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/*
* Copyright (c) 2016 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_RTC_BASE_RACE_CHECKER_H_
#define WEBRTC_RTC_BASE_RACE_CHECKER_H_
#include "webrtc/rtc_base/checks.h"
#include "webrtc/rtc_base/platform_thread.h"
#include "webrtc/rtc_base/thread_annotations.h"
namespace rtc {
namespace internal {
class RaceCheckerScope;
} // namespace internal
// Best-effort race-checking implementation. This primitive uses no
// synchronization at all to be as-fast-as-possible in the non-racy case.
class LOCKABLE RaceChecker {
public:
friend class internal::RaceCheckerScope;
RaceChecker();
private:
bool Acquire() const EXCLUSIVE_LOCK_FUNCTION();
void Release() const UNLOCK_FUNCTION();
// Volatile to prevent code being optimized away in Acquire()/Release().
mutable volatile int access_count_ = 0;
mutable volatile PlatformThreadRef accessing_thread_;
};
namespace internal {
class SCOPED_LOCKABLE RaceCheckerScope {
public:
explicit RaceCheckerScope(const RaceChecker* race_checker)
EXCLUSIVE_LOCK_FUNCTION(race_checker);
bool RaceDetected() const;
~RaceCheckerScope() UNLOCK_FUNCTION();
private:
const RaceChecker* const race_checker_;
const bool race_check_ok_;
};
class SCOPED_LOCKABLE RaceCheckerScopeDoNothing {
public:
explicit RaceCheckerScopeDoNothing(const RaceChecker* race_checker)
EXCLUSIVE_LOCK_FUNCTION(race_checker) {}
~RaceCheckerScopeDoNothing() UNLOCK_FUNCTION() {}
};
} // namespace internal
} // namespace rtc
#define RTC_CHECK_RUNS_SERIALIZED(x) \
rtc::internal::RaceCheckerScope race_checker(x); \
RTC_CHECK(!race_checker.RaceDetected())
#if RTC_DCHECK_IS_ON
#define RTC_DCHECK_RUNS_SERIALIZED(x) \
rtc::internal::RaceCheckerScope race_checker(x); \
RTC_DCHECK(!race_checker.RaceDetected())
#else
#define RTC_DCHECK_RUNS_SERIALIZED(x) \
rtc::internal::RaceCheckerScopeDoNothing race_checker(x)
#endif
#endif // WEBRTC_RTC_BASE_RACE_CHECKER_H_