/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsIRunnable.idl"

/**
 * Represents a task which can be dispatched to a thread for execution and
 * which can be cancelled if necessary.
 */

[scriptable, uuid(de93dc4c-5eea-4eb7-b6d1-dbf1e0cef65c)]
interface nsICancelableRunnable : nsIRunnable
{
    /**
     * Cancels a pending task.  If the task has already been executed this will
     * be a no-op.  Calling this method twice is considered an error.
     * If cancel() is called, run() will not be called.
     *
     * @throws NS_ERROR_UNEXPECTED
     *   Indicates that the runnable has already been canceled.
     */
    void cancel();
};
