/* -*- 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 "nsISupports.idl"

interface nsIURI;
interface nsIRequest;

/**
 * nsIProgressEventSink
 *
 * This interface is used to asynchronously convey channel status and progress
 * information that is generally not critical to the processing of the channel.
 * The information is intended to be displayed to the user in some meaningful
 * way.
 *
 * An implementation of this interface can be passed to a channel via the
 * channel's notificationCallbacks attribute.  See nsIChannel for more info.
 *
 * The channel will begin passing notifications to the progress event sink
 * after its asyncOpen method has been called.  Notifications will cease once
 * the channel calls its listener's onStopRequest method or once the channel
 * is canceled (via nsIRequest::cancel).
 *
 * NOTE: This interface is actually not specific to channels and may be used
 * with other implementations of nsIRequest.
 */
[scriptable, uuid(87d55fba-cb7e-4f38-84c1-5c6c2b2a55e9)]
interface nsIProgressEventSink : nsISupports
{
    /**
     * Called to notify the event sink that progress has occurred for the
     * given request.
     *
     * @param aRequest
     *        the request being observed (may QI to nsIChannel).
     * @param aProgress
     *        numeric value in the range 0 to aProgressMax indicating the
     *        number of bytes transfered thus far.
     * @param aProgressMax
     *        numeric value indicating maximum number of bytes that will be
     *        transfered (or -1 if total is unknown).
     */
    void onProgress(in nsIRequest aRequest,
                    in long long aProgress,
                    in long long aProgressMax);

    /**
     * Called to notify the event sink with a status message for the given
     * request.
     *
     * @param aRequest
     *        the request being observed (may QI to nsIChannel).
     * @param aStatus
     *        status code (not necessarily an error code) indicating the
     *        state of the channel (usually the state of the underlying
     *        transport).  see nsISocketTransport for socket specific status
     *        codes.
     * @param aStatusArg
     *        status code argument to be used with the string bundle service
     *        to convert the status message into localized, human readable
     *        text.  the meaning of this parameter is specific to the value
     *        of the status code.  for socket status codes, this parameter
     *        indicates the host:port associated with the status code.
     */
    void onStatus(in nsIRequest aRequest,
                  in nsresult aStatus,
                  in wstring aStatusArg);

};