internal void RemoveAllInternal(bool saveRecycleQueue)
{
// Take _itemMap offline, to protect against reentrancy (bug 1285179)
ItemBlock itemMap = _itemMap;
_itemMap = null;
try
{
// de-initialize the containers that are being removed
if (itemMap != null)
{
for (ItemBlock block = itemMap.Next; block != itemMap; block = block.Next)
{
RealizedItemBlock rib = block as RealizedItemBlock;
if (rib != null)
{
for (int offset = 0; offset < rib.ContainerCount; ++offset)
{
UnlinkContainerFromItem(rib.ContainerAt(offset), rib.ItemAt(offset));
}
}
}
}
}
finally
{
PrepareGrouping();
// re-initialize the data structure
_itemMap = new ItemBlock();
_itemMap.Prev = _itemMap.Next = _itemMap;
UnrealizedItemBlock uib = new UnrealizedItemBlock();
uib.InsertAfter(_itemMap);
uib.ItemCount = ItemsInternal.Count;
if (!saveRecycleQueue)
{
ResetRecyclableContainers();
}
SetAlternationCount();
// tell generators what happened
if (MapChanged != null)
{
MapChanged(null, -1, 0, uib, 0, 0);
}
}
}
// "Realize" the item in a block at the given offset, to be
// the given item with corresponding container. This means updating
// the item map data structure so that the item belongs to a Realized block.
// It also requires updating the state of every generator to track the
// changes we make here.
void Realize(UnrealizedItemBlock block, int offset, object item, DependencyObject container)
{
RealizedItemBlock prevR, nextR;
RealizedItemBlock newBlock; // new location of the target item
int newOffset; // its offset within the new block
int deltaCount; // diff between cumulative item count of block and newBlock
// if we're realizing the leftmost item and there's room in the
// previous block, move it there
if (offset == 0 &&
(prevR = block.Prev as RealizedItemBlock) != null &&
prevR.ItemCount < ItemBlock.BlockSize)
{
newBlock = prevR;
newOffset = prevR.ItemCount;
MoveItems(block, offset, 1, newBlock, newOffset, -prevR.ItemCount);
MoveItems(block, 1, block.ItemCount, block, 0, +1);
}
// if we're realizing the rightmost item and there's room in the
// next block, move it there
else if (offset == block.ItemCount - 1 &&
(nextR = block.Next as RealizedItemBlock) != null &&
nextR.ItemCount < ItemBlock.BlockSize)
{
newBlock = nextR;
newOffset = 0;
MoveItems(newBlock, 0, newBlock.ItemCount, newBlock, 1, -1);
MoveItems(block, offset, 1, newBlock, newOffset, offset);
}
// otherwise we need a new block for the target item
else
{
newBlock = new RealizedItemBlock();
newOffset = 0;
deltaCount = offset;
// if target is leftmost item, insert it before remaining items
if (offset == 0)
{
newBlock.InsertBefore(block);
MoveItems(block, offset, 1, newBlock, newOffset, 0);
MoveItems(block, 1, block.ItemCount, block, 0, +1);
}
// if target is rightmost item, insert it after remaining items
else if (offset == block.ItemCount - 1)
{
newBlock.InsertAfter(block);
MoveItems(block, offset, 1, newBlock, newOffset, offset);
}
// otherwise split the block into two, with the target in the middle
else
{
UnrealizedItemBlock newUBlock = new UnrealizedItemBlock();
newUBlock.InsertAfter(block);
newBlock.InsertAfter(block);
MoveItems(block, offset+1, block.ItemCount-offset-1, newUBlock, 0, offset+1);
MoveItems(block, offset, 1, newBlock, 0, offset);
}
}
RemoveAndCoalesceBlocksIfNeeded(block);
// add the new target to the map
newBlock.RealizeItem(newOffset, item, container);
}
