gecko/netwerk/base/public/nsIInputStreamPump.idl

/* ***** 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 Mozilla.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2002
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Darin Fisher <darin@netscape.com>
 *   Christian Biesinger <cbiesinger@web.de>
 *
 * 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
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 * ***** END LICENSE BLOCK ***** */

#include "nsIRequest.idl"

interface nsIInputStream;
interface nsIStreamListener;

/**
 * nsIInputStreamPump
 *
 * This interface provides a means to configure and use a input stream pump
 * instance.  The input stream pump will asynchronously read from a input
 * stream, and push data to a nsIStreamListener instance.  It utilizes the
 * current thread's nsIEventTarget in order to make reading from the stream
 * asynchronous.
 *
 * If the given stream supports nsIAsyncInputStream, then the stream pump will
 * call the stream's AsyncWait method to drive the stream listener.  Otherwise,
 * the stream will be read on a background thread utilizing the stream
 * transport service.  More details are provided below.
 */
[scriptable, uuid(400F5468-97E7-4d2b-9C65-A82AECC7AE82)]
interface nsIInputStreamPump : nsIRequest
{
    /**
     * Initialize the input stream pump.
     *
     * @param aStream
     *        contains the data to be read.  if the input stream is non-blocking,
     *        then it will be QI'd to nsIAsyncInputStream.  if the QI succeeds
     *        then the stream will be read directly.  otherwise, it will be read
     *        on a background thread using the stream transport service.
     * @param aStreamPos
     *        specifies the stream offset from which to start reading.  the
     *        offset value is absolute.  pass -1 to specify the current offset.
     *        NOTE: this parameter is ignored if the underlying stream does not
     *        implement nsISeekableStream.
     * @param aStreamLen
     *        specifies how much data to read from the stream.  pass -1 to read
     *        all data available in the stream.
     * @param aSegmentSize
     *        if the stream transport service is used, then this parameter
     *        specifies the segment size for the stream transport's buffer.
     *        pass 0 to specify the default value.
     * @param aSegmentCount
     *        if the stream transport service is used, then this parameter
     *        specifies the segment count for the stream transport's buffer.
     *        pass 0 to specify the default value.
     * @param aCloseWhenDone
     *        if true, the input stream will be closed after it has been read.
     */
    void init(in nsIInputStream aStream,
              in long long      aStreamPos,
              in long long      aStreamLen,
              in unsigned long  aSegmentSize,
              in unsigned long  aSegmentCount,
              in boolean        aCloseWhenDone);

    /**
     * asyncRead causes the input stream to be read in chunks and delivered
     * asynchronously to the listener via OnDataAvailable.
     *
     * @param aListener
     *        receives notifications.
     * @param aListenerContext
     *        passed to listener methods.
     */
    void asyncRead(in nsIStreamListener aListener,
                   in nsISupports       aListenerContext);
};