gecko/xpcom/threads/nsIThreadInternal.idl

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla code.
*
* The Initial Developer of the Original Code is Google Inc.
* Portions created by the Initial Developer are Copyright (C) 2006
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Darin Fisher <darin@meer.net>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "nsIThread.idl"
interface nsIThreadObserver;
interface nsIThreadEventFilter;
/**
* The XPCOM thread object implements this interface, which allows a consumer
* to observe dispatch activity on the thread.
*/
[scriptable, uuid(e0d35c22-53d5-4b48-8627-93e05b94cf2c)]
interface nsIThreadInternal : nsIThread
{
/**
* Get/set the current thread observer (may be null). This attribute may be
* read from any thread, but must only be set on the thread corresponding to
* this thread object. The observer will be released on the thread
* corresponding to this thread object after all other events have been
* processed during a call to Shutdown.
*/
attribute nsIThreadObserver observer;
/**
* This method causes any events currently enqueued on the thread to be
* suppressed until PopEventQueue is called. Additionally, any new events
* dispatched to the thread will only be processed if they are accepted by
* the given filter. If the filter is null, then new events are accepted.
* Calls to PushEventQueue may be nested and must each be paired with a call
* to PopEventQueue in order to restore the original state of the thread.
*
* @param filter
* The thread event filter to apply to dispatched events, or null to accept
* all dispatched events.
*/
void pushEventQueue(in nsIThreadEventFilter filter);
/**
* Revert a call to PushEventQueue. When an event queue is popped, any
* events remaining in the queue are appended to the elder queue.
*/
void popEventQueue();
/**
* The current recursion depth, 0 when no events are running, 1 when a single
* event is running, and higher when nested events are running. Must only be
* called on the target thread.
*/
readonly attribute unsigned long recursionDepth;
/**
* Add an observer that will *only* receive onProcessNextEvent and
* afterProcessNextEvent callbacks. Always called on the target thread, and
* the implementation does not have to be threadsafe. Order of callbacks is
* not guaranteed (i.e. afterProcessNextEvent may be called first depending on
* whether or not the observer is added in a nested loop). Holds a strong ref.
*/
void addObserver(in nsIThreadObserver observer);
/**
* Remove an observer added via the addObserver call. Once removed the
* observer will never be called again by the thread.
*/
void removeObserver(in nsIThreadObserver observer);
};
/**
* This interface provides the observer with hooks to implement a layered
* event queue. For example, it is possible to overlay processing events
* for a GUI toolkit on top of the events for a thread:
*
* var NativeQueue;
* Observer = {
* onDispatchedEvent(thread) {
* NativeQueue.signal();
* }
* onProcessNextEvent(thread, mayWait, recursionDepth) {
* if (NativeQueue.hasNextEvent())
* NativeQueue.processNextEvent();
* while (mayWait && !thread.hasPendingEvent()) {
* NativeQueue.wait();
* NativeQueue.processNextEvent();
* }
* }
* };
*
* NOTE: The implementation of this interface must be threadsafe.
*
* NOTE: It is valid to change the thread's observer during a call to an
* observer method.
*
* NOTE: Will be split into two interfaces soon: one for onProcessNextEvent and
* afterProcessNextEvent, then another that inherits the first and adds
* onDispatchedEvent.
*/
[scriptable, uuid(81D0B509-F198-4417-8020-08EB4271491F)]
interface nsIThreadObserver : nsISupports
{
/**
* This method is called after an event has been dispatched to the thread.
* This method may be called from any thread.
*
* @param thread
* The thread where the event is being dispatched.
*/
void onDispatchedEvent(in nsIThreadInternal thread);
/**
* This method is called (from nsIThread::ProcessNextEvent) before an event
* is processed. This method is only called on the target thread.
*
* @param thread
* The thread being asked to process another event.
* @param mayWait
* Indicates whether or not the method is allowed to block the calling
* thread. For example, this parameter is false during thread shutdown.
* @param recursionDepth
* Indicates the number of calls to ProcessNextEvent on the call stack in
* addition to the current call.
*/
void onProcessNextEvent(in nsIThreadInternal thread, in boolean mayWait,
in unsigned long recursionDepth);
/**
* This method is called (from nsIThread::ProcessNextEvent) after an event
* is processed. This method is only called on the target thread.
*
* @param thread
* The thread that processed another event.
* @param recursionDepth
* Indicates the number of calls to ProcessNextEvent on the call stack in
* addition to the current call.
*/
void afterProcessNextEvent(in nsIThreadInternal thread,
in unsigned long recursionDepth);
};
/**
* Interface passed to the nsIThreadInternal::PushEventQueue method.
*/
[scriptable, uuid(a0605c0b-17f5-4681-b8cd-a1cd75d42559)]
interface nsIThreadEventFilter : nsISupports
{
/**
* This method is called to determine whether or not an event may be accepted
* by a "nested" event queue (see nsIThreadInternal::PushEventQueue).
*
* @param event
* The event being dispatched.
*
* WARNING: This method must not make any calls on the thread object.
*/
[notxpcom] boolean acceptEvent(in nsIRunnable event);
};