gecko-dev/widget/NativeMenu.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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_widget_NativeMenu_h
#define mozilla_widget_NativeMenu_h

#include "nsISupportsImpl.h"
#include "Units.h"

class nsIFrame;
class nsPresContext;

namespace mozilla {
using Modifiers = uint16_t;
class ErrorResult;
}  // namespace mozilla

namespace mozilla::dom {
class Element;
}

namespace mozilla::widget {

class NativeMenu {
 public:
  NS_INLINE_DECL_REFCOUNTING(NativeMenu)

  // Show this menu as a context menu at the specified position.
  // This call assumes that the popupshowing event for the root popup has
  // already been sent and "approved", i.e. preventDefault() was not called.
  virtual void ShowAsContextMenu(nsIFrame* aClickedFrame,
                                 const CSSIntPoint& aPosition,
                                 bool aIsContextMenu) = 0;

  // Close the menu and synchronously fire popuphiding / popuphidden events.
  // Returns false if the menu wasn't open.
  virtual bool Close() = 0;

  // Activate aItemElement and close this menu.
  // aItemElement can be nested arbitrarily deeply within submenus inside this
  // menu. Only works while this menu (and any submenus on the path to the
  // item) is open, otherwise aRv reports an error.
  virtual void ActivateItem(dom::Element* aItemElement, Modifiers aModifiers,
                            int16_t aButton, ErrorResult& aRv) = 0;

  // Open, or simulate the opening of, a submenu.
  // aMenuElement can be nested arbitrarily deeply within submenus inside this
  // menu. Only works while this menu (and any submenus on the path to the
  // submenu) is open.
  virtual void OpenSubmenu(dom::Element* aMenuElement) = 0;

  // Closing, or simulate the closing of, a submenu.
  // aMenuElement can be nested arbitrarily deeply within submenus inside this
  // menu. Only works while this menu (and any submenus on the path to the
  // submenu) is open.
  virtual void CloseSubmenu(dom::Element* aMenuElement) = 0;

  // Return this NativeMenu's DOM element.
  virtual RefPtr<dom::Element> Element() = 0;

  class Observer {
   public:
    // Called when the menu opened, after popupshown.
    // No strong reference is held to the observer during the call.
    virtual void OnNativeMenuOpened() = 0;

    // Called when the menu closed, after popuphidden.
    // No strong reference is held to the observer during the call.
    virtual void OnNativeMenuClosed() = 0;

    // Called before the popupshowing event of a submenu fires.
    virtual void OnNativeSubMenuWillOpen(dom::Element* aPopupElement) = 0;

    // Called after the popupshown event of a submenu fired.
    virtual void OnNativeSubMenuDidOpen(dom::Element* aPopupElement) = 0;

    // Called after the popuphidden event of a submenu fired.
    virtual void OnNativeSubMenuClosed(dom::Element* aPopupElement) = 0;

    // Called before the command event of an activated menu item fires.
    virtual void OnNativeMenuWillActivateItem(
        dom::Element* aMenuItemElement) = 0;
  };

  // Add an observer that gets notified of menu opening and closing.
  // The menu does not keep a strong reference the observer. The observer must
  // remove itself before it is destroyed.
  virtual void AddObserver(Observer* aObserver) = 0;

  // Remove an observer that was previously added with AddObserver.
  virtual void RemoveObserver(Observer* aObserver) = 0;

 protected:
  virtual ~NativeMenu() = default;
};

}  // namespace mozilla::widget

#endif  // mozilla_widget_NativeMenu_h