pjs/netwerk/streamconv/public/nsIStreamConverter.idl

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/* -*- 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 "nsIStreamListener.idl"
#include "nsIInputStream.idl"
#include "nsIURI.idl"
/**
* nsIStreamConverter provides an interface to implement when you have code
* that converts data from one type to another.
*
* Suppose you had code that converted plain text into HTML. You could implement
* this interface to allow everyone else to use your conversion logic using a
* standard api.
* <p>
* <b>STREAM CONVERTER USERS</b>
*
* There are currently two ways to use a stream converter:
* <ol>
* <li> <b>SYNCHRONOUS</b> Stream to Stream
* You can supply the service with a stream of type X
* and it will convert it to your desired output type and return
* a converted (blocking) stream to you.</li>
*
* <li> <b>ASYNCHRONOUS</b> nsIStreamListener to nsIStreamListener
* You can supply data directly to the converter by calling it's
* nsIStreamListener::OnDataAvailable() method. It will then
* convert that data from type X to your desired output type and
* return converted data to you via the nsIStreamListener you passed
* in by calling its OnDataAvailable() method.</li>
* </ol>
* <p>
*
* <b>STREAM CONVERTER SUPPLIERS</b>
*
* Registering a stream converter:
* Stream converter registration is a two step process. First of all the stream
* converter implementation must register itself with the component manager using
* a progid in the format below. Second, the stream converter must add the progid
* to the registry.
*
* Stream converter progid format (the stream converter root key is defined in this
* file):
*
* <pre>Software/Netscape/streamconv/?from=FROM_MIME_TYPE?to=TO_MIME_TYPE</pre>
*
* @author Jud Valeski
* @see nsIStreamConverterService
*/
[scriptable, uuid(46484B30-3BD2-11d3-A16C-0050041CAF44)]
interface nsIStreamConverter : nsIStreamListener {
/**
* <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 aCtxt 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 aCtxt);
/**
* <b>ASYNCRONOUS VERSION</b>
* Converts data arriving via the converter's nsIStreamListener::OnDataAvailable()
* method from one type to another, pushing the converted data out to the caller
* via aListener::OnDataAvailable().
*
* 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).
*/
void AsyncConvertData(in wstring aFromType,
in wstring aToType,
in nsIStreamListener aListener,
in nsISupports aCtxt);
};
%{C++
#define NS_ISTREAMCONVERTER_KEY "Software/Netscape/streamconv/"
%}