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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/condition_variable.h"
#include <errno.h>
#include <stdint.h>
#include <sys/time.h>
#include "base/lock.h"
#include "base/logging.h"
#include "base/time.h"
ConditionVariable::ConditionVariable(Lock* user_lock)
: user_mutex_(user_lock->lock_.native_handle()) {
int rv = 0;
// http://crbug.com/293736
// On older Android platform versions, monotonic clock based absolute
// deadlines are supported through the non-standard
// pthread_cond_timedwait_monotonic_np. Newer platform versions have
// pthread_condattr_setclock.
// Mac can use relative time deadlines.
#if !defined(XP_DARWIN) && \
!(defined(ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC))
pthread_condattr_t attrs;
rv = pthread_condattr_init(&attrs);
DCHECK_EQ(0, rv);
pthread_condattr_setclock(&attrs, CLOCK_MONOTONIC);
rv = pthread_cond_init(&condition_, &attrs);
pthread_condattr_destroy(&attrs);
#else
rv = pthread_cond_init(&condition_, NULL);
#endif
DCHECK_EQ(0, rv);
}
ConditionVariable::~ConditionVariable() {
#if defined(XP_DARWIN)
// This hack is necessary to avoid a fatal pthreads subsystem bug in the
// Darwin kernel. http://crbug.com/517681.
{
Lock lock;
AutoLock l(lock);
struct timespec ts;
ts.tv_sec = 0;
ts.tv_nsec = 1;
pthread_cond_timedwait_relative_np(&condition_, lock.lock_.native_handle(),
&ts);
}
#endif
int rv = pthread_cond_destroy(&condition_);
DCHECK_EQ(0, rv);
}
void ConditionVariable::Wait() {
int rv = pthread_cond_wait(&condition_, user_mutex_);
DCHECK_EQ(0, rv);
}
void ConditionVariable::TimedWait(const base::TimeDelta& max_time) {
int64_t usecs = max_time.InMicroseconds();
struct timespec relative_time;
relative_time.tv_sec = usecs / base::Time::kMicrosecondsPerSecond;
relative_time.tv_nsec = (usecs % base::Time::kMicrosecondsPerSecond) *
base::Time::kNanosecondsPerMicrosecond;
#if defined(XP_DARWIN)
int rv = pthread_cond_timedwait_relative_np(&condition_, user_mutex_,
&relative_time);
#else
// The timeout argument to pthread_cond_timedwait is in absolute time.
struct timespec absolute_time;
struct timespec now;
clock_gettime(CLOCK_MONOTONIC, &now);
absolute_time.tv_sec = now.tv_sec;
absolute_time.tv_nsec = now.tv_nsec;
absolute_time.tv_sec += relative_time.tv_sec;
absolute_time.tv_nsec += relative_time.tv_nsec;
absolute_time.tv_sec +=
absolute_time.tv_nsec / base::Time::kNanosecondsPerSecond;
absolute_time.tv_nsec %= base::Time::kNanosecondsPerSecond;
DCHECK_GE(absolute_time.tv_sec, now.tv_sec); // Overflow paranoia
# if defined(ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC)
int rv = pthread_cond_timedwait_monotonic_np(&condition_, user_mutex_,
&absolute_time);
# else
int rv = pthread_cond_timedwait(&condition_, user_mutex_, &absolute_time);
# endif // ANDROID && HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC
#endif // XP_DARWIN
// On failure, we only expect the CV to timeout. Any other error value means
// that we've unexpectedly woken up.
DCHECK(rv == 0 || rv == ETIMEDOUT);
}
void ConditionVariable::Broadcast() {
int rv = pthread_cond_broadcast(&condition_);
DCHECK_EQ(0, rv);
}
void ConditionVariable::Signal() {
int rv = pthread_cond_signal(&condition_);
DCHECK_EQ(0, rv);
}
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