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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 */
#ifndef mozilla_GlobalKeyListener_h_
#define mozilla_GlobalKeyListener_h_
#include "mozilla/EventForwards.h"
#include "mozilla/layers/KeyboardMap.h"
#include "nsIDOMEventListener.h"
#include "nsIWeakReferenceUtils.h"
class nsAtom;
namespace mozilla {
class EventListenerManager;
class WidgetKeyboardEvent;
struct IgnoreModifierState;
namespace layers {
class KeyboardMap;
namespace dom {
class Element;
class EventTarget;
class KeyboardEvent;
} // namespace dom
class KeyEventHandler;
* A generic listener for key events.
* Maintains a list of shortcut handlers and is registered as a listener for DOM
* key events from a target. Responsible for executing the appropriate handler
* when a keyboard event is received.
class GlobalKeyListener : public nsIDOMEventListener {
explicit GlobalKeyListener(dom::EventTarget* aTarget);
void InstallKeyboardEventListenersTo(
EventListenerManager* aEventListenerManager);
void RemoveKeyboardEventListenersFrom(
EventListenerManager* aEventListenerManager);
virtual ~GlobalKeyListener() = default;
void WalkHandlers(dom::KeyboardEvent* aKeyEvent);
enum class Purpose {
struct MOZ_STACK_CLASS WalkHandlersResult {
// Set to true if it found a command matches with given keyboard event and
// it's available.
bool mMeaningfulHandlerFound = false;
// Set to true if the command which is found or executed is reserved for
// chrome.
bool mReservedHandlerForChromeFound = false;
// Set to true if found handler is disabled.
bool mDisabledHandlerFound = false;
// walk the handlers, looking for one to handle the event
WalkHandlersResult WalkHandlersInternal(Purpose aPurpose,
dom::KeyboardEvent* aKeyEvent);
// Walk the handlers for aEvent, aCharCode and aIgnoreModifierState.
WalkHandlersResult WalkHandlersAndExecute(
Purpose aPurpose, dom::KeyboardEvent* aKeyEvent, uint32_t aCharCode,
const IgnoreModifierState& aIgnoreModifierState);
// HandleEvent function for the capturing phase in the default event group.
void HandleEventOnCaptureInDefaultEventGroup(dom::KeyboardEvent* aEvent);
// HandleEvent function for the capturing phase in the system event group.
void HandleEventOnCaptureInSystemEventGroup(dom::KeyboardEvent* aEvent);
// Check if any handler would handle the given event. Optionally returns
// whether the command handler for the event is marked with the "reserved"
// attribute.
WalkHandlersResult HasHandlerForEvent(dom::KeyboardEvent* aEvent);
// Returns true if the key would be reserved for the given handler. A reserved
// key is not sent to a content process or single-process equivalent.
bool IsReservedKey(WidgetKeyboardEvent* aKeyEvent, KeyEventHandler* aHandler);
// lazily load the handlers. Overridden to handle being attached
// to a particular element rather than the document
virtual void EnsureHandlers() = 0;
virtual bool CanHandle(KeyEventHandler* aHandler, bool aWillExecute) const {
return true;
virtual bool IsDisabled() const { return false; }
virtual already_AddRefed<dom::EventTarget> GetHandlerTarget(
KeyEventHandler* aHandler) {
return do_AddRef(mTarget);
dom::EventTarget* mTarget; // weak ref;
KeyEventHandler* mHandler; // Linked list of event handlers.
* A listener for shortcut keys defined in XUL keyset elements.
* Listens for keyboard events from the document object and triggers the
* appropriate XUL key elements.
class XULKeySetGlobalKeyListener final : public GlobalKeyListener {
explicit XULKeySetGlobalKeyListener(dom::Element* aElement,
dom::EventTarget* aTarget);
static void AttachKeyHandler(dom::Element* aElementTarget);
static void DetachKeyHandler(dom::Element* aElementTarget);
virtual ~XULKeySetGlobalKeyListener();
// Returns the element which was passed as a parameter to the constructor,
// unless the element has been removed from the document. Optionally returns
// whether the disabled attribute is set on the element (assuming the element
// is non-null).
dom::Element* GetElement(bool* aIsDisabled = nullptr) const;
virtual void EnsureHandlers() override;
virtual bool CanHandle(KeyEventHandler* aHandler,
bool aWillExecute) const override;
virtual bool IsDisabled() const override;
virtual already_AddRefed<dom::EventTarget> GetHandlerTarget(
KeyEventHandler* aHandler) override;
* GetElementForHandler() retrieves an element for the handler. The element
* may be a command element or a key element.
* @param aHandler The handler.
* @param aElementForHandler Must not be nullptr. The element is returned to
* this.
* @return true if the handler is valid. Otherwise, false.
bool GetElementForHandler(KeyEventHandler* aHandler,
dom::Element** aElementForHandler) const;
* IsExecutableElement() returns true if aElement is executable.
* Otherwise, false. aElement should be a command element or a key element.
bool IsExecutableElement(dom::Element* aElement) const;
// Using weak pointer to the DOM Element.
nsWeakPtr mWeakPtrForElement;
* Listens for built-in shortcut keys.
* Listens to DOM keyboard events from the window or text input and runs the
* built-in shortcuts (see dom/events/keyevents) as necessary.
class RootWindowGlobalKeyListener final : public GlobalKeyListener {
explicit RootWindowGlobalKeyListener(dom::EventTarget* aTarget);
static void AttachKeyHandler(dom::EventTarget* aTarget);
static layers::KeyboardMap CollectKeyboardShortcuts();
// Is an HTML editable element focused
static bool IsHTMLEditorFocused();
virtual void EnsureHandlers() override;
} // namespace mozilla