gecko/dom/indexedDB/IDBTransaction.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Indexed Database.
 *
 * The Initial Developer of the Original Code is
 * The Mozilla Foundation.
 * Portions created by the Initial Developer are Copyright (C) 2010
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Ben Turner <bent.mozilla@gmail.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "IDBTransaction.h"

#include "mozilla/storage.h"
#include "nsDOMClassInfo.h"
#include "nsProxyRelease.h"
#include "nsThreadUtils.h"

#include "IDBEvents.h"
#include "IDBCursor.h"
#include "IDBObjectStore.h"
#include "IDBFactory.h"
#include "DatabaseInfo.h"
#include "TransactionThreadPool.h"

#define SAVEPOINT_INITIAL "initial"
#define SAVEPOINT_INTERMEDIATE "intermediate"

USING_INDEXEDDB_NAMESPACE

namespace {

PLDHashOperator
DoomCachedStatements(const nsACString& aQuery,
                     nsCOMPtr<mozIStorageStatement>& aStatement,
                     void* aUserArg)
{
  CommitHelper* helper = static_cast<CommitHelper*>(aUserArg);
  helper->AddDoomedObject(aStatement);
  return PL_DHASH_REMOVE;
}

} // anonymous namespace

// static
already_AddRefed<IDBTransaction>
IDBTransaction::Create(IDBDatabase* aDatabase,
                       nsTArray<nsString>& aObjectStoreNames,
                       PRUint16 aMode,
                       PRUint32 aTimeout)
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");

  nsRefPtr<IDBTransaction> transaction = new IDBTransaction();

  transaction->mDatabase = aDatabase;
  transaction->mMode = aMode;
  transaction->mTimeout = aTimeout;

  if (!transaction->mObjectStoreNames.AppendElements(aObjectStoreNames)) {
    NS_ERROR("Out of memory!");
    return nsnull;
  }

  if (!transaction->mCachedStatements.Init()) {
    NS_ERROR("Failed to initialize hash!");
    return nsnull;
  }

  return transaction.forget();
}

IDBTransaction::IDBTransaction()
: mReadyState(nsIIDBTransaction::INITIAL),
  mMode(nsIIDBTransaction::READ_ONLY),
  mTimeout(0),
  mPendingRequests(0),
  mSavepointCount(0),
  mHasInitialSavepoint(false),
  mAborted(false)
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
}

IDBTransaction::~IDBTransaction()
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
  NS_ASSERTION(!mPendingRequests, "Should have no pending requests here!");
  NS_ASSERTION(!mSavepointCount, "Should have released them all!");
  NS_ASSERTION(!mConnection, "Should have called CommitOrRollback!");

  if (mListenerManager) {
    mListenerManager->Disconnect();
  }
}

void
IDBTransaction::OnNewRequest()
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
  if (!mPendingRequests) {
    NS_ASSERTION(mReadyState == nsIIDBTransaction::INITIAL,
                 "Reusing a transaction!");
    mReadyState = nsIIDBTransaction::LOADING;
  }
  ++mPendingRequests;
}

void
IDBTransaction::OnRequestFinished()
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
  NS_ASSERTION(mPendingRequests, "Mismatched calls!");
  --mPendingRequests;
  if (!mPendingRequests) {
    if (!mAborted) {
      NS_ASSERTION(mReadyState == nsIIDBTransaction::LOADING, "Bad state!");
    }
    mReadyState = nsIIDBTransaction::DONE;

    CommitOrRollback();
  }
}

nsresult
IDBTransaction::CommitOrRollback()
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
  NS_ASSERTION(mReadyState == nsIIDBTransaction::DONE, "Bad readyState!");

  TransactionThreadPool* pool = TransactionThreadPool::GetOrCreate();
  NS_ENSURE_STATE(pool);

  nsRefPtr<CommitHelper> helper(new CommitHelper(this));

  mCachedStatements.Enumerate(DoomCachedStatements, helper);
  NS_ASSERTION(!mCachedStatements.Count(), "Statements left!");

  nsresult rv = pool->Dispatch(this, helper, true, helper);
  NS_ENSURE_SUCCESS(rv, rv);

  return NS_OK;
}

bool
IDBTransaction::StartSavepoint()
{
  NS_PRECONDITION(!NS_IsMainThread(), "Wrong thread!");
  NS_PRECONDITION(mConnection, "No connection!");

  nsresult rv;

  if (!mHasInitialSavepoint) {
    NS_NAMED_LITERAL_CSTRING(beginSavepoint,
                             "SAVEPOINT " SAVEPOINT_INITIAL);
    rv = mConnection->ExecuteSimpleSQL(beginSavepoint);
    NS_ENSURE_SUCCESS(rv, false);

    mHasInitialSavepoint = true;
  }

  NS_ASSERTION(!mSavepointCount, "Mismatch!");
  mSavepointCount = 1;

  // TODO try to cache this statement
  NS_NAMED_LITERAL_CSTRING(savepoint, "SAVEPOINT " SAVEPOINT_INTERMEDIATE);
  rv = mConnection->ExecuteSimpleSQL(savepoint);
  NS_ENSURE_SUCCESS(rv, false);

  return true;
}

nsresult
IDBTransaction::ReleaseSavepoint()
{
  NS_PRECONDITION(!NS_IsMainThread(), "Wrong thread!");
  NS_PRECONDITION(mConnection, "No connection!");

  NS_ASSERTION(mSavepointCount == 1, "Mismatch!");
  mSavepointCount = 0;

  // TODO try to cache this statement
  NS_NAMED_LITERAL_CSTRING(savepoint, "RELEASE " SAVEPOINT_INTERMEDIATE);
  nsresult rv = mConnection->ExecuteSimpleSQL(savepoint);
  NS_ENSURE_SUCCESS(rv, rv);

  return NS_OK;
}

void
IDBTransaction::RollbackSavepoint()
{
  NS_PRECONDITION(!NS_IsMainThread(), "Wrong thread!");
  NS_PRECONDITION(mConnection, "No connection!");

  NS_ASSERTION(mSavepointCount == 1, "Mismatch!");
  mSavepointCount = 0;

  // TODO try to cache this statement
  NS_NAMED_LITERAL_CSTRING(savepoint, "ROLLBACK TO " SAVEPOINT_INTERMEDIATE);
  if (NS_FAILED(mConnection->ExecuteSimpleSQL(savepoint))) {
    NS_ERROR("Rollback failed!");
  }
}

nsresult
IDBTransaction::GetOrCreateConnection(mozIStorageConnection** aResult)
{
  NS_ASSERTION(!NS_IsMainThread(), "Wrong thread!");

  if (!mConnection) {
    nsCOMPtr<mozIStorageConnection> connection =
      IDBFactory::GetConnection(mDatabase->FilePath());
    NS_ENSURE_TRUE(connection, NS_ERROR_FAILURE);

    connection.swap(mConnection);
  }

  nsCOMPtr<mozIStorageConnection> result(mConnection);
  result.forget(aResult);
  return NS_OK;
}

already_AddRefed<mozIStorageStatement>
IDBTransaction::AddStatement(bool aCreate,
                             bool aOverwrite,
                             bool aAutoIncrement)
{
#ifdef DEBUG
  if (!aCreate) {
    NS_ASSERTION(aOverwrite, "Bad param combo!");
  }
#endif

  if (aAutoIncrement) {
    if (aCreate) {
      if (aOverwrite) {
        return GetCachedStatement(
          "INSERT OR FAIL INTO ai_object_data (object_store_id, id, data) "
          "VALUES (:osid, :key_value, :data)"
        );
      }
      return GetCachedStatement(
        "INSERT INTO ai_object_data (object_store_id, data) "
        "VALUES (:osid, :data)"
      );
    }
    return GetCachedStatement(
      "UPDATE ai_object_data "
      "SET data = :data "
      "WHERE object_store_id = :osid "
      "AND id = :key_value"
    );
  }
  if (aCreate) {
    if (aOverwrite) {
      return GetCachedStatement(
        "INSERT OR FAIL INTO object_data (object_store_id, key_value, data) "
        "VALUES (:osid, :key_value, :data)"
      );
    }
    return GetCachedStatement(
      "INSERT INTO object_data (object_store_id, key_value, data) "
      "VALUES (:osid, :key_value, :data)"
    );
  }
  return GetCachedStatement(
    "UPDATE object_data "
    "SET data = :data "
    "WHERE object_store_id = :osid "
    "AND key_value = :key_value"
  );
}

already_AddRefed<mozIStorageStatement>
IDBTransaction::RemoveStatement(bool aAutoIncrement)
{
  if (aAutoIncrement) {
    return GetCachedStatement(
      "DELETE FROM ai_object_data "
      "WHERE id = :key_value "
      "AND object_store_id = :osid"
    );
  }
  return GetCachedStatement(
    "DELETE FROM object_data "
    "WHERE key_value = :key_value "
    "AND object_store_id = :osid"
  );
}

already_AddRefed<mozIStorageStatement>
IDBTransaction::GetStatement(bool aAutoIncrement)
{
  if (aAutoIncrement) {
    return GetCachedStatement(
      "SELECT data "
      "FROM ai_object_data "
      "WHERE id = :id "
      "AND object_store_id = :osid"
    );
  }
  return GetCachedStatement(
    "SELECT data "
    "FROM object_data "
    "WHERE key_value = :id "
    "AND object_store_id = :osid"
  );
}

already_AddRefed<mozIStorageStatement>
IDBTransaction::IndexGetStatement(bool aUnique,
                                  bool aAutoIncrement)
{
  if (aAutoIncrement) {
    if (aUnique) {
      return GetCachedStatement(
        "SELECT ai_object_data_id "
        "FROM ai_unique_index_data "
        "WHERE index_id = :index_id "
        "AND value = :value"
      );
    }
    return GetCachedStatement(
      "SELECT ai_object_data_id "
      "FROM ai_index_data "
      "WHERE index_id = :index_id "
      "AND value = :value"
    );
  }
  if (aUnique) {
    return GetCachedStatement(
      "SELECT object_data_key "
      "FROM unique_index_data "
      "WHERE index_id = :index_id "
      "AND value = :value"
    );
  }
  return GetCachedStatement(
    "SELECT object_data_key "
    "FROM index_data "
    "WHERE index_id = :index_id "
    "AND value = :value"
  );
}

already_AddRefed<mozIStorageStatement>
IDBTransaction::IndexGetObjectStatement(bool aUnique,
                                        bool aAutoIncrement)
{
  if (aAutoIncrement) {
    if (aUnique) {
      return GetCachedStatement(
        "SELECT data "
        "FROM ai_object_data "
        "INNER JOIN ai_unique_index_data "
        "ON ai_object_data.id = ai_unique_index_data.ai_object_data_id "
        "WHERE index_id = :index_id "
        "AND value = :value"
      );
    }
    return GetCachedStatement(
      "SELECT data "
      "FROM ai_object_data "
      "INNER JOIN ai_index_data "
      "ON ai_object_data.id = ai_index_data.ai_object_data_id "
      "WHERE index_id = :index_id "
      "AND value = :value"
    );
  }
  if (aUnique) {
    return GetCachedStatement(
      "SELECT data "
      "FROM object_data "
      "INNER JOIN unique_index_data "
      "ON object_data.id = unique_index_data.object_data_id "
      "WHERE index_id = :index_id "
      "AND value = :value"
    );
  }
  return GetCachedStatement(
    "SELECT data "
    "FROM object_data "
    "INNER JOIN index_data "
    "ON object_data.id = index_data.object_data_id "
    "WHERE index_id = :index_id "
    "AND value = :value"
  );
}

already_AddRefed<mozIStorageStatement>
IDBTransaction::IndexUpdateStatement(bool aAutoIncrement,
                                     bool aUnique,
                                     bool aOverwrite)
{
  if (aAutoIncrement) {
    if (aUnique) {
      if (aOverwrite) {
        return GetCachedStatement(
          "INSERT OR REPLACE INTO ai_unique_index_data "
            "(index_id, ai_object_data_id, id, value) "
          "VALUES (:index_id, :object_data_id, :object_data_key, :value)"
        );
      }
      return GetCachedStatement(
        "INSERT INTO ai_unique_index_data "
          "(index_id, aI_object_data_id, id, value) "
        "VALUES (:index_id, :object_data_id, :object_data_key, :value)"
      );
    }
    if (aOverwrite) {
      return GetCachedStatement(
        "INSERT OR REPLACE INTO ai_index_data "
          "(index_id, ai_object_data_id, id, value) "
        "VALUES (:index_id, :object_data_id, :object_data_key, :value)"
      );
    }
    return GetCachedStatement(
      "INSERT INTO ai_index_data "
        "(index_id, ai_object_data_id, id, value) "
      "VALUES (:index_id, :object_data_id, :object_data_key, :value)"
    );
  }
  if (aUnique) {
    if (aOverwrite) {
      return GetCachedStatement(
        "INSERT OR REPLACE INTO unique_index_data "
          "(index_id, object_data_id, object_data_key, value) "
        "VALUES (:index_id, :object_data_id, :object_data_key, :value)"
      );
    }
    return GetCachedStatement(
      "INSERT INTO unique_index_data "
        "(index_id, object_data_id, object_data_key, value) "
      "VALUES (:index_id, :object_data_id, :object_data_key, :value)"
    );
  }
  if (aOverwrite) {
    return GetCachedStatement(
      "INSERT INTO index_data ("
        "index_id, object_data_id, object_data_key, value) "
      "VALUES (:index_id, :object_data_id, :object_data_key, :value)"
    );
  }
  return GetCachedStatement(
    "INSERT INTO index_data ("
      "index_id, object_data_id, object_data_key, value) "
    "VALUES (:index_id, :object_data_id, :object_data_key, :value)"
  );
}

already_AddRefed<mozIStorageStatement>
IDBTransaction::GetCachedStatement(const nsACString& aQuery)
{
  NS_ASSERTION(!NS_IsMainThread(), "Wrong thread!");
  NS_ASSERTION(!aQuery.IsEmpty(), "Empty sql statement!");
  NS_ASSERTION(mConnection, "No connection!");

  nsCOMPtr<mozIStorageStatement> stmt;

  if (!mCachedStatements.Get(aQuery, getter_AddRefs(stmt))) {
    nsresult rv = mConnection->CreateStatement(aQuery, getter_AddRefs(stmt));
#ifdef DEBUG
    if (NS_FAILED(rv)) {
      nsCString error;
      error.AppendLiteral("The statement `");
      error.Append(aQuery);
      error.AppendLiteral("` failed to compile with the error message `");
      nsCString msg;
      (void)mConnection->GetLastErrorString(msg);
      error.Append(msg);
      error.AppendLiteral("`.");
      NS_ERROR(error.get());
    }
#endif
    NS_ENSURE_SUCCESS(rv, nsnull);

    if (!mCachedStatements.Put(aQuery, stmt)) {
      NS_ERROR("Out of memory?!");
    }
  }

  return stmt.forget();
}

#ifdef DEBUG
bool
IDBTransaction::TransactionIsOpen() const
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
  return mReadyState == nsIIDBTransaction::INITIAL ||
         mReadyState == nsIIDBTransaction::LOADING;
}

bool
IDBTransaction::IsWriteAllowed() const
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
  return mMode == nsIIDBTransaction::READ_WRITE;
}
#endif

NS_IMPL_CYCLE_COLLECTION_CLASS(IDBTransaction)

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(IDBTransaction,
                                                  nsDOMEventTargetHelper)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR(mOnCompleteListener)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR(mOnAbortListener)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR(mOnTimeoutListener)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(IDBTransaction,
                                                nsDOMEventTargetHelper)
  NS_IMPL_CYCLE_COLLECTION_UNLINK_NSCOMPTR(mOnCompleteListener)
  NS_IMPL_CYCLE_COLLECTION_UNLINK_NSCOMPTR(mOnAbortListener)
  NS_IMPL_CYCLE_COLLECTION_UNLINK_NSCOMPTR(mOnTimeoutListener)
NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(IDBTransaction)
  NS_INTERFACE_MAP_ENTRY(nsIIDBTransaction)
  NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(IDBTransaction)
NS_INTERFACE_MAP_END_INHERITING(nsDOMEventTargetHelper)

NS_IMPL_ADDREF_INHERITED(IDBTransaction, nsDOMEventTargetHelper)
NS_IMPL_RELEASE_INHERITED(IDBTransaction, nsDOMEventTargetHelper)

DOMCI_DATA(IDBTransaction, IDBTransaction)

NS_IMETHODIMP
IDBTransaction::GetDb(nsIIDBDatabase** aDB)
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");

  NS_ADDREF(*aDB = mDatabase);
  return NS_OK;
}

NS_IMETHODIMP
IDBTransaction::GetReadyState(PRUint16* aReadyState)
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");

  *aReadyState = mReadyState;
  return NS_OK;
}

NS_IMETHODIMP
IDBTransaction::GetMode(PRUint16* aMode)
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");

  *aMode = mMode == IDBTransaction::FULL_LOCK ?
           nsIIDBTransaction::READ_WRITE : mMode;
  return NS_OK;
}

NS_IMETHODIMP
IDBTransaction::GetObjectStoreNames(nsIDOMDOMStringList** aObjectStores)
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");

  nsRefPtr<nsDOMStringList> list(new nsDOMStringList());

  nsTArray<nsString> stackArray;
  nsTArray<nsString>* arrayOfNames;

  if (mMode == IDBTransaction::FULL_LOCK) {
    DatabaseInfo* info;
    if (!DatabaseInfo::Get(mDatabase->Id(), &info)) {
      NS_ERROR("This should never fail!");
      return NS_ERROR_UNEXPECTED;
    }

    if (!info->GetObjectStoreNames(stackArray)) {
      NS_ERROR("Out of memory!");
      return NS_ERROR_OUT_OF_MEMORY;
    }

    arrayOfNames = &stackArray;
  }
  else {
    arrayOfNames = &mObjectStoreNames;
  }

  PRUint32 count = arrayOfNames->Length();
  for (PRUint32 index = 0; index < count; index++) {
    NS_ENSURE_TRUE(list->Add(arrayOfNames->ElementAt(index)),
                   NS_ERROR_OUT_OF_MEMORY);
  }
  list.forget(aObjectStores);
  return NS_OK;
}

NS_IMETHODIMP
IDBTransaction::ObjectStore(const nsAString& aName,
                            nsIIDBObjectStore** _retval)
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");

  if (!TransactionIsOpen()) {
    return NS_ERROR_UNEXPECTED;
  }

  ObjectStoreInfo* info = nsnull;

  PRUint32 count = mObjectStoreNames.Length();
  for (PRUint32 index = 0; index < count; index++) {
    nsString& name = mObjectStoreNames[index];
    if (name == aName) {
      if (!ObjectStoreInfo::Get(mDatabase->Id(), aName, &info)) {
        NS_ERROR("Don't know about this one?!");
      }
      break;
    }
  }

  if (!info) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  nsRefPtr<IDBObjectStore> objectStore =
    IDBObjectStore::Create(mDatabase, this, info, mMode);
  NS_ENSURE_TRUE(objectStore, NS_ERROR_FAILURE);

  objectStore.forget(_retval);
  return NS_OK;
}

NS_IMETHODIMP
IDBTransaction::Abort()
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");

  if (!TransactionIsOpen()) {
    return NS_ERROR_UNEXPECTED;
  }

  mAborted = true;
  mReadyState = nsIIDBTransaction::DONE;

  return NS_OK;
}

NS_IMETHODIMP
IDBTransaction::GetOncomplete(nsIDOMEventListener** aOncomplete)
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");

  return GetInnerEventListener(mOnCompleteListener, aOncomplete);
}

NS_IMETHODIMP
IDBTransaction::SetOncomplete(nsIDOMEventListener* aOncomplete)
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");

  return RemoveAddEventListener(NS_LITERAL_STRING(COMPLETE_EVT_STR),
                                mOnCompleteListener, aOncomplete);
}

NS_IMETHODIMP
IDBTransaction::GetOnabort(nsIDOMEventListener** aOnabort)
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");

  return GetInnerEventListener(mOnAbortListener, aOnabort);
}

NS_IMETHODIMP
IDBTransaction::SetOnabort(nsIDOMEventListener* aOnabort)
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");

  return RemoveAddEventListener(NS_LITERAL_STRING(ABORT_EVT_STR),
                                mOnAbortListener, aOnabort);
}

NS_IMETHODIMP
IDBTransaction::GetOntimeout(nsIDOMEventListener** aOntimeout)
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");

  return GetInnerEventListener(mOnTimeoutListener, aOntimeout);
}

NS_IMETHODIMP
IDBTransaction::SetOntimeout(nsIDOMEventListener* aOntimeout)
{
  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");

  return RemoveAddEventListener(NS_LITERAL_STRING(TIMEOUT_EVT_STR),
                                mOnTimeoutListener, aOntimeout);
}

NS_IMPL_THREADSAFE_ISUPPORTS1(CommitHelper, nsIRunnable)

NS_IMETHODIMP
CommitHelper::Run()
{
  if (NS_IsMainThread()) {
    NS_ASSERTION(mDoomedObjects.IsEmpty(), "Didn't release doomed objects!");

    nsCOMPtr<nsIDOMEvent> event;
    if (mAborted) {
      event = IDBEvent::CreateGenericEvent(NS_LITERAL_STRING(ABORT_EVT_STR));
    }
    else {
      event = IDBEvent::CreateGenericEvent(NS_LITERAL_STRING(COMPLETE_EVT_STR));
    }
    NS_ENSURE_TRUE(event, NS_ERROR_FAILURE);

    PRBool dummy;
    if (NS_FAILED(mTransaction->DispatchEvent(event, &dummy))) {
      NS_WARNING("Dispatch failed!");
    }

    mTransaction = nsnull;
    return NS_OK;
  }

  if (mAborted) {
    NS_ASSERTION(mConnection, "This had better not be null!");

    NS_NAMED_LITERAL_CSTRING(rollback, "ROLLBACK TRANSACTION");
    if (NS_FAILED(mConnection->ExecuteSimpleSQL(rollback))) {
      NS_WARNING("Failed to rollback transaction!");
    }
  }
  else if (mHasInitialSavepoint) {
    NS_ASSERTION(mConnection, "This had better not be null!");

    NS_NAMED_LITERAL_CSTRING(release, "RELEASE " SAVEPOINT_INITIAL);
    if (NS_FAILED(mConnection->ExecuteSimpleSQL(release))) {
      NS_WARNING("Failed to release transaction!");
    }
  }

  mDoomedObjects.Clear();

  mConnection->Close();
  mConnection = nsnull;

  return NS_OK;
}