gecko-dev/widget/xpwidgets/nsBaseAppShell.h

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/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
/* ***** 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 Widget 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> (original author)
*
* 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 ***** */
#ifndef nsBaseAppShell_h__
#define nsBaseAppShell_h__
#include "nsIAppShell.h"
#include "nsIThreadInternal.h"
#include "nsIObserver.h"
#include "nsIRunnable.h"
#include "nsCOMArray.h"
#include "nsCOMPtr.h"
#include "prinrval.h"
/**
* A singleton that manages the UI thread's event queue. Subclass this class
* to enable platform-specific event queue support.
*/
class nsBaseAppShell : public nsIAppShell, public nsIThreadObserver,
public nsIObserver
{
public:
NS_DECL_ISUPPORTS
NS_DECL_NSIAPPSHELL
NS_DECL_NSITHREADOBSERVER
NS_DECL_NSIOBSERVER
nsBaseAppShell();
protected:
virtual ~nsBaseAppShell();
/**
* This method is called by subclasses when the app shell singleton is
* instantiated.
*/
nsresult Init();
/**
* Called by subclasses from a native event. See ScheduleNativeEventCallback.
*/
void NativeEventCallback();
/**
* Make a decision as to whether or not NativeEventCallback will
* trigger gecko event processing when there are pending gecko
* events.
*/
virtual void DoProcessMoreGeckoEvents();
/**
* Implemented by subclasses. Invoke NativeEventCallback from a native
* event. This method may be called on any thread.
*/
virtual void ScheduleNativeEventCallback() = 0;
/**
* Implemented by subclasses. Process the next native event. Only wait for
* the next native event if mayWait is true. This method is only called on
* the main application thread.
*
* @param mayWait
* If "true", then this method may wait if necessary for the next available
* native event. DispatchNativeEvent may be called to unblock a call to
* ProcessNextNativeEvent that is waiting.
* @return
* This method returns "true" if a native event was processed.
*/
virtual bool ProcessNextNativeEvent(bool mayWait) = 0;
PRInt32 mSuspendNativeCount;
PRUint32 mEventloopNestingLevel;
private:
bool DoProcessNextNativeEvent(bool mayWait);
/**
* Runs all synchronous sections which are queued up in mSyncSections.
*/
void RunSyncSections();
nsCOMPtr<nsIRunnable> mDummyEvent;
/**
* mBlockedWait points back to a slot that controls the wait loop in
* an outer OnProcessNextEvent invocation. Nested calls always set
* it to false to unblock an outer loop, since all events may
* have been consumed by the inner event loop(s).
*/
bool *mBlockedWait;
PRInt32 mFavorPerf;
PRInt32 mNativeEventPending;
PRIntervalTime mStarvationDelay;
PRIntervalTime mSwitchTime;
PRIntervalTime mLastNativeEventTime;
enum EventloopNestingState {
eEventloopNone, // top level thread execution
eEventloopXPCOM, // innermost native event loop is ProcessNextNativeEvent
eEventloopOther // innermost native event loop is a native library/plugin etc
};
EventloopNestingState mEventloopNestingState;
nsCOMArray<nsIRunnable> mSyncSections;
bool mRunning;
bool mExiting;
/**
* mBlockNativeEvent blocks the appshell from processing native events.
* It is set to true while a nested native event loop (eEventloopOther)
* is processing gecko events in NativeEventCallback(), thus queuing up
* native events until we return to that loop (bug 420148).
* We force mBlockNativeEvent to false in case handling one of the gecko
* events spins up a nested XPCOM event loop (eg. modal window) which would
* otherwise lead to a "deadlock" where native events aren't processed at all.
*/
bool mBlockNativeEvent;
/**
* Tracks whether we have processed any gecko events in NativeEventCallback so
* that we can avoid erroneously entering a blocking loop waiting for gecko
* events to show up during OnProcessNextEvent. This is required because on
* OS X ProcessGeckoEvents may be invoked inside the context of
* ProcessNextNativeEvent and may result in NativeEventCallback being invoked
* and in turn invoking NS_ProcessPendingEvents. Because
* ProcessNextNativeEvent may be invoked prior to the NS_HasPendingEvents
* waiting loop, this is the only way to make the loop aware that events may
* have been processed.
*
* This variable is set to false in OnProcessNextEvent prior to the first
* call to DoProcessNextNativeEvent. It is set to true by
* NativeEventCallback after calling NS_ProcessPendingEvents.
*/
bool mProcessedGeckoEvents;
};
#endif // nsBaseAppShell_h__