Initial work

external/android-emugl/shared/emugl/common/mutex.h

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+// Copyright (C) 2014 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef EMUGL_MUTEX_H
+#define EMUGL_MUTEX_H
+
+#ifdef _WIN32
+#  define WIN32_LEAN_AND_MEAN 1
+#  include <windows.h>
+#else
+#  include <pthread.h>
+#endif
+
+namespace emugl {
+
+class ConditionVariable;
+
+// Simple wrapper class for mutexes.
+class Mutex {
+public:
+    // Constructor.
+    Mutex() {
+#ifdef _WIN32
+        ::InitializeCriticalSection(&mLock);
+#else
+        ::pthread_mutex_init(&mLock, NULL);
+#endif
+    }
+
+    // Destructor.
+    ~Mutex() {
+#ifdef _WIN32
+        ::DeleteCriticalSection(&mLock);
+#else
+        ::pthread_mutex_destroy(&mLock);
+#endif
+    }
+
+    // Acquire the mutex.
+    void lock() {
+#ifdef _WIN32
+      ::EnterCriticalSection(&mLock);
+#else
+      ::pthread_mutex_lock(&mLock);
+#endif
+    }
+
+    // Release the mutex.
+    void unlock() {
+#ifdef _WIN32
+       ::LeaveCriticalSection(&mLock);
+#else
+       ::pthread_mutex_unlock(&mLock);
+#endif
+    }
+
+    // Helper class to lock / unlock a mutex automatically on scope
+    // entry and exit.
+    class AutoLock {
+    public:
+        AutoLock(Mutex& mutex) : mMutex(&mutex) {
+            mMutex->lock();
+        }
+
+        ~AutoLock() {
+            mMutex->unlock();
+        }
+    private:
+        Mutex* mMutex;
+    };
+
+private:
+#ifdef _WIN32
+    CRITICAL_SECTION mLock;
+#else
+    friend class ConditionVariable;
+    pthread_mutex_t mLock;
+#endif
+
+};
+
+}  // namespace emugl
+
+#endif  // EMUGL_MUTEX_H