134 lines
4.7 KiB
C++
134 lines
4.7 KiB
C++
/*
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File: CAGuard.h
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Abstract: Part of CoreAudio Utility Classes
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Version: 1.1
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Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple
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Inc. ("Apple") in consideration of your agreement to the following
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terms, and your use, installation, modification or redistribution of
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this Apple software constitutes acceptance of these terms. If you do
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not agree with these terms, please do not use, install, modify or
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redistribute this Apple software.
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In consideration of your agreement to abide by the following terms, and
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subject to these terms, Apple grants you a personal, non-exclusive
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license, under Apple's copyrights in this original Apple software (the
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"Apple Software"), to use, reproduce, modify and redistribute the Apple
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Software, with or without modifications, in source and/or binary forms;
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provided that if you redistribute the Apple Software in its entirety and
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without modifications, you must retain this notice and the following
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text and disclaimers in all such redistributions of the Apple Software.
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Neither the name, trademarks, service marks or logos of Apple Inc. may
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be used to endorse or promote products derived from the Apple Software
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without specific prior written permission from Apple. Except as
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expressly stated in this notice, no other rights or licenses, express or
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implied, are granted by Apple herein, including but not limited to any
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patent rights that may be infringed by your derivative works or by other
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works in which the Apple Software may be incorporated.
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The Apple Software is provided by Apple on an "AS IS" basis. APPLE
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MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
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THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS
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FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
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OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
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IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
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OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
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MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED
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AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),
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STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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Copyright (C) 2014 Apple Inc. All Rights Reserved.
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*/
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#if !defined(__CAGuard_h__)
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#define __CAGuard_h__
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//==================================================================================================
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// Includes
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//=============================================================================
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// Super Class Includes
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#include "CAMutex.h"
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#if CoreAudio_Debug
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// #define Log_Average_Latency 1
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#endif
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//==================================================================================================
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// CAGuard
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//
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// This is your typical mutex with signalling implemented via pthreads.
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// Lock() will return true if and only if the guard is locked on that call.
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// A thread that already has the guard will receive 'false' if it locks it
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// again. Use of the stack-based CAGuard::Locker class is highly recommended
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// to properly manage the recursive nesting. The Wait calls with timeouts
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// will return true if and only if the timeout period expired. They will
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// return false if they receive notification any other way.
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//==================================================================================================
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class CAGuard : public CAMutex
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{
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// Construction/Destruction
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public:
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CAGuard(const char* inName);
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virtual ~CAGuard();
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// Actions
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public:
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virtual void Wait();
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virtual bool WaitFor(UInt64 inNanos);
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virtual bool WaitUntil(UInt64 inNanos);
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virtual void Notify();
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virtual void NotifyAll();
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// Implementation
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protected:
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#if TARGET_OS_MAC
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pthread_cond_t mCondVar;
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#else
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HANDLE mEvent;
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#endif
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#if Log_Average_Latency
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Float64 mAverageLatencyAccumulator;
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UInt32 mAverageLatencyCount;
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#endif
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// Helper class to manage taking and releasing recursively
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public:
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class Locker
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{
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// Construction/Destruction
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public:
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Locker(CAGuard& inGuard) : mGuard(inGuard), mNeedsRelease(false) { mNeedsRelease = mGuard.Lock(); }
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~Locker() { if(mNeedsRelease) { mGuard.Unlock(); } }
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private:
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Locker(const Locker&);
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Locker& operator=(const Locker&);
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// Actions
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public:
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void Wait() { mGuard.Wait(); }
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bool WaitFor(UInt64 inNanos) { return mGuard.WaitFor(inNanos); }
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bool WaitUntil(UInt64 inNanos) { return mGuard.WaitUntil(inNanos); }
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void Notify() { mGuard.Notify(); }
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void NotifyAll() { mGuard.NotifyAll(); }
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// Implementation
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private:
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CAGuard& mGuard;
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bool mNeedsRelease;
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};
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};
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#endif
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