/// <inheritdoc/>
public ITransaction CreateTransaction()
{
lock (lockObject)
{
if (RollInProgress)
throw new TransactionException("Unable to create a transaction. A rollback or rollforward operation is in progress.");
var transaction = new Transaction(this);
transactionsInProgress.Push(transaction);
TransactionInProgress = true;
return transaction;
}
}
/// <inheritdoc/>
public void CompleteTransaction(Transaction transaction)
{
lock (lockObject)
{
try
{
if (transactionsInProgress.Count == 0)
throw new TransactionException("There is not transaction in progress in the transaction stack.");
if (transaction != transactionsInProgress.Pop())
throw new TransactionException("The transaction being completed is not that last created transaction.");
// Check if we're completing the last transaction
TransactionInProgress = transactionsInProgress.Count > 0;
// Ignore the transaction if it is empty
if (transaction.IsEmpty)
return;
// If this transaction has no effect, discard it.
if (transaction.Operations.All(x => !x.HasEffect))
return;
// If we're not the last transaction, consider this transaction as an operation of its parent transaction
if (TransactionInProgress)
{
// Avoid useless nested transaction if we have a single operation inside.
PushOperation(transaction.Operations.Count == 1 ? transaction.Operations.Single() : transaction);
return;
}
// Remove transactions that will be overwritten by this one
if (currentPosition < transactions.Count)
{
PurgeFromIndex(currentPosition);
}
if (currentPosition == Capacity)
{
// If the stack has a capacity of 0, immediately freeze the new transaction.
var oldestTransaction = Capacity > 0 ? transactions[0] : transaction;
oldestTransaction.Interface.Freeze();
for (var i = 1; i < transactions.Count; ++i)
{
transactions[i - 1] = transactions[i];
}
if (Capacity > 0)
{
transactions[--currentPosition] = null;
}
TransactionDiscarded?.Invoke(this, new TransactionsDiscardedEventArgs(oldestTransaction, DiscardReason.StackFull));
}
if (Capacity > 0)
{
if (currentPosition == transactions.Count)
{
transactions.Add(transaction);
}
else
{
transactions[currentPosition] = transaction;
}
++currentPosition;
}
}
finally
{
if (!TransactionInProgress)
{
TransactionCompleted?.Invoke(this, new TransactionEventArgs(transaction));
}
}
}
}
