pjs/content/events/public/nsEventDispatcher.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** 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.org code.
*
* The Initial Developer of the Original Code is
* Olli Pettay (Olli.Pettay@helsinki.fi)
* Portions created by the Initial Developer are Copyright (C) 2006
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of 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 ***** */
#ifdef MOZILLA_INTERNAL_API
#ifndef nsEventDispatcher_h___
#define nsEventDispatcher_h___
#include "nsGUIEvent.h"
class nsIContent;
class nsIDocument;
class nsPresContext;
class nsPIDOMEventTarget;
class nsIScriptGlobalObject;
class nsEventTargetChainItem;
/**
* About event dispatching:
* When either nsEventDispatcher::Dispatch or
* nsEventDispatcher::DispatchDOMEvent is called an event target chain is
* created. nsEventDispatcher creates the chain by calling PreHandleEvent
* on each event target and the creation continues until either the mCanHandle
* member of the nsEventChainPreVisitor object is PR_FALSE or the mParentTarget
* does not point to a new target. The event target chain is created in the
* heap.
*
* If the event needs retargeting, mEventTargetAtParent must be set in
* PreHandleEvent.
*
* The capture, target and bubble phases of the event dispatch are handled
* by iterating through the event target chain. Iteration happens twice,
* first for the default event group and then for the system event group.
* While dispatching the event for the system event group PostHandleEvent
* is called right after calling event listener for the current event target.
*/
class nsEventChainVisitor {
public:
nsEventChainVisitor(nsPresContext* aPresContext,
nsEvent* aEvent,
nsIDOMEvent* aDOMEvent,
nsEventStatus aEventStatus = nsEventStatus_eIgnore)
: mPresContext(aPresContext), mEvent(aEvent), mDOMEvent(aDOMEvent),
mEventStatus(aEventStatus), mItemFlags(0)
{}
/**
* The prescontext, possibly nsnull.
*/
nsPresContext* const mPresContext;
/**
* The nsEvent which is being dispatched. Never nsnull.
*/
nsEvent* const mEvent;
/**
* The DOM Event assiciated with the mEvent. Possibly nsnull if a DOM Event
* is not (yet) created.
*/
nsIDOMEvent* mDOMEvent;
/**
* The status of the event.
* @see nsEventStatus.h
*/
nsEventStatus mEventStatus;
/**
* Bits for items in the event target chain.
* Set in PreHandleEvent() and used in PostHandleEvent().
*
* @note These bits are different for each item in the event target chain.
* It is up to the Pre/PostHandleEvent implementation to decide how to
* use these bits.
*
* @note Using PRUint16 because that is used also in nsEventTargetChainItem.
*/
PRUint16 mItemFlags;
/**
* Data for items in the event target chain.
* Set in PreHandleEvent() and used in PostHandleEvent().
*
* @note This data is different for each item in the event target chain.
* It is up to the Pre/PostHandleEvent implementation to decide how to
* use this.
*/
nsCOMPtr<nsISupports> mItemData;
};
class nsEventChainPreVisitor : public nsEventChainVisitor {
public:
nsEventChainPreVisitor(nsPresContext* aPresContext,
nsEvent* aEvent,
nsIDOMEvent* aDOMEvent,
nsEventStatus aEventStatus = nsEventStatus_eIgnore)
: nsEventChainVisitor(aPresContext, aEvent, aDOMEvent, aEventStatus),
mCanHandle(PR_TRUE), mForceContentDispatch(PR_FALSE),
mRelatedTargetIsInAnon(PR_FALSE) {}
void Reset() {
mItemFlags = 0;
mItemData = nsnull;
mCanHandle = PR_TRUE;
mForceContentDispatch = PR_FALSE;
mParentTarget = nsnull;
mEventTargetAtParent = nsnull;
}
/**
* Member that must be set in PreHandleEvent by event targets. If set to false,
* indicates that this event target will not be handling the event and
* construction of the event target chain is complete. The target that sets
* mCanHandle to false is NOT included in the event target chain.
*/
PRPackedBool mCanHandle;
/**
* If mForceContentDispatch is set to PR_TRUE,
* content dispatching is not disabled for this event target.
* FIXME! This is here for backward compatibility. Bug 329119
*/
PRPackedBool mForceContentDispatch;
/**
* PR_TRUE if it is known that related target is or is a descendant of an
* element which is anonymous for events.
*/
PRPackedBool mRelatedTargetIsInAnon;
/**
* Parent item in the event target chain.
*/
nsCOMPtr<nsISupports> mParentTarget;
/**
* If the event needs to be retargeted, this is the event target,
* which should be used when the event is handled at mParentTarget.
*/
nsCOMPtr<nsISupports> mEventTargetAtParent;
};
class nsEventChainPostVisitor : public nsEventChainVisitor {
public:
nsEventChainPostVisitor(nsEventChainVisitor& aOther)
: nsEventChainVisitor(aOther.mPresContext, aOther.mEvent, aOther.mDOMEvent,
aOther.mEventStatus)
{}
};
/**
* If an nsDispatchingCallback object is passed to Dispatch,
* its HandleEvent method is called after handling the default event group,
* before handling the system event group.
* This is used in nsPresShell.
*/
class nsDispatchingCallback {
public:
virtual void HandleEvent(nsEventChainPostVisitor& aVisitor) = 0;
};
/**
* The generic class for event dispatching.
* Must not be used outside Gecko!
*/
class nsEventDispatcher
{
public:
/**
* aTarget should QI to nsPIDOMEventTarget.
* If the target of aEvent is set before calling this method, the target of
* aEvent is used as the target (unless there is event
* retargeting) and the originalTarget of the DOM Event.
* aTarget is always used as the starting point for constructing the event
* target chain, no matter what the value of aEvent->target is.
* In other words, aEvent->target is only a property of the event and it has
* nothing to do with the construction of the event target chain.
* Neither aTarget nor aEvent is allowed to be nsnull.
* @note Use this method when dispatching an nsEvent.
*/
static nsresult Dispatch(nsISupports* aTarget,
nsPresContext* aPresContext,
nsEvent* aEvent,
nsIDOMEvent* aDOMEvent = nsnull,
nsEventStatus* aEventStatus = nsnull,
nsDispatchingCallback* aCallback = nsnull);
/**
* Dispatches an event.
* If aDOMEvent is not nsnull, it is used for dispatching
* (aEvent can then be nsnull) and (if aDOMEvent is not |trusted| already),
* the |trusted| flag is set based on the UniversalBrowserWrite capability.
* Otherwise this works like nsEventDispatcher::Dispatch.
* @note Use this method when dispatching nsIDOMEvent.
*/
static nsresult DispatchDOMEvent(nsISupports* aTarget,
nsEvent* aEvent, nsIDOMEvent* aDOMEvent,
nsPresContext* aPresContext,
nsEventStatus* aEventStatus);
/**
* Creates a DOM Event.
*/
static nsresult CreateEvent(nsPresContext* aPresContext,
nsEvent* aEvent,
const nsAString& aEventType,
nsIDOMEvent** aDOMEvent);
};
#endif
#endif