/* -*- 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 "nsCOMPtr.h"
#include "nsGkAtoms.h"
#include "nsCycleCollectionParticipant.h"
#include "nsPIDOMWindow.h"
#include "nsIScriptGlobalObject.h"
#include "nsIScriptContext.h"
#include "nsIWeakReferenceUtils.h"
#include "MainThreadUtils.h"
#include "mozilla/Attributes.h"
#include "mozilla/EventListenerManager.h"
#include "mozilla/dom/EventTarget.h"

struct JSCompartment;
class nsIDocument;

namespace mozilla {

class ErrorResult;

#define NS_DOMEVENTTARGETHELPER_IID                  \
  {                                                  \
    0xa28385c6, 0x9451, 0x4d7e, {                    \
      0xa3, 0xdd, 0xf4, 0xb6, 0x87, 0x2f, 0xa4, 0x76 \
    }                                                \
  }

class DOMEventTargetHelper : public dom::EventTarget {
 public:
  DOMEventTargetHelper()
      : mParentObject(nullptr),
        mOwnerWindow(nullptr),
        mHasOrHasHadOwnerWindow(false),
        mIsKeptAlive(false) {}
  explicit DOMEventTargetHelper(nsPIDOMWindowInner* aWindow)
      : mParentObject(nullptr),
        mOwnerWindow(nullptr),
        mHasOrHasHadOwnerWindow(false),
        mIsKeptAlive(false) {
    BindToOwner(aWindow);
  }
  explicit DOMEventTargetHelper(nsIGlobalObject* aGlobalObject)
      : mParentObject(nullptr),
        mOwnerWindow(nullptr),
        mHasOrHasHadOwnerWindow(false),
        mIsKeptAlive(false) {
    BindToOwner(aGlobalObject);
  }
  explicit DOMEventTargetHelper(DOMEventTargetHelper* aOther)
      : mParentObject(nullptr),
        mOwnerWindow(nullptr),
        mHasOrHasHadOwnerWindow(false),
        mIsKeptAlive(false) {
    BindToOwner(aOther);
  }

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_CYCLE_COLLECTION_SKIPPABLE_SCRIPT_HOLDER_CLASS(DOMEventTargetHelper)

  NS_DECL_NSIDOMEVENTTARGET

  virtual EventListenerManager* GetExistingListenerManager() const override;
  virtual EventListenerManager* GetOrCreateListenerManager() override;

  using dom::EventTarget::RemoveEventListener;
  virtual void AddEventListener(
      const nsAString& aType, dom::EventListener* aListener,
      const dom::AddEventListenerOptionsOrBoolean& aOptions,
      const dom::Nullable<bool>& aWantsUntrusted, ErrorResult& aRv) override;

  NS_DECLARE_STATIC_IID_ACCESSOR(NS_DOMEVENTTARGETHELPER_IID)

  void GetParentObject(nsIScriptGlobalObject** aParentObject) {
    if (mParentObject) {
      CallQueryInterface(mParentObject, aParentObject);
    } else {
      *aParentObject = nullptr;
    }
  }

  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) {
    return mListenerManager && mListenerManager->HasListenersFor(aType);
  }

  bool HasListenersFor(nsAtom* aTypeWithOn) {
    return mListenerManager && mListenerManager->HasListenersFor(aTypeWithOn);
  }

  virtual nsPIDOMWindowOuter* GetOwnerGlobalForBindings() override {
    return nsPIDOMWindowOuter::GetFromCurrentInner(GetOwner());
  }

  nsresult CheckInnerWindowCorrectness() const {
    NS_ENSURE_STATE(!mHasOrHasHadOwnerWindow || mOwnerWindow);
    if (mOwnerWindow && !mOwnerWindow->IsCurrentInnerWindow()) {
      return NS_ERROR_FAILURE;
    }
    return NS_OK;
  }

  nsPIDOMWindowInner* GetOwner() const { return mOwnerWindow; }
  // 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.
  nsIDocument* GetDocumentIfCurrent() const;
  void BindToOwner(nsIGlobalObject* aOwner);
  void BindToOwner(nsPIDOMWindowInner* aOwner);
  void BindToOwner(DOMEventTargetHelper* aOther);
  virtual void DisconnectFromOwner();
  using EventTarget::GetParentObject;
  virtual nsIGlobalObject* GetOwnerGlobal() const override {
    return mParentObject;
  }
  bool HasOrHasHadOwner() { return mHasOrHasHadOwnerWindow; }

  virtual void EventListenerAdded(nsAtom* aType) override;
  virtual void EventListenerAdded(const nsAString& aType) override;

  virtual void EventListenerRemoved(nsAtom* aType) override;
  virtual void EventListenerRemoved(const nsAString& aType) override;

  virtual void EventListenerWasAdded(const nsAString& aType, ErrorResult& aRv,
                                     JSCompartment* aCompartment = nullptr) {}
  virtual void EventListenerWasRemoved(const nsAString& aType, ErrorResult& aRv,
                                       JSCompartment* aCompartment = nullptr) {}

  // 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(nsIDOMEvent* aEvent);

  virtual void LastRelease() {}

  void KeepAliveIfHasListenersFor(const nsAString& aType);
  void KeepAliveIfHasListenersFor(nsAtom* aType);

  void IgnoreKeepAliveIfHasListenersFor(const nsAString& aType);
  void IgnoreKeepAliveIfHasListenersFor(nsAtom* aType);

 private:
  // The parent global object.  The global will clear this when
  // it is destroyed by calling DisconnectFromOwner().
  nsIGlobalObject* MOZ_NON_OWNING_REF mParentObject;
  // mParentObject pre QI-ed and cached (inner window)
  // (it is needed for off main thread access)
  // It is obtained in BindToOwner and reset in DisconnectFromOwner.
  nsPIDOMWindowInner* MOZ_NON_OWNING_REF mOwnerWindow;
  bool mHasOrHasHadOwnerWindow;

  struct {
    nsTArray<nsString> mStrings;
    nsTArray<RefPtr<nsAtom>> mAtoms;
  } mKeepingAliveTypes;

  bool mIsKeptAlive;
};

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() {               \
    if (NS_IsMainThread()) {                                                \
      return GetEventHandler(nsGkAtoms::on##_event, EmptyString());         \
    }                                                                       \
    return GetEventHandler(nullptr, NS_LITERAL_STRING(#_event));            \
  }                                                                         \
  inline void SetOn##_event(mozilla::dom::EventHandlerNonNull* aCallback) { \
    if (NS_IsMainThread()) {                                                \
      SetEventHandler(nsGkAtoms::on##_event, EmptyString(), aCallback);     \
    } else {                                                                \
      SetEventHandler(nullptr, NS_LITERAL_STRING(#_event), aCallback);      \
    }                                                                       \
  }

/* Use this macro to declare functions that forward the behavior of this
 * interface to another object.
 * This macro doesn't forward GetEventTargetParent because sometimes subclasses
 * want to override it.
 */
#define NS_FORWARD_NSIDOMEVENTTARGET_NOGETEVENTTARGETPARENT(_to)               \
  NS_IMETHOD AddEventListener(const nsAString& type,                           \
                              nsIDOMEventListener* listener, bool useCapture,  \
                              bool wantsUntrusted, uint8_t _argc) override {   \
    return _to AddEventListener(type, listener, useCapture, wantsUntrusted,    \
                                _argc);                                        \
  }                                                                            \
  NS_IMETHOD AddSystemEventListener(                                           \
      const nsAString& type, nsIDOMEventListener* listener, bool aUseCapture,  \
      bool aWantsUntrusted, uint8_t _argc) override {                          \
    return _to AddSystemEventListener(type, listener, aUseCapture,             \
                                      aWantsUntrusted, _argc);                 \
  }                                                                            \
  NS_IMETHOD RemoveEventListener(                                              \
      const nsAString& type, nsIDOMEventListener* listener, bool useCapture)   \
      override {                                                               \
    return _to RemoveEventListener(type, listener, useCapture);                \
  }                                                                            \
  NS_IMETHOD RemoveSystemEventListener(                                        \
      const nsAString& type, nsIDOMEventListener* listener, bool aUseCapture)  \
      override {                                                               \
    return _to RemoveSystemEventListener(type, listener, aUseCapture);         \
  }                                                                            \
  NS_IMETHOD DispatchEvent(nsIDOMEvent* evt, bool* _retval) override {         \
    return _to DispatchEvent(evt, _retval);                                    \
  }                                                                            \
  virtual mozilla::dom::EventTarget* GetTargetForDOMEvent() {                  \
    return _to GetTargetForDOMEvent();                                         \
  }                                                                            \
  virtual mozilla::dom::EventTarget* GetTargetForEventTargetChain() {          \
    return _to GetTargetForEventTargetChain();                                 \
  }                                                                            \
  virtual nsresult WillHandleEvent(mozilla::EventChainPostVisitor& aVisitor) { \
    return _to WillHandleEvent(aVisitor);                                      \
  }                                                                            \
  virtual nsresult PostHandleEvent(mozilla::EventChainPostVisitor& aVisitor) { \
    return _to PostHandleEvent(aVisitor);                                      \
  }                                                                            \
  virtual nsresult DispatchDOMEvent(                                           \
      mozilla::WidgetEvent* aEvent, nsIDOMEvent* aDOMEvent,                    \
      nsPresContext* aPresContext, nsEventStatus* aEventStatus) {              \
    return _to DispatchDOMEvent(aEvent, aDOMEvent, aPresContext,               \
                                aEventStatus);                                 \
  }                                                                            \
  virtual mozilla::EventListenerManager* GetOrCreateListenerManager() {        \
    return _to GetOrCreateListenerManager();                                   \
  }                                                                            \
  virtual mozilla::EventListenerManager* GetExistingListenerManager() const {  \
    return _to GetExistingListenerManager();                                   \
  }                                                                            \
  virtual nsIScriptContext* GetContextForEventHandlers(nsresult* aRv) {        \
    return _to GetContextForEventHandlers(aRv);                                \
  }

#define NS_REALLY_FORWARD_NSIDOMEVENTTARGET(_class)                   \
  using _class::AddEventListener;                                     \
  using _class::RemoveEventListener;                                  \
  NS_FORWARD_NSIDOMEVENTTARGET(_class::)                              \
  virtual mozilla::EventListenerManager* GetOrCreateListenerManager() \
      override {                                                      \
    return _class::GetOrCreateListenerManager();                      \
  }                                                                   \
  virtual mozilla::EventListenerManager* GetExistingListenerManager() \
      const override {                                                \
    return _class::GetExistingListenerManager();                      \
  }

#endif  // mozilla_DOMEventTargetHelper_h_