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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_INTERFACE_CRITICAL_SECTION_WRAPPER_H_
     12 #define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_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 "common_types.h"
     18 
     19 namespace webrtc {
     20 class CriticalSectionWrapper
     21 {
     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() = 0;
     31 
     32     // Returns a grabbed lock, end of critical section.
     33     virtual void Leave() = 0;
     34 };
     35 
     36 // RAII extension of the critical section. Prevents Enter/Leave mismatches and
     37 // provides more compact critical section syntax.
     38 class CriticalSectionScoped
     39 {
     40 public:
     41     // Deprecated, don't add more users of this constructor.
     42     // TODO(mflodman) Remove this version of the constructor when no one is
     43     // using it any longer.
     44     explicit CriticalSectionScoped(CriticalSectionWrapper& critsec)
     45         : _ptrCritSec(&critsec)
     46     {
     47         _ptrCritSec->Enter();
     48     }
     49 
     50     explicit CriticalSectionScoped(CriticalSectionWrapper* critsec)
     51         : _ptrCritSec(critsec)
     52     {
     53       _ptrCritSec->Enter();
     54     }
     55 
     56     ~CriticalSectionScoped()
     57     {
     58         if (_ptrCritSec)
     59         {
     60             Leave();
     61         }
     62     }
     63 
     64 private:
     65     void Leave()
     66     {
     67         _ptrCritSec->Leave();
     68         _ptrCritSec = 0;
     69     }
     70 
     71     CriticalSectionWrapper* _ptrCritSec;
     72 };
     73 } // namespace webrtc
     74 #endif // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_CRITICAL_SECTION_WRAPPER_H_
     75