gecko/netwerk/streamconv/public/nsIStreamConverter.idl

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/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** 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.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* 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
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#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 contractid in the format below. Second, the stream converter must add the contractid
* to the registry.
*
* Stream converter contractid format (the stream converter root key is defined in this
* file):
*
* <pre>@mozilla.org/streamconv;1?from=FROM_MIME_TYPE&to=TO_MIME_TYPE</pre>
*
* @author Jud Valeski
* @see nsIStreamConverterService
*/
[scriptable, uuid(0b6e2c69-5cf5-48b0-9dfd-c95950e2cc7b)]
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 string aFromType,
in string 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 string aFromType,
in string aToType,
in nsIStreamListener aListener,
in nsISupports aCtxt);
};
%{C++
#define NS_ISTREAMCONVERTER_KEY "@mozilla.org/streamconv;1"
%}