gecko-dev/dom/events/Event.h

/* -*- 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_dom_Event_h_
#define mozilla_dom_Event_h_

#include "mozilla/Attributes.h"
#include "mozilla/BasicEvents.h"
#include "nsISupports.h"
#include "nsCOMPtr.h"
#include "nsPIDOMWindow.h"
#include "nsPoint.h"
#include "nsCycleCollectionParticipant.h"
#include "mozilla/dom/BindingDeclarations.h"
#include "mozilla/dom/EventBinding.h"
#include "mozilla/dom/PopupBlocker.h"
#include "nsIScriptGlobalObject.h"
#include "Units.h"
#include "js/TypeDecls.h"
#include "nsIGlobalObject.h"

class nsIContent;
class nsPresContext;
class PickleIterator;

namespace IPC {
class Message;
}  // namespace IPC

namespace mozilla {
namespace dom {

class BeforeUnloadEvent;
class CustomEvent;
class DragEvent;
class EventTarget;
class EventMessageAutoOverride;
// ExtendableEvent is a ServiceWorker event that is not
// autogenerated since it has some extra methods.
class ExtendableEvent;
class KeyboardEvent;
class MouseEvent;
class TimeEvent;
class UIEvent;
class WantsPopupControlCheck;
class XULCommandEvent;
#define GENERATED_EVENT(EventClass_) class EventClass_;
#include "mozilla/dom/GeneratedEventList.h"
#undef GENERATED_EVENT

// IID for Event
#define NS_EVENT_IID                                 \
  {                                                  \
    0x71139716, 0x4d91, 0x4dee, {                    \
      0xba, 0xf9, 0xe3, 0x3b, 0x80, 0xc1, 0x61, 0x61 \
    }                                                \
  }

class Event : public nsISupports, public nsWrapperCache {
 public:
  NS_DECLARE_STATIC_IID_ACCESSOR(NS_EVENT_IID)

  Event(EventTarget* aOwner, nsPresContext* aPresContext, WidgetEvent* aEvent);
  explicit Event(nsPIDOMWindowInner* aWindow);

 protected:
  virtual ~Event();

 private:
  void ConstructorInit(EventTarget* aOwner, nsPresContext* aPresContext,
                       WidgetEvent* aEvent);

 public:
  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(Event)

  nsIGlobalObject* GetParentObject() { return mOwner; }

  JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) final;

  virtual JSObject* WrapObjectInternal(JSContext* aCx,
                                       JS::Handle<JSObject*> aGivenProto);

#define GENERATED_EVENT(EventClass_) \
  virtual EventClass_* As##EventClass_() { return nullptr; }
#include "mozilla/dom/GeneratedEventList.h"
#undef GENERATED_EVENT

  // ExtendableEvent is a ServiceWorker event that is not
  // autogenerated since it has some extra methods.
  virtual ExtendableEvent* AsExtendableEvent() { return nullptr; }

  virtual TimeEvent* AsTimeEvent() { return nullptr; }

  // BeforeUnloadEvent is not autogenerated because it has a setter.
  virtual BeforeUnloadEvent* AsBeforeUnloadEvent() { return nullptr; }

  // KeyboardEvent has all sorts of non-autogeneratable bits so far.
  virtual KeyboardEvent* AsKeyboardEvent() { return nullptr; }

  // DragEvent has a non-autogeneratable initDragEvent.
  virtual DragEvent* AsDragEvent() { return nullptr; }

  // XULCommandEvent has a non-autogeneratable initCommandEvent.
  virtual XULCommandEvent* AsXULCommandEvent() { return nullptr; }

  // MouseEvent has a non-autogeneratable initMouseEvent and other
  // non-autogeneratable methods.
  virtual MouseEvent* AsMouseEvent() { return nullptr; }

  // UIEvent has a non-autogeneratable initUIEvent.
  virtual UIEvent* AsUIEvent() { return nullptr; }

  // CustomEvent has a non-autogeneratable initCustomEvent.
  virtual CustomEvent* AsCustomEvent() { return nullptr; }

  void InitEvent(const nsAString& aEventTypeArg, bool aCanBubble,
                 bool aCancelable) {
    InitEvent(aEventTypeArg, aCanBubble ? CanBubble::eYes : CanBubble::eNo,
              aCancelable ? Cancelable::eYes : Cancelable::eNo);
  }

  void InitEvent(const nsAString& aEventTypeArg, mozilla::CanBubble,
                 mozilla::Cancelable,
                 mozilla::Composed = mozilla::Composed::eDefault);

  void SetTarget(EventTarget* aTarget);
  virtual void DuplicatePrivateData();
  bool IsDispatchStopped();
  WidgetEvent* WidgetEventPtr();
  virtual void Serialize(IPC::Message* aMsg, bool aSerializeInterfaceType);
  virtual bool Deserialize(const IPC::Message* aMsg, PickleIterator* aIter);
  void SetOwner(EventTarget* aOwner);
  void StopCrossProcessForwarding();
  void SetTrusted(bool aTrusted);

  void InitPresContextData(nsPresContext* aPresContext);

  // Returns true if the event should be trusted.
  bool Init(EventTarget* aGlobal);

  static const char* GetEventName(EventMessage aEventType);
  static CSSIntPoint GetClientCoords(nsPresContext* aPresContext,
                                     WidgetEvent* aEvent,
                                     LayoutDeviceIntPoint aPoint,
                                     CSSIntPoint aDefaultPoint);
  static CSSIntPoint GetPageCoords(nsPresContext* aPresContext,
                                   WidgetEvent* aEvent,
                                   LayoutDeviceIntPoint aPoint,
                                   CSSIntPoint aDefaultPoint);
  static CSSIntPoint GetScreenCoords(nsPresContext* aPresContext,
                                     WidgetEvent* aEvent,
                                     LayoutDeviceIntPoint aPoint);
  MOZ_CAN_RUN_SCRIPT_BOUNDARY
  static CSSIntPoint GetOffsetCoords(nsPresContext* aPresContext,
                                     WidgetEvent* aEvent,
                                     LayoutDeviceIntPoint aPoint,
                                     CSSIntPoint aDefaultPoint);

  static already_AddRefed<Event> Constructor(EventTarget* aEventTarget,
                                             const nsAString& aType,
                                             const EventInit& aParam);

  static already_AddRefed<Event> Constructor(const GlobalObject& aGlobal,
                                             const nsAString& aType,
                                             const EventInit& aParam);

  void GetType(nsAString& aType) const;

  EventTarget* GetTarget() const;
  EventTarget* GetCurrentTarget() const;

  // This method returns the document which is associated with the event target.
  already_AddRefed<Document> GetDocument() const;

  void ComposedPath(nsTArray<RefPtr<EventTarget>>& aPath);

  uint16_t EventPhase() const;

  void StopPropagation();

  void StopImmediatePropagation();

  bool Bubbles() const { return mEvent->mFlags.mBubbles; }

  bool Cancelable() const { return mEvent->mFlags.mCancelable; }

  bool Composed() const { return mEvent->mFlags.mComposed; }

  bool CancelBubble() const { return mEvent->PropagationStopped(); }
  void SetCancelBubble(bool aCancelBubble) {
    if (aCancelBubble) {
      mEvent->StopPropagation();
    }
  }

  // For C++ consumers only!
  void PreventDefault();

  // You MUST NOT call PreventDefault(JSContext*, CallerType) from C++ code.  A
  // call of this method always sets Event.defaultPrevented true for web
  // contents.  If default action handler calls this, web applications see wrong
  // defaultPrevented value.
  virtual void PreventDefault(JSContext* aCx, CallerType aCallerType);

  // You MUST NOT call DefaultPrevented(CallerType) from C++ code.  This may
  // return false even if PreventDefault() has been called.
  // See comments in its implementation for the details.
  bool DefaultPrevented(CallerType aCallerType) const;

  bool DefaultPrevented() const { return mEvent->DefaultPrevented(); }

  bool DefaultPreventedByChrome() const {
    return mEvent->mFlags.mDefaultPreventedByChrome;
  }

  bool DefaultPreventedByContent() const {
    return mEvent->mFlags.mDefaultPreventedByContent;
  }

  void PreventMultipleActions() {
    mEvent->mFlags.mMultipleActionsPrevented = true;
  }

  bool MultipleActionsPrevented() const {
    return mEvent->mFlags.mMultipleActionsPrevented;
  }

  bool ReturnValue(CallerType aCallerType) const;

  void SetReturnValue(bool aReturnValue, CallerType aCallerType);

  bool IsTrusted() const { return mEvent->IsTrusted(); }

  bool IsSynthesized() const { return mEvent->mFlags.mIsSynthesizedForTests; }

  bool IsSafeToBeDispatchedAsynchronously() const {
    // If mEvent is not created by dom::Event nor its subclasses, its lifetime
    // is not guaranteed.  So, only when mEventIsInternal is true, it's safe
    // to be dispatched asynchronously.
    return mEventIsInternal;
  }

  double TimeStamp();

  EventTarget* GetOriginalTarget() const;
  EventTarget* GetExplicitOriginalTarget() const;
  EventTarget* GetComposedTarget() const;

  /**
   * @param aCalledByDefaultHandler     Should be true when this is called by
   *                                    C++ or Chrome.  Otherwise, e.g., called
   *                                    by a call of Event.preventDefault() in
   *                                    content script, false.
   */
  void PreventDefaultInternal(bool aCalledByDefaultHandler,
                              nsIPrincipal* aPrincipal = nullptr);

  bool IsMainThreadEvent() { return mIsMainThreadEvent; }

  void MarkUninitialized() {
    mEvent->mMessage = eVoidEvent;
    mEvent->mSpecifiedEventTypeString.Truncate();
    mEvent->mSpecifiedEventType = nullptr;
  }

  /**
   * For WidgetEvent, return it's type in string.
   *
   * @param aEvent is a WidgetEvent to get its type.
   * @param aType is a string where to return the type.
   */
  static void GetWidgetEventType(WidgetEvent* aEvent, nsAString& aType);

 protected:
  // Internal helper functions
  void SetEventType(const nsAString& aEventTypeArg);
  already_AddRefed<nsIContent> GetTargetFromFrame();

  friend class EventMessageAutoOverride;
  friend class PopupBlocker;
  friend class WantsPopupControlCheck;
  void SetWantsPopupControlCheck(bool aCheck) {
    mWantsPopupControlCheck = aCheck;
  }

  bool GetWantsPopupControlCheck() {
    return IsTrusted() && mWantsPopupControlCheck;
  }

  void SetComposed(bool aComposed) { mEvent->SetComposed(aComposed); }

  already_AddRefed<EventTarget> EnsureWebAccessibleRelatedTarget(
      EventTarget* aRelatedTarget);

  mozilla::WidgetEvent* mEvent;
  RefPtr<nsPresContext> mPresContext;
  nsCOMPtr<EventTarget> mExplicitOriginalTarget;
  nsCOMPtr<nsIGlobalObject> mOwner;
  bool mEventIsInternal;
  bool mPrivateDataDuplicated;
  bool mIsMainThreadEvent;
  // True when popup control check should rely on event.type, not
  // WidgetEvent.mMessage.
  bool mWantsPopupControlCheck;
};

/**
 * RAII helper-class to override an event's message (i.e. its DOM-exposed
 * type), for as long as the object is alive.  Restores the original
 * EventMessage when destructed.
 *
 * Notable requirements:
 *  - The original & overriding messages must be known (not eUnidentifiedEvent).
 *  - The original & overriding messages must be different.
 *  - The passed-in Event must outlive this RAII helper.
 */
class MOZ_RAII EventMessageAutoOverride {
 public:
  explicit EventMessageAutoOverride(Event* aEvent,
                                    EventMessage aOverridingMessage)
      : mEvent(aEvent), mOrigMessage(mEvent->mEvent->mMessage) {
    MOZ_ASSERT(aOverridingMessage != mOrigMessage,
               "Don't use this class if you're not actually overriding");
    MOZ_ASSERT(aOverridingMessage != eUnidentifiedEvent,
               "Only use this class with a valid overriding EventMessage");
    MOZ_ASSERT(mOrigMessage != eUnidentifiedEvent &&
                   mEvent->mEvent->mSpecifiedEventTypeString.IsEmpty(),
               "Only use this class on events whose overridden type is "
               "known (so we can restore it properly)");

    mEvent->mEvent->mMessage = aOverridingMessage;
  }

  ~EventMessageAutoOverride() { mEvent->mEvent->mMessage = mOrigMessage; }

 protected:
  // Non-owning ref, which should be safe since we're a stack-allocated object
  // with limited lifetime. Whoever creates us should keep mEvent alive.
  Event* const MOZ_NON_OWNING_REF mEvent;
  const EventMessage mOrigMessage;
};

class MOZ_STACK_CLASS WantsPopupControlCheck {
 public:
  explicit WantsPopupControlCheck(Event* aEvent) : mEvent(aEvent) {
    mOriginalWantsPopupControlCheck = mEvent->GetWantsPopupControlCheck();
    mEvent->SetWantsPopupControlCheck(mEvent->IsTrusted());
  }

  ~WantsPopupControlCheck() {
    mEvent->SetWantsPopupControlCheck(mOriginalWantsPopupControlCheck);
  }

 private:
  Event* mEvent;
  bool mOriginalWantsPopupControlCheck;
};

NS_DEFINE_STATIC_IID_ACCESSOR(Event, NS_EVENT_IID)

}  // namespace dom
}  // namespace mozilla

already_AddRefed<mozilla::dom::Event> NS_NewDOMEvent(
    mozilla::dom::EventTarget* aOwner, nsPresContext* aPresContext,
    mozilla::WidgetEvent* aEvent);

#endif  // mozilla_dom_Event_h_