Added the mutex support to ease the streaming (ie to prevent all race

conditions between an 'append' and a playing by the sound
thread). Porters should add the relevant stuff to their OSystem
interfaces.

But finally, the bug reported by Valgrind was much more trivial than
that and is also fixed in this commit :-)

svn-id: r4398

2 files changed, 17 insertions, 6 deletions

diff --git a/sound/mixer.cpp b/sound/mixer.cpp
index 723b790e38..5f1d3fba11 100644
--- a/sound/mixer.cpp
+++ b/sound/mixer.cpp
@@ -39,14 +39,18 @@ void SoundMixer::uninsert(Channel *chan) {
 }
 
 int SoundMixer::append(int index, void *sound, uint32 size, uint rate, byte flags) {
+	_syst->lock_mutex(_mutex);
+
 	Channel *chan = _channels[index];
 	if (!chan) {
 		warning("Trying to stream to an unexistant streamer ");
 		play_stream(NULL, index, sound, size, rate, flags);
 		chan = _channels[index];
+	} else {
+		chan->append(sound, size);
 	}
 
-	chan->append(sound, size);
+	_syst->unlock_mutex(_mutex);
 	return 1;
 }
 
@@ -111,10 +115,12 @@ void SoundMixer::mix(int16 *buf, uint len) {
 		memset(buf, 0, 2 * len * sizeof(int16));
 	}
 
+	_syst->lock_mutex(_mutex);
 	/* now mix all channels */
 	for(int i=0; i!=NUM_CHANNELS; i++)
 		if (_channels[i])
 			_channels[i]->mix(buf, len);
+	_syst->unlock_mutex(_mutex);
 }
 
 void SoundMixer::on_generate_samples(void *s, byte *samples, int len) {
@@ -128,9 +134,12 @@ bool SoundMixer::bind_to_system(OSystem *syst) {
 
 	_output_rate = rate;
 	
+	_syst = syst;
+	_mutex = _syst->create_mutex();
+
 	if (rate == 0)
 		error("OSystem returned invalid sample rate");
-	
+
 	return syst->set_sound_proc(this, on_generate_samples, OSystem::SOUND_16BIT);
 }
 
@@ -408,14 +417,14 @@ SoundMixer::Channel_STREAM::Channel_STREAM(SoundMixer *mixer, void *sound, uint3
 void SoundMixer::Channel_STREAM::append(void *data, uint32 len) {   
 	byte *new_end = _end_of_data + len;
 	byte *cur_pos = _pos; /* This is just to prevent the variable to move during the tests :-) */
-
 	if (new_end > (_ptr + _buffer_size)) {
 		/* Wrap-around case */
 		if ((_end_of_data < cur_pos) ||
 		    (new_end >= cur_pos)) {
 			warning("Mixer full... Trying to not break too much ");
 			return;	
-		}		memcpy(_end_of_data, data, (_ptr + _buffer_size) - _end_of_data);
+		}
+		memcpy(_end_of_data, data, (_ptr + _buffer_size) - _end_of_data);
 		memcpy(_ptr, (byte *) data + ((_ptr + _buffer_size) - _end_of_data), len - ((_ptr + _buffer_size) - _end_of_data));
 	} else {
 		if ((_end_of_data < cur_pos) &&
diff --git a/sound/mixer.h b/sound/mixer.h
index 99b36903bb..ac38312b19 100644
--- a/sound/mixer.h
+++ b/sound/mixer.h
@@ -69,7 +69,6 @@ private:
 		uint32 _buffer_size;
 		uint32 _rate;
 		byte _flags;
-		
 
 	public:
 		void append(void *sound, uint32 size);		
@@ -125,6 +124,9 @@ private:
 public:
 	typedef void PremixProc(void *param, int16 *data, uint len);
 
+	OSystem *_syst;
+	void *_mutex;
+	
 	uint _output_rate;
 
 	int16 *_volume_table;
@@ -140,7 +142,7 @@ public:
 
 	Channel *_channels[NUM_CHANNELS];
 	PlayingSoundHandle *_handles[NUM_CHANNELS];
-	
+
 	int insert(PlayingSoundHandle *handle, Channel *chan);
 	int insert_at(PlayingSoundHandle *handle, int index, Channel *chan);
 	void append(void *data, uint32 len);