mirror of
https://github.com/danog/libtgvoip.git
synced 2024-12-12 00:59:48 +01:00
55 lines
2.1 KiB
C++
55 lines
2.1 KiB
C++
|
/*
|
||
|
|
* 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.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "rtc_base/race_checker.h"
|
||
|
|
|
||
|
|
namespace rtc {
|
||
|
|
|
||
|
|
RaceChecker::RaceChecker() {}
|
||
|
|
|
||
|
|
// Note that the implementation here is in itself racy, but we pretend it does
|
||
|
|
// not matter because we want this useful in release builds without having to
|
||
|
|
// pay the cost of using atomics. A race hitting the race checker is likely to
|
||
|
|
// cause access_count_ to diverge from zero and therefore cause the ThreadRef
|
||
|
|
// comparison to fail, signaling a race, although it may not be in the exact
|
||
|
|
// spot where a race *first* appeared in the code we're trying to protect. There
|
||
|
|
// is also a chance that an actual race is missed, however the probability of
|
||
|
|
// that has been considered small enough to be an acceptable trade off.
|
||
|
|
bool RaceChecker::Acquire() const {
|
||
|
|
const PlatformThreadRef current_thread = CurrentThreadRef();
|
||
|
|
// Set new accessing thread if this is a new use.
|
||
|
|
if (access_count_++ == 0)
|
||
|
|
accessing_thread_ = current_thread;
|
||
|
|
// If this is being used concurrently this check will fail for the second
|
||
|
|
// thread entering since it won't set the thread. Recursive use of checked
|
||
|
|
// methods are OK since the accessing thread remains the same.
|
||
|
|
const PlatformThreadRef accessing_thread = accessing_thread_;
|
||
|
|
return IsThreadRefEqual(accessing_thread, current_thread);
|
||
|
|
}
|
||
|
|
|
||
|
|
void RaceChecker::Release() const {
|
||
|
|
--access_count_;
|
||
|
|
}
|
||
|
|
|
||
|
|
namespace internal {
|
||
|
|
RaceCheckerScope::RaceCheckerScope(const RaceChecker* race_checker)
|
||
|
|
: race_checker_(race_checker), race_check_ok_(race_checker->Acquire()) {}
|
||
|
|
|
||
|
|
bool RaceCheckerScope::RaceDetected() const {
|
||
|
|
return !race_check_ok_;
|
||
|
|
}
|
||
|
|
|
||
|
|
RaceCheckerScope::~RaceCheckerScope() {
|
||
|
|
race_checker_->Release();
|
||
|
|
}
|
||
|
|
|
||
|
|
} // namespace internal
|
||
|
|
} // namespace rtc
|