/*
 * Copyright (C) 2012 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.
 */

/*
 *  Encapsulate a mutex for thread synchronization.
 */

#pragma once
#include <pthread.h>


class Mutex
{
public:
    /*******************************************************************************
    **
    ** Function:        Mutex
    **
    ** Description:     Initialize member variables.
    **
    ** Returns:         None.
    **
    *******************************************************************************/
    Mutex ();


    /*******************************************************************************
    **
    ** Function:        ~Mutex
    **
    ** Description:     Cleanup all resources.
    **
    ** Returns:         None.
    **
    *******************************************************************************/
    ~Mutex ();


    /*******************************************************************************
    **
    ** Function:        lock
    **
    ** Description:     Block the thread and try lock the mutex.
    **
    ** Returns:         None.
    **
    *******************************************************************************/
    void lock ();


    /*******************************************************************************
    **
    ** Function:        unlock
    **
    ** Description:     Unlock a mutex to unblock a thread.
    **
    ** Returns:         None.
    **
    *******************************************************************************/
    void unlock ();


    /*******************************************************************************
    **
    ** Function:        tryLock
    **
    ** Description:     Try to lock the mutex.
    **
    ** Returns:         True if the mutex is locked.
    **
    *******************************************************************************/
    bool tryLock ();


    /*******************************************************************************
    **
    ** Function:        nativeHandle
    **
    ** Description:     Get the handle of the mutex.
    **
    ** Returns:         Handle of the mutex.
    **
    *******************************************************************************/
    pthread_mutex_t* nativeHandle ();

    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:
    pthread_mutex_t mMutex;
};

typedef Mutex::Autolock AutoMutex;