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/*
* Copyright 2015 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "webrtc/base/criticalsection.h"
#include "webrtc/base/checks.h"
namespace rtc {
CriticalSection::CriticalSection() {
#if defined(WEBRTC_WIN)
InitializeCriticalSection(&crit_);
#else
pthread_mutexattr_t mutex_attribute;
pthread_mutexattr_init(&mutex_attribute);
pthread_mutexattr_settype(&mutex_attribute, PTHREAD_MUTEX_RECURSIVE);
pthread_mutex_init(&mutex_, &mutex_attribute);
pthread_mutexattr_destroy(&mutex_attribute);
CS_DEBUG_CODE(thread_ = 0);
CS_DEBUG_CODE(recursion_count_ = 0);
#endif
}
CriticalSection::~CriticalSection() {
#if defined(WEBRTC_WIN)
DeleteCriticalSection(&crit_);
#else
pthread_mutex_destroy(&mutex_);
#endif
}
void CriticalSection::Enter() EXCLUSIVE_LOCK_FUNCTION() {
#if defined(WEBRTC_WIN)
EnterCriticalSection(&crit_);
#else
pthread_mutex_lock(&mutex_);
#if CS_DEBUG_CHECKS
if (!recursion_count_) {
RTC_DCHECK(!thread_);
thread_ = pthread_self();
} else {
RTC_DCHECK(CurrentThreadIsOwner());
}
++recursion_count_;
#endif
#endif
}
bool CriticalSection::TryEnter() EXCLUSIVE_TRYLOCK_FUNCTION(true) {
#if defined(WEBRTC_WIN)
return TryEnterCriticalSection(&crit_) != FALSE;
#else
if (pthread_mutex_trylock(&mutex_) != 0)
return false;
#if CS_DEBUG_CHECKS
if (!recursion_count_) {
RTC_DCHECK(!thread_);
thread_ = pthread_self();
} else {
RTC_DCHECK(CurrentThreadIsOwner());
}
++recursion_count_;
#endif
return true;
#endif
}
void CriticalSection::Leave() UNLOCK_FUNCTION() {
RTC_DCHECK(CurrentThreadIsOwner());
#if defined(WEBRTC_WIN)
LeaveCriticalSection(&crit_);
#else
#if CS_DEBUG_CHECKS
--recursion_count_;
RTC_DCHECK(recursion_count_ >= 0);
if (!recursion_count_)
thread_ = 0;
#endif
pthread_mutex_unlock(&mutex_);
#endif
}
bool CriticalSection::CurrentThreadIsOwner() const {
#if defined(WEBRTC_WIN)
// OwningThread has type HANDLE but actually contains the Thread ID:
// http://stackoverflow.com/questions/12675301/why-is-the-owningthread-member-of-critical-section-of-type-handle-when-it-is-de
// Converting through size_t avoids the VS 2015 warning C4312: conversion from
// 'type1' to 'type2' of greater size
return crit_.OwningThread ==
reinterpret_cast<HANDLE>(static_cast<size_t>(GetCurrentThreadId()));
#else
#if CS_DEBUG_CHECKS
return pthread_equal(thread_, pthread_self());
#else
return true;
#endif // CS_DEBUG_CHECKS
#endif
}
bool CriticalSection::IsLocked() const {
#if defined(WEBRTC_WIN)
return crit_.LockCount != -1;
#else
#if CS_DEBUG_CHECKS
return thread_ != 0;
#else
return true;
#endif
#endif
}
CritScope::CritScope(CriticalSection* cs) : cs_(cs) { cs_->Enter(); }
CritScope::~CritScope() { cs_->Leave(); }
TryCritScope::TryCritScope(CriticalSection* cs)
: cs_(cs), locked_(cs->TryEnter()) {
CS_DEBUG_CODE(lock_was_called_ = false);
}
TryCritScope::~TryCritScope() {
CS_DEBUG_CODE(RTC_DCHECK(lock_was_called_));
if (locked_)
cs_->Leave();
}
bool TryCritScope::locked() const {
CS_DEBUG_CODE(lock_was_called_ = true);
return locked_;
}
void GlobalLockPod::Lock() {
#if !defined(WEBRTC_WIN)
const struct timespec ts_null = {0, 0};
#endif
while (AtomicOps::CompareAndSwap(&lock_acquired, 0, 1)) {
#if defined(WEBRTC_WIN)
::Sleep(0);
#else
nanosleep(&ts_null, nullptr);
#endif
}
}
void GlobalLockPod::Unlock() {
int old_value = AtomicOps::CompareAndSwap(&lock_acquired, 1, 0);
RTC_DCHECK_EQ(1, old_value) << "Unlock called without calling Lock first";
}
GlobalLock::GlobalLock() {
lock_acquired = 0;
}
GlobalLockScope::GlobalLockScope(GlobalLockPod* lock)
: lock_(lock) {
lock_->Lock();
}
GlobalLockScope::~GlobalLockScope() {
lock_->Unlock();
}
} // namespace rtc
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