scummvm/engines/bladerunner/audio_mixer.h
antoniou79 1a25c2b69a BLADERUNNER: Remove timerprocs for next track and fadeout
The timers are replaced with "application" timers, which are checked in AudioMixer::tick()

The timerprocs for next and fadeout could potentially cause a game freeze.
This is because they could, under certain race conditions, come to a deadend
while trying to lock the mutexes for access to AudioMixer and Music methods.
The particular use case (non-deterministic) for this was loading a save game
while playing a game that had a music track playing (eg. at MA05, McCoy's balcony).
Here's a rough explanation of a possible lock situation (others could also be possible)
The "Main Thread" and "SDLTimer" threads (as reported from MSVC debug) could become hardlocked.
::Main Thread::
	A. LoadGame() calls _music->stop(0u);
		A1. Locks a Music::_mutex
		A2. Calls vm->_audioMixer->stop()
		A3. AudioMixer::stop() locks AudioMixer::_mutex [THIS DONE]
		A4. calls the endCallback for the music which is Music::ended()
			at Music::ended,
			A41. lock a Music::_mutex (presumably this is ok, even though it's a second lock, because it's the same thread(?))
			A42. call installTimerProc()
				A421. which tries to lock DefaultTimerManager::_mutex from default-timer [THIS FREEZES] - conflict with B11
::SDLTimer::
	B. calls timer_handler,
		B1. calls DefaultTimerManager::handler()
			B11. locks the DefaultTimerManager::_mutex from default-timer [THIS IS DONE]
			B12. we try to service the callbacks from TimerProcs that are currently entered in the TimerSlots queue
				B121. Such a slot is the AudioMixer BladeRunnerAudioMixerTimer, which has the AudioMixer::timerCallback()
				B1211. which calls the at AudioMixer::tick().
						tick() tries to lock the AudioMixer::_mutex [THIS FREEZES] conflict with A3
2021-06-12 14:58:07 +03:00

120 lines
3.9 KiB
C++

/* ScummVM - Graphic Adventure Engine
*
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* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
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* 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
#ifndef BLADERUNNER_AUDIO_MIXER_H
#define BLADERUNNER_AUDIO_MIXER_H
#include "audio/audiostream.h"
#include "audio/mixer.h"
#include "common/mutex.h"
namespace BladeRunner {
class BladeRunnerEngine;
#if !BLADERUNNER_ORIGINAL_BUG
enum audioMixerAppTimers {
kAudioMixerAppTimerMusicNext = 0,
kAudioMixerAppTimerMusicFadeOut = 1
};
#endif
class AudioMixer {
#if BLADERUNNER_ORIGINAL_BUGS
static const int kChannels = 9;
static const int kUsableChannels = 8;
static const int kMusicChannel = 8;
#else
static const int kChannels = 15;
static const int kUsableChannels = 14;
static const int kMusicChannel = 14;
static const int kAudioMixerAppTimersNum = 2;
#endif // BLADERUNNER_ORIGINAL_BUGS
static const int kUpdatesPerSecond = 40;
struct Channel {
bool isPresent;
int priority;
bool loop;
Audio::SoundHandle handle;
Audio::AudioStream *stream;
float volume;
float volumeDelta;
float volumeTarget;
float pan;
float panDelta;
float panTarget;
void (*endCallback)(int channel, void *data);
void *callbackData;
uint32 timeStarted;
uint32 trackDurationMs;
bool sentToMixer;
};
BladeRunnerEngine *_vm;
Channel _channels[kChannels];
Common::Mutex _mutex;
#if !BLADERUNNER_ORIGINAL_BUGS
struct audioMixerAppTimer {
bool started;
uint32 intervalMillis; // expiration interval in milliseconds
uint32 lastFired; // time of last time the timer expired in milliseconds
};
audioMixerAppTimer _audioMixerAppTimers[kAudioMixerAppTimersNum];
#endif // !BLADERUNNER_ORIGINAL_BUGS
public:
AudioMixer(BladeRunnerEngine *vm);
~AudioMixer();
int play(Audio::Mixer::SoundType type, Audio::RewindableAudioStream *stream, int priority, bool loop, int volume, int pan, void(*endCallback)(int, void *), void *callbackData, uint32 trackDurationMs);
int playMusic(Audio::RewindableAudioStream *stream, int volume, void(*endCallback)(int, void *), void *callbackData, uint32 trackDurationMs);
void stop(int channel, uint32 time);
void adjustVolume(int channel, int newVolume, uint32 time);
void adjustPan(int channel, int newPan, uint32 time);
#if !BLADERUNNER_ORIGINAL_BUGS
void startAppTimerProc(int audioMixAppTimerId, uint32 intervalMillis);
void stopAppTimerProc(int audioMixAppTimerId);
#endif // !BLADERUNNER_ORIGINAL_BUGS
// TODO Are these completely unused?
// void resume(int channel, uint32 delay);
// void pause(int channel, uint32 delay);
private:
int playInChannel(int channel, Audio::Mixer::SoundType type, Audio::RewindableAudioStream *stream, int priority, bool loop, int volume, int pan, void(*endCallback)(int, void *), void *callbackData, uint32 trackDurationMs);
bool isActive(int channel) const;
void tick();
static void timerCallback(void *refCon);
};
} // End of namespace BladeRunner
#endif