michael@0: /* -*- Mode: C++; 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 nsIStreamListener;
michael@0: 
michael@0: /**
michael@0:  * A channel implementing this interface allows one to intercept its data by
michael@0:  * inserting intermediate stream listeners.
michael@0:  */
michael@0: [scriptable, uuid(68167b0b-ef34-4d79-a09a-8045f7c5140e)]
michael@0: interface nsITraceableChannel : nsISupports
michael@0: {
michael@0:     /*
michael@0:      * Replace the channel's listener with a new one, and return the listener 
michael@0:      * the channel used to have. The new listener intercepts OnStartRequest, 
michael@0:      * OnDataAvailable and OnStopRequest calls and must pass them to 
michael@0:      * the original listener after examination. If multiple callers replace 
michael@0:      * the channel's listener, a chain of listeners is created.
michael@0:      * The caller of setNewListener has no way to control at which place 
michael@0:      * in the chain its listener is placed.
michael@0:      *
michael@0:      * Note: The caller of setNewListener must not delay passing 
michael@0:      * OnStartRequest to the original listener.
michael@0:      *
michael@0:      * Note2: A channel may restrict when the listener can be replaced.
michael@0:      * It is not recommended to allow listener replacement after OnStartRequest
michael@0:      * has been called.
michael@0:      */
michael@0:     nsIStreamListener setNewListener(in nsIStreamListener aListener);
michael@0: };