widget/public/nsIAppShell.idl

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  *
   3  * ***** BEGIN LICENSE BLOCK *****
   4  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   5  *
   6  * The contents of this file are subject to the Mozilla Public License Version
   7  * 1.1 (the "License"); you may not use this file except in compliance with
   8  * the License. You may obtain a copy of the License at
   9  * http://www.mozilla.org/MPL/
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  11  * Software distributed under the License is distributed on an "AS IS" basis,
  12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  13  * for the specific language governing rights and limitations under the
  14  * License.
  15  *
  16  * The Original Code is the Mozilla browser.
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  18  * The Initial Developer of the Original Code is
  19  * Netscape Communications Corporation.
  20  * Portions created by the Initial Developer are Copyright (C) 1999
  21  * the Initial Developer. All Rights Reserved.
  22  *
  23  * Contributor(s):
  24  *   Stuart Parmenter <pavlov@netscape.com>
  25  *
  26  * Alternatively, the contents of this file may be used under the terms of
  27  * either the GNU General Public License Version 2 or later (the "GPL"), or
  28  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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  38  * ***** END LICENSE BLOCK ***** */
  39
  40 #include "nsISupports.idl"
  41
  42 /**
  43  * Interface for the native event system layer.  This interface is designed
  44  * to be used on the main application thread only.
  45  */
  46 [uuid(501403e9-a091-4780-ba55-cfd1e21287a1)]
  47 interface nsIAppShell : nsISupports
  48 {
  49   /**
  50    * Enter an event loop.  Don't leave until exit() is called.
  51    */
  52   void run();
  53
  54   /**
  55    * Exit the handle event loop
  56    */
  57   void exit();
  58
  59   /**
  60    * Give hint to native event queue notification mechanism. If the native
  61    * platform needs to tradeoff performance vs. native event starvation this
  62    * hint tells the native dispatch code which to favor.  The default is to
  63    * prevent native event starvation.
  64    *
  65    * Calls to this function may be nested. When the number of calls that pass
  66    * PR_TRUE is subtracted from the number of calls that pass PR_FALSE is
  67    * greater than 0, performance is given precedence over preventing event
  68    * starvation.
  69    *
  70    * The starvationDelay arg is only used when favorPerfOverStarvation is
  71    * PR_FALSE. It is the amount of time in milliseconds to wait before the
  72    * PR_FALSE actually takes effect.
  73    */
  74   void favorPerformanceHint(in boolean favorPerfOverStarvation,
  75                             in unsigned long starvationDelay);
  76
  77   /**
  78    * Suspends the use of additional platform-specific methods (besides the
  79    * nsIAppShell->run() event loop) to run Gecko events on the main
  80    * application thread.  Under some circumstances these "additional methods"
  81    * can cause Gecko event handlers to be re-entered, sometimes leading to
  82    * hangs and crashes.  Calls to suspendNative() and resumeNative() may be
  83    * nested.  On some platforms (those that don't use any "additional
  84    * methods") this will be a no-op.  Does not (in itself) stop Gecko events
  85    * from being processed on the main application thread.  But if the
  86    * nsIAppShell->run() event loop is blocked when this call is made, Gecko
  87    * events will stop being processed until resumeNative() is called (even
  88    * if a plugin or library is temporarily processing events on a nested
  89    * event loop).
  90    */
  91   void suspendNative();
  92
  93   /**
  94    * Resumes the use of additional platform-specific methods to run Gecko
  95    * events on the main application thread.  Calls to suspendNative() and
  96    * resumeNative() may be nested.  On some platforms this will be a no-op.
  97    */
  98   void resumeNative();
  99
 100   /**
 101    * The current event loop nesting level.
 102    */
 103   readonly attribute unsigned long eventloopNestingLevel;
 104 };