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      1 /*
      2  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #ifndef WEBRTC_SYSTEM_WRAPPERS_INCLUDE_CRITICAL_SECTION_WRAPPER_H_
     12 #define WEBRTC_SYSTEM_WRAPPERS_INCLUDE_CRITICAL_SECTION_WRAPPER_H_
     13 
     14 // If the critical section is heavily contended it may be beneficial to use
     15 // read/write locks instead.
     16 
     17 #include "webrtc/base/thread_annotations.h"
     18 #include "webrtc/common_types.h"
     19 
     20 namespace webrtc {
     21 class LOCKABLE CriticalSectionWrapper {
     22  public:
     23   // Factory method, constructor disabled
     24   static CriticalSectionWrapper* CreateCriticalSection();
     25 
     26   virtual ~CriticalSectionWrapper() {}
     27 
     28   // Tries to grab lock, beginning of a critical section. Will wait for the
     29   // lock to become available if the grab failed.
     30   virtual void Enter() EXCLUSIVE_LOCK_FUNCTION() = 0;
     31 
     32   // Returns a grabbed lock, end of critical section.
     33   virtual void Leave() UNLOCK_FUNCTION() = 0;
     34 };
     35 
     36 // RAII extension of the critical section. Prevents Enter/Leave mismatches and
     37 // provides more compact critical section syntax.
     38 class SCOPED_LOCKABLE CriticalSectionScoped {
     39  public:
     40   explicit CriticalSectionScoped(CriticalSectionWrapper* critsec)
     41       EXCLUSIVE_LOCK_FUNCTION(critsec)
     42       : ptr_crit_sec_(critsec) {
     43     ptr_crit_sec_->Enter();
     44   }
     45 
     46   ~CriticalSectionScoped() UNLOCK_FUNCTION() { ptr_crit_sec_->Leave(); }
     47 
     48  private:
     49   CriticalSectionWrapper* ptr_crit_sec_;
     50 };
     51 
     52 }  // namespace webrtc
     53 
     54 #endif  // WEBRTC_SYSTEM_WRAPPERS_INCLUDE_CRITICAL_SECTION_WRAPPER_H_
     55