gecko-dev/widget/nsIAppShell.idl
2012-05-21 12:12:37 +01:00

92 lines
3.6 KiB
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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* 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"
interface nsIRunnable;
/**
* Interface for the native event system layer. This interface is designed
* to be used on the main application thread only.
*/
[uuid(2d10ca53-f143-439a-bb2e-c1fbc71f6a05)]
interface nsIAppShell : nsISupports
{
/**
* Enter an event loop. Don't leave until exit() is called.
*/
void run();
/**
* Exit the handle event loop
*/
void exit();
/**
* Give hint to native event queue notification mechanism. If the native
* platform needs to tradeoff performance vs. native event starvation this
* hint tells the native dispatch code which to favor. The default is to
* prevent native event starvation.
*
* Calls to this function may be nested. When the number of calls that pass
* PR_TRUE is subtracted from the number of calls that pass PR_FALSE is
* greater than 0, performance is given precedence over preventing event
* starvation.
*
* The starvationDelay arg is only used when favorPerfOverStarvation is
* PR_FALSE. It is the amount of time in milliseconds to wait before the
* PR_FALSE actually takes effect.
*/
void favorPerformanceHint(in boolean favorPerfOverStarvation,
in unsigned long starvationDelay);
/**
* Suspends the use of additional platform-specific methods (besides the
* nsIAppShell->run() event loop) to run Gecko events on the main
* application thread. Under some circumstances these "additional methods"
* can cause Gecko event handlers to be re-entered, sometimes leading to
* hangs and crashes. Calls to suspendNative() and resumeNative() may be
* nested. On some platforms (those that don't use any "additional
* methods") this will be a no-op. Does not (in itself) stop Gecko events
* from being processed on the main application thread. But if the
* nsIAppShell->run() event loop is blocked when this call is made, Gecko
* events will stop being processed until resumeNative() is called (even
* if a plugin or library is temporarily processing events on a nested
* event loop).
*/
void suspendNative();
/**
* Resumes the use of additional platform-specific methods to run Gecko
* events on the main application thread. Calls to suspendNative() and
* resumeNative() may be nested. On some platforms this will be a no-op.
*/
void resumeNative();
/**
* The current event loop nesting level.
*/
readonly attribute unsigned long eventloopNestingLevel;
/**
* Allows running of a "synchronous section", in the form of an nsIRunnable
* once the event loop has reached a "stable state". We've reached a stable
* state when the currently executing task/event has finished, see:
* http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#synchronous-section
* In practice this runs aRunnable once the currently executing event
* finishes. If called multiple times per task/event, all the runnables will
* be executed, in the order in which runInStableState() was called.
*/
void runInStableState(in nsIRunnable runnable);
/**
* Run the given runnable before the next iteration of the event loop (this
* includes native events too). If a nested loop is spawned within the current
* event then the runnable will not be run until that loop has terminated.
*/
void runBeforeNextEvent(in nsIRunnable runnable);
};