/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsISupports.idl"
#include "msgIDelegateList.idl"

/**
 * Mailnews code typically has a C++ base class for objects, which is then
 * specialized for each account type with a C++ subclass of the base class.
 *
 * This interface provides the ability of JavaScript-based account
 * implementations to use the same C++ base classes as core objects, but
 * use JavaScript to override methods instead of C++.
 */

[scriptable, uuid(68075269-8BBD-4a09-AC04-3241BF44F633)]
interface msgIOverride : nsISupports
{
  /**
   *
   * A list of methods in the C++ base class that will be delegated to the JS
   * delegate. This is calculated once, and then a fixed value is set to
   * all subsequent instances so that it does not need to be recalculated each
   * time. If the value has not yet been set, this will return a new instance.
   */
  attribute msgIDelegateList methodsToDelegate;

  /**
   * JavaScript-based xpcom object that overrides C++ methods.
   */
  attribute nsISupports jsDelegate;

  /**
   * C++ class used to implement default functionality. This is used when
   * JavaScript methods want to call the base class default action, bypassing a
   * possible JS override.
   */
  readonly attribute nsISupports cppBase;
};