void WorkerThreadableLoader::MainThreadBridge::cancel()
{
    m_loaderProxy.postTaskToLoader(createCallbackTask(&MainThreadBridge::mainThreadCancel, this));
    ThreadableLoaderClientWrapper* clientWrapper = m_workerClientWrapper.get();
    if (!clientWrapper->done()) {
        // If the client hasn't reached a termination state, then transition it by sending a cancellation error.
        // Note: no more client callbacks will be done after this method -- the clearClientWrapper() call ensures that.
        ResourceError error(String(), 0, String(), String());
        error.setIsCancellation(true);
        clientWrapper->didFail(error);
    }
    clearClientWrapper();
}

void WorkerThreadableWebSocketChannel::Bridge::mainThreadCreateWebSocketChannel(ScriptExecutionContext* context, Bridge* thisPtr, PassRefPtr<ThreadableWebSocketChannelClientWrapper> prpClientWrapper, const String& taskMode)
{
    ASSERT(isMainThread());
    ASSERT_UNUSED(context, context->isDocument());

    RefPtr<ThreadableWebSocketChannelClientWrapper> clientWrapper = prpClientWrapper;

    Peer* peer = Peer::create(clientWrapper, thisPtr->m_loaderProxy, context, taskMode);
    thisPtr->m_loaderProxy.postTaskForModeToWorkerContext(
        createCallbackTask(&Bridge::setWebSocketChannel,
                           AllowCrossThreadAccess(thisPtr),
                           AllowCrossThreadAccess(peer), clientWrapper, peer->useHixie76Protocol()), taskMode);
}

void Database::runTransaction(PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback,
    PassRefPtr<VoidCallback> successCallback, bool readOnly, const ChangeVersionData* changeVersionData)
{
    RefPtr<SQLTransactionErrorCallback> anotherRefToErrorCallback = errorCallback;
    RefPtr<SQLTransaction> transaction = SQLTransaction::create(this, callback, successCallback, anotherRefToErrorCallback, readOnly);

    RefPtr<SQLTransactionBackend> transactionBackend;
    transactionBackend = backend()->runTransaction(transaction.release(), readOnly, changeVersionData);
    if (!transactionBackend && anotherRefToErrorCallback) {
        RefPtr<SQLError> error = SQLError::create(SQLError::UNKNOWN_ERR, "database has been closed");
        scriptExecutionContext()->postTask(createCallbackTask(&callTransactionErrorCallback, anotherRefToErrorCallback, error.release()));
    }
}

WorkerThreadableWebSocketChannel::Bridge::Bridge(PassRefPtr<ThreadableWebSocketChannelClientWrapper> workerClientWrapper, PassRefPtr<WorkerContext> workerContext, const String& taskMode, const KURL& url, const String& protocol)
    : m_workerClientWrapper(workerClientWrapper)
    , m_workerContext(workerContext)
    , m_loaderProxy(m_workerContext->thread()->workerLoaderProxy())
    , m_taskMode(taskMode)
    , m_peer(0)
{
    ASSERT(m_workerClientWrapper.get());
    setMethodNotCompleted();
    m_loaderProxy.postTaskToLoader(createCallbackTask(&Bridge::mainThreadCreateWebSocketChannel, this, m_workerClientWrapper, m_taskMode, url, protocol));
    waitForMethodCompletion();
    ASSERT(m_peer);
}

void IDBDatabaseBackendImpl::runIntVersionChangeTransaction(int64_t requestedVersion, PassRefPtr<IDBCallbacks> prpCallbacks, PassRefPtr<IDBDatabaseCallbacks> prpDatabaseCallbacks)
{
    RefPtr<IDBCallbacks> callbacks = prpCallbacks;
    RefPtr<IDBDatabaseCallbacks> databaseCallbacks = prpDatabaseCallbacks;
    ASSERT(callbacks);
    for (DatabaseCallbacksSet::const_iterator it = m_databaseCallbacksSet.begin(); it != m_databaseCallbacksSet.end(); ++it) {
        // Front end ensures the event is not fired at connections that have closePending set.
        if (*it != databaseCallbacks)
            (*it)->onVersionChange(m_metadata.intVersion, requestedVersion);
    }
    // The spec dictates we wait until all the version change events are
    // delivered and then check m_databaseCallbacks.empty() before proceeding
    // or firing a blocked event, but instead we should be consistent with how
    // the old setVersion (incorrectly) did it.
    // FIXME: Remove the call to onBlocked and instead wait until the frontend
    // tells us that all the blocked events have been delivered. See
    // https://bugs.webkit.org/show_bug.cgi?id=71130
    if (connectionCount())
        callbacks->onBlocked(m_metadata.intVersion);
    // FIXME: Add test for m_runningVersionChangeTransaction.
    if (m_runningVersionChangeTransaction || connectionCount()) {
        m_pendingOpenWithVersionCalls.append(PendingOpenWithVersionCall::create(callbacks, databaseCallbacks, requestedVersion));
        return;
    }

    Vector<int64_t> objectStoreIds;
    RefPtr<IDBTransactionBackendInterface> transactionInterface = transaction(objectStoreIds, IDBTransaction::VERSION_CHANGE);
    RefPtr<IDBTransactionBackendImpl> transaction = IDBTransactionBackendImpl::from(transactionInterface.get());

    RefPtr<IDBDatabaseBackendImpl> database = this;
    OwnPtr<ScriptExecutionContext::Task> intVersionTask = createCallbackTask(&IDBDatabaseBackendImpl::setIntVersionInternal, database, requestedVersion, callbacks, databaseCallbacks, transaction);
    OwnPtr<ScriptExecutionContext::Task> resetVersionOnAbortTask = createCallbackTask(&IDBDatabaseBackendImpl::resetVersion, database, m_metadata.version, m_metadata.intVersion);
    if (!transaction->scheduleTask(intVersionTask.release(), resetVersionOnAbortTask.release())) {
        ASSERT_NOT_REACHED();
    }
    ASSERT(!m_pendingSecondHalfOpenWithVersion);
    m_databaseCallbacksSet.add(databaseCallbacks);
}

void FileReader::abort()
{
    WTF_LOG(FileAPI, "FileReader: aborting\n");

    if (m_loadingState != LoadingStateLoading
        && m_loadingState != LoadingStatePending) {
        return;
    }
    m_loadingState = LoadingStateAborted;

    // Schedule to have the abort done later since abort() might be called from the event handler and we do not want the resource loading code to be in the stack.
    executionContext()->postTask(
        createCallbackTask(&delayedAbort, AllowAccessLater(this)));
}

PassRefPtr<IDBObjectStoreBackendInterface>  IDBDatabaseBackendImpl::createObjectStore(const String& name, const String& keyPath, bool autoIncrement, IDBTransactionBackendInterface* transactionPtr, ExceptionCode& ec)
{
    ASSERT(transactionPtr->mode() == IDBTransaction::VERSION_CHANGE);

    if (m_objectStores.contains(name)) {
        ec = IDBDatabaseException::CONSTRAINT_ERR;
        return 0;
    }

    RefPtr<IDBObjectStoreBackendImpl> objectStore = IDBObjectStoreBackendImpl::create(m_sqliteDatabase.get(), name, keyPath, autoIncrement);
    ASSERT(objectStore->name() == name);

    RefPtr<IDBDatabaseBackendImpl> database = this;
    RefPtr<IDBTransactionBackendInterface> transaction = transactionPtr;
    if (!transaction->scheduleTask(createCallbackTask(&IDBDatabaseBackendImpl::createObjectStoreInternal, database, objectStore, transaction),
                                   createCallbackTask(&IDBDatabaseBackendImpl::removeObjectStoreFromMap, database, objectStore))) {
        ec = IDBDatabaseException::NOT_ALLOWED_ERR;
        return 0;
    }

    m_objectStores.set(name, objectStore);
    return objectStore.release();
}

void Database::runTransaction(PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback,
                              PassRefPtr<VoidCallback> successCallback, PassRefPtr<SQLTransactionWrapper> wrapper, bool readOnly)
{
    MutexLocker locker(m_transactionInProgressMutex);
    if (!m_isTransactionQueueEnabled) {
        if (errorCallback) {
            RefPtr<SQLError> error = SQLError::create(SQLError::UNKNOWN_ERR, "database has been closed");
            scriptExecutionContext()->postTask(createCallbackTask(&callTransactionErrorCallback, errorCallback, error.release()));
        }
        return;
    }
    RefPtr<SQLTransaction> transaction = SQLTransaction::create(this, callback, errorCallback, successCallback, wrapper, readOnly);
    m_transactionQueue.append(transaction.release());
    if (!m_transactionInProgress)
        scheduleTransaction();
}

void WebWorkerImpl::postMessageToWorkerContext(const WebString& message,
                                               const WebMessagePortChannelArray& webChannels)
{
    OwnPtr<MessagePortChannelArray> channels;
    if (webChannels.size()) {
        channels = new MessagePortChannelArray(webChannels.size());
        for (size_t i = 0; i < webChannels.size(); ++i) {
            RefPtr<PlatformMessagePortChannel> platform_channel =
                PlatformMessagePortChannel::create(webChannels[i]);
            webChannels[i]->setClient(platform_channel.get());
            (*channels)[i] = MessagePortChannel::create(platform_channel);
        }
    }

    workerThread()->runLoop().postTask(
        createCallbackTask(&postMessageToWorkerContextTask,
                           this, String(message), channels.release()));
}

void WebWorkerClientImpl::startWorkerContext(const KURL& scriptURL,
                                             const String& userAgent,
                                             const String& sourceCode)
{
    // Worker.terminate() could be called from JS before the context is started.
    if (m_askedToTerminate)
        return;
    if (!isMainThread()) {
        WebWorkerBase::dispatchTaskToMainThread(createCallbackTask(
            &startWorkerContextTask,
            AllowCrossThreadAccess(this),
            scriptURL.string(),
            userAgent,
            sourceCode));
        return;
    }
    m_webWorker->startWorkerContext(scriptURL, userAgent, sourceCode);
}

void WebWorkerClientImpl::postExceptionToWorkerObject(const WebString& errorMessage,
                                                      int lineNumber,
                                                      const WebString& sourceURL)
{
    if (currentThread() != m_workerThreadId) {
        m_scriptExecutionContext->postTask(createCallbackTask(&postExceptionToWorkerObjectTask,
                                                              AllowCrossThreadAccess(this),
                                                              String(errorMessage),
                                                              lineNumber,
                                                              String(sourceURL)));
        return;
    }

    bool unhandled = m_worker->dispatchEvent(ErrorEvent::create(errorMessage,
                                                                sourceURL,
                                                                lineNumber));
    if (unhandled)
        m_scriptExecutionContext->reportException(errorMessage, lineNumber, sourceURL, 0);
}

void IDBCursorBackendImpl::continueFunction(PassRefPtr<IDBKey> prpKey, PassRefPtr<IDBCallbacks> prpCallbacks, ExceptionCode& ec)
{
    IDB_TRACE("IDBCursorBackendImpl::continue");
    RefPtr<IDBKey> key = prpKey;

    if (m_cursor && key) {
        ASSERT(m_cursor->key());
        if (m_direction == IDBCursor::NEXT || m_direction == IDBCursor::NEXT_NO_DUPLICATE) {
            if (!m_cursor->key()->isLessThan(key.get())) {
                ec = IDBDatabaseException::DATA_ERR;
                return;
            }
        } else {
            if (!key->isLessThan(m_cursor->key().get())) {
                ec = IDBDatabaseException::DATA_ERR;
                return;
            }
        }
    }

    if (!m_transaction->scheduleTask(createCallbackTask(&IDBCursorBackendImpl::continueFunctionInternal, this, key, prpCallbacks)))
        ec = IDBDatabaseException::TRANSACTION_INACTIVE_ERR;
}

void WebWorkerClientImpl::postMessageToWorkerContext(
    PassRefPtr<SerializedScriptValue> message,
    PassOwnPtr<MessagePortChannelArray> channels)
{
    // Worker.terminate() could be called from JS before the context is started.
    if (m_askedToTerminate)
        return;
    ++m_unconfirmedMessageCount;
    if (!isMainThread()) {
        WebWorkerBase::dispatchTaskToMainThread(createCallbackTask(&postMessageToWorkerContextTask,
                                                                   AllowCrossThreadAccess(this),
                                                                   message->toWireString(),
                                                                   channels));
        return;
    }
    WebMessagePortChannelArray webChannels(channels.get() ? channels->size() : 0);
    for (size_t i = 0; i < webChannels.size(); ++i) {
        WebMessagePortChannel* webchannel =
                        (*channels)[i]->channel()->webChannelRelease();
        webchannel->setClient(0);
        webChannels[i] = webchannel;
    }
    m_webWorker->postMessageToWorkerContext(message->toWireString(), webChannels);
}