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// Copyright 2014 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.
#[cfg(stage0)]
use prelude::v1::*;
use cell::UnsafeCell;
use libc;
use ptr;
use sys::mutex::{self, Mutex};
use sys::time;
use sys::sync as ffi;
use time::Duration;
pub struct Condvar { inner: UnsafeCell<ffi::pthread_cond_t> }
unsafe impl Send for Condvar {}
unsafe impl Sync for Condvar {}
impl Condvar {
pub const fn new() -> Condvar {
// Might be moved and address is changing it is better to avoid
// initialization of potentially opaque OS data before it landed
Condvar { inner: UnsafeCell::new(ffi::PTHREAD_COND_INITIALIZER) }
}
#[inline]
pub unsafe fn notify_one(&self) {
let r = ffi::pthread_cond_signal(self.inner.get());
debug_assert_eq!(r, 0);
}
#[inline]
pub unsafe fn notify_all(&self) {
let r = ffi::pthread_cond_broadcast(self.inner.get());
debug_assert_eq!(r, 0);
}
#[inline]
pub unsafe fn wait(&self, mutex: &Mutex) {
let r = ffi::pthread_cond_wait(self.inner.get(), mutex::raw(mutex));
debug_assert_eq!(r, 0);
}
// This implementation is modeled after libcxx's condition_variable
// https://github.com/llvm-mirror/libcxx/blob/release_35/src/condition_variable.cpp#L46
// https://github.com/llvm-mirror/libcxx/blob/release_35/include/__mutex_base#L367
pub unsafe fn wait_timeout(&self, mutex: &Mutex, dur: Duration) -> bool {
// First, figure out what time it currently is, in both system and
// stable time. pthread_cond_timedwait uses system time, but we want to
// report timeout based on stable time.
let mut sys_now = libc::timeval { tv_sec: 0, tv_usec: 0 };
let stable_now = time::SteadyTime::now();
let r = ffi::gettimeofday(&mut sys_now, ptr::null_mut());
debug_assert_eq!(r, 0);
let nsec = dur.subsec_nanos() as libc::c_long +
(sys_now.tv_usec * 1000) as libc::c_long;
let extra = (nsec / 1_000_000_000) as libc::time_t;
let nsec = nsec % 1_000_000_000;
let seconds = dur.as_secs() as libc::time_t;
let timeout = sys_now.tv_sec.checked_add(extra).and_then(|s| {
s.checked_add(seconds)
}).map(|s| {
libc::timespec { tv_sec: s, tv_nsec: nsec }
}).unwrap_or_else(|| {
libc::timespec {
tv_sec: <libc::time_t>::max_value(),
tv_nsec: 1_000_000_000 - 1,
}
});
// And wait!
let r = ffi::pthread_cond_timedwait(self.inner.get(), mutex::raw(mutex),
&timeout);
debug_assert!(r == libc::ETIMEDOUT || r == 0);
// ETIMEDOUT is not a totally reliable method of determining timeout due
// to clock shifts, so do the check ourselves
&time::SteadyTime::now() - &stable_now < dur
}
#[inline]
#[cfg(not(target_os = "dragonfly"))]
pub unsafe fn destroy(&self) {
let r = ffi::pthread_cond_destroy(self.inner.get());
debug_assert_eq!(r, 0);
}
#[inline]
#[cfg(target_os = "dragonfly")]
pub unsafe fn destroy(&self) {
let r = ffi::pthread_cond_destroy(self.inner.get());
// On DragonFly pthread_cond_destroy() returns EINVAL if called on
// a condvar that was just initialized with
// ffi::PTHREAD_COND_INITIALIZER. Once it is used or
// pthread_cond_init() is called, this behaviour no longer occurs.
debug_assert!(r == 0 || r == libc::EINVAL);
}
}
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