Added BeginBatch(), EndBatch(), BeginTransaction() and EndTransaction()
methods. Modified Do() method to use Begin/EndTransaction().
This commit is contained in:
kin%netscape.com
Родитель
c280f0ee5d
Коммит
a05e1af615
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@ -82,128 +82,21 @@ nsTransactionManager::QueryInterface(REFNSIID aIID, void** aInstancePtr)
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nsresult
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nsTransactionManager::Do(nsITransaction *aTransaction)
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{
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nsTransactionItem *tx;
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nsresult result = NS_OK;
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nsresult result;
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if (!aTransaction)
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return NS_ERROR_NULL_POINTER;
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NS_ADDREF(aTransaction);
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// XXX: POSSIBLE OPTIMIZATION
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// We could use a factory that pre-allocates/recycles transaction items.
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tx = new nsTransactionItem(aTransaction);
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if (!tx) {
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NS_RELEASE(aTransaction);
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return NS_ERROR_OUT_OF_MEMORY;
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}
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LOCK_TX_MANAGER(this);
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result = mDoStack.Push(tx);
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result = BeginTransaction(aTransaction);
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if (! NS_SUCCEEDED(result)) {
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delete tx;
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if (NS_FAILED(result)) {
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UNLOCK_TX_MANAGER(this);
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return result;
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}
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result = tx->Do();
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if (! NS_SUCCEEDED(result)) {
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mDoStack.Pop(&tx);
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delete tx;
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UNLOCK_TX_MANAGER(this);
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return result;
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}
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mDoStack.Pop(&tx);
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// Check if the transaction is transient. If it is, there's nothing
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// more to do, just return.
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PRBool isTransient = PR_FALSE;
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result = aTransaction->GetIsTransient(&isTransient);
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if (! NS_SUCCEEDED(result) || isTransient || !mMaxTransactionCount) {
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delete tx;
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UNLOCK_TX_MANAGER(this);
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return result;
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}
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nsTransactionItem *top = 0;
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// Check if there is a transaction on the do stack. If there is,
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// the current transaction is a "sub" transaction, and should
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// be added to the transaction at the top of the do stack.
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result = mDoStack.Peek(&top);
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if (top) {
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result = top->AddChild(tx);
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// XXX: What do we do if this fails?
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UNLOCK_TX_MANAGER(this);
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return result;
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}
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// The transaction succeeded, so clear the redo stack.
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result = ClearRedoStack();
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// Check if we can coalesce this transaction with the one at the top
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// of the undo stack.
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top = 0;
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result = mUndoStack.Peek(&top);
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if (top) {
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PRBool didMerge = PR_FALSE;
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nsITransaction *topTransaction = 0;
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result = top->GetTransaction(&topTransaction);
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if (topTransaction) {
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result = topTransaction->Merge(&didMerge, aTransaction);
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// XXX: What do we do if this fails?
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if (didMerge) {
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delete tx;
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UNLOCK_TX_MANAGER(this);
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return result;
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}
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}
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}
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// Check to see if we've hit the max level of undo. If so,
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// pop the bottom transaction off the undo stack and release it!
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PRInt32 sz = 0;
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result = mUndoStack.GetSize(&sz);
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if (mMaxTransactionCount > 0 && sz >= mMaxTransactionCount) {
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nsTransactionItem *overflow = 0;
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result = mUndoStack.PopBottom(&overflow);
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// XXX: What do we do in the case where this fails?
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if (overflow)
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delete overflow;
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}
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// Push the transaction on the undo stack:
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result = mUndoStack.Push(tx);
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if (! NS_SUCCEEDED(result)) {
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// XXX: What do we do in the case where a clear fails?
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// Remove the transaction from the stack, and release it?
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}
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result = EndTransaction();
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UNLOCK_TX_MANAGER(this);
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@ -333,6 +226,67 @@ nsTransactionManager::Clear()
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return result;
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}
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nsresult
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nsTransactionManager::BeginBatch()
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{
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nsresult result;
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// We can batch independent transactions together by simply pushing
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// a dummy transaction item on the do stack. This dummy transaction item
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// will be popped off the do stack, and then pushed on the undo stack
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// in EndBatch().
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LOCK_TX_MANAGER(this);
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result = BeginTransaction(0);
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UNLOCK_TX_MANAGER(this);
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return result;
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}
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nsresult
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nsTransactionManager::EndBatch()
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{
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nsTransactionItem *tx = 0;
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nsITransaction *ti = 0;
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nsresult result;
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LOCK_TX_MANAGER(this);
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// XXX: Need to add some mechanism to detect the case where the transaction
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// at the top of the do stack isn't the dummy transaction, so we can
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// throw an error!! This can happen if someone calls EndBatch() within
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// the Do() method of a transaction.
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//
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// For now, we can detect this case by checking the value of the
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// dummy transaction's mTransaction field. If it is our dummy
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// transaction, it should be NULL. This may not be true in the
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// future when we allow users to execute a transaction when beginning
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// a batch!!!!
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result = mDoStack.Peek(&tx);
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if (NS_FAILED(result)) {
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UNLOCK_TX_MANAGER(this);
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return result;
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}
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if (tx)
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tx->GetTransaction(&ti);
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if (!tx || ti) {
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UNLOCK_TX_MANAGER(this);
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return NS_ERROR_FAILURE;
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}
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result = EndTransaction();
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UNLOCK_TX_MANAGER(this);
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return result;
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}
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nsresult
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nsTransactionManager::GetNumberOfUndoItems(PRInt32 *aNumItems)
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{
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@ -568,3 +522,171 @@ nsTransactionManager::ClearRedoStack()
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return result;
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}
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nsresult
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nsTransactionManager::BeginTransaction(nsITransaction *aTransaction)
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{
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nsTransactionItem *tx;
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nsresult result = NS_OK;
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// No need for LOCK/UNLOCK_TX_MANAGER() calls since the calling routine
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// should have done this already!
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NS_IF_ADDREF(aTransaction);
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// XXX: POSSIBLE OPTIMIZATION
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// We could use a factory that pre-allocates/recycles transaction items.
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tx = new nsTransactionItem(aTransaction);
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if (!tx) {
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NS_IF_RELEASE(aTransaction);
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return NS_ERROR_OUT_OF_MEMORY;
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}
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result = mDoStack.Push(tx);
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if (NS_FAILED(result)) {
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delete tx;
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return result;
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}
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result = tx->Do();
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if (NS_FAILED(result)) {
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mDoStack.Pop(&tx);
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delete tx;
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return result;
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}
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return NS_OK;
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}
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nsresult
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nsTransactionManager::EndTransaction()
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{
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nsITransaction *tint = 0;
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nsTransactionItem *tx = 0;
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nsresult result = NS_OK;
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// No need for LOCK/UNLOCK_TX_MANAGER() calls since the calling routine
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// should have done this already!
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result = mDoStack.Pop(&tx);
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if (NS_FAILED(result) || !tx)
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return result;
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result = tx->GetTransaction(&tint);
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if (NS_FAILED(result)) {
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// XXX: What do we do with the transaction item at this point?
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return result;
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}
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if (!tint) {
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PRInt32 nc = 0;
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// If we get here, the transaction must be a dummy batch transaction
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// created by BeginBatch(). If it contains no children, get rid of it!
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tx->GetNumberOfChildren(&nc);
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if (!nc) {
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delete tx;
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return result;
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}
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}
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// Check if the transaction is transient. If it is, there's nothing
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// more to do, just return.
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PRBool isTransient = PR_FALSE;
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if (tint)
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result = tint->GetIsTransient(&isTransient);
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if (NS_FAILED(result) || isTransient || !mMaxTransactionCount) {
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// XXX: Should we be clearing the redo stack if the transaction
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// is transient and there is nothing on the do stack?
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delete tx;
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return result;
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}
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nsTransactionItem *top = 0;
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// Check if there is a transaction on the do stack. If there is,
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// the current transaction is a "sub" transaction, and should
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// be added to the transaction at the top of the do stack.
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result = mDoStack.Peek(&top);
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if (top) {
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result = top->AddChild(tx);
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// XXX: What do we do if this fails?
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return result;
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}
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// The transaction succeeded, so clear the redo stack.
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result = ClearRedoStack();
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if (NS_FAILED(result)) {
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// XXX: What do we do if this fails?
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}
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// Check if we can coalesce this transaction with the one at the top
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// of the undo stack.
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top = 0;
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result = mUndoStack.Peek(&top);
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if (tint && top) {
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PRBool didMerge = PR_FALSE;
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nsITransaction *topTransaction = 0;
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result = top->GetTransaction(&topTransaction);
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if (topTransaction) {
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result = topTransaction->Merge(&didMerge, tint);
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if (NS_FAILED(result)) {
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// XXX: What do we do if this fails?
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}
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if (didMerge) {
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delete tx;
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return result;
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}
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}
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}
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// Check to see if we've hit the max level of undo. If so,
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// pop the bottom transaction off the undo stack and release it!
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PRInt32 sz = 0;
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result = mUndoStack.GetSize(&sz);
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if (mMaxTransactionCount > 0 && sz >= mMaxTransactionCount) {
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nsTransactionItem *overflow = 0;
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result = mUndoStack.PopBottom(&overflow);
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// XXX: What do we do in the case where this fails?
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if (overflow)
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delete overflow;
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}
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// Push the transaction on the undo stack:
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result = mUndoStack.Push(tx);
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if (NS_FAILED(result)) {
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// XXX: What do we do in the case where a clear fails?
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// Remove the transaction from the stack, and release it?
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}
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return result;
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}
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@ -52,6 +52,8 @@ public:
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virtual nsresult Undo(void);
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virtual nsresult Redo(void);
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virtual nsresult Clear(void);
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virtual nsresult BeginBatch(void);
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virtual nsresult EndBatch(void);
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virtual nsresult GetNumberOfUndoItems(PRInt32 *aNumItems);
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virtual nsresult GetNumberOfRedoItems(PRInt32 *aNumItems);
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virtual nsresult SetMaxTransactionCount(PRInt32 aMaxCount);
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@ -64,6 +66,12 @@ public:
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/* nsTransactionManager specific methods. */
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virtual nsresult ClearUndoStack(void);
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virtual nsresult ClearRedoStack(void);
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private:
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/* nsTransactionManager specific private methods. */
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virtual nsresult BeginTransaction(nsITransaction *aTransaction);
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virtual nsresult EndTransaction(void);
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};
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#endif // nsTransactionManager_h__
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