git-svn-id: http://webrtc.googlecode.com/svn/trunk@6 4adac7df-926f-26a2-2b94-8c16560cd09d

system_wrappers/interface/critical_section_wrapper.h

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+/*
+ *  Copyright (c) 2011 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.
+ */
+
+#ifndef WEBRTC_SYSTEM_WRAPPERS_INTERFACE_CRITICAL_SECTION_WRAPPER_H_
+#define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_CRITICAL_SECTION_WRAPPER_H_
+
+// If the critical section is heavily contended it may be beneficial to use
+// read/write locks instead.
+
+#include "common_types.h"
+
+namespace webrtc {
+class CriticalSectionWrapper
+{
+public:
+    // Factory method, constructor disabled
+    static CriticalSectionWrapper* CreateCriticalSection();
+
+    virtual ~CriticalSectionWrapper() {}
+
+    // Tries to grab lock, beginning of a critical section. Will wait for the
+    // lock to become available if the grab failed.
+    virtual void Enter() = 0;
+
+    // Returns a grabbed lock, end of critical section.
+    virtual void Leave() = 0;
+};
+
+// RAII extension of the critical section. Prevents Enter/Leave missmatches and
+// provides more compact critical section syntax.
+class CriticalSectionScoped
+{
+public:
+    CriticalSectionScoped(CriticalSectionWrapper& critsec)
+        :
+        _ptrCritSec(&critsec)
+    {
+        _ptrCritSec->Enter();
+    }
+
+    ~CriticalSectionScoped()
+    {
+        if (_ptrCritSec)
+        {
+            Leave();
+        }
+    }
+
+private:
+    void Leave()
+    {
+        _ptrCritSec->Leave();
+        _ptrCritSec = 0;
+    }
+
+    CriticalSectionWrapper* _ptrCritSec;
+};
+} // namespace webrtc
+#endif // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_CRITICAL_SECTION_WRAPPER_H_