blob: 60a50755b245a7e400ba4e9703e1e61973845313 [file] [log] [blame]
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <vector>
#include "base/containers/stack.h"
#include "base/macros.h"
#include "ui/events/event_constants.h"
#include "ui/events/events_export.h"
namespace ui {
class CancelModeEvent;
class Event;
class EventDispatcher;
class EventTarget;
class GestureEvent;
class KeyEvent;
class MouseEvent;
class ScrollEvent;
class TouchEvent;
// Dispatches events to appropriate targets. The default implementations of
// all of the specific handlers (e.g. OnKeyEvent, OnMouseEvent) do nothing.
class EVENTS_EXPORT EventHandler {
virtual ~EventHandler();
// Disables a CHECK() that this has been removed from all pre-target
// handlers in the destructor.
// TODO(sky): remove, used to track
static void DisableCheckTargets() { check_targets_ = false; }
// This is called for all events. The default implementation routes the event
// to one of the event-specific callbacks (OnKeyEvent, OnMouseEvent etc.). If
// this is overridden, then normally, the override should chain into the
// default implementation for un-handled events.
virtual void OnEvent(Event* event);
virtual void OnKeyEvent(KeyEvent* event);
virtual void OnMouseEvent(MouseEvent* event);
virtual void OnScrollEvent(ScrollEvent* event);
virtual void OnTouchEvent(TouchEvent* event);
virtual void OnGestureEvent(GestureEvent* event);
virtual void OnCancelMode(CancelModeEvent* event);
friend class EventDispatcher;
friend class EventTarget;
// EventDispatcher pushes itself on the top of this stack while dispatching
// events to this then pops itself off when done.
base::stack<EventDispatcher*> dispatchers_;
// Set of EventTargets |this| has been installed as a pre-target handler on.
// This is a vector as AddPreTargetHandler() may be called multiple times for
// the same EventTarget.
// TODO(sky): remove, used to track
std::vector<EventTarget*> targets_installed_on_;
static bool check_targets_;
typedef std::vector<EventHandler*> EventHandlerList;
} // namespace ui