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livetrax/libs/appleutility/CoreAudio/PublicUtility/CAGuard.h

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/*
File: CAGuard.h
Abstract: Part of CoreAudio Utility Classes
Version: 1.1
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*/
#if !defined(__CAGuard_h__)
#define __CAGuard_h__
//==================================================================================================
// Includes
//=============================================================================
// Super Class Includes
#include "CAMutex.h"
#if CoreAudio_Debug
// #define Log_Average_Latency 1
#endif
//==================================================================================================
// CAGuard
//
// This is your typical mutex with signalling implemented via pthreads.
// Lock() will return true if and only if the guard is locked on that call.
// A thread that already has the guard will receive 'false' if it locks it
// again. Use of the stack-based CAGuard::Locker class is highly recommended
// to properly manage the recursive nesting. The Wait calls with timeouts
// will return true if and only if the timeout period expired. They will
// return false if they receive notification any other way.
//==================================================================================================
class CAGuard : public CAMutex
{
// Construction/Destruction
public:
CAGuard(const char* inName);
virtual ~CAGuard();
// Actions
public:
virtual void Wait();
virtual bool WaitFor(UInt64 inNanos);
virtual bool WaitUntil(UInt64 inNanos);
virtual void Notify();
virtual void NotifyAll();
// Implementation
protected:
#if TARGET_OS_MAC
pthread_cond_t mCondVar;
#else
HANDLE mEvent;
#endif
#if Log_Average_Latency
Float64 mAverageLatencyAccumulator;
UInt32 mAverageLatencyCount;
#endif
// Helper class to manage taking and releasing recursively
public:
class Locker
{
// Construction/Destruction
public:
Locker(CAGuard& inGuard) : mGuard(inGuard), mNeedsRelease(false) { mNeedsRelease = mGuard.Lock(); }
~Locker() { if(mNeedsRelease) { mGuard.Unlock(); } }
private:
Locker(const Locker&);
Locker& operator=(const Locker&);
// Actions
public:
void Wait() { mGuard.Wait(); }
bool WaitFor(UInt64 inNanos) { return mGuard.WaitFor(inNanos); }
bool WaitUntil(UInt64 inNanos) { return mGuard.WaitUntil(inNanos); }
void Notify() { mGuard.Notify(); }
void NotifyAll() { mGuard.NotifyAll(); }
// Implementation
private:
CAGuard& mGuard;
bool mNeedsRelease;
};
};
#endif