/* -*- Mode: C++; 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) 2001
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Darin Fisher <darin@netscape.com> (original author)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of 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
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 * ***** END LICENSE BLOCK ***** */

#include "nsIInputStream.idl"

interface nsIOutputStream;
interface nsIEventTarget;

/**
 * A nsIInputStreamTee is a wrapper for an input stream, that when read
 * reads the specified amount of data from its |source| and copies that
 * data to its |sink|.  |sink| must be a blocking output stream.
 */
[scriptable, uuid(90a9d790-3bca-421e-a73b-98f68e13c917)]
interface nsIInputStreamTee : nsIInputStream
{
    attribute nsIInputStream source;
    attribute nsIOutputStream sink;
    
    /**
     * If |eventTarget| is set, copying to sink is done asynchronously using
     * the event-target (e.g. a thread). If |eventTarget| is not set, or if
     * storage-policy is STORE_ON_DISK_AS_FILE, copying to sink happens
     * synchronously while reading from the source.
     */
    attribute nsIEventTarget eventTarget;
};

%{C++
// factory methods
extern nsresult
NS_NewInputStreamTee(nsIInputStream **tee, // read from this input stream
                     nsIInputStream *source,
                     nsIOutputStream *sink);
                     
extern nsresult
NS_NewInputStreamTeeAsync(nsIInputStream **tee, // read from this input stream
                     nsIInputStream *source,
                     nsIOutputStream *sink,
                     nsIEventTarget *eventTarget);
%}
