/* -*- 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_