Provide (mostly) lockless updates for effect slots

Similar to the listener, separate containers are provided atomically for the
mixer thread to apply updates without needing to block, and a free-list is used
to reuse container objects.

A couple things to note. First, the lock is still used when the effect state's
deviceUpdate method is called to prevent asynchronous calls to reset the device
from interfering. This can be fixed by using the list lock in ALc.c instead.

Secondly, old effect states aren't immediately deleted when the effect type
changes (the actual type, not just its properties). This is because the mixer
thread is intended to be real-time safe, and so can't be freeing anything. They
are cleared away when updates reuse the container they were kept in, and they
don't incur any extra processing cost, but there may be cases where the memory
is kept around until the effect slot is deleted.

1 files changed, 116 insertions, 50 deletions

diff --git a/OpenAL32/alAuxEffectSlot.c b/OpenAL32/alAuxEffectSlot.c
index 7f570ef8..1407e1b1 100644
--- a/OpenAL32/alAuxEffectSlot.c
+++ b/OpenAL32/alAuxEffectSlot.c
@@ -86,7 +86,7 @@ AL_API ALvoid AL_APIENTRY alGenAuxiliaryEffectSlots(ALsizei n, ALuint *effectslo
         if(err != AL_NO_ERROR)
         {
             FreeThunkEntry(slot->id);
-            DELETE_OBJ(slot->EffectState);
+            DELETE_OBJ(slot->Params.EffectState);
             al_free(slot);
 
             alDeleteAuxiliaryEffectSlots(cur, effectslots);
@@ -139,7 +139,7 @@ AL_API ALvoid AL_APIENTRY alDeleteAuxiliaryEffectSlots(ALsizei n, const ALuint *
         FreeThunkEntry(slot->id);
 
         RemoveEffectSlotArray(context, slot);
-        DELETE_OBJ(slot->EffectState);
+        DeinitEffectSlot(slot);
 
         memset(slot, 0, sizeof(*slot));
         al_free(slot);
@@ -175,12 +175,13 @@ AL_API ALvoid AL_APIENTRY alAuxiliaryEffectSloti(ALuint effectslot, ALenum param
     context = GetContextRef();
     if(!context) return;
 
-    device = context->Device;
+    WriteLock(&context->PropLock);
     if((slot=LookupEffectSlot(context, effectslot)) == NULL)
         SET_ERROR_AND_GOTO(context, AL_INVALID_NAME, done);
     switch(param)
     {
     case AL_EFFECTSLOT_EFFECT:
+        device = context->Device;
         effect = (value ? LookupEffect(device, value) : NULL);
         if(!(value == 0 || effect != NULL))
             SET_ERROR_AND_GOTO(context, AL_INVALID_VALUE, done);
@@ -193,19 +194,16 @@ AL_API ALvoid AL_APIENTRY alAuxiliaryEffectSloti(ALuint effectslot, ALenum param
     case AL_EFFECTSLOT_AUXILIARY_SEND_AUTO:
         if(!(value == AL_TRUE || value == AL_FALSE))
             SET_ERROR_AND_GOTO(context, AL_INVALID_VALUE, done);
-
         slot->AuxSendAuto = value;
         break;
 
     default:
         SET_ERROR_AND_GOTO(context, AL_INVALID_ENUM, done);
     }
-    /* HACK: Force sources to update by doing a listener update */
-    ReadLock(&context->PropLock);
-    UpdateListenerProps(context);
-    ReadUnlock(&context->PropLock);
+    UpdateEffectSlotProps(slot);
 
 done:
+    WriteUnlock(&context->PropLock);
     ALCcontext_DecRef(context);
 }
 
@@ -244,6 +242,7 @@ AL_API ALvoid AL_APIENTRY alAuxiliaryEffectSlotf(ALuint effectslot, ALenum param
     context = GetContextRef();
     if(!context) return;
 
+    WriteLock(&context->PropLock);
     if((slot=LookupEffectSlot(context, effectslot)) == NULL)
         SET_ERROR_AND_GOTO(context, AL_INVALID_NAME, done);
     switch(param)
@@ -251,16 +250,16 @@ AL_API ALvoid AL_APIENTRY alAuxiliaryEffectSlotf(ALuint effectslot, ALenum param
     case AL_EFFECTSLOT_GAIN:
         if(!(value >= 0.0f && value <= 1.0f))
             SET_ERROR_AND_GOTO(context, AL_INVALID_VALUE, done);
-
         slot->Gain = value;
-        ATOMIC_STORE(&slot->NeedsUpdate, AL_TRUE);
         break;
 
     default:
         SET_ERROR_AND_GOTO(context, AL_INVALID_ENUM, done);
     }
+    UpdateEffectSlotProps(slot);
 
 done:
+    WriteUnlock(&context->PropLock);
     ALCcontext_DecRef(context);
 }
 
@@ -451,7 +450,7 @@ ALenum InitializeEffect(ALCdevice *Device, ALeffectslot *EffectSlot, ALeffect *e
     ALenum newtype = (effect ? effect->type : AL_EFFECT_NULL);
     ALeffectStateFactory *factory;
 
-    if(newtype != EffectSlot->EffectType)
+    if(newtype != EffectSlot->Effect.Type)
     {
         ALeffectState *State;
         FPUCtl oldMode;
@@ -467,7 +466,9 @@ ALenum InitializeEffect(ALCdevice *Device, ALeffectslot *EffectSlot, ALeffect *e
             return AL_OUT_OF_MEMORY;
 
         SetMixerFPUMode(&oldMode);
-
+        /* FIXME: This just needs to prevent the device from being reset during
+         * the state's device update, so the list lock in ALc.c should do here.
+         */
         ALCdevice_Lock(Device);
         State->OutBuffer = Device->Dry.Buffer;
         State->OutChannels = Device->Dry.NumChannels;
@@ -478,70 +479,135 @@ ALenum InitializeEffect(ALCdevice *Device, ALeffectslot *EffectSlot, ALeffect *e
             DELETE_OBJ(State);
             return AL_OUT_OF_MEMORY;
         }
-
-        State = ExchangePtr((XchgPtr*)&EffectSlot->EffectState, State);
-        if(!effect)
-        {
-            memset(&EffectSlot->EffectProps, 0, sizeof(EffectSlot->EffectProps));
-            EffectSlot->EffectType = AL_EFFECT_NULL;
-        }
-        else
-        {
-            memcpy(&EffectSlot->EffectProps, &effect->Props, sizeof(effect->Props));
-            EffectSlot->EffectType = effect->type;
-        }
-
-        /* FIXME: This should be done asynchronously, but since the EffectState
-         * object was changed, it needs an update before its Process method can
-         * be called. */
-        ATOMIC_STORE(&EffectSlot->NeedsUpdate, AL_FALSE);
-        V(EffectSlot->EffectState,update)(Device, EffectSlot);
         ALCdevice_Unlock(Device);
-
         RestoreFPUMode(&oldMode);
 
-        DELETE_OBJ(State);
-        State = NULL;
+        EffectSlot->Effect.State = State;
+    }
+
+    if(!effect)
+    {
+        EffectSlot->Effect.Type = AL_EFFECT_NULL;
+        memset(&EffectSlot->Effect.Props, 0, sizeof(EffectSlot->Effect.Props));
     }
     else
     {
-        if(effect)
-        {
-            ALCdevice_Lock(Device);
-            memcpy(&EffectSlot->EffectProps, &effect->Props, sizeof(effect->Props));
-            ALCdevice_Unlock(Device);
-            ATOMIC_STORE(&EffectSlot->NeedsUpdate, AL_TRUE);
-        }
+        EffectSlot->Effect.Type = effect->type;
+        memcpy(&EffectSlot->Effect.Props, &effect->Props, sizeof(EffectSlot->Effect.Props));
     }
 
     return AL_NO_ERROR;
 }
 
 
+void ALeffectState_Destruct(ALeffectState *UNUSED(state))
+{
+}
+
+
 ALenum InitEffectSlot(ALeffectslot *slot)
 {
     ALeffectStateFactory *factory;
-    ALuint i, c;
 
-    slot->EffectType = AL_EFFECT_NULL;
+    slot->Effect.Type = AL_EFFECT_NULL;
 
     factory = getFactoryByType(AL_EFFECT_NULL);
-    if(!(slot->EffectState=V0(factory,create)()))
+    if(!(slot->Effect.State=V0(factory,create)()))
         return AL_OUT_OF_MEMORY;
 
     slot->Gain = 1.0;
     slot->AuxSendAuto = AL_TRUE;
-    ATOMIC_INIT(&slot->NeedsUpdate, AL_FALSE);
-    for(c = 0;c < 1;c++)
-    {
-        for(i = 0;i < BUFFERSIZE;i++)
-            slot->WetBuffer[c][i] = 0.0f;
-    }
     InitRef(&slot->ref, 0);
 
+    ATOMIC_INIT(&slot->Update, NULL);
+    ATOMIC_INIT(&slot->FreeList, NULL);
+
+    slot->Params.Gain = 1.0f;
+    slot->Params.AuxSendAuto = AL_TRUE;
+    slot->Params.EffectState = slot->Effect.State;
+    slot->Params.RoomRolloff = 0.0f;
+    slot->Params.DecayTime = 0.0f;
+    slot->Params.AirAbsorptionGainHF = 1.0f;
+
     return AL_NO_ERROR;
 }
 
+void DeinitEffectSlot(ALeffectslot *slot)
+{
+    struct ALeffectslotProps *props;
+    size_t count = 0;
+
+    props = ATOMIC_LOAD(&slot->Update);
+    if(props)
+    {
+        DELETE_OBJ(props->State);
+        TRACE("Freed unapplied AuxiliaryEffectSlot update %p\n", props);
+        al_free(props);
+    }
+    props = ATOMIC_LOAD(&slot->FreeList, almemory_order_relaxed);
+    while(props)
+    {
+        struct ALeffectslotProps *next;
+        next = ATOMIC_LOAD(&props->next, almemory_order_relaxed);
+        DELETE_OBJ(props->State);
+        al_free(props);
+        props = next;
+        ++count;
+    }
+    TRACE("Freed "SZFMT" AuxiliaryEffectSlot property object%s\n", count, (count==1)?"":"s");
+
+    DELETE_OBJ(slot->Params.EffectState);
+}
+
+void UpdateEffectSlotProps(ALeffectslot *slot)
+{
+    struct ALeffectslotProps *props;
+    ALeffectState *oldstate;
+
+    /* Get an unused property container, or allocate a new one as needed. */
+    props = ATOMIC_LOAD(&slot->FreeList, almemory_order_acquire);
+    if(!props)
+        props = al_calloc(16, sizeof(*props));
+    else
+    {
+        struct ALeffectslotProps *next;
+        do {
+            next = ATOMIC_LOAD(&props->next, almemory_order_relaxed);
+        } while(ATOMIC_COMPARE_EXCHANGE_WEAK(struct ALeffectslotProps*,
+                &slot->FreeList, &props, next, almemory_order_seq_cst,
+                almemory_order_consume) == 0);
+    }
+
+    /* Copy in current property values. */
+    ATOMIC_STORE(&props->Gain, slot->Gain, almemory_order_relaxed);
+    ATOMIC_STORE(&props->AuxSendAuto, slot->AuxSendAuto, almemory_order_relaxed);
+
+    ATOMIC_STORE(&props->Type, slot->Effect.Type, almemory_order_relaxed);
+    memcpy(&props->Props, &slot->Effect.Props, sizeof(props->Props));
+    /* Swap out any stale effect state object there may be in the container, to
+     * delete it.
+     */
+    oldstate = ATOMIC_EXCHANGE(ALeffectState*, &props->State, slot->Effect.State,
+                               almemory_order_relaxed);
+
+    /* Set the new container for updating internal parameters. */
+    props = ATOMIC_EXCHANGE(struct ALeffectslotProps*, &slot->Update, props,
+                            almemory_order_acq_rel);
+    if(props)
+    {
+        /* If there was an unused update container, put it back in the
+         * freelist.
+         */
+        struct ALeffectslotProps *first = ATOMIC_LOAD(&slot->FreeList);
+        do {
+            ATOMIC_STORE(&props->next, first, almemory_order_relaxed);
+        } while(ATOMIC_COMPARE_EXCHANGE_WEAK(struct ALeffectslotProps*,
+                &slot->FreeList, &first, props) == 0);
+    }
+
+    DELETE_OBJ(oldstate);
+}
+
 ALvoid ReleaseALAuxiliaryEffectSlots(ALCcontext *Context)
 {
     ALsizei pos;
@@ -550,7 +616,7 @@ ALvoid ReleaseALAuxiliaryEffectSlots(ALCcontext *Context)
         ALeffectslot *temp = Context->EffectSlotMap.array[pos].value;
         Context->EffectSlotMap.array[pos].value = NULL;
 
-        DELETE_OBJ(temp->EffectState);
+        DeinitEffectSlot(temp);
 
         FreeThunkEntry(temp->id);
         memset(temp, 0, sizeof(ALeffectslot));