gecko-dev/dom/events/AsyncEventDispatcher.h

176 строки
5.8 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */
#ifndef mozilla_AsyncEventDispatcher_h_
#define mozilla_AsyncEventDispatcher_h_
#include "mozilla/Attributes.h"
#include "mozilla/EventForwards.h"
#include "mozilla/RefPtr.h"
#include "mozilla/dom/Event.h"
#include "nsCOMPtr.h"
#include "nsIDocument.h"
#include "nsString.h"
#include "nsThreadUtils.h"
class nsINode;
namespace mozilla {
/**
* Use AsyncEventDispatcher to fire a DOM event that requires safe a stable DOM.
* For example, you may need to fire an event from within layout, but
* want to ensure that the event handler doesn't mutate the DOM at
* the wrong time, in order to avoid resulting instability.
*/
class AsyncEventDispatcher : public CancelableRunnable
{
public:
/**
* If aOnlyChromeDispatch is true, the event is dispatched to only
* chrome node. In that case, if aTarget is already a chrome node,
* the event is dispatched to it, otherwise the dispatch path starts
* at the first chrome ancestor of that target.
*/
AsyncEventDispatcher(nsINode* aTarget,
const nsAString& aEventType,
CanBubble aCanBubble,
ChromeOnlyDispatch aOnlyChromeDispatch,
Composed aComposed = Composed::eDefault)
: CancelableRunnable("AsyncEventDispatcher")
, mTarget(aTarget)
, mEventType(aEventType)
, mEventMessage(eUnidentifiedEvent)
, mCanBubble(aCanBubble)
, mOnlyChromeDispatch(aOnlyChromeDispatch)
, mComposed(aComposed)
{
}
/**
* If aOnlyChromeDispatch is true, the event is dispatched to only
* chrome node. In that case, if aTarget is already a chrome node,
* the event is dispatched to it, otherwise the dispatch path starts
* at the first chrome ancestor of that target.
*/
AsyncEventDispatcher(nsINode* aTarget,
mozilla::EventMessage aEventMessage,
CanBubble aCanBubble,
ChromeOnlyDispatch aOnlyChromeDispatch)
: CancelableRunnable("AsyncEventDispatcher")
, mTarget(aTarget)
, mEventMessage(aEventMessage)
, mCanBubble(aCanBubble)
, mOnlyChromeDispatch(aOnlyChromeDispatch)
{
mEventType.SetIsVoid(true);
MOZ_ASSERT(mEventMessage != eUnidentifiedEvent);
}
AsyncEventDispatcher(dom::EventTarget* aTarget,
const nsAString& aEventType,
CanBubble aCanBubble)
: CancelableRunnable("AsyncEventDispatcher")
, mTarget(aTarget)
, mEventType(aEventType)
, mEventMessage(eUnidentifiedEvent)
, mCanBubble(aCanBubble)
{
}
AsyncEventDispatcher(dom::EventTarget* aTarget,
mozilla::EventMessage aEventMessage,
CanBubble aCanBubble)
: CancelableRunnable("AsyncEventDispatcher")
, mTarget(aTarget)
, mEventMessage(aEventMessage)
, mCanBubble(aCanBubble)
{
mEventType.SetIsVoid(true);
MOZ_ASSERT(mEventMessage != eUnidentifiedEvent);
}
/**
* aEvent must have been created without Widget*Event and Internal*Event
* because this constructor assumes that it's safe to use aEvent
* asynchronously (i.e., after all objects allocated in the stack are
* destroyed).
*/
AsyncEventDispatcher(dom::EventTarget* aTarget, dom::Event* aEvent)
: CancelableRunnable("AsyncEventDispatcher")
, mTarget(aTarget)
, mEvent(aEvent)
, mEventMessage(eUnidentifiedEvent)
{
MOZ_ASSERT(aEvent->IsSafeToBeDispatchedAsynchronously(),
"The DOM event should be created without Widget*Event and Internal*Event "
"because if it needs to be safe to be dispatched asynchronously");
}
AsyncEventDispatcher(dom::EventTarget* aTarget, WidgetEvent& aEvent);
NS_IMETHOD Run() override;
nsresult Cancel() override;
nsresult PostDOMEvent();
void RunDOMEventWhenSafe();
// Calling this causes the Run() method to check that
// mTarget->IsInComposedDoc(). mTarget must be an nsINode or else we'll
// assert.
void RequireNodeInDocument();
nsCOMPtr<dom::EventTarget> mTarget;
RefPtr<dom::Event> mEvent;
// If mEventType is set, mEventMessage will be eUnidentifiedEvent.
// If mEventMessage is set, mEventType will be void.
// They can never both be set at the same time.
nsString mEventType;
EventMessage mEventMessage;
CanBubble mCanBubble = CanBubble::eNo;
ChromeOnlyDispatch mOnlyChromeDispatch = ChromeOnlyDispatch::eNo;
Composed mComposed = Composed::eDefault;
bool mCanceled = false;
bool mCheckStillInDoc = false;
};
class LoadBlockingAsyncEventDispatcher final : public AsyncEventDispatcher
{
public:
LoadBlockingAsyncEventDispatcher(nsINode* aEventNode,
const nsAString& aEventType,
CanBubble aBubbles,
ChromeOnlyDispatch aDispatchChromeOnly)
: AsyncEventDispatcher(aEventNode,
aEventType,
aBubbles,
aDispatchChromeOnly)
, mBlockedDoc(aEventNode->OwnerDoc())
{
if (mBlockedDoc) {
mBlockedDoc->BlockOnload();
}
}
LoadBlockingAsyncEventDispatcher(nsINode* aEventNode, dom::Event* aEvent)
: AsyncEventDispatcher(aEventNode, aEvent)
, mBlockedDoc(aEventNode->OwnerDoc())
{
if (mBlockedDoc) {
mBlockedDoc->BlockOnload();
}
}
~LoadBlockingAsyncEventDispatcher();
private:
nsCOMPtr<nsIDocument> mBlockedDoc;
};
} // namespace mozilla
#endif // mozilla_AsyncEventDispatcher_h_