Use a lockless method for updating listener and context properties

This uses a separate container to provide the relevant properties to the
internal update method, using atomic pointer swaps. A free-list is used to
avoid having too many individual containers.

This allows the mixer to update the internal listener properties without
requiring the lock to protect against async updates. It also allows concurrent
read access to the user-facing property values, even the multi-value ones (e.g.
the vectors).

1 files changed, 3 insertions, 4 deletions

diff --git a/OpenAL32/Include/alMain.h b/OpenAL32/Include/alMain.h
index e818245b..44ce4fe0 100644
--- a/OpenAL32/Include/alMain.h
+++ b/OpenAL32/Include/alMain.h
@@ -679,8 +679,7 @@ struct ALCdevice_struct
 #define RECORD_THREAD_NAME "alsoft-record"
 
 
-struct ALCcontext_struct
-{
+struct ALCcontext_struct {
     RefCount ref;
 
     struct ALlistener *Listener;
@@ -690,8 +689,6 @@ struct ALCcontext_struct
 
     ATOMIC(ALenum) LastError;
 
-    ATOMIC(ALenum) UpdateSources;
-
     volatile enum DistanceModel DistanceModel;
     volatile ALboolean SourceDistanceModel;
 
@@ -700,6 +697,8 @@ struct ALCcontext_struct
     volatile ALfloat SpeedOfSound;
     volatile ALenum  DeferUpdates;
 
+    RWLock PropLock;
+
     struct ALvoice *Voices;
     ALsizei VoiceCount;
     ALsizei MaxVoices;