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

system_wrappers/interface/rw_lock_wrapper.h

@@ -0,0 +1,76 @@
+/*
+ *  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_RW_LOCK_WRAPPER_H_
+#define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_RW_LOCK_WRAPPER_H_
+
+// Note, Windows pre-Vista version of RW locks are not supported nativly. For
+// these OSs regular critical sections have been used to approximate RW lock
+// functionality and will therefore have worse performance.
+
+namespace webrtc {
+class RWLockWrapper
+{
+public:
+    static RWLockWrapper* CreateRWLock();
+    virtual ~RWLockWrapper();
+
+    virtual void AcquireLockExclusive() = 0;
+    virtual void ReleaseLockExclusive() = 0;
+
+    virtual void AcquireLockShared() = 0;
+    virtual void ReleaseLockShared() = 0;
+
+protected:
+    virtual int Init() = 0;
+};
+
+// RAII extensions of the RW lock. Prevents Acquire/Release missmatches and
+// provides more compact locking syntax.
+class ReadLockScoped
+{
+public:
+    ReadLockScoped(RWLockWrapper& rwLock)
+        :
+        _rwLock(rwLock)
+    {
+        _rwLock.AcquireLockShared();
+    }
+
+    ~ReadLockScoped()
+    {
+        _rwLock.ReleaseLockShared();
+    }
+
+private:
+    RWLockWrapper& _rwLock;
+};
+
+class WriteLockScoped
+{
+public:
+    WriteLockScoped(RWLockWrapper& rwLock)
+        :
+        _rwLock(rwLock)
+    {
+        _rwLock.AcquireLockExclusive();
+    }
+
+    ~WriteLockScoped()
+    {
+        _rwLock.ReleaseLockExclusive();
+    }
+
+private:
+    RWLockWrapper& _rwLock;
+};
+} // namespace webrtc
+
+#endif // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_RW_LOCK_WRAPPER_H_