text: /*
       File: CAMutex.cpp 
   Abstract:  CAMutex.h  
    Version: 1.0.4 
    
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  */
  //==================================================================================================
  //	Includes
  //==================================================================================================
  
  //	Self Include
  #include "CAMutex.h"
  
  #if TARGET_OS_MAC
  	#include <errno.h>
  #endif
  
  //	PublicUtility Includes
  #include "CADebugMacros.h"
  #include "CAException.h"
  #include "CAHostTimeBase.h"
  
  //==================================================================================================
  //	Logging
  //==================================================================================================
  
  #if CoreAudio_Debug
  //	#define	Log_Ownership		1
  //	#define	Log_Errors			1
  //	#define Log_LongLatencies	1
  //	#define LongLatencyThreshholdNS	1000000ULL	// nanoseconds
  #endif
  
  //==================================================================================================
  //	CAMutex
  //==================================================================================================
  
  CAMutex::CAMutex(const char* inName)
  :
  	mName(inName),
  	mOwner(0)
  {
  #if TARGET_OS_MAC
  	OSStatus theError = pthread_mutex_init(&mMutex, NULL);
  	ThrowIf(theError != 0, CAException(theError), "CAMutex::CAMutex: Could not init the mutex");
  	
  	#if	Log_Ownership
  		DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAMutex::CAMutex: creating %s, owner: %p\n", pthread_self(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), mName, mOwner);
  	#endif
  #elif TARGET_OS_WIN32
  	mMutex = CreateMutex(NULL, false, NULL);
  	ThrowIfNULL(mMutex, CAException(GetLastError()), "CAMutex::CAMutex: could not create the mutex.");
  	
  	#if	Log_Ownership
  		DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAMutex::CAMutex: creating %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), mName, mOwner);
  	#endif
  #endif
  }
  
  CAMutex::~CAMutex()
  {
  #if TARGET_OS_MAC
  	#if	Log_Ownership
  		DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAMutex::~CAMutex: destroying %s, owner: %p\n", pthread_self(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), mName, mOwner);
  	#endif
  	pthread_mutex_destroy(&mMutex);
  #elif TARGET_OS_WIN32
  	#if	Log_Ownership
  		DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAMutex::~CAMutex: destroying %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), mName, mOwner);
  	#endif
  	if(mMutex != NULL)
  	{
  		CloseHandle(mMutex);
  	}
  #endif
  }
  
  bool	CAMutex::Lock()
  {
  	bool theAnswer = false;
  	
  #if TARGET_OS_MAC
  	pthread_t theCurrentThread = pthread_self();
  	if(!pthread_equal(theCurrentThread, mOwner))
  	{
  		#if	Log_Ownership
  			DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAMutex::Lock: thread %p is locking %s, owner: %p\n", theCurrentThread, ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), theCurrentThread, mName, mOwner);
  		#endif
  		
  		#if Log_LongLatencies
  			UInt64 lockTryTime = CAHostTimeBase::GetCurrentTimeInNanos();
  		#endif
  		
  		OSStatus theError = pthread_mutex_lock(&mMutex);
  		ThrowIf(theError != 0, CAException(theError), "CAMutex::Lock: Could not lock the mutex");
  		mOwner = theCurrentThread;
  		theAnswer = true;
  	
  		#if Log_LongLatencies
  			UInt64 lockAcquireTime = CAHostTimeBase::GetCurrentTimeInNanos();
  			if (lockAcquireTime - lockTryTime >= LongLatencyThresholdNS)
  				DebugPrintfRtn(DebugPrintfFileComma "Thread %p took %.6fs to acquire the lock %s\n", theCurrentThread, (lockAcquireTime - lockTryTime) * 1.0e-9 /* nanos to seconds */, mName);
  		#endif
  		
  		#if	Log_Ownership
  			DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAMutex::Lock: thread %p has locked %s, owner: %p\n", pthread_self(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), pthread_self(), mName, mOwner);
  		#endif
  	}
  #elif TARGET_OS_WIN32
  	if(mOwner != GetCurrentThreadId())
  	{
  		#if	Log_Ownership
  			DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAMutex::Lock: thread %lu is locking %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), GetCurrentThreadId(), mName, mOwner);
  		#endif
  
  		OSStatus theError = WaitForSingleObject(mMutex, INFINITE);
  		ThrowIfError(theError, CAException(theError), "CAMutex::Lock: could not lock the mutex");
  		mOwner = GetCurrentThreadId();
  		theAnswer = true;
  	
  		#if	Log_Ownership
  			DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAMutex::Lock: thread %lu has locked %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), GetCurrentThreadId(), mName, mOwner);
  		#endif
  	}
  #endif
  
  	return theAnswer;
  }
  
  void	CAMutex::Unlock()
  {
  #if TARGET_OS_MAC
  	if(pthread_equal(pthread_self(), mOwner))
  	{
  		#if	Log_Ownership
  			DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAMutex::Unlock: thread %p is unlocking %s, owner: %p\n", pthread_self(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), pthread_self(), mName, mOwner);
  		#endif
  
  		mOwner = 0;
  		OSStatus theError = pthread_mutex_unlock(&mMutex);
  		ThrowIf(theError != 0, CAException(theError), "CAMutex::Unlock: Could not unlock the mutex");
  	
  		#if	Log_Ownership
  			DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAMutex::Unlock: thread %p has unlocked %s, owner: %p\n", pthread_self(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), pthread_self(), mName, mOwner);
  		#endif
  	}
  	else
  	{
  		DebugMessage("CAMutex::Unlock: A thread is attempting to unlock a Mutex it doesn't own");
  	}
  #elif TARGET_OS_WIN32
  	if(mOwner == GetCurrentThreadId())
  	{
  		#if	Log_Ownership
  			DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAMutex::Unlock: thread %lu is unlocking %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), GetCurrentThreadId(), mName, mOwner);
  		#endif
  
  		mOwner = 0;
  		bool wasReleased = ReleaseMutex(mMutex);
  		ThrowIf(!wasReleased, CAException(GetLastError()), "CAMutex::Unlock: Could not unlock the mutex");
  	
  		#if	Log_Ownership
  			DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAMutex::Unlock: thread %lu has unlocked %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), GetCurrentThreadId(), mName, mOwner);
  		#endif
  	}
  	else
  	{
  		DebugMessage("CAMutex::Unlock: A thread is attempting to unlock a Mutex it doesn't own");
  	}
  #endif
  }
  
  bool	CAMutex::Try(bool& outWasLocked)
  {
  	bool theAnswer = false;
  	outWasLocked = false;
  
  #if TARGET_OS_MAC
  	pthread_t theCurrentThread = pthread_self();
  	if(!pthread_equal(theCurrentThread, mOwner))
  	{
  		//	this means the current thread doesn't already own the lock
  		#if	Log_Ownership
  			DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAMutex::Try: thread %p is try-locking %s, owner: %p\n", theCurrentThread, ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), theCurrentThread, mName, mOwner);
  		#endif
  
  		//	go ahead and call trylock to see if we can lock it.
  		int theError = pthread_mutex_trylock(&mMutex);
  		if(theError == 0)
  		{
  			//	return value of 0 means we successfully locked the lock
  			mOwner = theCurrentThread;
  			theAnswer = true;
  			outWasLocked = true;
  	
  			#if	Log_Ownership
  				DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAMutex::Try: thread %p has locked %s, owner: %p\n", theCurrentThread, ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), theCurrentThread, mName, mOwner);
  			#endif
  		}
  		else if(theError == EBUSY)
  		{
  			//	return value of EBUSY means that the lock was already locked by another thread
  			theAnswer = false;
  			outWasLocked = false;
  	
  			#if	Log_Ownership
  				DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAMutex::Try: thread %p failed to lock %s, owner: %p\n", theCurrentThread, ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), theCurrentThread, mName, mOwner);
  			#endif
  		}
  		else
  		{
  			//	any other return value means something really bad happenned
  			ThrowIfError(theError, CAException(theError), "CAMutex::Try: call to pthread_mutex_trylock failed");
  		}
  	}
  	else
  	{
  		//	this means the current thread already owns the lock
  		theAnswer = true;
  		outWasLocked = false;
  	}
  #elif TARGET_OS_WIN32
  	if(mOwner != GetCurrentThreadId())
  	{
  		//	this means the current thread doesn't own the lock
  		#if	Log_Ownership
  			DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAMutex::Try: thread %lu is try-locking %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), GetCurrentThreadId(), mName, mOwner);
  		#endif
  		
  		//	try to acquire the mutex
  		OSStatus theError = WaitForSingleObject(mMutex, 0);
  		if(theError == WAIT_OBJECT_0)
  		{
  			//	this means we successfully locked the lock
  			mOwner = GetCurrentThreadId();
  			theAnswer = true;
  			outWasLocked = true;
  	
  			#if	Log_Ownership
  				DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAMutex::Try: thread %lu has locked %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), GetCurrentThreadId(), mName, mOwner);
  			#endif
  		}
  		else if(theError == WAIT_TIMEOUT)
  		{
  			//	this means that the lock was already locked by another thread
  			theAnswer = false;
  			outWasLocked = false;
  	
  			#if	Log_Ownership
  				DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAMutex::Try: thread %lu failed to lock %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), GetCurrentThreadId(), mName, mOwner);
  			#endif
  		}
  		else
  		{
  			//	any other return value means something really bad happenned
  			ThrowIfError(theError, CAException(GetLastError()), "CAMutex::Try: call to lock the mutex failed");
  		}
  	}
  	else
  	{
  		//	this means the current thread already owns the lock
  		theAnswer = true;
  		outWasLocked = false;
  	}
  #endif
  	
  	return theAnswer;
  }
  
  bool	CAMutex::IsFree() const
  {
  	return mOwner == 0;
  }
  
  bool	CAMutex::IsOwnedByCurrentThread() const
  {
  	bool theAnswer = true;
  	
  #if TARGET_OS_MAC
  	theAnswer = pthread_equal(pthread_self(), mOwner);
  #elif TARGET_OS_WIN32
  	theAnswer = (mOwner == GetCurrentThreadId());
  #endif
  
  	return theAnswer;
  }
  
  
  CAMutex::Unlocker::Unlocker(CAMutex& inMutex)
  :	mMutex(inMutex),
  	mNeedsLock(false)
  {
  	Assert(mMutex.IsOwnedByCurrentThread(), "Major problem: Unlocker attempted to unlock a mutex not owned by the current thread!");
  
  	mMutex.Unlock();
  	mNeedsLock = true;
  }
  
  CAMutex::Unlocker::~Unlocker()
  {
  	if(mNeedsLock)
  	{
  		mMutex.Lock();
  	}
  }
  