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/* -*- 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
#include "mozilla/TransactionManager.h"
#include "mozilla/Assertions.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/HTMLEditor.h"
#include "mozilla/mozalloc.h"
#include "mozilla/TransactionStack.h"
#include "nsCOMPtr.h"
#include "nsDebug.h"
#include "nsError.h"
#include "nsISupports.h"
#include "nsISupportsUtils.h"
#include "nsITransaction.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(mHTMLEditor)
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(mHTMLEditor)
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)
void TransactionManager::Attach(HTMLEditor& aHTMLEditor) {
mHTMLEditor = &aHTMLEditor;
}
void TransactionManager::Detach(const HTMLEditor& aHTMLEditor) {
MOZ_DIAGNOSTIC_ASSERT_IF(mHTMLEditor, &aHTMLEditor == mHTMLEditor);
if (mHTMLEditor == &aHTMLEditor) {
mHTMLEditor = nullptr;
}
}
MOZ_CAN_RUN_SCRIPT_BOUNDARY NS_IMETHODIMP
TransactionManager::DoTransaction(nsITransaction* aTransaction) {
if (NS_WARN_IF(!aTransaction)) {
return NS_ERROR_INVALID_ARG;
}
OwningNonNull<nsITransaction> transaction = *aTransaction;
nsresult rv = BeginTransaction(transaction, nullptr);
if (NS_FAILED(rv)) {
NS_WARNING("TransactionManager::BeginTransaction() failed");
DidDoNotify(transaction, rv);
return rv;
}
rv = EndTransaction(false);
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
"TransactionManager::EndTransaction() failed");
DidDoNotify(transaction, rv);
return rv;
}
MOZ_CAN_RUN_SCRIPT 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();
nsresult rv = transactionItem->UndoTransaction(this);
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
"TransactionItem::UndoTransaction() failed");
if (NS_SUCCEEDED(rv)) {
transactionItem = mUndoStack.Pop();
mRedoStack.Push(transactionItem.forget());
}
if (transaction) {
DidUndoNotify(*transaction, rv);
}
return rv;
}
MOZ_CAN_RUN_SCRIPT_BOUNDARY 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();
nsresult rv = transactionItem->RedoTransaction(this);
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
"TransactionItem::RedoTransaction() failed");
if (NS_SUCCEEDED(rv)) {
transactionItem = mRedoStack.Pop();
mUndoStack.Push(transactionItem.forget());
}
if (transaction) {
DidRedoNotify(*transaction, rv);
}
return 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().
nsresult rv = BeginTransaction(nullptr, aData);
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
"TransactionManager::BeginTransaction() failed");
return 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;
}
nsresult rv = EndTransaction(aAllowEmpty);
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
"TransactionManager::EndTransaction() failed");
return 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::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;
}
void TransactionManager::DidDoNotify(nsITransaction& aTransaction,
nsresult aDoResult) {
if (mHTMLEditor) {
RefPtr<HTMLEditor> htmlEditor(mHTMLEditor);
htmlEditor->DidDoTransaction(*this, aTransaction, aDoResult);
}
}
void TransactionManager::DidUndoNotify(nsITransaction& aTransaction,
nsresult aUndoResult) {
if (mHTMLEditor) {
RefPtr<HTMLEditor> htmlEditor(mHTMLEditor);
htmlEditor->DidUndoTransaction(*this, aTransaction, aUndoResult);
}
}
void TransactionManager::DidRedoNotify(nsITransaction& aTransaction,
nsresult aRedoResult) {
if (mHTMLEditor) {
RefPtr<HTMLEditor> htmlEditor(mHTMLEditor);
htmlEditor->DidRedoTransaction(*this, aTransaction, aRedoResult);
}
}
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) {
nsresult rv = topTransaction->Merge(transaction, &didMerge);
if (didMerge) {
return rv;
}
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
"nsITransaction::Merge() failed, but 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