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// Copyright 2017 The ChromiumOS Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <gtest/gtest.h> // for FRIEND_TEST
#include "include/filter_interpreter.h"
#include "include/gestures.h"
#include "include/prop_registry.h"
#include "include/tracer.h"
#ifndef GESTURES_TIMESTAMP_FILTER_INTERPRETER_H_
#define GESTURES_TIMESTAMP_FILTER_INTERPRETER_H_
// This class fixes up the timestamp of the hardware state. There are three
// possibilities:
// 1) hwstate.timestamp is reliable.
// 2) hwstate.timestamp may be unreliable, but a reliable
// hwstate.msc_timestamp has been provided.
// 3) hwstate.timestamp and hwstate.msc_timestamp are both unreliable.
// ComputeTimestampDefault handles the first two cases, and
// ComputeTimestampUsingFake handles the third case.
namespace gestures {
class TimestampFilterInterpreter : public FilterInterpreter {
FRIEND_TEST(TimestampFilterInterpreterTest, FakeTimestampTest);
FRIEND_TEST(TimestampFilterInterpreterTest, FakeTimestampJumpForwardTest);
FRIEND_TEST(TimestampFilterInterpreterTest, FakeTimestampFallBackwardTest);
public:
// Takes ownership of |next|:
explicit TimestampFilterInterpreter(PropRegistry* prop_reg,
Interpreter* next,
Tracer* tracer);
virtual ~TimestampFilterInterpreter() {}
protected:
virtual void SyncInterpretImpl(HardwareState& hwstate, stime_t* timeout);
virtual void HandleTimerImpl(stime_t now, stime_t* timeout);
private:
// Before this function is applied, there are two possibilities:
// 1) hwstate.timestamp == CLOCK_MONOTONIC &&
// hwstate.msc_timestamp == 0.0
// - No changes are needed in this case
// 2) hwstate.timestamp == CLOCK_MONOTONIC &&
// hwstate.msc_timestamp == MSC_TIMESTAMP
// - MSC_TIMESTAMP will be more accurate than CLOCK_MONOTONIC, so we
// want to use it for time deltas in the gesture library. However,
// MSC_TIMESTAMP will reset to 0.0 if there are no touch events for
// at least 1 second. So whenever MSC_TIMESTAMP resets, we record the
// offset between CLOCK_MONOTONIC and MSC_TIMESTAMP and add this
// offset to subsequent events.
// After this function is applied:
// - hwstate.timestamp uses CLOCK_MONOTONIC as the time base, possibly with
// fine tuning provided by MSC_TIMESTAMP.
// - hwstate.msc_timestamp should not be used.
void ChangeTimestampDefault(HardwareState& hwstate);
// If neither hwstate.timestamp nor hwstate.msc_timestamp has reliable
// deltas, we use fake_timestamp_delta_ as the delta between consecutive
// reports, but don't allow our faked timestamp to diverge too far from
// hwstate.timestamp.
void ChangeTimestampUsingFake(HardwareState& hwstate);
void ConsumeGesture(const Gesture& gs);
stime_t prev_msc_timestamp_;
// Difference between msc_timestamp and timestamp as of last timestamp reset.
stime_t msc_timestamp_offset_;
// If we are using fake timestamps, this holds the most recent fake
stime_t fake_timestamp_;
// Maximum we let fake_timestamp_ diverge from hwstate.timestamp
stime_t fake_timestamp_max_divergence_;
// The difference between the original timestamp and the timestamp after
// adjustment by this interpreter. When contact begins this will be zero, but
// the two clocks may get out of sync by a small amount as time goes on
stime_t skew_;
// Maximum skew_ since the last reset.
stime_t max_skew_;
// If we don't have a reliable timestamp, we use this as the timestamp delta.
DoubleProperty fake_timestamp_delta_;
};
} // namespace gestures
#endif // GESTURES_TIMESTAMP_FILTER_INTERPRETER_H_
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