gecko/netwerk/base/public/nsITraceableChannel.idl

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 * The Initial Developer of the Original Code is
 * Jan Wrobel <wrobel@blues.ath.cx>
 * Portions created by the Initial Developer are Copyright (C) 2008
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 *   Jan Odvarko <odvarko@gmail.com>
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#include "nsISupports.idl"

interface nsIStreamListener;

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