) {
|
|
if i == 10 { return }
|
|
|
|
spawn(move|| {
|
|
assert!(rx.recv() == box i);
|
|
recv(rx, i + 1);
|
|
});
|
|
}
|
|
}
|
|
} }
|
|
|
|
test! { fn recv_a_lot() {
|
|
// Regression test that we don't run out of stack in scheduler context
|
|
let (tx, rx) = sync_channel(10000);
|
|
for _ in range(0u, 10000) { tx.send(()); }
|
|
for _ in range(0u, 10000) { rx.recv(); }
|
|
} }
|
|
|
|
test! { fn shared_chan_stress() {
|
|
let (tx, rx) = sync_channel(0);
|
|
let total = stress_factor() + 100;
|
|
for _ in range(0, total) {
|
|
let tx = tx.clone();
|
|
spawn(move|| {
|
|
tx.send(());
|
|
});
|
|
}
|
|
|
|
for _ in range(0, total) {
|
|
rx.recv();
|
|
}
|
|
} }
|
|
|
|
test! { fn test_nested_recv_iter() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
let (total_tx, total_rx) = sync_channel::<int>(0);
|
|
|
|
spawn(move|| {
|
|
let mut acc = 0;
|
|
for x in rx.iter() {
|
|
acc += x;
|
|
}
|
|
total_tx.send(acc);
|
|
});
|
|
|
|
tx.send(3);
|
|
tx.send(1);
|
|
tx.send(2);
|
|
drop(tx);
|
|
assert_eq!(total_rx.recv(), 6);
|
|
} }
|
|
|
|
test! { fn test_recv_iter_break() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
let (count_tx, count_rx) = sync_channel(0);
|
|
|
|
spawn(move|| {
|
|
let mut count = 0;
|
|
for x in rx.iter() {
|
|
if count >= 3 {
|
|
break;
|
|
} else {
|
|
count += x;
|
|
}
|
|
}
|
|
count_tx.send(count);
|
|
});
|
|
|
|
tx.send(2);
|
|
tx.send(2);
|
|
tx.send(2);
|
|
let _ = tx.try_send(2);
|
|
drop(tx);
|
|
assert_eq!(count_rx.recv(), 4);
|
|
} }
|
|
|
|
test! { fn try_recv_states() {
|
|
let (tx1, rx1) = sync_channel::<int>(1);
|
|
let (tx2, rx2) = sync_channel::<()>(1);
|
|
let (tx3, rx3) = sync_channel::<()>(1);
|
|
spawn(move|| {
|
|
rx2.recv();
|
|
tx1.send(1);
|
|
tx3.send(());
|
|
rx2.recv();
|
|
drop(tx1);
|
|
tx3.send(());
|
|
});
|
|
|
|
assert_eq!(rx1.try_recv(), Err(Empty));
|
|
tx2.send(());
|
|
rx3.recv();
|
|
assert_eq!(rx1.try_recv(), Ok(1));
|
|
assert_eq!(rx1.try_recv(), Err(Empty));
|
|
tx2.send(());
|
|
rx3.recv();
|
|
assert_eq!(rx1.try_recv(), Err(Disconnected));
|
|
} }
|
|
|
|
// This bug used to end up in a livelock inside of the Receiver destructor
|
|
// because the internal state of the Shared packet was corrupted
|
|
test! { fn destroy_upgraded_shared_port_when_sender_still_active() {
|
|
let (tx, rx) = sync_channel::<()>(0);
|
|
let (tx2, rx2) = sync_channel::<()>(0);
|
|
spawn(move|| {
|
|
rx.recv(); // wait on a oneshot
|
|
drop(rx); // destroy a shared
|
|
tx2.send(());
|
|
});
|
|
// make sure the other task has gone to sleep
|
|
for _ in range(0u, 5000) { Thread::yield_now(); }
|
|
|
|
// upgrade to a shared chan and send a message
|
|
let t = tx.clone();
|
|
drop(tx);
|
|
t.send(());
|
|
|
|
// wait for the child task to exit before we exit
|
|
rx2.recv();
|
|
} }
|
|
|
|
test! { fn send_opt1() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
spawn(move|| { rx.recv(); });
|
|
assert_eq!(tx.send_opt(1), Ok(()));
|
|
} }
|
|
|
|
test! { fn send_opt2() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
spawn(move|| { drop(rx); });
|
|
assert_eq!(tx.send_opt(1), Err(1));
|
|
} }
|
|
|
|
test! { fn send_opt3() {
|
|
let (tx, rx) = sync_channel::<int>(1);
|
|
assert_eq!(tx.send_opt(1), Ok(()));
|
|
spawn(move|| { drop(rx); });
|
|
assert_eq!(tx.send_opt(1), Err(1));
|
|
} }
|
|
|
|
test! { fn send_opt4() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
let tx2 = tx.clone();
|
|
let (done, donerx) = channel();
|
|
let done2 = done.clone();
|
|
spawn(move|| {
|
|
assert_eq!(tx.send_opt(1), Err(1));
|
|
done.send(());
|
|
});
|
|
spawn(move|| {
|
|
assert_eq!(tx2.send_opt(2), Err(2));
|
|
done2.send(());
|
|
});
|
|
drop(rx);
|
|
donerx.recv();
|
|
donerx.recv();
|
|
} }
|
|
|
|
test! { fn try_send1() {
|
|
let (tx, _rx) = sync_channel::<int>(0);
|
|
assert_eq!(tx.try_send(1), Err(Full(1)));
|
|
} }
|
|
|
|
test! { fn try_send2() {
|
|
let (tx, _rx) = sync_channel::<int>(1);
|
|
assert_eq!(tx.try_send(1), Ok(()));
|
|
assert_eq!(tx.try_send(1), Err(Full(1)));
|
|
} }
|
|
|
|
test! { fn try_send3() {
|
|
let (tx, rx) = sync_channel::<int>(1);
|
|
assert_eq!(tx.try_send(1), Ok(()));
|
|
drop(rx);
|
|
assert_eq!(tx.try_send(1), Err(RecvDisconnected(1)));
|
|
} }
|
|
|
|
test! { fn try_send4() {
|
|
let (tx, rx) = sync_channel::<int>(0);
|
|
spawn(move|| {
|
|
for _ in range(0u, 1000) { Thread::yield_now(); }
|
|
assert_eq!(tx.try_send(1), Ok(()));
|
|
});
|
|
assert_eq!(rx.recv(), 1);
|
|
} #[ignore(reason = "flaky on libnative")] }
|
|
|
|
test! { fn issue_15761() {
|
|
fn repro() {
|
|
let (tx1, rx1) = sync_channel::<()>(3);
|
|
let (tx2, rx2) = sync_channel::<()>(3);
|
|
|
|
spawn(move|| {
|
|
rx1.recv();
|
|
tx2.try_send(()).unwrap();
|
|
});
|
|
|
|
tx1.try_send(()).unwrap();
|
|
rx2.recv();
|
|
}
|
|
|
|
for _ in range(0u, 100) {
|
|
repro()
|
|
}
|
|
} }
|
|
}
|