diff options
Diffstat (limited to '')
| -rw-r--r-- | editor/txmgr/TransactionManager.cpp | 789 |
1 files changed, 789 insertions, 0 deletions
diff --git a/editor/txmgr/TransactionManager.cpp b/editor/txmgr/TransactionManager.cpp new file mode 100644 index 0000000000..f0e6d44b2d --- /dev/null +++ b/editor/txmgr/TransactionManager.cpp @@ -0,0 +1,789 @@ +/* -*- 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/TransactionManager.h" + +#include "mozilla/Assertions.h" +#include "mozilla/DebugOnly.h" +#include "mozilla/mozalloc.h" +#include "mozilla/TransactionStack.h" +#include "nsCOMPtr.h" +#include "nsDebug.h" +#include "nsError.h" +#include "nsISupportsBase.h" +#include "nsISupportsUtils.h" +#include "nsITransaction.h" +#include "nsITransactionListener.h" +#include "nsIWeakReference.h" +#include "TransactionItem.h" + +namespace mozilla { + +TransactionManager::TransactionManager(int32_t aMaxTransactionCount) + : mMaxTransactionCount(aMaxTransactionCount), + mDoStack(TransactionStack::FOR_UNDO), + mUndoStack(TransactionStack::FOR_UNDO), + mRedoStack(TransactionStack::FOR_REDO) {} + +NS_IMPL_CYCLE_COLLECTION_CLASS(TransactionManager) + +NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(TransactionManager) + NS_IMPL_CYCLE_COLLECTION_UNLINK(mListeners) + tmp->mDoStack.DoUnlink(); + tmp->mUndoStack.DoUnlink(); + tmp->mRedoStack.DoUnlink(); + NS_IMPL_CYCLE_COLLECTION_UNLINK_WEAK_REFERENCE +NS_IMPL_CYCLE_COLLECTION_UNLINK_END + +NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(TransactionManager) + 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(TransactionManager) + 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(TransactionManager) +NS_IMPL_CYCLE_COLLECTING_RELEASE(TransactionManager) + +NS_IMETHODIMP TransactionManager::DoTransaction(nsITransaction* aTransaction) { + if (NS_WARN_IF(!aTransaction)) { + return NS_ERROR_INVALID_ARG; + } + + bool doInterrupt = false; + + nsresult rv = WillDoNotify(aTransaction, &doInterrupt); + if (NS_FAILED(rv)) { + NS_WARNING("TransactionManager::WillDoNotify() failed"); + return rv; + } + if (doInterrupt) { + return NS_OK; + } + + rv = BeginTransaction(aTransaction, nullptr); + if (NS_FAILED(rv)) { + NS_WARNING("TransactionManager::BeginTransaction() failed"); + DebugOnly<nsresult> rvIgnored = DidDoNotify(aTransaction, rv); + NS_WARNING_ASSERTION( + NS_SUCCEEDED(rvIgnored), + "TransactionManager::DidDoNotify() failed, but ignored"); + return rv; + } + + rv = EndTransaction(false); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), + "TransactionManager::EndTransaction() failed"); + + nsresult rv2 = DidDoNotify(aTransaction, rv); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv2), + "TransactionManager::DidDoNotify() failed"); + + // XXX The result of EndTransaction() or DidDoNotify() if EndTransaction() + // succeeded. + return NS_SUCCEEDED(rv) ? rv2 : rv; +} + +NS_IMETHODIMP TransactionManager::UndoTransaction() { return Undo(); } + +nsresult TransactionManager::Undo() { + // It's possible to be called Undo() again while the transaction manager is + // executing a transaction's DoTransaction() method. If this happens, + // the Undo() request is ignored, and we return NS_ERROR_FAILURE. This + // may occur if a mutation event listener calls document.execCommand("undo"). + if (NS_WARN_IF(!mDoStack.IsEmpty())) { + return NS_ERROR_FAILURE; + } + + // Peek at the top of the undo stack. Don't remove the transaction + // until it has successfully completed. + RefPtr<TransactionItem> transactionItem = mUndoStack.Peek(); + if (!transactionItem) { + // Bail if there's nothing on the stack. + return NS_OK; + } + + nsCOMPtr<nsITransaction> transaction = transactionItem->GetTransaction(); + bool doInterrupt = false; + nsresult rv = WillUndoNotify(transaction, &doInterrupt); + if (NS_FAILED(rv)) { + NS_WARNING("TransactionManager::WillUndoNotify() failed"); + return rv; + } + if (doInterrupt) { + return NS_OK; + } + + rv = transactionItem->UndoTransaction(this); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), + "TransactionItem::UndoTransaction() failed"); + if (NS_SUCCEEDED(rv)) { + transactionItem = mUndoStack.Pop(); + mRedoStack.Push(transactionItem.forget()); + } + + nsresult rv2 = DidUndoNotify(transaction, rv); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv2), + "TransactionManager::DidUndoNotify() failed"); + + // XXX The result of UndoTransaction() or DidUndoNotify() if UndoTransaction() + // succeeded. + return NS_SUCCEEDED(rv) ? rv2 : rv; +} + +NS_IMETHODIMP TransactionManager::RedoTransaction() { return Redo(); } + +nsresult TransactionManager::Redo() { + // It's possible to be called Redo() again while the transaction manager is + // executing a transaction's DoTransaction() method. If this happens, + // the Redo() request is ignored, and we return NS_ERROR_FAILURE. This + // may occur if a mutation event listener calls document.execCommand("redo"). + if (NS_WARN_IF(!mDoStack.IsEmpty())) { + return NS_ERROR_FAILURE; + } + + // Peek at the top of the redo stack. Don't remove the transaction + // until it has successfully completed. + RefPtr<TransactionItem> transactionItem = mRedoStack.Peek(); + if (!transactionItem) { + // Bail if there's nothing on the stack. + return NS_OK; + } + + nsCOMPtr<nsITransaction> transaction = transactionItem->GetTransaction(); + bool doInterrupt = false; + nsresult rv = WillRedoNotify(transaction, &doInterrupt); + if (NS_FAILED(rv)) { + NS_WARNING("TransactionManager::WillRedoNotify() failed"); + return rv; + } + if (doInterrupt) { + return NS_OK; + } + + rv = transactionItem->RedoTransaction(this); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), + "TransactionItem::RedoTransaction() failed"); + if (NS_SUCCEEDED(rv)) { + transactionItem = mRedoStack.Pop(); + mUndoStack.Push(transactionItem.forget()); + } + + nsresult rv2 = DidRedoNotify(transaction, rv); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv2), + "TransactionManager::DidRedoNotify() failed"); + + // XXX The result of RedoTransaction() or DidRedoNotify() if RedoTransaction() + // succeeded. + return NS_SUCCEEDED(rv) ? rv2 : rv; +} + +NS_IMETHODIMP TransactionManager::Clear() { + return NS_WARN_IF(!ClearUndoRedo()) ? NS_ERROR_FAILURE : NS_OK; +} + +NS_IMETHODIMP TransactionManager::BeginBatch(nsISupports* aData) { + nsresult rv = BeginBatchInternal(aData); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), + "TransactionManager::BeginBatchInternal() failed"); + return rv; +} + +nsresult TransactionManager::BeginBatchInternal(nsISupports* aData) { + // 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; + nsresult rv = WillBeginBatchNotify(&doInterrupt); + if (NS_FAILED(rv)) { + NS_WARNING("TransactionManager::WillBeginBatchNotify() failed"); + return rv; + } + if (doInterrupt) { + return NS_OK; + } + + rv = BeginTransaction(nullptr, aData); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), + "TransactionManager::BeginTransaction() failed"); + + nsresult rv2 = DidBeginBatchNotify(rv); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv2), + "TransactionManager::DidBeginBatchNotify() failed"); + + // XXX The result of BeginTransaction() or DidBeginBatchNotify() if + // BeginTransaction() succeeded. + return NS_SUCCEEDED(rv) ? rv2 : rv; +} + +NS_IMETHODIMP TransactionManager::EndBatch(bool aAllowEmpty) { + nsresult rv = EndBatchInternal(aAllowEmpty); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), + "TransactionManager::EndBatchInternal() failed"); + return rv; +} + +nsresult TransactionManager::EndBatchInternal(bool aAllowEmpty) { + // 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!!!! + RefPtr<TransactionItem> transactionItem = mDoStack.Peek(); + if (NS_WARN_IF(!transactionItem)) { + return NS_ERROR_FAILURE; + } + nsCOMPtr<nsITransaction> transaction = transactionItem->GetTransaction(); + if (NS_WARN_IF(transaction)) { + return NS_ERROR_FAILURE; + } + + bool doInterrupt = false; + nsresult rv = WillEndBatchNotify(&doInterrupt); + if (NS_FAILED(rv)) { + NS_WARNING("TransactionManager::WillEndBatchNotify() failed"); + return rv; + } + if (doInterrupt) { + return NS_OK; + } + + rv = EndTransaction(aAllowEmpty); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), + "TransactionManager::EndTransaction() failed"); + + nsresult rv2 = DidEndBatchNotify(rv); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv2), + "TransactionManager::DidEndBatchNotify() failed"); + + // XXX The result of EndTransaction() or DidEndBatchNotify() if + // EndTransaction() succeeded. + return NS_SUCCEEDED(rv) ? rv2 : rv; +} + +NS_IMETHODIMP TransactionManager::GetNumberOfUndoItems(int32_t* aNumItems) { + *aNumItems = static_cast<int32_t>(NumberOfUndoItems()); + MOZ_ASSERT(*aNumItems >= 0); + return NS_OK; +} + +NS_IMETHODIMP TransactionManager::GetNumberOfRedoItems(int32_t* aNumItems) { + *aNumItems = static_cast<int32_t>(NumberOfRedoItems()); + MOZ_ASSERT(*aNumItems >= 0); + return NS_OK; +} + +NS_IMETHODIMP TransactionManager::GetMaxTransactionCount(int32_t* aMaxCount) { + if (NS_WARN_IF(!aMaxCount)) { + return NS_ERROR_INVALID_ARG; + } + *aMaxCount = mMaxTransactionCount; + return NS_OK; +} + +NS_IMETHODIMP TransactionManager::SetMaxTransactionCount(int32_t aMaxCount) { + return NS_WARN_IF(!EnableUndoRedo(aMaxCount)) ? NS_ERROR_FAILURE : NS_OK; +} + +bool TransactionManager::EnableUndoRedo(int32_t aMaxTransactionCount) { + // It is illegal to call EnableUndoRedo() while the transaction manager is + // executing a transaction's DoTransaction() method because the undo and redo + // stacks might get pruned. If this happens, the EnableUndoRedo() request is + // ignored, and we return false. + if (NS_WARN_IF(!mDoStack.IsEmpty())) { + return false; + } + + // If aMaxTransactionCount is 0, it means to disable undo/redo. + if (!aMaxTransactionCount) { + mUndoStack.Clear(); + mRedoStack.Clear(); + mMaxTransactionCount = 0; + return true; + } + + // If aMaxTransactionCount is less than zero, the user wants unlimited + // levels of undo! No need to prune the undo or redo stacks. + if (aMaxTransactionCount < 0) { + mMaxTransactionCount = -1; + return true; + } + + // If new max transaction count is greater than or equal to current max + // transaction count, we don't need to remove any transactions. + if (mMaxTransactionCount >= 0 && + mMaxTransactionCount <= aMaxTransactionCount) { + mMaxTransactionCount = aMaxTransactionCount; + return true; + } + + // If aMaxTransactionCount 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. + size_t numUndoItems = NumberOfUndoItems(); + size_t numRedoItems = NumberOfRedoItems(); + size_t total = numUndoItems + numRedoItems; + size_t newMaxTransactionCount = static_cast<size_t>(aMaxTransactionCount); + if (newMaxTransactionCount > total) { + mMaxTransactionCount = aMaxTransactionCount; + return true; + } + + // Try getting rid of some transactions on the undo stack! Start at + // the bottom of the stack and pop towards the top. + for (; numUndoItems && (numRedoItems + numUndoItems) > newMaxTransactionCount; + numUndoItems--) { + RefPtr<TransactionItem> transactionItem = mUndoStack.PopBottom(); + MOZ_ASSERT(transactionItem); + } + + // If necessary, get rid of some transactions on the redo stack! Start at + // the bottom of the stack and pop towards the top. + for (; numRedoItems && (numRedoItems + numUndoItems) > newMaxTransactionCount; + numRedoItems--) { + RefPtr<TransactionItem> transactionItem = mRedoStack.PopBottom(); + MOZ_ASSERT(transactionItem); + } + + mMaxTransactionCount = aMaxTransactionCount; + return true; +} + +NS_IMETHODIMP TransactionManager::PeekUndoStack(nsITransaction** aTransaction) { + MOZ_ASSERT(aTransaction); + *aTransaction = PeekUndoStack().take(); + return NS_OK; +} + +already_AddRefed<nsITransaction> TransactionManager::PeekUndoStack() { + RefPtr<TransactionItem> transactionItem = mUndoStack.Peek(); + if (!transactionItem) { + return nullptr; + } + return transactionItem->GetTransaction(); +} + +NS_IMETHODIMP TransactionManager::PeekRedoStack(nsITransaction** aTransaction) { + MOZ_ASSERT(aTransaction); + *aTransaction = PeekRedoStack().take(); + return NS_OK; +} + +already_AddRefed<nsITransaction> TransactionManager::PeekRedoStack() { + RefPtr<TransactionItem> transactionItem = mRedoStack.Peek(); + if (!transactionItem) { + return nullptr; + } + return transactionItem->GetTransaction(); +} + +nsresult TransactionManager::BatchTopUndo() { + if (mUndoStack.GetSize() < 2) { + // Not enough transactions to merge into one batch. + return NS_OK; + } + + RefPtr<TransactionItem> lastUndo = mUndoStack.Pop(); + MOZ_ASSERT(lastUndo, "There should be at least two transactions."); + + RefPtr<TransactionItem> previousUndo = mUndoStack.Peek(); + MOZ_ASSERT(previousUndo, "There should be at least two transactions."); + + nsresult rv = previousUndo->AddChild(*lastUndo); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "TransactionItem::AddChild() failed"); + + // 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(); + if (!previousData.AppendObjects(lastData)) { + NS_WARNING("nsISupports::AppendObjects() failed"); + return NS_ERROR_FAILURE; + } + lastData.Clear(); + return rv; +} + +nsresult TransactionManager::RemoveTopUndo() { + if (mUndoStack.IsEmpty()) { + return NS_OK; + } + + RefPtr<TransactionItem> lastUndo = mUndoStack.Pop(); + return NS_OK; +} + +NS_IMETHODIMP TransactionManager::AddListener( + nsITransactionListener* aListener) { + if (NS_WARN_IF(!aListener)) { + return NS_ERROR_INVALID_ARG; + } + return NS_WARN_IF(!AddTransactionListener(*aListener)) ? NS_ERROR_FAILURE + : NS_OK; +} + +NS_IMETHODIMP TransactionManager::RemoveListener( + nsITransactionListener* aListener) { + if (NS_WARN_IF(!aListener)) { + return NS_ERROR_INVALID_ARG; + } + return NS_WARN_IF(!RemoveTransactionListener(*aListener)) ? NS_ERROR_FAILURE + : NS_OK; +} + +NS_IMETHODIMP TransactionManager::ClearUndoStack() { + if (NS_WARN_IF(!mDoStack.IsEmpty())) { + return NS_ERROR_FAILURE; + } + mUndoStack.Clear(); + return NS_OK; +} + +NS_IMETHODIMP TransactionManager::ClearRedoStack() { + if (NS_WARN_IF(!mDoStack.IsEmpty())) { + return NS_ERROR_FAILURE; + } + mRedoStack.Clear(); + return NS_OK; +} + +nsresult TransactionManager::WillDoNotify(nsITransaction* aTransaction, + bool* aInterrupt) { + nsCOMArray<nsITransactionListener> listeners(mListeners); + for (nsITransactionListener* listener : listeners) { + if (NS_WARN_IF(!listener)) { + return NS_ERROR_FAILURE; + } + nsresult rv = listener->WillDo(this, aTransaction, aInterrupt); + if (NS_FAILED(rv)) { + NS_WARNING("nsITransactionListener::WillDo() failed"); + return rv; + } + if (*aInterrupt) { + return NS_OK; + } + } + return NS_OK; +} + +nsresult TransactionManager::DidDoNotify(nsITransaction* aTransaction, + nsresult aDoResult) { + nsCOMArray<nsITransactionListener> listeners(mListeners); + for (nsITransactionListener* listener : listeners) { + if (NS_WARN_IF(!listener)) { + return NS_ERROR_FAILURE; + } + nsresult rv = listener->DidDo(this, aTransaction, aDoResult); + if (NS_FAILED(rv)) { + NS_WARNING("nsITransactionListener::DidDo() failed"); + return rv; + } + } + return NS_OK; +} + +nsresult TransactionManager::WillUndoNotify(nsITransaction* aTransaction, + bool* aInterrupt) { + nsCOMArray<nsITransactionListener> listeners(mListeners); + for (nsITransactionListener* listener : listeners) { + if (NS_WARN_IF(!listener)) { + return NS_ERROR_FAILURE; + } + nsresult rv = listener->WillUndo(this, aTransaction, aInterrupt); + if (NS_FAILED(rv)) { + NS_WARNING("nsITransactionListener::WillUndo() failed"); + return rv; + } + if (*aInterrupt) { + return NS_OK; + } + } + return NS_OK; +} + +nsresult TransactionManager::DidUndoNotify(nsITransaction* aTransaction, + nsresult aUndoResult) { + nsCOMArray<nsITransactionListener> listeners(mListeners); + for (nsITransactionListener* listener : listeners) { + if (NS_WARN_IF(!listener)) { + return NS_ERROR_FAILURE; + } + nsresult rv = listener->DidUndo(this, aTransaction, aUndoResult); + if (NS_FAILED(rv)) { + NS_WARNING("nsITransactionListener::DidUndo() failed"); + return rv; + } + } + return NS_OK; +} + +nsresult TransactionManager::WillRedoNotify(nsITransaction* aTransaction, + bool* aInterrupt) { + nsCOMArray<nsITransactionListener> listeners(mListeners); + for (nsITransactionListener* listener : listeners) { + if (NS_WARN_IF(!listener)) { + return NS_ERROR_FAILURE; + } + nsresult rv = listener->WillRedo(this, aTransaction, aInterrupt); + if (NS_FAILED(rv)) { + NS_WARNING("nsITransactionListener::WillRedo() failed"); + return rv; + } + if (*aInterrupt) { + return NS_OK; + } + } + return NS_OK; +} + +nsresult TransactionManager::DidRedoNotify(nsITransaction* aTransaction, + nsresult aRedoResult) { + nsCOMArray<nsITransactionListener> listeners(mListeners); + for (nsITransactionListener* listener : listeners) { + if (NS_WARN_IF(!listener)) { + return NS_ERROR_FAILURE; + } + nsresult rv = listener->DidRedo(this, aTransaction, aRedoResult); + if (NS_FAILED(rv)) { + NS_WARNING("nsITransactionListener::DidRedo() failed"); + return rv; + } + } + return NS_OK; +} + +nsresult TransactionManager::WillBeginBatchNotify(bool* aInterrupt) { + nsCOMArray<nsITransactionListener> listeners(mListeners); + for (nsITransactionListener* listener : listeners) { + if (NS_WARN_IF(!listener)) { + return NS_ERROR_FAILURE; + } + nsresult rv = listener->WillBeginBatch(this, aInterrupt); + if (NS_FAILED(rv)) { + NS_WARNING("nsITransactionListener::WillBeginBatch() failed"); + return rv; + } + if (*aInterrupt) { + return NS_OK; + } + } + return NS_OK; +} + +nsresult TransactionManager::DidBeginBatchNotify(nsresult aResult) { + nsCOMArray<nsITransactionListener> listeners(mListeners); + for (nsITransactionListener* listener : listeners) { + if (NS_WARN_IF(!listener)) { + return NS_ERROR_FAILURE; + } + nsresult rv = listener->DidBeginBatch(this, aResult); + if (NS_FAILED(rv)) { + NS_WARNING("nsITransactionListener::DidBeginBatch() failed"); + return rv; + } + } + return NS_OK; +} + +nsresult TransactionManager::WillEndBatchNotify(bool* aInterrupt) { + nsCOMArray<nsITransactionListener> listeners(mListeners); + for (nsITransactionListener* listener : listeners) { + if (NS_WARN_IF(!listener)) { + return NS_ERROR_FAILURE; + } + nsresult rv = listener->WillEndBatch(this, aInterrupt); + if (NS_FAILED(rv)) { + NS_WARNING("nsITransactionListener::WillEndBatch() failed"); + return rv; + } + if (*aInterrupt) { + return NS_OK; + } + } + return NS_OK; +} + +nsresult TransactionManager::DidEndBatchNotify(nsresult aResult) { + nsCOMArray<nsITransactionListener> listeners(mListeners); + for (nsITransactionListener* listener : listeners) { + if (NS_WARN_IF(!listener)) { + return NS_ERROR_FAILURE; + } + nsresult rv = listener->DidEndBatch(this, aResult); + if (NS_FAILED(rv)) { + NS_WARNING("nsITransactionListener::DidEndBatch() failed"); + return rv; + } + } + return NS_OK; +} + +nsresult TransactionManager::WillMergeNotify(nsITransaction* aTop, + nsITransaction* aTransaction, + bool* aInterrupt) { + nsCOMArray<nsITransactionListener> listeners(mListeners); + for (nsITransactionListener* listener : listeners) { + if (NS_WARN_IF(!listener)) { + return NS_ERROR_FAILURE; + } + nsresult rv = listener->WillMerge(this, aTop, aTransaction, aInterrupt); + if (NS_FAILED(rv)) { + NS_WARNING("nsITransactionListener::WillMerge() failed"); + return rv; + } + if (*aInterrupt) { + return NS_OK; + } + } + return NS_OK; +} + +nsresult TransactionManager::DidMergeNotify(nsITransaction* aTop, + nsITransaction* aTransaction, + bool aDidMerge, + nsresult aMergeResult) { + nsCOMArray<nsITransactionListener> listeners(mListeners); + for (nsITransactionListener* listener : listeners) { + if (NS_WARN_IF(!listener)) { + return NS_ERROR_FAILURE; + } + nsresult rv = + listener->DidMerge(this, aTop, aTransaction, aDidMerge, aMergeResult); + if (NS_FAILED(rv)) { + NS_WARNING("nsITransactionListener::DidMerge() failed"); + return rv; + } + } + return NS_OK; +} + +nsresult TransactionManager::BeginTransaction(nsITransaction* aTransaction, + nsISupports* aData) { + // XXX: POSSIBLE OPTIMIZATION + // We could use a factory that pre-allocates/recycles transaction items. + RefPtr<TransactionItem> transactionItem = new TransactionItem(aTransaction); + + if (aData) { + nsCOMArray<nsISupports>& data = transactionItem->GetData(); + data.AppendObject(aData); + } + + mDoStack.Push(transactionItem); + + nsresult rv = transactionItem->DoTransaction(); + if (NS_FAILED(rv)) { + NS_WARNING("TransactionItem::DoTransaction() failed"); + transactionItem = mDoStack.Pop(); + } + return rv; +} + +nsresult TransactionManager::EndTransaction(bool aAllowEmpty) { + RefPtr<TransactionItem> transactionItem = mDoStack.Pop(); + if (NS_WARN_IF(!transactionItem)) { + return NS_ERROR_FAILURE; + } + + nsCOMPtr<nsITransaction> transaction = transactionItem->GetTransaction(); + if (!transaction && !aAllowEmpty) { + // If we get here, the transaction must be a dummy batch transaction + // created by BeginBatch(). If it contains no children, get rid of it! + if (!transactionItem->NumberOfChildren()) { + return NS_OK; + } + } + + // Check if the transaction is transient. If it is, there's nothing + // more to do, just return. + if (transaction) { + bool isTransient = false; + nsresult rv = transaction->GetIsTransient(&isTransient); + if (NS_FAILED(rv)) { + NS_WARNING("nsITransaction::GetIsTransient() failed"); + return rv; + } + // XXX: Should we be clearing the redo stack if the transaction + // is transient and there is nothing on the do stack? + if (isTransient) { + return NS_OK; + } + } + + if (!mMaxTransactionCount) { + return NS_OK; + } + + // 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. + RefPtr<TransactionItem> topTransactionItem = mDoStack.Peek(); + if (topTransactionItem) { + // XXX: What do we do if this fails? + nsresult rv = topTransactionItem->AddChild(*transactionItem); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), + "TransactionItem::AddChild() failed"); + return rv; + } + + // The transaction succeeded, so clear the redo stack. + mRedoStack.Clear(); + + // Check if we can coalesce this transaction with the one at the top + // of the undo stack. + topTransactionItem = mUndoStack.Peek(); + if (transaction && topTransactionItem) { + bool didMerge = false; + nsCOMPtr<nsITransaction> topTransaction = + topTransactionItem->GetTransaction(); + if (topTransaction) { + bool doInterrupt = false; + nsresult rv = WillMergeNotify(topTransaction, transaction, &doInterrupt); + if (NS_FAILED(rv)) { + NS_WARNING("TransactionManager::WillMergeNotify() failed"); + return rv; + } + + if (!doInterrupt) { + nsresult rv = topTransaction->Merge(transaction, &didMerge); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), + "nsITransaction::Merge() failed"); + nsresult rv2 = + DidMergeNotify(topTransaction, transaction, didMerge, rv); + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv2), + "TransactionManager::DidMergeNotify() failed"); + if (didMerge) { + return NS_SUCCEEDED(rv) ? rv2 : rv; + } + NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), + "The previous error was ignored"); + } + } + } + + // 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) { + RefPtr<TransactionItem> overflow = mUndoStack.PopBottom(); + } + + // Push the transaction on the undo stack: + mUndoStack.Push(transactionItem.forget()); + return NS_OK; +} + +} // namespace mozilla |