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/*
* 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"
#if defined(WEBRTC_WIN)
#include "webrtc/base/win32.h"
#endif
#if defined(WEBRTC_POSIX)
#include <pthread.h>
#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 CriticalSection {
public:
CriticalSection() {
InitializeCriticalSection(&crit_);
// Windows docs say 0 is not a valid thread id
TRACK_OWNER(thread_ = 0);
}
~CriticalSection() {
DeleteCriticalSection(&crit_);
}
void Enter() {
EnterCriticalSection(&crit_);
TRACK_OWNER(thread_ = GetCurrentThreadId());
}
bool TryEnter() {
if (TryEnterCriticalSection(&crit_) != FALSE) {
TRACK_OWNER(thread_ = GetCurrentThreadId());
return true;
}
return false;
}
void Leave() {
TRACK_OWNER(thread_ = 0);
LeaveCriticalSection(&crit_);
}
#if CS_TRACK_OWNER
bool CurrentThreadIsOwner() const { return thread_ == GetCurrentThreadId(); }
#endif // CS_TRACK_OWNER
private:
CRITICAL_SECTION crit_;
TRACK_OWNER(DWORD thread_); // The section's owning thread id
};
#endif // WEBRTC_WIN
#if defined(WEBRTC_POSIX)
class CriticalSection {
public:
CriticalSection() {
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() {
pthread_mutex_lock(&mutex_);
TRACK_OWNER(thread_ = pthread_self());
}
bool TryEnter() {
if (pthread_mutex_trylock(&mutex_) == 0) {
TRACK_OWNER(thread_ = pthread_self());
return true;
}
return false;
}
void Leave() {
TRACK_OWNER(thread_ = 0);
pthread_mutex_unlock(&mutex_);
}
#if CS_TRACK_OWNER
bool CurrentThreadIsOwner() const { return pthread_equal(thread_, pthread_self()); }
#endif // CS_TRACK_OWNER
private:
pthread_mutex_t mutex_;
TRACK_OWNER(pthread_t thread_);
};
#endif // WEBRTC_POSIX
// CritScope, for serializing execution through a scope.
class CritScope {
public:
explicit CritScope(CriticalSection *pcrit) {
pcrit_ = pcrit;
pcrit_->Enter();
}
~CritScope() {
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(int* i) {
return ::InterlockedIncrement(reinterpret_cast<LONG*>(i));
}
static int Decrement(int* i) {
return ::InterlockedDecrement(reinterpret_cast<LONG*>(i));
}
#else
static int Increment(int* i) {
return __sync_add_and_fetch(i, 1);
}
static int Decrement(int* i) {
return __sync_sub_and_fetch(i, 1);
}
#endif
};
} // namespace rtc
#endif // WEBRTC_BASE_CRITICALSECTION_H__
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