ui/views/input_event_activation_protector.h

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_VIEWS_INPUT_EVENT_ACTIVATION_PROTECTOR_H_
#define UI_VIEWS_INPUT_EVENT_ACTIVATION_PROTECTOR_H_

#include "base/time/time.h"
#include "ui/views/views_export.h"

namespace ui {
class Event;
}

namespace views {

// The goal of this class is to prevent potentially unintentional user
// interaction with a UI element.
class VIEWS_EXPORT InputEventActivationProtector {
 public:
  InputEventActivationProtector() = default;

  InputEventActivationProtector(const InputEventActivationProtector&) = delete;
  InputEventActivationProtector& operator=(
      const InputEventActivationProtector&) = delete;

  virtual ~InputEventActivationProtector() = default;

  // Updates the state of the protector based off of visibility changes. This
  // method must be called when the visibility of the view is changed.
  void VisibilityChanged(bool is_visible);

  // Updates the |view_shown_time_stamp_| if needed. This function will be
  // called when we want to reset back the input protector to "initial shown"
  // state, basically under some certain view's proprieties changed events.
  void UpdateViewShownTimeStamp();

  // Returns true if the event is a mouse, touch, or pointer event that took
  // place within the double-click time interval after |view_shown_time_stamp_|.
  virtual bool IsPossiblyUnintendedInteraction(const ui::Event& event);

  // Resets the state for click tracking.
  void ResetForTesting();

  // Integration tests can disable all input event activation protectors.
  static void DisableForTesting();

 private:
  // Timestamp of when the view being tracked is first shown.
  base::TimeTicks view_shown_time_stamp_;
  // Timestamp of the last event.
  base::TimeTicks last_event_timestamp_;
  // Number of repeated UI events with short intervals.
  size_t repeated_event_count_ = 0;
};

}  // namespace views

#endif  // UI_VIEWS_INPUT_EVENT_ACTIVATION_PROTECTOR_H_