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/* -*- 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 "nsCOMPtr.h"
#include "nsIDocument.h"
#include "nsIDOMEvent.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,
                       bool aBubbles, bool aOnlyChromeDispatch)
      : CancelableRunnable("AsyncEventDispatcher"),
        mTarget(aTarget),
        mEventType(aEventType),
        mEventMessage(eUnidentifiedEvent),
        mBubbles(aBubbles),
        mOnlyChromeDispatch(aOnlyChromeDispatch) {}

  /**
   * 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,
                       bool aBubbles, bool aOnlyChromeDispatch)
      : CancelableRunnable("AsyncEventDispatcher"),
        mTarget(aTarget),
        mEventMessage(aEventMessage),
        mBubbles(aBubbles),
        mOnlyChromeDispatch(aOnlyChromeDispatch) {
    mEventType.SetIsVoid(true);
    MOZ_ASSERT(mEventMessage != eUnidentifiedEvent);
  }

  AsyncEventDispatcher(dom::EventTarget* aTarget, const nsAString& aEventType,
                       bool aBubbles)
      : CancelableRunnable("AsyncEventDispatcher"),
        mTarget(aTarget),
        mEventType(aEventType),
        mEventMessage(eUnidentifiedEvent),
        mBubbles(aBubbles) {}

  AsyncEventDispatcher(dom::EventTarget* aTarget,
                       mozilla::EventMessage aEventMessage, bool aBubbles)
      : CancelableRunnable("AsyncEventDispatcher"),
        mTarget(aTarget),
        mEventMessage(aEventMessage),
        mBubbles(aBubbles) {
    mEventType.SetIsVoid(true);
    MOZ_ASSERT(mEventMessage != eUnidentifiedEvent);
  }

  AsyncEventDispatcher(dom::EventTarget* aTarget, nsIDOMEvent* aEvent)
      : CancelableRunnable("AsyncEventDispatcher"),
        mTarget(aTarget),
        mEvent(aEvent),
        mEventMessage(eUnidentifiedEvent) {}

  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;
  nsCOMPtr<nsIDOMEvent> 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;
  mozilla::EventMessage mEventMessage;
  bool mBubbles = false;
  bool mOnlyChromeDispatch = false;
  bool mCanceled = false;
  bool mCheckStillInDoc = false;
};

class LoadBlockingAsyncEventDispatcher final : public AsyncEventDispatcher {
 public:
  LoadBlockingAsyncEventDispatcher(nsINode* aEventNode,
                                   const nsAString& aEventType, bool aBubbles,
                                   bool aDispatchChromeOnly)
      : AsyncEventDispatcher(aEventNode, aEventType, aBubbles,
                             aDispatchChromeOnly),
        mBlockedDoc(aEventNode->OwnerDoc()) {
    if (mBlockedDoc) {
      mBlockedDoc->BlockOnload();
    }
  }

  LoadBlockingAsyncEventDispatcher(nsINode* aEventNode, nsIDOMEvent* aEvent)
      : AsyncEventDispatcher(aEventNode, aEvent),
        mBlockedDoc(aEventNode->OwnerDoc()) {
    if (mBlockedDoc) {
      mBlockedDoc->BlockOnload();
    }
  }

  ~LoadBlockingAsyncEventDispatcher();

 private:
  nsCOMPtr<nsIDocument> mBlockedDoc;
};

}  // namespace mozilla

#endif  // mozilla_AsyncEventDispatcher_h_