mirror of
https://github.com/kyleneideck/BackgroundMusic
synced 2024-11-10 06:34:22 +00:00
488ed16dfc
Issue #276 reported a segfault that occurred while BGMApp was launching. It was caused by BGM_PlayThrough's output IOProc when it tried to read from the ring buffer. I haven't been able to reproduce the problem, so I don't know whether this commit will actually fix it. Hopefully it will at least make it easier to diagnose. This commit adds locking around accesses to the buffer so that the IOProcs will skip the current IO cycle if it isn't safe to use the ring buffer. That should only happen during launch or when changing the output device. (And only if something else has gone wrong.)
192 lines
6.3 KiB
C++
192 lines
6.3 KiB
C++
// This file is part of Background Music.
|
|
//
|
|
// Background Music is free software: you can redistribute it and/or
|
|
// modify it under the terms of the GNU General Public License as
|
|
// published by the Free Software Foundation, either version 2 of the
|
|
// License, or (at your option) any later version.
|
|
//
|
|
// Background Music is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU General Public License
|
|
// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
//
|
|
// CAMutex.h
|
|
// PublicUtility
|
|
//
|
|
// Copyright (C) 2014 Apple Inc. All Rights Reserved.
|
|
// Copyright © 2020 Kyle Neideck
|
|
//
|
|
// Original license header follows.
|
|
//
|
|
|
|
/*
|
|
File: CAMutex.h
|
|
Abstract: Part of CoreAudio Utility Classes
|
|
Version: 1.1
|
|
|
|
Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple
|
|
Inc. ("Apple") in consideration of your agreement to the following
|
|
terms, and your use, installation, modification or redistribution of
|
|
this Apple software constitutes acceptance of these terms. If you do
|
|
not agree with these terms, please do not use, install, modify or
|
|
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
|
|
license, under Apple's copyrights in this original Apple software (the
|
|
"Apple Software"), to use, reproduce, modify and redistribute the Apple
|
|
Software, with or without modifications, in source and/or binary forms;
|
|
provided that if you redistribute the Apple Software in its entirety and
|
|
without modifications, you must retain this notice and the following
|
|
text and disclaimers in all such redistributions of the Apple Software.
|
|
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
|
|
implied, are granted by Apple herein, including but not limited to any
|
|
patent rights that may be infringed by your derivative works or by other
|
|
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,
|
|
MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED
|
|
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
|
|
//==================================================================================================
|
|
|
|
#include "BGMThreadSafetyAnalysis.h"
|
|
|
|
// 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 CAPABILITY("mutex") CAMutex
|
|
{
|
|
// Construction/Destruction
|
|
public:
|
|
CAMutex(const char* inName);
|
|
virtual ~CAMutex();
|
|
|
|
// Actions
|
|
public:
|
|
virtual bool Lock() ACQUIRE();
|
|
virtual void Unlock() RELEASE();
|
|
virtual bool Try(bool& outWasLocked) TRY_ACQUIRE(true); // 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 SCOPED_CAPABILITY Locker
|
|
{
|
|
|
|
// Construction/Destruction
|
|
public:
|
|
Locker(CAMutex& inMutex) ACQUIRE(inMutex) : mMutex(&inMutex), mNeedsRelease(false) { mNeedsRelease = mMutex->Lock(); }
|
|
Locker(CAMutex* inMutex) ACQUIRE(inMutex) : mMutex(inMutex), mNeedsRelease(false) { mNeedsRelease = (mMutex != NULL && mMutex->Lock()); }
|
|
// in this case the mutex can be null
|
|
~Locker() RELEASE() { if(mNeedsRelease) { mMutex->Unlock(); } }
|
|
|
|
|
|
private:
|
|
Locker(const Locker&);
|
|
Locker& operator=(const Locker&);
|
|
|
|
// Implementation
|
|
private:
|
|
CAMutex* mMutex;
|
|
bool mNeedsRelease;
|
|
|
|
};
|
|
|
|
// Clang's static analysis doesn't work for unlocker classes. See
|
|
// <https://clang.llvm.org/docs/ThreadSafetyAnalysis.html#no-alias-analysis>.
|
|
// 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 SCOPED_CAPABILITY Tryer {
|
|
|
|
// Construction/Destruction
|
|
public:
|
|
Tryer (CAMutex &mutex) TRY_ACQUIRE(true, mutex) : mMutex(mutex), mNeedsRelease(false), mHasLock(false) { mHasLock = mMutex.Try (mNeedsRelease); }
|
|
~Tryer () RELEASE() { 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__
|