public void Remove(Transaction trans, int index)
{
if (!_isLeaf)
{
throw new InvalidOperationException();
}
PrepareWrite(trans);
SetStateDirty();
object obj = null;
BTreePatch patch = KeyPatch(index);
if (patch == null)
{
obj = _keys[index];
}
else
{
BTreePatch transPatch = patch.ForTransaction(trans);
if (transPatch != null)
{
obj = transPatch.GetObject();
}
else
{
// There could be more than one patch with different object
// identities. We have no means to determine a "best" object
// so we just take any one. Could be problematic.
obj = patch.GetObject();
}
}
Remove(trans, obj, index);
}
public override object Key(Transaction trans)
{
BTreePatch patch = ForTransaction(trans);
if (patch == null)
{
return(GetObject());
}
if (patch.IsRemove())
{
return(No4.Instance);
}
return(patch.GetObject());
}
public bool Remove(Transaction trans, object obj, int index)
{
if (!_isLeaf)
{
throw new InvalidOperationException();
}
PrepareWrite(trans);
SetStateDirty();
BTreePatch patch = KeyPatch(index);
// no patch, no problem, can remove
if (patch == null)
{
_keys[index] = ApplyNewRemovePatch(trans, obj);
KeyChanged(trans, index);
return(true);
}
BTreePatch transPatch = patch.ForTransaction(trans);
if (transPatch != null)
{
if (transPatch.IsAdd())
{
CancelAdding(trans, index);
return(true);
}
if (transPatch.IsCancelledRemoval())
{
BTreeRemove removePatch = ApplyNewRemovePatch(trans, transPatch.GetObject());
_keys[index] = ((BTreeUpdate)patch).ReplacePatch(transPatch, removePatch);
KeyChanged(trans, index);
return(true);
}
}
else
{
// If the patch is a removal of a cancelled removal for another
// transaction, we need one for this transaction also.
if (!patch.IsAdd())
{
((BTreeUpdate)patch).Append(ApplyNewRemovePatch(trans, obj));
return(true);
}
}
return(false);
}