/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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"

/**
 * nsITabUnloader: interface to represent TabUnloader
 *
 * nsIAvailableMemoryWatcherBase: interface to watch the system's memory
 * status and invoke a registered TabUnloader when it detected a low-memory
 * and high-memory situation.  The logic to detect such a memory situation
 * is defined per platform.
 */

[scriptable, uuid(2e530956-6054-464f-9f4c-0ae6f8de5523)]
interface nsITabUnloader : nsISupports
{
  /*
   * Unload the least-recently-used tab.
   * JS implementation of this interface TabUnloader.unloadTabAsync takes
   * one parameter that defines a threshold to exclude fresh tabs from the
   * unloading candidate tabs.  Currently the memory watcher is the only one
   * caller of this interface and it always expects the default threshold,
   * so this interface takes no parameter.
   */
  void unloadTabAsync();
};

[scriptable, uuid(b0b5701e-239d-49db-9009-37e89f86441c)]
interface nsIAvailableMemoryWatcherBase : nsISupports
{
  void registerTabUnloader(in nsITabUnloader aTabUnloader);
  void onUnloadAttemptCompleted(in nsresult aResult);
};