gecko-dev/editor/base/PlaceholderTxn.cpp
buster%netscape.com d5932338f7 added PlaceholderTxn. This is an aggregate transaction that sits on the undo stack
and merges in subsequent transactions indiscriminately until it's told to stop.
It also gives the last transaction in its child list a chance to merge the
next transaction.
All this is in support of complex transactions that result in text insertion
being able to collapse into a single undoable event.
Also improved tracking of bogus content node used when document is empty.
1999-03-15 00:57:32 +00:00

75 lines
1.9 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
* Reserved.
*/
#include "PlaceholderTxn.h"
#include "nsVoidArray.h"
#ifdef NS_DEBUG
static PRBool gNoisy = PR_TRUE;
#else
static const PRBool gNoisy = PR_FALSE;
#endif
PlaceholderTxn::PlaceholderTxn()
: EditAggregateTxn()
{
mAbsorb=PR_TRUE;
}
PlaceholderTxn::~PlaceholderTxn()
{
}
NS_IMETHODIMP PlaceholderTxn::Do(void)
{
return NS_OK;
}
NS_IMETHODIMP PlaceholderTxn::Merge(PRBool *aDidMerge, nsITransaction *aTransaction)
{
// set out param default value
if (nsnull!=aDidMerge)
*aDidMerge=PR_FALSE;
nsresult result = NS_OK;
if ((nsnull!=aDidMerge) && (nsnull!=aTransaction))
{
EditTxn *editTxn = (EditTxn*)aTransaction; //XXX: hack, not safe! need nsIEditTransaction!
if (PR_TRUE==mAbsorb)
{ // yep, it's one of ours. Assimilate it.
AppendChild(editTxn);
*aDidMerge = PR_TRUE;
}
else
{ // let our last child txn make the choice
PRInt32 count = mChildren->Count();
if (0<count)
{
EditTxn *lastTxn = (EditTxn*)(mChildren->ElementAt(count-1));
if (lastTxn)
{
lastTxn->Merge(aDidMerge, aTransaction);
}
}
}
}
return result;
}