150 lines
4.6 KiB
C++
150 lines
4.6 KiB
C++
// Copyright (c) 2011 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "base/synchronization/condition_variable.h"
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#include <errno.h>
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#include <stdint.h>
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#include <sys/time.h>
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#include "base/optional.h"
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#include "base/synchronization/lock.h"
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#include "base/threading/scoped_blocking_call.h"
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#include "base/threading/thread_restrictions.h"
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#include "base/time/time.h"
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#include "build/build_config.h"
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namespace base {
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ConditionVariable::ConditionVariable(Lock* user_lock)
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: user_mutex_(user_lock->lock_.native_handle())
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#if DCHECK_IS_ON()
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, user_lock_(user_lock)
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#endif
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{
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int rv = 0;
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// http://crbug.com/293736
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// NaCl doesn't support monotonic clock based absolute deadlines.
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// On older Android platform versions, it's supported through the
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// non-standard pthread_cond_timedwait_monotonic_np. Newer platform
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// versions have pthread_condattr_setclock.
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// Mac can use relative time deadlines.
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#if !defined(OS_MACOSX) && !defined(OS_NACL) && \
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!(defined(OS_ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC))
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pthread_condattr_t attrs;
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rv = pthread_condattr_init(&attrs);
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DCHECK_EQ(0, rv);
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pthread_condattr_setclock(&attrs, CLOCK_MONOTONIC);
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rv = pthread_cond_init(&condition_, &attrs);
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pthread_condattr_destroy(&attrs);
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#else
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rv = pthread_cond_init(&condition_, NULL);
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#endif
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DCHECK_EQ(0, rv);
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}
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ConditionVariable::~ConditionVariable() {
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#if defined(OS_MACOSX)
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// This hack is necessary to avoid a fatal pthreads subsystem bug in the
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// Darwin kernel. http://crbug.com/517681.
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{
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base::Lock lock;
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base::AutoLock l(lock);
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struct timespec ts;
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ts.tv_sec = 0;
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ts.tv_nsec = 1;
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pthread_cond_timedwait_relative_np(&condition_, lock.lock_.native_handle(),
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&ts);
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}
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#endif
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int rv = pthread_cond_destroy(&condition_);
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DCHECK_EQ(0, rv);
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}
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void ConditionVariable::Wait() {
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Optional<internal::ScopedBlockingCallWithBaseSyncPrimitives>
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scoped_blocking_call;
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if (waiting_is_blocking_)
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scoped_blocking_call.emplace(FROM_HERE, BlockingType::MAY_BLOCK);
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#if DCHECK_IS_ON()
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user_lock_->CheckHeldAndUnmark();
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#endif
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int rv = pthread_cond_wait(&condition_, user_mutex_);
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DCHECK_EQ(0, rv);
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#if DCHECK_IS_ON()
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user_lock_->CheckUnheldAndMark();
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#endif
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}
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void ConditionVariable::TimedWait(const TimeDelta& max_time) {
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Optional<internal::ScopedBlockingCallWithBaseSyncPrimitives>
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scoped_blocking_call;
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if (waiting_is_blocking_)
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scoped_blocking_call.emplace(FROM_HERE, BlockingType::MAY_BLOCK);
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int64_t usecs = max_time.InMicroseconds();
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struct timespec relative_time;
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relative_time.tv_sec = usecs / Time::kMicrosecondsPerSecond;
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relative_time.tv_nsec =
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(usecs % Time::kMicrosecondsPerSecond) * Time::kNanosecondsPerMicrosecond;
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#if DCHECK_IS_ON()
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user_lock_->CheckHeldAndUnmark();
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#endif
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#if defined(OS_MACOSX)
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int rv = pthread_cond_timedwait_relative_np(
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&condition_, user_mutex_, &relative_time);
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#else
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// The timeout argument to pthread_cond_timedwait is in absolute time.
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struct timespec absolute_time;
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#if defined(OS_NACL)
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// See comment in constructor for why this is different in NaCl.
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struct timeval now;
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gettimeofday(&now, NULL);
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absolute_time.tv_sec = now.tv_sec;
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absolute_time.tv_nsec = now.tv_usec * Time::kNanosecondsPerMicrosecond;
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#else
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struct timespec now;
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clock_gettime(CLOCK_MONOTONIC, &now);
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absolute_time.tv_sec = now.tv_sec;
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absolute_time.tv_nsec = now.tv_nsec;
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#endif
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absolute_time.tv_sec += relative_time.tv_sec;
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absolute_time.tv_nsec += relative_time.tv_nsec;
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absolute_time.tv_sec += absolute_time.tv_nsec / Time::kNanosecondsPerSecond;
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absolute_time.tv_nsec %= Time::kNanosecondsPerSecond;
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DCHECK_GE(absolute_time.tv_sec, now.tv_sec); // Overflow paranoia
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#if defined(OS_ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC)
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int rv = pthread_cond_timedwait_monotonic_np(
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&condition_, user_mutex_, &absolute_time);
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#else
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int rv = pthread_cond_timedwait(&condition_, user_mutex_, &absolute_time);
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#endif // OS_ANDROID && HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC
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#endif // OS_MACOSX
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// On failure, we only expect the CV to timeout. Any other error value means
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// that we've unexpectedly woken up.
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DCHECK(rv == 0 || rv == ETIMEDOUT);
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#if DCHECK_IS_ON()
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user_lock_->CheckUnheldAndMark();
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#endif
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}
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void ConditionVariable::Broadcast() {
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int rv = pthread_cond_broadcast(&condition_);
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DCHECK_EQ(0, rv);
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}
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void ConditionVariable::Signal() {
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int rv = pthread_cond_signal(&condition_);
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DCHECK_EQ(0, rv);
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}
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} // namespace base
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