| /* |
| * Copyright 2004 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. |
| */ |
| |
| #ifndef WEBRTC_BASE_CRITICALSECTION_H__ |
| #define WEBRTC_BASE_CRITICALSECTION_H__ |
| |
| #include "webrtc/base/constructormagic.h" |
| #include "webrtc/base/thread_annotations.h" |
| |
| #if defined(WEBRTC_WIN) |
| #include "webrtc/base/win32.h" |
| #endif |
| |
| #if defined(WEBRTC_POSIX) |
| #include <pthread.h> |
| #endif |
| |
| #if defined(WEBRTC_MAC) |
| // TODO(tommi): This is a temporary test to see if critical section objects are |
| // somehow causing pointer co-member variables that follow a critical section |
| // variable, are somehow throwing off the alignment and causing crash on |
| // the Mac 10.9 debug bot: |
| // http://build.chromium.org/p/chromium.mac/builders/Mac10.9%20Tests%20(dbg) |
| #define _MUTEX_ALIGNMENT __attribute__((__aligned__(8))) |
| #define _STATIC_ASSERT_CRITICAL_SECTION_SIZE() \ |
| static_assert(sizeof(CriticalSection) % 8 == 0, \ |
| "Bad size of CriticalSection") |
| |
| #else |
| #define _MUTEX_ALIGNMENT |
| #define _STATIC_ASSERT_CRITICAL_SECTION_SIZE() |
| #endif |
| |
| #ifdef _DEBUG |
| #define CS_TRACK_OWNER 1 |
| #endif // _DEBUG |
| |
| #if CS_TRACK_OWNER |
| #define TRACK_OWNER(x) x |
| #else // !CS_TRACK_OWNER |
| #define TRACK_OWNER(x) |
| #endif // !CS_TRACK_OWNER |
| |
| namespace rtc { |
| |
| #if defined(WEBRTC_WIN) |
| class LOCKABLE CriticalSection { |
| public: |
| CriticalSection() { InitializeCriticalSection(&crit_); } |
| ~CriticalSection() { DeleteCriticalSection(&crit_); } |
| void Enter() EXCLUSIVE_LOCK_FUNCTION() { |
| EnterCriticalSection(&crit_); |
| } |
| bool TryEnter() EXCLUSIVE_TRYLOCK_FUNCTION(true) { |
| return TryEnterCriticalSection(&crit_) != FALSE; |
| } |
| void Leave() UNLOCK_FUNCTION() { |
| LeaveCriticalSection(&crit_); |
| } |
| |
| // Used for debugging. |
| bool CurrentThreadIsOwner() const { |
| return crit_.OwningThread == reinterpret_cast<HANDLE>(GetCurrentThreadId()); |
| } |
| |
| private: |
| CRITICAL_SECTION crit_; |
| }; |
| #endif // WEBRTC_WIN |
| |
| #if defined(WEBRTC_POSIX) |
| class LOCKABLE CriticalSection { |
| public: |
| CriticalSection() { |
| _STATIC_ASSERT_CRITICAL_SECTION_SIZE(); |
| 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); |
| TRACK_OWNER(thread_ = 0); |
| } |
| ~CriticalSection() { |
| pthread_mutex_destroy(&mutex_); |
| } |
| void Enter() EXCLUSIVE_LOCK_FUNCTION() { |
| pthread_mutex_lock(&mutex_); |
| TRACK_OWNER(thread_ = pthread_self()); |
| } |
| bool TryEnter() EXCLUSIVE_TRYLOCK_FUNCTION(true) { |
| if (pthread_mutex_trylock(&mutex_) == 0) { |
| TRACK_OWNER(thread_ = pthread_self()); |
| return true; |
| } |
| return false; |
| } |
| void Leave() UNLOCK_FUNCTION() { |
| TRACK_OWNER(thread_ = 0); |
| pthread_mutex_unlock(&mutex_); |
| } |
| |
| // Used for debugging. |
| bool CurrentThreadIsOwner() const { |
| #if CS_TRACK_OWNER |
| return pthread_equal(thread_, pthread_self()); |
| #else |
| return true; |
| #endif // CS_TRACK_OWNER |
| } |
| |
| private: |
| _MUTEX_ALIGNMENT pthread_mutex_t mutex_; |
| TRACK_OWNER(pthread_t thread_); |
| }; |
| #endif // WEBRTC_POSIX |
| |
| // CritScope, for serializing execution through a scope. |
| class SCOPED_LOCKABLE CritScope { |
| public: |
| explicit CritScope(CriticalSection *pcrit) EXCLUSIVE_LOCK_FUNCTION(pcrit) { |
| pcrit_ = pcrit; |
| pcrit_->Enter(); |
| } |
| ~CritScope() UNLOCK_FUNCTION() { |
| pcrit_->Leave(); |
| } |
| private: |
| CriticalSection *pcrit_; |
| DISALLOW_COPY_AND_ASSIGN(CritScope); |
| }; |
| |
| // Tries to lock a critical section on construction via |
| // CriticalSection::TryEnter, and unlocks on destruction if the |
| // lock was taken. Never blocks. |
| // |
| // IMPORTANT: Unlike CritScope, the lock may not be owned by this thread in |
| // subsequent code. Users *must* check locked() to determine if the |
| // lock was taken. If you're not calling locked(), you're doing it wrong! |
| class TryCritScope { |
| public: |
| explicit TryCritScope(CriticalSection *pcrit) { |
| pcrit_ = pcrit; |
| locked_ = pcrit_->TryEnter(); |
| } |
| ~TryCritScope() { |
| if (locked_) { |
| pcrit_->Leave(); |
| } |
| } |
| bool locked() const { |
| return locked_; |
| } |
| private: |
| CriticalSection *pcrit_; |
| bool locked_; |
| DISALLOW_COPY_AND_ASSIGN(TryCritScope); |
| }; |
| |
| // TODO: Move this to atomicops.h, which can't be done easily because of |
| // complex compile rules. |
| class AtomicOps { |
| public: |
| #if defined(WEBRTC_WIN) |
| // Assumes sizeof(int) == sizeof(LONG), which it is on Win32 and Win64. |
| static int Increment(volatile int* i) { |
| return ::InterlockedIncrement(reinterpret_cast<volatile LONG*>(i)); |
| } |
| static int Decrement(volatile int* i) { |
| return ::InterlockedDecrement(reinterpret_cast<volatile LONG*>(i)); |
| } |
| static int Load(volatile const int* i) { |
| return *i; |
| } |
| #else |
| static int Increment(volatile int* i) { |
| return __sync_add_and_fetch(i, 1); |
| } |
| static int Decrement(volatile int* i) { |
| return __sync_sub_and_fetch(i, 1); |
| } |
| static int Load(volatile const int* i) { |
| // Adding 0 is a no-op, so const_cast is fine. |
| return __sync_add_and_fetch(const_cast<volatile int*>(i), 0); |
| } |
| #endif |
| }; |
| |
| } // namespace rtc |
| |
| #endif // WEBRTC_BASE_CRITICALSECTION_H__ |