widget/nsIAppShell.idl

   1 /* -*- Mode: C++; tab-width: 2; 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 interface nsIRunnable;
  10 %{ C++
  11 template <class T> struct already_AddRefed;
  12
  13 /**
  14  * After the default timezone changes, this topic is notified. Some systems may
  15  * not support monitoring timezone.
  16  */
  17 #define DEFAULT_TIMEZONE_CHANGED_OBSERVER_TOPIC "default-timezone-changed"
  18 %}
  19
  20 /**
  21  * Interface for the native event system layer.  This interface is designed
  22  * to be used on the main application thread only.
  23  */
  24 [uuid(7cd5c71d-223b-4afe-931d-5eedb1f2b01f)]
  25 interface nsIAppShell : nsISupports
  26 {
  27   /**
  28    * Enter an event loop.  Don't leave until exit() is called.
  29    */
  30   void run();
  31
  32   /**
  33    * Exit the handle event loop
  34    */
  35   void exit();
  36
  37   /**
  38    * Ask the native event queue notification mechanism to favor Gecko tasks
  39    * (instead of native tasks) for a short while. (Content processes always
  40    * favor Gecko tasks.)
  41    */
  42   void geckoTaskBurst();
  43
  44   /**
  45    * Suspends the use of additional platform-specific methods (besides the
  46    * nsIAppShell->run() event loop) to run Gecko events on the main
  47    * application thread.  Under some circumstances these "additional methods"
  48    * can cause Gecko event handlers to be re-entered, sometimes leading to
  49    * hangs and crashes.  Calls to suspendNative() and resumeNative() may be
  50    * nested.  On some platforms (those that don't use any "additional
  51    * methods") this will be a no-op.  Does not (in itself) stop Gecko events
  52    * from being processed on the main application thread.  But if the
  53    * nsIAppShell->run() event loop is blocked when this call is made, Gecko
  54    * events will stop being processed until resumeNative() is called (even
  55    * if a plugin or library is temporarily processing events on a nested
  56    * event loop).
  57    */
  58   void suspendNative();
  59
  60   /**
  61    * Resumes the use of additional platform-specific methods to run Gecko
  62    * events on the main application thread.  Calls to suspendNative() and
  63    * resumeNative() may be nested.  On some platforms this will be a no-op.
  64    */
  65   void resumeNative();
  66
  67   /**
  68    * The current event loop nesting level.
  69    */
  70   readonly attribute unsigned long eventloopNestingLevel;
  71 };