DOMEventTargetHelper.h

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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_DOMEventTargetHelper_h_

#define mozilla_DOMEventTargetHelper_h_

#include "mozilla/Attributes.h"

#include "mozilla/dom/EventTarget.h"

#include "mozilla/GlobalTeardownObserver.h"

#include "mozilla/RefPtr.h"

#include "nsAtom.h"

#include "nsCOMPtr.h"

#include "nsCycleCollectionParticipant.h"

#include "nsDebug.h"

#include "nsGkAtoms.h"

#include "nsID.h"

#include "nsIGlobalObject.h"

#include "nsISupports.h"

#include "nsPIDOMWindow.h"

#include "nsStringFwd.h"

#include "nsTArray.h"

class nsCycleCollectionTraversalCallback;

namespace mozilla {

class ErrorResult;

class EventChainPostVisitor;

class EventChainPreVisitor;

class EventListenerManager;

namespace dom {

class Document;

class Event;

enum class CallerType : uint32_t;

}  // namespace dom

#define NS_DOMEVENTTARGETHELPER_IID                  \

  {                                                  \

    0xa28385c6, 0x9451, 0x4d7e, {                    \

      0xa3, 0xdd, 0xf4, 0xb6, 0x87, 0x2f, 0xa4, 0x76 \

    }                                                \

class DOMEventTargetHelper : public dom::EventTarget,

                             public GlobalTeardownObserver {

 public:

  DOMEventTargetHelper();

  explicit DOMEventTargetHelper(nsPIDOMWindowInner* aWindow);

  explicit DOMEventTargetHelper(nsIGlobalObject* aGlobalObject);

  explicit DOMEventTargetHelper(DOMEventTargetHelper* aOther);

  NS_DECL_ISUPPORTS_INHERITED

  NS_IMETHOD_(void) DeleteCycleCollectable() override;

  NS_DECL_CYCLE_COLLECTION_SKIPPABLE_WRAPPERCACHE_CLASS_AMBIGUOUS(

      DOMEventTargetHelper, dom::EventTarget)

  EventListenerManager* GetExistingListenerManager() const override;

  EventListenerManager* GetOrCreateListenerManager() override;

  bool ComputeDefaultWantsUntrusted(ErrorResult& aRv) override;

  using EventTarget::DispatchEvent;

  // TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230)

  MOZ_CAN_RUN_SCRIPT_BOUNDARY bool DispatchEvent(dom::Event& aEvent,

                                                 dom::CallerType aCallerType,

                                                 ErrorResult& aRv) override;

  void GetEventTargetParent(EventChainPreVisitor& aVisitor) override;

  nsresult PostHandleEvent(EventChainPostVisitor& aVisitor) override;

  NS_DECLARE_STATIC_IID_ACCESSOR(NS_DOMEVENTTARGETHELPER_IID)

  nsIGlobalObject* GetOwnerGlobal() const override {

    return GlobalTeardownObserver::GetOwnerGlobal();

  static DOMEventTargetHelper* FromSupports(nsISupports* aSupports) {

    dom::EventTarget* target = static_cast<dom::EventTarget*>(aSupports);

#ifdef DEBUG

      nsCOMPtr<dom::EventTarget> target_qi = do_QueryInterface(aSupports);

      // If this assertion fires the QI implementation for the object in

      // question doesn't use the EventTarget pointer as the

      // nsISupports pointer. That must be fixed, or we'll crash...

      NS_ASSERTION(target_qi == target, "Uh, fix QI!");

#endif

    return static_cast<DOMEventTargetHelper*>(target);

  bool HasListenersFor(const nsAString& aType) const;

  bool HasListenersFor(nsAtom* aTypeWithOn) const;

  nsPIDOMWindowOuter* GetOwnerGlobalForBindingsInternal() override;

  // Like GetOwner, but only returns non-null if the window being returned is

  // current (in the "current document" sense of the HTML spec).

  nsPIDOMWindowInner* GetWindowIfCurrent() const;

  // Returns the document associated with this event target, if that document is

  // the current document of its browsing context.  Will return null otherwise.

  mozilla::dom::Document* GetDocumentIfCurrent() const;

  void DisconnectFromOwner() override;

  using EventTarget::GetParentObject;

  void EventListenerAdded(nsAtom* aType) override;

  void EventListenerRemoved(nsAtom* aType) override;

  // Dispatch a trusted, non-cancellable and non-bubbling event to |this|.

  nsresult DispatchTrustedEvent(const nsAString& aEventName);

 protected:

  virtual ~DOMEventTargetHelper();

  nsresult WantsUntrusted(bool* aRetVal);

  void MaybeUpdateKeepAlive();

  void MaybeDontKeepAlive();

  // If this method returns true your object is kept alive until it returns

  // false. You can use this method instead using

  // NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_BEGIN macro.

  virtual bool IsCertainlyAliveForCC() const { return mIsKeptAlive; }

  RefPtr<EventListenerManager> mListenerManager;

  // Make |event| trusted and dispatch |aEvent| to |this|.

  nsresult DispatchTrustedEvent(dom::Event* aEvent);

  virtual void LastRelease() {}

  void KeepAliveIfHasListenersFor(nsAtom* aType);

  void IgnoreKeepAliveIfHasListenersFor(nsAtom* aType);

 private:

  nsTArray<RefPtr<nsAtom>> mKeepingAliveTypes;

  bool mIsKeptAlive = false;

};

NS_DEFINE_STATIC_IID_ACCESSOR(DOMEventTargetHelper, NS_DOMEVENTTARGETHELPER_IID)

}  // namespace mozilla

// WebIDL event handlers

#define IMPL_EVENT_HANDLER(_event)                                          \

  inline mozilla::dom::EventHandlerNonNull* GetOn##_event() {               \

    return GetEventHandler(nsGkAtoms::on##_event);                          \

  }                                                                         \

  inline void SetOn##_event(mozilla::dom::EventHandlerNonNull* aCallback) { \

    SetEventHandler(nsGkAtoms::on##_event, aCallback);                      \

#endif  // mozilla_DOMEventTargetHelper_h_