d60d79a145
Effectively re-lands r5516 which was reverted because talk/-only checkouts existed. This now resides in webrtc/base/, so no talk/-only checkouts should be possible. This change also enables -Wthread-safety for talk/ and fixes a bug in talk/media/webrtc/webrtcvideoengine2.cc where a guarded variable was read without taking the corresponding lock. R=andresp@webrtc.org, mflodman@webrtc.org, pthatcher@webrtc.org BUG= Review URL: https://webrtc-codereview.appspot.com/27569004 git-svn-id: http://webrtc.googlecode.com/svn/trunk@7284 4adac7df-926f-26a2-2b94-8c16560cd09d
76 lines
2.0 KiB
C++
76 lines
2.0 KiB
C++
/*
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* Copyright 2011 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef WEBRTC_BASE_SHAREDEXCLUSIVELOCK_H_
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#define WEBRTC_BASE_SHAREDEXCLUSIVELOCK_H_
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#include "webrtc/base/constructormagic.h"
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#include "webrtc/base/criticalsection.h"
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#include "webrtc/base/event.h"
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namespace rtc {
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// This class provides shared-exclusive lock. It can be used in cases like
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// multiple-readers/single-writer model.
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class LOCKABLE SharedExclusiveLock {
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public:
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SharedExclusiveLock();
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// Locking/unlocking methods. It is encouraged to use SharedScope or
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// ExclusiveScope for protection.
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void LockExclusive() EXCLUSIVE_LOCK_FUNCTION();
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void UnlockExclusive() UNLOCK_FUNCTION();
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void LockShared();
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void UnlockShared();
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private:
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rtc::CriticalSection cs_exclusive_;
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rtc::CriticalSection cs_shared_;
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rtc::Event shared_count_is_zero_;
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int shared_count_;
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DISALLOW_COPY_AND_ASSIGN(SharedExclusiveLock);
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};
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class SCOPED_LOCKABLE SharedScope {
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public:
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explicit SharedScope(SharedExclusiveLock* lock) SHARED_LOCK_FUNCTION(lock)
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: lock_(lock) {
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lock_->LockShared();
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}
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~SharedScope() UNLOCK_FUNCTION() { lock_->UnlockShared(); }
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private:
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SharedExclusiveLock* lock_;
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DISALLOW_COPY_AND_ASSIGN(SharedScope);
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};
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class SCOPED_LOCKABLE ExclusiveScope {
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public:
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explicit ExclusiveScope(SharedExclusiveLock* lock)
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EXCLUSIVE_LOCK_FUNCTION(lock)
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: lock_(lock) {
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lock_->LockExclusive();
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}
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~ExclusiveScope() UNLOCK_FUNCTION() { lock_->UnlockExclusive(); }
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private:
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SharedExclusiveLock* lock_;
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DISALLOW_COPY_AND_ASSIGN(ExclusiveScope);
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};
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} // namespace rtc
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#endif // WEBRTC_BASE_SHAREDEXCLUSIVELOCK_H_
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