/*

Copyright (C) 2016 Apple Inc. All Rights Reserved.

See LICENSE.txt for this sample’s licensing information

Abstract:

Part of Core Audio Public Utility Classes

*/

#ifndef __CAMutex_h__

#define __CAMutex_h__

//==================================================================================================

//  Includes

//==================================================================================================

//  System Includes

#if !defined(__COREAUDIO_USE_FLAT_INCLUDES__)

    #include <CoreAudio/CoreAudioTypes.h>

#else

    #include <CoreAudioTypes.h>

#endif

#if TARGET_OS_MAC

    #include <pthread.h>

#elif TARGET_OS_WIN32

    #include <windows.h>

#else

    #error  Unsupported operating system

#endif

//==================================================================================================

//  A recursive mutex.

//==================================================================================================

class   CAMutex

{

//  Construction/Destruction

public:

                    CAMutex(const char* inName);

    virtual         ~CAMutex();

//  Actions

public:

    virtual bool    Lock();

    virtual void    Unlock();

    virtual bool    Try(bool& outWasLocked);    // returns true if lock is free, false if not

    virtual bool    IsFree() const;

    virtual bool    IsOwnedByCurrentThread() const;

//  Implementation

protected:

    const char*     mName;

#if TARGET_OS_MAC

    pthread_t       mOwner;

    pthread_mutex_t mMutex;

#elif TARGET_OS_WIN32

    UInt32          mOwner;

    HANDLE          mMutex;

#endif

//  Helper class to manage taking and releasing recursively

public:

    class           Locker

    {

    //  Construction/Destruction

    public:

                    Locker(CAMutex& inMutex) : mMutex(&inMutex), mNeedsRelease(false) { mNeedsRelease = mMutex->Lock(); }

                    Locker(CAMutex* inMutex) : mMutex(inMutex), mNeedsRelease(false) { mNeedsRelease = (mMutex != NULL && mMutex->Lock()); }

                        // in this case the mutex can be null

                    ~Locker() { if(mNeedsRelease) { mMutex->Unlock(); } }

    private:

                    Locker(const Locker&);

        Locker&     operator=(const Locker&);

    //  Implementation

    private:

        CAMutex*    mMutex;

        bool        mNeedsRelease;

    };

// Unlocker

    class Unlocker

    {

    public:

                        Unlocker(CAMutex& inMutex);

                        ~Unlocker();

    private:

        CAMutex&    mMutex;

        bool        mNeedsLock;

        // Hidden definitions of copy ctor, assignment operator

        Unlocker(const Unlocker& copy);             // Not implemented

        Unlocker& operator=(const Unlocker& copy);  // Not implemented

    };

// you can use this with Try - if you take the lock in try, pass in the outWasLocked var

    class Tryer {

    //  Construction/Destruction

    public:

        Tryer (CAMutex &mutex) : mMutex(mutex), mNeedsRelease(false), mHasLock(false) { mHasLock = mMutex.Try (mNeedsRelease); }

        ~Tryer () { if (mNeedsRelease) mMutex.Unlock(); }

        bool HasLock () const { return mHasLock; }

    private:

                    Tryer(const Tryer&);

        Tryer&      operator=(const Tryer&);

    //  Implementation

    private:

        CAMutex &       mMutex;

        bool            mNeedsRelease;

        bool            mHasLock;

    };

};

#endif // __CAMutex_h__