5cccf3cd25
This commit is an implementation of [RFC 1184][rfc] which tweaks the behavior of the `#![no_std]` attribute and adds a new `#![no_core]` attribute. The `#![no_std]` attribute now injects `extern crate core` at the top of the crate as well as the libcore prelude into all modules (in the same manner as the standard library's prelude). The `#![no_core]` attribute disables both std and core injection. [rfc]: https://github.com/rust-lang/rfcs/pull/1184
109 lines
3.9 KiB
Rust
109 lines
3.9 KiB
Rust
// Copyright 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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#[cfg(stage0)]
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use prelude::v1::*;
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use cell::UnsafeCell;
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use libc;
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use ptr;
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use sys::mutex::{self, Mutex};
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use sys::time;
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use sys::sync as ffi;
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use time::Duration;
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pub struct Condvar { inner: UnsafeCell<ffi::pthread_cond_t> }
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unsafe impl Send for Condvar {}
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unsafe impl Sync for Condvar {}
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impl Condvar {
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pub const fn new() -> Condvar {
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// Might be moved and address is changing it is better to avoid
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// initialization of potentially opaque OS data before it landed
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Condvar { inner: UnsafeCell::new(ffi::PTHREAD_COND_INITIALIZER) }
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}
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#[inline]
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pub unsafe fn notify_one(&self) {
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let r = ffi::pthread_cond_signal(self.inner.get());
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debug_assert_eq!(r, 0);
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}
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#[inline]
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pub unsafe fn notify_all(&self) {
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let r = ffi::pthread_cond_broadcast(self.inner.get());
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debug_assert_eq!(r, 0);
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}
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#[inline]
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pub unsafe fn wait(&self, mutex: &Mutex) {
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let r = ffi::pthread_cond_wait(self.inner.get(), mutex::raw(mutex));
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debug_assert_eq!(r, 0);
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}
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// This implementation is modeled after libcxx's condition_variable
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// https://github.com/llvm-mirror/libcxx/blob/release_35/src/condition_variable.cpp#L46
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// https://github.com/llvm-mirror/libcxx/blob/release_35/include/__mutex_base#L367
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pub unsafe fn wait_timeout(&self, mutex: &Mutex, dur: Duration) -> bool {
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// First, figure out what time it currently is, in both system and
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// stable time. pthread_cond_timedwait uses system time, but we want to
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// report timeout based on stable time.
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let mut sys_now = libc::timeval { tv_sec: 0, tv_usec: 0 };
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let stable_now = time::SteadyTime::now();
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let r = ffi::gettimeofday(&mut sys_now, ptr::null_mut());
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debug_assert_eq!(r, 0);
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let nsec = dur.extra_nanos() as libc::c_long +
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(sys_now.tv_usec * 1000) as libc::c_long;
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let extra = (nsec / 1_000_000_000) as libc::time_t;
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let nsec = nsec % 1_000_000_000;
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let seconds = dur.secs() as libc::time_t;
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let timeout = sys_now.tv_sec.checked_add(extra).and_then(|s| {
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s.checked_add(seconds)
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}).map(|s| {
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libc::timespec { tv_sec: s, tv_nsec: nsec }
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}).unwrap_or_else(|| {
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libc::timespec {
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tv_sec: <libc::time_t>::max_value(),
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tv_nsec: 1_000_000_000 - 1,
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}
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});
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// And wait!
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let r = ffi::pthread_cond_timedwait(self.inner.get(), mutex::raw(mutex),
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&timeout);
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debug_assert!(r == libc::ETIMEDOUT || r == 0);
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// ETIMEDOUT is not a totally reliable method of determining timeout due
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// to clock shifts, so do the check ourselves
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&time::SteadyTime::now() - &stable_now < dur
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}
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#[inline]
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#[cfg(not(target_os = "dragonfly"))]
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pub unsafe fn destroy(&self) {
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let r = ffi::pthread_cond_destroy(self.inner.get());
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debug_assert_eq!(r, 0);
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}
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#[inline]
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#[cfg(target_os = "dragonfly")]
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pub unsafe fn destroy(&self) {
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let r = ffi::pthread_cond_destroy(self.inner.get());
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// On DragonFly pthread_cond_destroy() returns EINVAL if called on
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// a condvar that was just initialized with
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// ffi::PTHREAD_COND_INITIALIZER. Once it is used or
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// pthread_cond_init() is called, this behaviour no longer occurs.
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debug_assert!(r == 0 || r == libc::EINVAL);
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}
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}
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