1 files changed, 148 insertions, 0 deletions
diff --git a/media/libstagefright/system/core/include/utils/Mutex.h b/media/libstagefright/system/core/include/utils/Mutex.h
new file mode 100644
index 000000000..b33efef76
--- /dev/null
+++ b/media/libstagefright/system/core/include/utils/Mutex.h
@@ -0,0 +1,148 @@
+/*
+ * Copyright (C) 2007 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 _LIBS_UTILS_MUTEX_H
+#define _LIBS_UTILS_MUTEX_H
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <time.h>
+
+#if defined(HAVE_PTHREADS)
+# include <pthread.h>
+#endif
+
+#include <utils/Errors.h>
+
+// ---------------------------------------------------------------------------
+namespace stagefright {
+// ---------------------------------------------------------------------------
+
+class Condition;
+
+/*
+ * Simple mutex class.  The implementation is system-dependent.
+ *
+ * The mutex must be unlocked by the thread that locked it.  They are not
+ * recursive, i.e. the same thread can't lock it multiple times.
+ */
+class Mutex {
+public:
+    enum {
+        PRIVATE = 0,
+        SHARED = 1
+    };
+    
+                Mutex();
+                Mutex(const char* name);
+                Mutex(int type, const char* name = NULL);
+                ~Mutex();
+
+    // lock or unlock the mutex
+    status_t    lock();
+    void        unlock();
+
+    // lock if possible; returns 0 on success, error otherwise
+    status_t    tryLock();
+
+    // Manages the mutex automatically. It'll be locked when Autolock is
+    // constructed and released when Autolock goes out of scope.
+    class Autolock {
+    public:
+        inline Autolock(Mutex& mutex) : mLock(mutex)  { mLock.lock(); }
+        inline Autolock(Mutex* mutex) : mLock(*mutex) { mLock.lock(); }
+        inline ~Autolock() { mLock.unlock(); }
+    private:
+        Mutex& mLock;
+    };
+
+private:
+    friend class Condition;
+    
+    // A mutex cannot be copied
+                Mutex(const Mutex&);
+    Mutex&      operator = (const Mutex&);
+    
+#if defined(HAVE_PTHREADS)
+    pthread_mutex_t mMutex;
+#else
+    void    _init();
+    void*   mState;
+#endif
+};
+
+// ---------------------------------------------------------------------------
+
+#if defined(HAVE_PTHREADS)
+
+inline Mutex::Mutex() {
+    pthread_mutex_init(&mMutex, NULL);
+}
+inline Mutex::Mutex(__attribute__((unused)) const char* name) {
+    pthread_mutex_init(&mMutex, NULL);
+}
+inline Mutex::Mutex(int type, __attribute__((unused)) const char* name) {
+    if (type == SHARED) {
+        pthread_mutexattr_t attr;
+        pthread_mutexattr_init(&attr);
+        pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
+        pthread_mutex_init(&mMutex, &attr);
+        pthread_mutexattr_destroy(&attr);
+    } else {
+        pthread_mutex_init(&mMutex, NULL);
+    }
+}
+inline Mutex::~Mutex() {
+    pthread_mutex_destroy(&mMutex);
+}
+inline status_t Mutex::lock() {
+    return -pthread_mutex_lock(&mMutex);
+}
+inline void Mutex::unlock() {
+    pthread_mutex_unlock(&mMutex);
+}
+inline status_t Mutex::tryLock() {
+    return -pthread_mutex_trylock(&mMutex);
+}
+
+#else
+
+inline Mutex::Mutex() {}
+inline Mutex::Mutex(const char* name) {}
+inline Mutex::Mutex(int type, const char* name) {}
+inline Mutex::~Mutex() {}
+inline status_t Mutex::lock() { return OK; }
+inline void Mutex::unlock() {}
+inline status_t Mutex::tryLock() { return OK; }
+inline void Mutex::_init() {}
+
+#endif // HAVE_PTHREADS
+
+// ---------------------------------------------------------------------------
+
+/*
+ * Automatic mutex.  Declare one of these at the top of a function.
+ * When the function returns, it will go out of scope, and release the
+ * mutex.
+ */
+ 
+typedef Mutex::Autolock AutoMutex;
+
+// ---------------------------------------------------------------------------
+}; // namespace stagefright
+// ---------------------------------------------------------------------------
+
+#endif // _LIBS_UTILS_MUTEX_H