CoreAudio/PublicUtility/CAGuard.h
/* |
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 |
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