xpcom/base/nsIInterfaceRequestor.idl

   1 /* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  *
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "nsISupports.idl"
   8
   9 /**
  10  * The nsIInterfaceRequestor interface defines a generic interface for
  11  * requesting interfaces that a given object might provide access to.
  12  * This is very similar to QueryInterface found in nsISupports.
  13  * The main difference is that interfaces returned from GetInterface()
  14  * are not required to provide a way back to the object implementing this
  15  * interface.  The semantics of QI() dictate that given an interface A that
  16  * you QI() on to get to interface B, you must be able to QI on B to get back
  17  * to A.  This interface however allows you to obtain an interface C from A
  18  * that may or most likely will not have the ability to get back to A.
  19  */
  20
  21 [scriptable, uuid(033A1470-8B2A-11d3-AF88-00A024FFC08C)]
  22 interface nsIInterfaceRequestor : nsISupports
  23 {
  24    /**
  25     * Retrieves the specified interface pointer.
  26     *
  27     * @param uuid The IID of the interface being requested.
  28     * @param result [out] The interface pointer to be filled in if
  29     *               the interface is accessible.
  30     * @throws NS_NOINTERFACE - interface not accessible.
  31     * @throws NS_ERROR* - method failure.
  32     */
  33     void getInterface(in nsIIDRef uuid,
  34                       [iid_is(uuid),retval] out nsQIResult result);
  35 };