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// Copyright 2014 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.
#ifndef CHROMEOS_ACCELEROMETER_ACCELEROMETER_READER_H_
#define CHROMEOS_ACCELEROMETER_ACCELEROMETER_READER_H_
#include <vector>
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "chromeos/chromeos_export.h"
#include "ui/accelerometer/accelerometer_types.h"
namespace base {
class TaskRunner;
}
namespace chromeos {
// Reads an accelerometer device and reports data back to an
// AccelerometerDelegate.
class CHROMEOS_EXPORT AccelerometerReader {
public:
// Configuration structure for accelerometer device.
struct ConfigurationData {
ConfigurationData();
~ConfigurationData();
// Scale of accelerometers (i.e. raw value * 1.0f / scale = G's).
unsigned int base_scale;
unsigned int lid_scale;
// Index of each accelerometer axis in data stream.
std::vector<unsigned int> index;
};
typedef base::RefCountedData<ConfigurationData> Configuration;
typedef base::RefCountedData<char[12]> Reading;
// An interface to receive data from the AccelerometerReader.
class Delegate {
public:
virtual void HandleAccelerometerUpdate(
const ui::AccelerometerUpdate& update) = 0;
};
AccelerometerReader(base::TaskRunner* blocking_task_runner,
Delegate* delegate);
~AccelerometerReader();
private:
// Dispatched when initialization is complete. If |success|, |configuration|
// provides the details of the detected accelerometer.
void OnInitialized(scoped_refptr<Configuration> configuration, bool success);
// Triggers an asynchronous read from the accelerometer, signalling
// OnDataRead with the result.
void TriggerRead();
// If |success|, converts the raw reading to an AccelerometerUpdate
// message and notifies the |delegate_| with the new readings.
// Triggers another read from the accelerometer at the current sampling rate.
void OnDataRead(scoped_refptr<Reading> reading, bool success);
// The task runner to use for blocking tasks.
scoped_refptr<base::TaskRunner> task_runner_;
// A weak pointer to the delegate to send accelerometer readings to.
Delegate* delegate_;
// The last seen accelerometer data.
ui::AccelerometerUpdate update_;
// The accelerometer configuration.
scoped_refptr<Configuration> configuration_;
base::WeakPtrFactory<AccelerometerReader> weak_factory_;
DISALLOW_COPY_AND_ASSIGN(AccelerometerReader);
};
} // namespace chromeos
#endif // CHROMEOS_ACCELEROMETER_ACCELEROMETER_READER_H_