/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * 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.org code.
 * 
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 2001 Netscape Communications Corporation.
 * All Rights Reserved.
 * 
 * Contributor(s):
 *   Stuart Parmenter <pavlov@netscape.com>
 */

#include "nsISupports.idl"

interface imgIDecoderObserver;
interface imgIRequest;

interface nsIChannel;
interface nsILoadGroup;
interface nsIStreamListener;
interface nsIURI;

interface nsISimpleEnumerator;

#include "nsIRequest.idl" // for nsLoadFlags

/**
 * imgILoader interface
 *
 * @author Stuart Parmenter <pavlov@netscape.com>
 * @version 0.3
 * @see imagelib2
 */
[scriptable, uuid(4c8cf1e0-1dd2-11b2-aff9-c51cdbfcb6da)]
interface imgILoader : nsISupports
{
  /**
   * Start the load and decode of an image.
   * @param aURI the URI to load
   * @param aInitialDocumentURI the URI that 'initiated' the load -- used for 3rd party cookie blocking
   * @param aReferrerURI the 'referring' URI
   * @param aLoadGroup Loadgroup to put the image load into
   * @param aObserver the observer
   * @param aCX some random data
   * @param aLoadFlags Load flags for the request
   * @param aCacheKey cache key to use for a load if the original
   *                  image came from a request that had post data
   * @param aRequest A newly created, unused imgIRequest object or NULL for one to
                     be created for you.


   * libpr0n does NOT keep a strong ref to the observer; this prevents
   * reference cycles.  This means that callers of loadImage should
   * make sure to Cancel() the resulting request before the observer
   * goes away.
   */
  imgIRequest loadImage(in nsIURI aURI,
                        in nsIURI aInitialDocumentURL,
                        in nsIURI aReferrerURI,
                        in nsILoadGroup aLoadGroup,
                        in imgIDecoderObserver aObserver,
                        in nsISupports aCX,
                        in nsLoadFlags aLoadFlags,
                        in nsISupports cacheKey,
                        in imgIRequest aRequest);

  /**
   * Start the load and decode of an image.
   * @param uri the URI to load
   * @param aObserver the observer
   * @param cx some random data
   *
   * libpr0n does NOT keep a strong ref to the observer; this prevents
   * reference cycles.  This means that callers of loadImageWithChannel should
   * make sure to Cancel() the resulting request before the observer goes away.
   */
  imgIRequest loadImageWithChannel(in nsIChannel aChannel, in imgIDecoderObserver aObserver, in nsISupports cx, out nsIStreamListener aListener);

  /**
   * Checks if a decoder for the an image with the given mime type is available
   * @param mimeType The type to find a decoder for
   * @return true if a decoder is available, false otherwise
   */
  boolean supportImageWithMimeType(in string mimeType);

  /**
   * Checks if a decoder for the given contents is available.
   * @param contents The first few bytes of the image
   * @param length The length of contents
   * @return The Content Type of the Image or null if no decoder was found.
   */
  string supportImageWithContents(in string contents, in unsigned long length);
};