/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * The contents of this file are subject to the Netscape 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/NPL/
 *
 * 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) 1998 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s): Jud Valeski
 */

#include "nsIInputStream.idl"
#include "nsIStreamListener.idl"

/**
 * The nsIStreamConverterService is a higher level stream converter factory
 * responsible for locating and creating stream converters (nsIStreamConverter).
 *
 * This service retrieves an interface that can convert data from a particular MIME
 * type, to a particular MIME type. It is responsible for any intermediary
 * conversion required in order to get from X to Z, assuming direct conversion is not
 * possible.
 *
 * @author Jud Valeski
 * @see nsIStreamConverter
 */

%{C++
#define NS_STREAMCONVERTERSERVICE_CID                \
{ /* 892FFEB0-3F80-11d3-A16C-0050041CAF44 */         \
    0x892ffeb0,                                      \
    0x3f80,                                          \
    0x11d3,                                          \
    {0xa1, 0x6c, 0x00, 0x50, 0x04, 0x1c, 0xaf, 0x44} \
}
#define NS_ISTREAMCONVERTER_KEY         "@mozilla.org/streamconv;1"
%}

[scriptable, uuid(00362090-3B97-11d3-A16C-0050041CAF44)]
interface nsIStreamConverterService : nsISupports {

    /**
     * <b>SYNCRONOUS VERSION</b>
     * Converts a stream of one type, to a stream of another type.
     *
     * Use this method when you have a stream you want to convert.
     *
     * @param aFromStream   The stream representing the original/raw data.
     * @param aFromType     The MIME type of aFromStream.
     * @param aToType       The MIME type of the returned stream.
     * @param aContext      Either an opaque context, or a converter specific context
     *                      (implementation specific).
     * @return              The converted stream. NOTE: The returned stream may not
     *                      already be converted. An efficient stream converter
     *                      implementation will converter data on demand rather than
     *                      buffering the converted data until it is used.
     */
    nsIInputStream Convert(in nsIInputStream aFromStream,
						   in wstring aFromType,
						   in wstring aToType,
                           in nsISupports aContext);

    /**
     * <b>ASYNCRONOUS VERSION</b>
     * Retrieves a nsIStreamListener that receives the original/raw data via its
     * nsIStreamListener::OnDataAvailable() callback, then converts and pushes 
     * the data to aListener.
     *
     * Use this method when you want to proxy (and convert) nsIStreamListener callbacks
     * asynchronously.
     *
     * @param aFromType     The MIME type of the original/raw data.
     * @param aToType       The MIME type of the converted data.
     * @param aListener     The listener who receives the converted data.
     * @param aCtxt         Either an opaque context, or a converter specific context
     *                      (implementation specific).
     * @return              A nsIStreamListener that receives data via its OnDataAvailable() method.
     */
    nsIStreamListener AsyncConvertData(in wstring aFromType, 
                                       in wstring aToType, 
                                       in nsIStreamListener aListener,
                                       in nsISupports aContext);
};
