int asCGarbageCollector::DestroyNewGarbage()
{
for(;;)
{
switch( destroyNewState )
{
case destroyGarbage_init:
{
// If there are no objects to be freed then don't start
if( gcNewObjects.GetLength() == 0 )
return 0;
destroyNewIdx = (asUINT)-1;
destroyNewState = destroyGarbage_loop;
}
break;
case destroyGarbage_loop:
case destroyGarbage_haveMore:
{
// If the refCount has reached 1, then only the GC still holds a
// reference to the object, thus we don't need to worry about the
// application touching the objects during collection.
// Destroy all objects that have refCount == 1. If any objects are
// destroyed, go over the list again, because it may have made more
// objects reach refCount == 1.
if( ++destroyNewIdx < gcNewObjects.GetLength() )
{
asSObjTypePair gcObj = GetNewObjectAtIdx(destroyNewIdx);
if( engine->CallObjectMethodRetInt(gcObj.obj, gcObj.type->beh.gcGetRefCount) == 1 )
{
// Release the object immediately
// Make sure the refCount is really 0, because the
// destructor may have increased the refCount again.
bool addRef = false;
if( gcObj.type->flags & asOBJ_SCRIPT_OBJECT )
{
// Script objects may actually be resurrected in the destructor
int refCount = ((asCScriptObject*)gcObj.obj)->Release();
if( refCount > 0 ) addRef = true;
}
else
engine->CallObjectMethod(gcObj.obj, gcObj.type->beh.release);
// Was the object really destroyed?
if( !addRef )
{
numDestroyed++;
numNewDestroyed++;
RemoveNewObjectAtIdx(destroyNewIdx);
destroyNewIdx--;
}
else
{
// Since the object was resurrected in the
// destructor, we must add our reference again
engine->CallObjectMethod(gcObj.obj, gcObj.type->beh.addref);
}
destroyNewState = destroyGarbage_haveMore;
}
else if( gcObj.count == 3 )
{
// We've already verified this object multiple times. It is likely
// to live for quite a long time so we'll move it to the list if old objects
MoveObjectToOldList(destroyNewIdx);
destroyNewIdx--;
}
else
{
// Increase the counter for the number of times the object has been verified
IncreaseCounterForNewObject(destroyNewIdx);
}
// Allow the application to work a little
return 1;
}
else
{
if( destroyNewState == destroyGarbage_haveMore )
{
// Restart the cycle
destroyNewState = destroyGarbage_init;
}
else
{
// Restart the cycle
destroyNewState = destroyGarbage_init;
// Return 0 to tell the application that there
// is no more garbage to destroy at the moment
return 0;
}
}
}
break;
}
}
// Shouldn't reach this point
UNREACHABLE_RETURN;
}
int asCGarbageCollector::GarbageCollect(asDWORD flags)
{
// If the GC is already processing in another thread, then don't enter here again
// TODO: What if it is already processing in this thread?
if( TRYENTERCRITICALSECTION(gcCollecting) )
{
bool doDetect = (flags & asGC_DETECT_GARBAGE) || !(flags & asGC_DESTROY_GARBAGE);
bool doDestroy = (flags & asGC_DESTROY_GARBAGE) || !(flags & asGC_DETECT_GARBAGE);
if( flags & asGC_FULL_CYCLE )
{
// Reset the state
if( doDetect )
{
// Move all objects to the old list, so we guarantee that all is detected
for( asUINT n = (asUINT)gcNewObjects.GetLength(); n-- > 0; )
MoveObjectToOldList(n);
detectState = clearCounters_init;
}
if( doDestroy )
{
destroyNewState = destroyGarbage_init;
destroyOldState = destroyGarbage_init;
}
int r = 1;
unsigned int count = (unsigned int)(gcNewObjects.GetLength() + gcOldObjects.GetLength());
for(;;)
{
// Detect all garbage with cyclic references
if( doDetect )
while( (r = IdentifyGarbageWithCyclicRefs()) == 1 );
// Now destroy all known garbage
if( doDestroy )
{
while( (r = DestroyNewGarbage()) == 1 );
while( (r = DestroyOldGarbage()) == 1 );
}
// Run another iteration if any garbage was destroyed
if( count != (unsigned int)(gcNewObjects.GetLength() + gcOldObjects.GetLength()) )
count = (unsigned int)(gcNewObjects.GetLength() + gcOldObjects.GetLength());
else
break;
}
// Take the opportunity to clear unused types as well
engine->ClearUnusedTypes();
LEAVECRITICALSECTION(gcCollecting);
return 0;
}
else
{
// Destroy the garbage that we know of
if( doDestroy )
{
DestroyNewGarbage();
DestroyOldGarbage();
}
// Run another incremental step of the identification of cyclic references
if( doDetect )
IdentifyGarbageWithCyclicRefs();
}
LEAVECRITICALSECTION(gcCollecting);
}
// Return 1 to indicate that the cycle wasn't finished
return 1;
}
int asCGarbageCollector::GarbageCollect(asDWORD flags)
{
// If the GC is already processing in another thread, then don't enter here again
if( TRYENTERCRITICALSECTION(gcCollecting) )
{
// If the GC is already processing in this thread, then don't enter here again
if( isProcessing )
{
LEAVECRITICALSECTION(gcCollecting);
return 1;
}
isProcessing = true;
bool doDetect = (flags & asGC_DETECT_GARBAGE) || !(flags & asGC_DESTROY_GARBAGE);
bool doDestroy = (flags & asGC_DESTROY_GARBAGE) || !(flags & asGC_DETECT_GARBAGE);
if( flags & asGC_FULL_CYCLE )
{
// Reset the state
if( doDetect )
{
// Move all objects to the old list, so we guarantee that all is detected
for( asUINT n = (asUINT)gcNewObjects.GetLength(); n-- > 0; )
MoveObjectToOldList(n);
detectState = clearCounters_init;
}
if( doDestroy )
{
destroyNewState = destroyGarbage_init;
destroyOldState = destroyGarbage_init;
}
unsigned int count = (unsigned int)(gcNewObjects.GetLength() + gcOldObjects.GetLength());
for(;;)
{
// Detect all garbage with cyclic references
if( doDetect )
while( IdentifyGarbageWithCyclicRefs() == 1 ) {}
// Now destroy all known garbage
if( doDestroy )
{
while( DestroyNewGarbage() == 1 ) {}
while( DestroyOldGarbage() == 1 ) {}
}
// Run another iteration if any garbage was destroyed
if( count != (unsigned int)(gcNewObjects.GetLength() + gcOldObjects.GetLength()) )
count = (unsigned int)(gcNewObjects.GetLength() + gcOldObjects.GetLength());
else
{
// Let the engine destroy the types that reached refCount 0
// If none were destroyed, then leave the GC
// TODO: The asCObjectType should destroy its content when refCount reaches 0
// since no-one is using them. The registered types should have their
// refcount increased by the config groups. Doing it like that will allow
// me to remove this call to ClearUnusedTypes() that the GC really
// shouldn't be calling.
if( engine->ClearUnusedTypes() == 0 )
break;
}
}
isProcessing = false;
LEAVECRITICALSECTION(gcCollecting);
return 0;
}
else
{
// Destroy the garbage that we know of
if( doDestroy )
{
DestroyNewGarbage();
DestroyOldGarbage();
}
// Run another incremental step of the identification of cyclic references
if( doDetect )
IdentifyGarbageWithCyclicRefs();
}
isProcessing = false;
LEAVECRITICALSECTION(gcCollecting);
}
// Return 1 to indicate that the cycle wasn't finished
return 1;
}
int asCGarbageCollector::DestroyNewGarbage()
{
// This function will only be called within the critical section gcCollecting
asASSERT(isProcessing);
for(;;)
{
switch( destroyNewState )
{
case destroyGarbage_init:
{
// If there are no objects to be freed then don't start
if( gcNewObjects.GetLength() == 0 )
return 0;
// Update the seqAtSweepStart which is used to determine when
// to move an object from the new set to the old set
seqAtSweepStart[0] = seqAtSweepStart[1];
seqAtSweepStart[1] = seqAtSweepStart[2];
seqAtSweepStart[2] = numAdded;
destroyNewIdx = (asUINT)-1;
destroyNewState = destroyGarbage_loop;
}
break;
case destroyGarbage_loop:
case destroyGarbage_haveMore:
{
// If the refCount has reached 1, then only the GC still holds a
// reference to the object, thus we don't need to worry about the
// application touching the objects during collection.
// Destroy all objects that have refCount == 1. If any objects are
// destroyed, go over the list again, because it may have made more
// objects reach refCount == 1.
if( ++destroyNewIdx < gcNewObjects.GetLength() )
{
asSObjTypePair gcObj = GetNewObjectAtIdx(destroyNewIdx);
if( engine->CallObjectMethodRetInt(gcObj.obj, gcObj.type->beh.gcGetRefCount) == 1 )
{
// Release the object immediately
// Make sure the refCount is really 0, because the
// destructor may have increased the refCount again.
bool addRef = false;
if( gcObj.type->flags & asOBJ_SCRIPT_OBJECT )
{
// Script objects may actually be resurrected in the destructor
int refCount = ((asCScriptObject*)gcObj.obj)->Release();
if( refCount > 0 ) addRef = true;
}
else
engine->CallObjectMethod(gcObj.obj, gcObj.type->beh.release);
// Was the object really destroyed?
if( !addRef )
{
numDestroyed++;
numNewDestroyed++;
RemoveNewObjectAtIdx(destroyNewIdx);
destroyNewIdx--;
}
else
{
// Since the object was resurrected in the
// destructor, we must add our reference again
engine->CallObjectMethod(gcObj.obj, gcObj.type->beh.addref);
}
destroyNewState = destroyGarbage_haveMore;
}
// Check if this object has been inspected 3 times already, and if so move it to the
// set of old objects that are less likely to become garbage in a short time
// TODO: Is 3 really a good value? Should the number of times be dynamic?
else if( gcObj.seqNbr < seqAtSweepStart[0] )
{
// We've already verified this object multiple times. It is likely
// to live for quite a long time so we'll move it to the list if old objects
MoveObjectToOldList(destroyNewIdx);
destroyNewIdx--;
}
// Allow the application to work a little
return 1;
}
else
{
if( destroyNewState == destroyGarbage_haveMore )
{
// Restart the cycle
destroyNewState = destroyGarbage_init;
}
else
{
// Restart the cycle
destroyNewState = destroyGarbage_init;
// Return 0 to tell the application that there
// is no more garbage to destroy at the moment
return 0;
}
}
}
break;
}
}
// Shouldn't reach this point
UNREACHABLE_RETURN;
}
