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// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_INPUT_TAP_SUPPRESSION_CONTROLLER_H_
#define COMPONENTS_INPUT_TAP_SUPPRESSION_CONTROLLER_H_
#include "base/time/time.h"
#include "base/timer/timer.h"
#include "base/component_export.h"
namespace input {
// The core controller for suppression of taps (touchpad or touchscreen)
// immediately following a GestureFlingCancel event (caused by the same tap).
// Only taps of sufficient speed and within a specified time window after a
// GestureFlingCancel are suppressed.
class COMPONENT_EXPORT(INPUT) TapSuppressionController {
public:
struct COMPONENT_EXPORT(INPUT) Config {
Config();
// Defaults to false, in which case no suppression is performed.
bool enabled;
// The maximum time allowed between a GestureFlingCancel and its
// corresponding tap down.
base::TimeDelta max_cancel_to_down_time;
};
TapSuppressionController(const Config& config);
TapSuppressionController(const TapSuppressionController&) = delete;
TapSuppressionController& operator=(const TapSuppressionController&) = delete;
virtual ~TapSuppressionController();
// Should be called whenever a GestureFlingCancel actually stopped a fling and
// therefore the controller should suppress the forwarding of the following
// tap.
void GestureFlingCancelStoppedFling();
// Should be called whenever a tap down (touchpad or touchscreen) is received.
// Returns true if the tap down should be suppressed.
bool ShouldSuppressTapDown();
// Should be called whenever a tap ending event is received. Returns true if
// the tap event should be suppressed.
bool ShouldSuppressTapEnd();
protected:
virtual base::TimeTicks Now();
private:
friend class MockTapSuppressionController;
enum State {
DISABLED,
NOTHING,
LAST_CANCEL_STOPPED_FLING,
// When the stashed TapDown event is dropped, the controller enters the
// SUPPRESSING_TAPS state. This state shows that the controller will
// suppress LongTap, TwoFingerTap, and TapCancel gesture events until the
// next tapDown event arrives.
SUPPRESSING_TAPS,
};
State state_;
base::TimeDelta max_cancel_to_down_time_;
// TODO(rjkroege): During debugging, the event times did not prove reliable.
// Replace the use of base::TimeTicks with an accurate event time when they
// become available post http://crbug.com/119556.
base::TimeTicks fling_cancel_time_;
};
} // namespace input
#endif // COMPONENTS_INPUT_TAP_SUPPRESSION_CONTROLLER_H_
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