gecko/editor/txmgr/nsTransactionManager.cpp
Birunthan Mohanathas 2d6e65c588 Bug 1028565 - Part 2: Flatten editor/txmgr/{idl,public,src}/ directories. r=ehsan
--HG--
rename : editor/txmgr/idl/nsITransaction.idl => editor/txmgr/nsITransaction.idl
rename : editor/txmgr/idl/nsITransactionList.idl => editor/txmgr/nsITransactionList.idl
rename : editor/txmgr/idl/nsITransactionListener.idl => editor/txmgr/nsITransactionListener.idl
rename : editor/txmgr/idl/nsITransactionManager.idl => editor/txmgr/nsITransactionManager.idl
rename : editor/txmgr/src/nsTransactionItem.cpp => editor/txmgr/nsTransactionItem.cpp
rename : editor/txmgr/src/nsTransactionItem.h => editor/txmgr/nsTransactionItem.h
rename : editor/txmgr/src/nsTransactionList.cpp => editor/txmgr/nsTransactionList.cpp
rename : editor/txmgr/src/nsTransactionList.h => editor/txmgr/nsTransactionList.h
rename : editor/txmgr/src/nsTransactionManager.cpp => editor/txmgr/nsTransactionManager.cpp
rename : editor/txmgr/src/nsTransactionManager.h => editor/txmgr/nsTransactionManager.h
rename : editor/txmgr/public/nsTransactionManagerCID.h => editor/txmgr/nsTransactionManagerCID.h
rename : editor/txmgr/src/nsTransactionManagerFactory.cpp => editor/txmgr/nsTransactionManagerFactory.cpp
rename : editor/txmgr/src/nsTransactionStack.cpp => editor/txmgr/nsTransactionStack.cpp
rename : editor/txmgr/src/nsTransactionStack.h => editor/txmgr/nsTransactionStack.h
2014-06-25 15:08:29 -07:00

906 lines
20 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/Assertions.h"
#include "mozilla/mozalloc.h"
#include "nsAutoPtr.h"
#include "nsCOMPtr.h"
#include "nsDebug.h"
#include "nsError.h"
#include "nsISupportsBase.h"
#include "nsISupportsUtils.h"
#include "nsITransaction.h"
#include "nsITransactionList.h"
#include "nsITransactionListener.h"
#include "nsIWeakReference.h"
#include "nsTransactionItem.h"
#include "nsTransactionList.h"
#include "nsTransactionManager.h"
#include "nsTransactionStack.h"
nsTransactionManager::nsTransactionManager(int32_t aMaxTransactionCount)
: mMaxTransactionCount(aMaxTransactionCount)
, mDoStack(nsTransactionStack::FOR_UNDO)
, mUndoStack(nsTransactionStack::FOR_UNDO)
, mRedoStack(nsTransactionStack::FOR_REDO)
{
}
nsTransactionManager::~nsTransactionManager()
{
}
NS_IMPL_CYCLE_COLLECTION_CLASS(nsTransactionManager)
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsTransactionManager)
NS_IMPL_CYCLE_COLLECTION_UNLINK(mListeners)
tmp->mDoStack.DoUnlink();
tmp->mUndoStack.DoUnlink();
tmp->mRedoStack.DoUnlink();
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsTransactionManager)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mListeners)
tmp->mDoStack.DoTraverse(cb);
tmp->mUndoStack.DoTraverse(cb);
tmp->mRedoStack.DoTraverse(cb);
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsTransactionManager)
NS_INTERFACE_MAP_ENTRY(nsITransactionManager)
NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsITransactionManager)
NS_INTERFACE_MAP_END
NS_IMPL_CYCLE_COLLECTING_ADDREF(nsTransactionManager)
NS_IMPL_CYCLE_COLLECTING_RELEASE(nsTransactionManager)
NS_IMETHODIMP
nsTransactionManager::DoTransaction(nsITransaction *aTransaction)
{
nsresult result;
NS_ENSURE_TRUE(aTransaction, NS_ERROR_NULL_POINTER);
bool doInterrupt = false;
result = WillDoNotify(aTransaction, &doInterrupt);
if (NS_FAILED(result)) {
return result;
}
if (doInterrupt) {
return NS_OK;
}
result = BeginTransaction(aTransaction, nullptr);
if (NS_FAILED(result)) {
DidDoNotify(aTransaction, result);
return result;
}
result = EndTransaction(false);
nsresult result2 = DidDoNotify(aTransaction, result);
if (NS_SUCCEEDED(result))
result = result2;
return result;
}
NS_IMETHODIMP
nsTransactionManager::UndoTransaction()
{
nsresult result = NS_OK;
// It is illegal to call UndoTransaction() while the transaction manager is
// executing a transaction's DoTransaction() method! If this happens,
// the UndoTransaction() request is ignored, and we return NS_ERROR_FAILURE.
nsRefPtr<nsTransactionItem> tx = mDoStack.Peek();
if (tx) {
return NS_ERROR_FAILURE;
}
// Peek at the top of the undo stack. Don't remove the transaction
// until it has successfully completed.
tx = mUndoStack.Peek();
// Bail if there's nothing on the stack.
if (!tx) {
return NS_OK;
}
nsCOMPtr<nsITransaction> t = tx->GetTransaction();
bool doInterrupt = false;
result = WillUndoNotify(t, &doInterrupt);
if (NS_FAILED(result)) {
return result;
}
if (doInterrupt) {
return NS_OK;
}
result = tx->UndoTransaction(this);
if (NS_SUCCEEDED(result)) {
tx = mUndoStack.Pop();
mRedoStack.Push(tx);
}
nsresult result2 = DidUndoNotify(t, result);
if (NS_SUCCEEDED(result))
result = result2;
return result;
}
NS_IMETHODIMP
nsTransactionManager::RedoTransaction()
{
nsresult result = NS_OK;
// It is illegal to call RedoTransaction() while the transaction manager is
// executing a transaction's DoTransaction() method! If this happens,
// the RedoTransaction() request is ignored, and we return NS_ERROR_FAILURE.
nsRefPtr<nsTransactionItem> tx = mDoStack.Peek();
if (tx) {
return NS_ERROR_FAILURE;
}
// Peek at the top of the redo stack. Don't remove the transaction
// until it has successfully completed.
tx = mRedoStack.Peek();
// Bail if there's nothing on the stack.
if (!tx) {
return NS_OK;
}
nsCOMPtr<nsITransaction> t = tx->GetTransaction();
bool doInterrupt = false;
result = WillRedoNotify(t, &doInterrupt);
if (NS_FAILED(result)) {
return result;
}
if (doInterrupt) {
return NS_OK;
}
result = tx->RedoTransaction(this);
if (NS_SUCCEEDED(result)) {
tx = mRedoStack.Pop();
mUndoStack.Push(tx);
}
nsresult result2 = DidRedoNotify(t, result);
if (NS_SUCCEEDED(result))
result = result2;
return result;
}
NS_IMETHODIMP
nsTransactionManager::Clear()
{
nsresult result;
result = ClearRedoStack();
if (NS_FAILED(result)) {
return result;
}
result = ClearUndoStack();
return result;
}
NS_IMETHODIMP
nsTransactionManager::BeginBatch(nsISupports* aData)
{
nsresult result;
// We can batch independent transactions together by simply pushing
// a dummy transaction item on the do stack. This dummy transaction item
// will be popped off the do stack, and then pushed on the undo stack
// in EndBatch().
bool doInterrupt = false;
result = WillBeginBatchNotify(&doInterrupt);
if (NS_FAILED(result)) {
return result;
}
if (doInterrupt) {
return NS_OK;
}
result = BeginTransaction(0, aData);
nsresult result2 = DidBeginBatchNotify(result);
if (NS_SUCCEEDED(result))
result = result2;
return result;
}
NS_IMETHODIMP
nsTransactionManager::EndBatch(bool aAllowEmpty)
{
nsCOMPtr<nsITransaction> ti;
nsresult result;
// XXX: Need to add some mechanism to detect the case where the transaction
// at the top of the do stack isn't the dummy transaction, so we can
// throw an error!! This can happen if someone calls EndBatch() within
// the DoTransaction() method of a transaction.
//
// For now, we can detect this case by checking the value of the
// dummy transaction's mTransaction field. If it is our dummy
// transaction, it should be nullptr. This may not be true in the
// future when we allow users to execute a transaction when beginning
// a batch!!!!
nsRefPtr<nsTransactionItem> tx = mDoStack.Peek();
if (tx) {
ti = tx->GetTransaction();
}
if (!tx || ti) {
return NS_ERROR_FAILURE;
}
bool doInterrupt = false;
result = WillEndBatchNotify(&doInterrupt);
if (NS_FAILED(result)) {
return result;
}
if (doInterrupt) {
return NS_OK;
}
result = EndTransaction(aAllowEmpty);
nsresult result2 = DidEndBatchNotify(result);
if (NS_SUCCEEDED(result))
result = result2;
return result;
}
NS_IMETHODIMP
nsTransactionManager::GetNumberOfUndoItems(int32_t *aNumItems)
{
*aNumItems = mUndoStack.GetSize();
return NS_OK;
}
NS_IMETHODIMP
nsTransactionManager::GetNumberOfRedoItems(int32_t *aNumItems)
{
*aNumItems = mRedoStack.GetSize();
return NS_OK;
}
NS_IMETHODIMP
nsTransactionManager::GetMaxTransactionCount(int32_t *aMaxCount)
{
NS_ENSURE_TRUE(aMaxCount, NS_ERROR_NULL_POINTER);
*aMaxCount = mMaxTransactionCount;
return NS_OK;
}
NS_IMETHODIMP
nsTransactionManager::SetMaxTransactionCount(int32_t aMaxCount)
{
int32_t numUndoItems = 0, numRedoItems = 0, total = 0;
// It is illegal to call SetMaxTransactionCount() while the transaction
// manager is executing a transaction's DoTransaction() method because
// the undo and redo stacks might get pruned! If this happens, the
// SetMaxTransactionCount() request is ignored, and we return
// NS_ERROR_FAILURE.
nsRefPtr<nsTransactionItem> tx = mDoStack.Peek();
if (tx) {
return NS_ERROR_FAILURE;
}
// If aMaxCount is less than zero, the user wants unlimited
// levels of undo! No need to prune the undo or redo stacks!
if (aMaxCount < 0) {
mMaxTransactionCount = -1;
return NS_OK;
}
numUndoItems = mUndoStack.GetSize();
numRedoItems = mRedoStack.GetSize();
total = numUndoItems + numRedoItems;
// If aMaxCount is greater than the number of transactions that currently
// exist on the undo and redo stack, there is no need to prune the
// undo or redo stacks!
if (aMaxCount > total ) {
mMaxTransactionCount = aMaxCount;
return NS_OK;
}
// Try getting rid of some transactions on the undo stack! Start at
// the bottom of the stack and pop towards the top.
while (numUndoItems > 0 && (numRedoItems + numUndoItems) > aMaxCount) {
tx = mUndoStack.PopBottom();
if (!tx) {
return NS_ERROR_FAILURE;
}
--numUndoItems;
}
// If necessary, get rid of some transactions on the redo stack! Start at
// the bottom of the stack and pop towards the top.
while (numRedoItems > 0 && (numRedoItems + numUndoItems) > aMaxCount) {
tx = mRedoStack.PopBottom();
if (!tx) {
return NS_ERROR_FAILURE;
}
--numRedoItems;
}
mMaxTransactionCount = aMaxCount;
return NS_OK;
}
NS_IMETHODIMP
nsTransactionManager::PeekUndoStack(nsITransaction **aTransaction)
{
MOZ_ASSERT(aTransaction);
*aTransaction = PeekUndoStack().take();
return NS_OK;
}
already_AddRefed<nsITransaction>
nsTransactionManager::PeekUndoStack()
{
nsRefPtr<nsTransactionItem> tx = mUndoStack.Peek();
if (!tx) {
return nullptr;
}
return tx->GetTransaction();
}
NS_IMETHODIMP
nsTransactionManager::PeekRedoStack(nsITransaction** aTransaction)
{
MOZ_ASSERT(aTransaction);
*aTransaction = PeekRedoStack().take();
return NS_OK;
}
already_AddRefed<nsITransaction>
nsTransactionManager::PeekRedoStack()
{
nsRefPtr<nsTransactionItem> tx = mRedoStack.Peek();
if (!tx) {
return nullptr;
}
return tx->GetTransaction();
}
NS_IMETHODIMP
nsTransactionManager::GetUndoList(nsITransactionList **aTransactionList)
{
NS_ENSURE_TRUE(aTransactionList, NS_ERROR_NULL_POINTER);
*aTransactionList = (nsITransactionList *)new nsTransactionList(this, &mUndoStack);
NS_IF_ADDREF(*aTransactionList);
return (! *aTransactionList) ? NS_ERROR_OUT_OF_MEMORY : NS_OK;
}
NS_IMETHODIMP
nsTransactionManager::GetRedoList(nsITransactionList **aTransactionList)
{
NS_ENSURE_TRUE(aTransactionList, NS_ERROR_NULL_POINTER);
*aTransactionList = (nsITransactionList *)new nsTransactionList(this, &mRedoStack);
NS_IF_ADDREF(*aTransactionList);
return (! *aTransactionList) ? NS_ERROR_OUT_OF_MEMORY : NS_OK;
}
nsresult
nsTransactionManager::BatchTopUndo()
{
if (mUndoStack.GetSize() < 2) {
// Not enough transactions to merge into one batch.
return NS_OK;
}
nsRefPtr<nsTransactionItem> lastUndo;
nsRefPtr<nsTransactionItem> previousUndo;
lastUndo = mUndoStack.Pop();
MOZ_ASSERT(lastUndo, "There should be at least two transactions.");
previousUndo = mUndoStack.Peek();
MOZ_ASSERT(previousUndo, "There should be at least two transactions.");
nsresult result = previousUndo->AddChild(lastUndo);
// Transfer data from the transactions that is going to be
// merged to the transaction that it is being merged with.
nsCOMArray<nsISupports>& lastData = lastUndo->GetData();
nsCOMArray<nsISupports>& previousData = previousUndo->GetData();
NS_ENSURE_TRUE(previousData.AppendObjects(lastData), NS_ERROR_UNEXPECTED);
lastData.Clear();
return result;
}
nsresult
nsTransactionManager::RemoveTopUndo()
{
nsRefPtr<nsTransactionItem> lastUndo;
lastUndo = mUndoStack.Peek();
if (!lastUndo) {
return NS_OK;
}
lastUndo = mUndoStack.Pop();
return NS_OK;
}
NS_IMETHODIMP
nsTransactionManager::AddListener(nsITransactionListener *aListener)
{
NS_ENSURE_TRUE(aListener, NS_ERROR_NULL_POINTER);
return mListeners.AppendObject(aListener) ? NS_OK : NS_ERROR_FAILURE;
}
NS_IMETHODIMP
nsTransactionManager::RemoveListener(nsITransactionListener *aListener)
{
NS_ENSURE_TRUE(aListener, NS_ERROR_NULL_POINTER);
return mListeners.RemoveObject(aListener) ? NS_OK : NS_ERROR_FAILURE;
}
NS_IMETHODIMP
nsTransactionManager::ClearUndoStack()
{
mUndoStack.Clear();
return NS_OK;
}
NS_IMETHODIMP
nsTransactionManager::ClearRedoStack()
{
mRedoStack.Clear();
return NS_OK;
}
nsresult
nsTransactionManager::WillDoNotify(nsITransaction *aTransaction, bool *aInterrupt)
{
nsresult result = NS_OK;
for (int32_t i = 0, lcount = mListeners.Count(); i < lcount; i++)
{
nsITransactionListener *listener = mListeners[i];
NS_ENSURE_TRUE(listener, NS_ERROR_FAILURE);
result = listener->WillDo(this, aTransaction, aInterrupt);
if (NS_FAILED(result) || *aInterrupt)
break;
}
return result;
}
nsresult
nsTransactionManager::DidDoNotify(nsITransaction *aTransaction, nsresult aDoResult)
{
nsresult result = NS_OK;
for (int32_t i = 0, lcount = mListeners.Count(); i < lcount; i++)
{
nsITransactionListener *listener = mListeners[i];
NS_ENSURE_TRUE(listener, NS_ERROR_FAILURE);
result = listener->DidDo(this, aTransaction, aDoResult);
if (NS_FAILED(result))
break;
}
return result;
}
nsresult
nsTransactionManager::WillUndoNotify(nsITransaction *aTransaction, bool *aInterrupt)
{
nsresult result = NS_OK;
for (int32_t i = 0, lcount = mListeners.Count(); i < lcount; i++)
{
nsITransactionListener *listener = mListeners[i];
NS_ENSURE_TRUE(listener, NS_ERROR_FAILURE);
result = listener->WillUndo(this, aTransaction, aInterrupt);
if (NS_FAILED(result) || *aInterrupt)
break;
}
return result;
}
nsresult
nsTransactionManager::DidUndoNotify(nsITransaction *aTransaction, nsresult aUndoResult)
{
nsresult result = NS_OK;
for (int32_t i = 0, lcount = mListeners.Count(); i < lcount; i++)
{
nsITransactionListener *listener = mListeners[i];
NS_ENSURE_TRUE(listener, NS_ERROR_FAILURE);
result = listener->DidUndo(this, aTransaction, aUndoResult);
if (NS_FAILED(result))
break;
}
return result;
}
nsresult
nsTransactionManager::WillRedoNotify(nsITransaction *aTransaction, bool *aInterrupt)
{
nsresult result = NS_OK;
for (int32_t i = 0, lcount = mListeners.Count(); i < lcount; i++)
{
nsITransactionListener *listener = mListeners[i];
NS_ENSURE_TRUE(listener, NS_ERROR_FAILURE);
result = listener->WillRedo(this, aTransaction, aInterrupt);
if (NS_FAILED(result) || *aInterrupt)
break;
}
return result;
}
nsresult
nsTransactionManager::DidRedoNotify(nsITransaction *aTransaction, nsresult aRedoResult)
{
nsresult result = NS_OK;
for (int32_t i = 0, lcount = mListeners.Count(); i < lcount; i++)
{
nsITransactionListener *listener = mListeners[i];
NS_ENSURE_TRUE(listener, NS_ERROR_FAILURE);
result = listener->DidRedo(this, aTransaction, aRedoResult);
if (NS_FAILED(result))
break;
}
return result;
}
nsresult
nsTransactionManager::WillBeginBatchNotify(bool *aInterrupt)
{
nsresult result = NS_OK;
for (int32_t i = 0, lcount = mListeners.Count(); i < lcount; i++)
{
nsITransactionListener *listener = mListeners[i];
NS_ENSURE_TRUE(listener, NS_ERROR_FAILURE);
result = listener->WillBeginBatch(this, aInterrupt);
if (NS_FAILED(result) || *aInterrupt)
break;
}
return result;
}
nsresult
nsTransactionManager::DidBeginBatchNotify(nsresult aResult)
{
nsresult result = NS_OK;
for (int32_t i = 0, lcount = mListeners.Count(); i < lcount; i++)
{
nsITransactionListener *listener = mListeners[i];
NS_ENSURE_TRUE(listener, NS_ERROR_FAILURE);
result = listener->DidBeginBatch(this, aResult);
if (NS_FAILED(result))
break;
}
return result;
}
nsresult
nsTransactionManager::WillEndBatchNotify(bool *aInterrupt)
{
nsresult result = NS_OK;
for (int32_t i = 0, lcount = mListeners.Count(); i < lcount; i++)
{
nsITransactionListener *listener = mListeners[i];
NS_ENSURE_TRUE(listener, NS_ERROR_FAILURE);
result = listener->WillEndBatch(this, aInterrupt);
if (NS_FAILED(result) || *aInterrupt)
break;
}
return result;
}
nsresult
nsTransactionManager::DidEndBatchNotify(nsresult aResult)
{
nsresult result = NS_OK;
for (int32_t i = 0, lcount = mListeners.Count(); i < lcount; i++)
{
nsITransactionListener *listener = mListeners[i];
NS_ENSURE_TRUE(listener, NS_ERROR_FAILURE);
result = listener->DidEndBatch(this, aResult);
if (NS_FAILED(result))
break;
}
return result;
}
nsresult
nsTransactionManager::WillMergeNotify(nsITransaction *aTop, nsITransaction *aTransaction, bool *aInterrupt)
{
nsresult result = NS_OK;
for (int32_t i = 0, lcount = mListeners.Count(); i < lcount; i++)
{
nsITransactionListener *listener = mListeners[i];
NS_ENSURE_TRUE(listener, NS_ERROR_FAILURE);
result = listener->WillMerge(this, aTop, aTransaction, aInterrupt);
if (NS_FAILED(result) || *aInterrupt)
break;
}
return result;
}
nsresult
nsTransactionManager::DidMergeNotify(nsITransaction *aTop,
nsITransaction *aTransaction,
bool aDidMerge,
nsresult aMergeResult)
{
nsresult result = NS_OK;
for (int32_t i = 0, lcount = mListeners.Count(); i < lcount; i++)
{
nsITransactionListener *listener = mListeners[i];
NS_ENSURE_TRUE(listener, NS_ERROR_FAILURE);
result = listener->DidMerge(this, aTop, aTransaction, aDidMerge, aMergeResult);
if (NS_FAILED(result))
break;
}
return result;
}
nsresult
nsTransactionManager::BeginTransaction(nsITransaction *aTransaction,
nsISupports *aData)
{
nsresult result = NS_OK;
// XXX: POSSIBLE OPTIMIZATION
// We could use a factory that pre-allocates/recycles transaction items.
nsRefPtr<nsTransactionItem> tx = new nsTransactionItem(aTransaction);
if (aData) {
nsCOMArray<nsISupports>& data = tx->GetData();
data.AppendObject(aData);
}
if (!tx) {
return NS_ERROR_OUT_OF_MEMORY;
}
mDoStack.Push(tx);
result = tx->DoTransaction();
if (NS_FAILED(result)) {
tx = mDoStack.Pop();
return result;
}
return NS_OK;
}
nsresult
nsTransactionManager::EndTransaction(bool aAllowEmpty)
{
nsresult result = NS_OK;
nsRefPtr<nsTransactionItem> tx = mDoStack.Pop();
if (!tx)
return NS_ERROR_FAILURE;
nsCOMPtr<nsITransaction> tint = tx->GetTransaction();
if (!tint && !aAllowEmpty) {
int32_t nc = 0;
// If we get here, the transaction must be a dummy batch transaction
// created by BeginBatch(). If it contains no children, get rid of it!
tx->GetNumberOfChildren(&nc);
if (!nc) {
return result;
}
}
// Check if the transaction is transient. If it is, there's nothing
// more to do, just return.
bool isTransient = false;
if (tint)
result = tint->GetIsTransient(&isTransient);
if (NS_FAILED(result) || isTransient || !mMaxTransactionCount) {
// XXX: Should we be clearing the redo stack if the transaction
// is transient and there is nothing on the do stack?
return result;
}
// Check if there is a transaction on the do stack. If there is,
// the current transaction is a "sub" transaction, and should
// be added to the transaction at the top of the do stack.
nsRefPtr<nsTransactionItem> top = mDoStack.Peek();
if (top) {
result = top->AddChild(tx);
// XXX: What do we do if this fails?
return result;
}
// The transaction succeeded, so clear the redo stack.
result = ClearRedoStack();
if (NS_FAILED(result)) {
// XXX: What do we do if this fails?
}
// Check if we can coalesce this transaction with the one at the top
// of the undo stack.
top = mUndoStack.Peek();
if (tint && top) {
bool didMerge = false;
nsCOMPtr<nsITransaction> topTransaction = top->GetTransaction();
if (topTransaction) {
bool doInterrupt = false;
result = WillMergeNotify(topTransaction, tint, &doInterrupt);
NS_ENSURE_SUCCESS(result, result);
if (!doInterrupt) {
result = topTransaction->Merge(tint, &didMerge);
nsresult result2 = DidMergeNotify(topTransaction, tint, didMerge, result);
if (NS_SUCCEEDED(result))
result = result2;
if (NS_FAILED(result)) {
// XXX: What do we do if this fails?
}
if (didMerge) {
return result;
}
}
}
}
// Check to see if we've hit the max level of undo. If so,
// pop the bottom transaction off the undo stack and release it!
int32_t sz = mUndoStack.GetSize();
if (mMaxTransactionCount > 0 && sz >= mMaxTransactionCount) {
nsRefPtr<nsTransactionItem> overflow = mUndoStack.PopBottom();
}
// Push the transaction on the undo stack:
mUndoStack.Push(tx);
return NS_OK;
}