alternative new version of the AppleUtility library

libs/appleutility/CoreAudio/PublicUtility/CAMutex.h

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+/*
+     File: CAMutex.h
+ Abstract: Part of CoreAudio Utility Classes
+  Version: 1.1
+ 
+ Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple
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+ redistribute this Apple software.
+ 
+ In consideration of your agreement to abide by the following terms, and
+ subject to these terms, Apple grants you a personal, non-exclusive
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+ "Apple Software"), to use, reproduce, modify and redistribute the Apple
+ Software, with or without modifications, in source and/or binary forms;
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+ Neither the name, trademarks, service marks or logos of Apple Inc. may
+ be used to endorse or promote products derived from the Apple Software
+ without specific prior written permission from Apple.  Except as
+ expressly stated in this notice, no other rights or licenses, express or
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+ works in which the Apple Software may be incorporated.
+ 
+ The Apple Software is provided by Apple on an "AS IS" basis.  APPLE
+ MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
+ THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS
+ FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
+ OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
+ 
+ IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
+ OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
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+ AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),
+ STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE
+ POSSIBILITY OF SUCH DAMAGE.
+ 
+ Copyright (C) 2014 Apple Inc. All Rights Reserved.
+ 
+*/
+#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__