mirror of
https://github.com/mozilla/gecko-dev.git
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293 lines
9.2 KiB
C++
293 lines
9.2 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifdef MOZILLA_INTERNAL_API
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#ifndef mozilla_EventDispatcher_h_
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#define mozilla_EventDispatcher_h_
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#include "mozilla/EventForwards.h"
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#include "nsCOMPtr.h"
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#include "nsTArray.h"
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// Microsoft's API Name hackery sucks
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#undef CreateEvent
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class nsIContent;
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class nsIDOMEvent;
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class nsIScriptGlobalObject;
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class nsPresContext;
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template<class E> class nsCOMArray;
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namespace mozilla {
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namespace dom {
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class EventTarget;
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} // namespace dom
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/**
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* About event dispatching:
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* When either EventDispatcher::Dispatch or
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* EventDispatcher::DispatchDOMEvent is called an event target chain is
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* created. EventDispatcher creates the chain by calling PreHandleEvent
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* on each event target and the creation continues until either the mCanHandle
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* member of the EventChainPreVisitor object is false or the mParentTarget
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* does not point to a new target. The event target chain is created in the
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* heap.
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*
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* If the event needs retargeting, mEventTargetAtParent must be set in
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* PreHandleEvent.
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*
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* The capture, target and bubble phases of the event dispatch are handled
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* by iterating through the event target chain. Iteration happens twice,
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* first for the default event group and then for the system event group.
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* While dispatching the event for the system event group PostHandleEvent
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* is called right after calling event listener for the current event target.
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*/
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class EventChainVisitor
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{
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public:
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EventChainVisitor(nsPresContext* aPresContext,
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WidgetEvent* aEvent,
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nsIDOMEvent* aDOMEvent,
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nsEventStatus aEventStatus = nsEventStatus_eIgnore)
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: mPresContext(aPresContext)
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, mEvent(aEvent)
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, mDOMEvent(aDOMEvent)
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, mEventStatus(aEventStatus)
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, mItemFlags(0)
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{
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}
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/**
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* The prescontext, possibly nullptr.
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*/
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nsPresContext* const mPresContext;
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/**
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* The WidgetEvent which is being dispatched. Never nullptr.
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*/
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WidgetEvent* const mEvent;
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/**
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* The DOM Event assiciated with the mEvent. Possibly nullptr if a DOM Event
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* is not (yet) created.
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*/
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nsIDOMEvent* mDOMEvent;
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/**
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* The status of the event.
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* @see nsEventStatus.h
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*/
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nsEventStatus mEventStatus;
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/**
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* Bits for items in the event target chain.
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* Set in PreHandleEvent() and used in PostHandleEvent().
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*
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* @note These bits are different for each item in the event target chain.
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* It is up to the Pre/PostHandleEvent implementation to decide how to
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* use these bits.
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*
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* @note Using uint16_t because that is used also in EventTargetChainItem.
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*/
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uint16_t mItemFlags;
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/**
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* Data for items in the event target chain.
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* Set in PreHandleEvent() and used in PostHandleEvent().
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*
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* @note This data is different for each item in the event target chain.
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* It is up to the Pre/PostHandleEvent implementation to decide how to
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* use this.
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*/
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nsCOMPtr<nsISupports> mItemData;
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};
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class EventChainPreVisitor : public EventChainVisitor
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{
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public:
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EventChainPreVisitor(nsPresContext* aPresContext,
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WidgetEvent* aEvent,
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nsIDOMEvent* aDOMEvent,
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nsEventStatus aEventStatus,
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bool aIsInAnon)
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: EventChainVisitor(aPresContext, aEvent, aDOMEvent, aEventStatus)
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, mCanHandle(true)
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, mAutomaticChromeDispatch(true)
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, mForceContentDispatch(false)
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, mRelatedTargetIsInAnon(false)
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, mOriginalTargetIsInAnon(aIsInAnon)
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, mWantsWillHandleEvent(false)
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, mMayHaveListenerManager(true)
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, mParentTarget(nullptr)
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, mEventTargetAtParent(nullptr)
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{
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}
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void Reset()
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{
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mItemFlags = 0;
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mItemData = nullptr;
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mCanHandle = true;
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mAutomaticChromeDispatch = true;
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mForceContentDispatch = false;
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mWantsWillHandleEvent = false;
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mMayHaveListenerManager = true;
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mParentTarget = nullptr;
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mEventTargetAtParent = nullptr;
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}
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/**
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* Member that must be set in PreHandleEvent by event targets. If set to false,
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* indicates that this event target will not be handling the event and
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* construction of the event target chain is complete. The target that sets
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* mCanHandle to false is NOT included in the event target chain.
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*/
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bool mCanHandle;
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/**
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* If mCanHandle is false and mAutomaticChromeDispatch is also false
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* event will not be dispatched to the chrome event handler.
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*/
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bool mAutomaticChromeDispatch;
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/**
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* If mForceContentDispatch is set to true,
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* content dispatching is not disabled for this event target.
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* FIXME! This is here for backward compatibility. Bug 329119
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*/
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bool mForceContentDispatch;
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/**
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* true if it is known that related target is or is a descendant of an
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* element which is anonymous for events.
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*/
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bool mRelatedTargetIsInAnon;
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/**
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* true if the original target of the event is inside anonymous content.
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* This is set before calling PreHandleEvent on event targets.
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*/
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bool mOriginalTargetIsInAnon;
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/**
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* Whether or not nsIDOMEventTarget::WillHandleEvent will be
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* called. Default is false;
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*/
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bool mWantsWillHandleEvent;
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/**
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* If it is known that the current target doesn't have a listener manager
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* when PreHandleEvent is called, set this to false.
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*/
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bool mMayHaveListenerManager;
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/**
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* Parent item in the event target chain.
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*/
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dom::EventTarget* mParentTarget;
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/**
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* If the event needs to be retargeted, this is the event target,
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* which should be used when the event is handled at mParentTarget.
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*/
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dom::EventTarget* mEventTargetAtParent;
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/**
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* An array of destination insertion points that need to be inserted
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* into the event path of nodes that are distributed by the
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* web components distribution algorithm.
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*/
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nsTArray<nsIContent*> mDestInsertionPoints;
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};
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class EventChainPostVisitor : public mozilla::EventChainVisitor
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{
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public:
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explicit EventChainPostVisitor(EventChainVisitor& aOther)
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: EventChainVisitor(aOther.mPresContext, aOther.mEvent,
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aOther.mDOMEvent, aOther.mEventStatus)
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{
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}
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};
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/**
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* If an EventDispatchingCallback object is passed to Dispatch,
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* its HandleEvent method is called after handling the default event group,
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* before handling the system event group.
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* This is used in nsPresShell.
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*/
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class MOZ_STACK_CLASS EventDispatchingCallback
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{
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public:
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virtual void HandleEvent(EventChainPostVisitor& aVisitor) = 0;
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};
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/**
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* The generic class for event dispatching.
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* Must not be used outside Gecko!
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*/
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class EventDispatcher
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{
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public:
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/**
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* aTarget should QI to EventTarget.
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* If the target of aEvent is set before calling this method, the target of
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* aEvent is used as the target (unless there is event
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* retargeting) and the originalTarget of the DOM Event.
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* aTarget is always used as the starting point for constructing the event
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* target chain, no matter what the value of aEvent->target is.
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* In other words, aEvent->target is only a property of the event and it has
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* nothing to do with the construction of the event target chain.
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* Neither aTarget nor aEvent is allowed to be nullptr.
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*
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* If aTargets is non-null, event target chain will be created, but
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* event won't be handled. In this case aEvent->message should be
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* NS_EVENT_NULL.
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* @note Use this method when dispatching a WidgetEvent.
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*/
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static nsresult Dispatch(nsISupports* aTarget,
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nsPresContext* aPresContext,
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WidgetEvent* aEvent,
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nsIDOMEvent* aDOMEvent = nullptr,
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nsEventStatus* aEventStatus = nullptr,
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EventDispatchingCallback* aCallback = nullptr,
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nsCOMArray<dom::EventTarget>* aTargets = nullptr);
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/**
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* Dispatches an event.
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* If aDOMEvent is not nullptr, it is used for dispatching
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* (aEvent can then be nullptr) and (if aDOMEvent is not |trusted| already),
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* the |trusted| flag is set based on the UniversalXPConnect capability.
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* Otherwise this works like EventDispatcher::Dispatch.
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* @note Use this method when dispatching nsIDOMEvent.
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*/
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static nsresult DispatchDOMEvent(nsISupports* aTarget,
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WidgetEvent* aEvent,
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nsIDOMEvent* aDOMEvent,
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nsPresContext* aPresContext,
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nsEventStatus* aEventStatus);
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/**
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* Creates a DOM Event.
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*/
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static nsresult CreateEvent(dom::EventTarget* aOwner,
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nsPresContext* aPresContext,
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WidgetEvent* aEvent,
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const nsAString& aEventType,
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nsIDOMEvent** aDOMEvent);
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/**
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* Called at shutting down.
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*/
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static void Shutdown();
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};
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} // namespace mozilla
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#endif // mozilla_EventDispatcher_h_
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#endif
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