michael@0: /* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "nsISupports.idl"
michael@0: 
michael@0: interface nsIInputStream;
michael@0: interface nsIStreamListener;
michael@0: 
michael@0: %{C++
michael@0: #define NS_ISTREAMCONVERTER_KEY         "@mozilla.org/streamconv;1"
michael@0: %}
michael@0: 
michael@0: /**
michael@0:  * The nsIStreamConverterService is a higher level stream converter factory
michael@0:  * responsible for locating and creating stream converters
michael@0:  * (nsIStreamConverter).
michael@0:  *
michael@0:  * This service retrieves an interface that can convert data from a particular
michael@0:  * MIME type, to a particular MIME type. It is responsible for any intermediary
michael@0:  * conversion required in order to get from X to Z, assuming direct conversion
michael@0:  * is not possible.
michael@0:  *
michael@0:  * @author Jud Valeski
michael@0:  * @see nsIStreamConverter
michael@0:  */
michael@0: [scriptable, uuid(f2b1ab53-f0bd-4adb-9365-e59b1701a258)]
michael@0: interface nsIStreamConverterService : nsISupports {
michael@0:     /**
michael@0:      * Tests whether conversion between the two specified types is possible.
michael@0:      * This is cheaper than calling convert()/asyncConvertData(); it is not
michael@0:      * necessary to call this function before calling one of those, though.
michael@0:      */
michael@0:     boolean canConvert(in string aFromType, in string aToType);
michael@0: 
michael@0:     /**
michael@0:      * <b>SYNCHRONOUS VERSION</b>
michael@0:      * Converts a stream of one type, to a stream of another type.
michael@0:      *
michael@0:      * Use this method when you have a stream you want to convert.
michael@0:      *
michael@0:      * @param aFromStream   The stream representing the original/raw data.
michael@0:      * @param aFromType     The MIME type of aFromStream.
michael@0:      * @param aToType       The MIME type of the returned stream.
michael@0:      * @param aContext      Either an opaque context, or a converter specific
michael@0:      *                      context (implementation specific).
michael@0:      * @return              The converted stream. NOTE: The returned stream
michael@0:      *                      may not already be converted. An efficient stream
michael@0:      *                      converter implementation will convert data on
michael@0:      *                      demand rather than buffering the converted data
michael@0:      *                      until it is used.
michael@0:      */
michael@0:     nsIInputStream convert(in nsIInputStream aFromStream,
michael@0:                            in string aFromType,
michael@0:                            in string aToType,
michael@0:                            in nsISupports aContext);
michael@0: 
michael@0:     /**
michael@0:      * <b>ASYNCHRONOUS VERSION</b>
michael@0:      * Retrieves a nsIStreamListener that receives the original/raw data via its
michael@0:      * nsIStreamListener::OnDataAvailable() callback, then converts and pushes 
michael@0:      * the data to aListener.
michael@0:      *
michael@0:      * Use this method when you want to proxy (and convert) nsIStreamListener
michael@0:      * callbacks asynchronously.
michael@0:      *
michael@0:      * @param aFromType     The MIME type of the original/raw data.
michael@0:      * @param aToType       The MIME type of the converted data.
michael@0:      * @param aListener     The listener that receives the converted data.
michael@0:      * @param aCtxt         Either an opaque context, or a converter specific
michael@0:      *                      context (implementation specific).
michael@0:      * @return              A nsIStreamListener that receives data via its
michael@0:      *                      OnDataAvailable() method.
michael@0:      */
michael@0:     nsIStreamListener asyncConvertData(in string aFromType, 
michael@0:                                        in string aToType, 
michael@0:                                        in nsIStreamListener aListener,
michael@0:                                        in nsISupports aContext);
michael@0: };