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 
~CriticalSectionWrapper()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.
CriticalSectionScoped(CriticalSectionWrapper & critsec)44     explicit CriticalSectionScoped(CriticalSectionWrapper& critsec)
45         : _ptrCritSec(&critsec)
46     {
47         _ptrCritSec->Enter();
48     }
49 
CriticalSectionScoped(CriticalSectionWrapper * critsec)50     explicit CriticalSectionScoped(CriticalSectionWrapper* critsec)
51         : _ptrCritSec(critsec)
52     {
53       _ptrCritSec->Enter();
54     }
55 
~CriticalSectionScoped()56     ~CriticalSectionScoped()
57     {
58         if (_ptrCritSec)
59         {
60             Leave();
61         }
62     }
63 
64 private:
Leave()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