Read and expose accelerometer values from cros-ec-accel trigger.

chromeos/accelerometer/accelerometer_reader.h

+// 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/weak_ptr.h"
+#include "base/observer_list.h"
+#include "chromeos/chromeos_export.h"
+#include "ui/gfx/geometry/vector3d_f.h"
+
+namespace chromeos {
+
+// An interface to receive data from the AccelerometerReader.
+class AccelerometerDelegate {

[Daniel Erat, 2014/03/26 22:26:14]

maybe move this be a public internal class of AccelerometerReader named
Delegate, so it's obvious from the name what it's a delegate for?

[flackr, 2014/03/27 15:21:07]

Done.

+ public:
+  virtual void OnAccelerometerRead(const gfx::Vector3dF& base,
+                                   const gfx::Vector3dF& lid) = 0;
+};
+
+// Reads an accelerometer device and reports data back to an
+// AccelerometerDelegate.
+class CHROMEOS_EXPORT AccelerometerReader {
+ public:
+  AccelerometerReader(AccelerometerDelegate* delegate);

[Daniel Erat, 2014/03/26 22:26:14]

nit: explicit

[flackr, 2014/03/27 15:21:07]

Done.

+  virtual ~AccelerometerReader();

[Daniel Erat, 2014/03/26 22:26:14]

nit: don't need virtual

[flackr, 2014/03/27 15:21:07]

Done.

+
+ private:
+  // Detects and reads configuration of the accelerometer device.
+  bool Initialize();
+
+  // Dispatched when initialization is complete. |success| is true if an
+  // accelerometer was detected and all configuration paramaters read.

[Daniel Erat, 2014/03/26 22:26:14]

nit: s/paramaters/parameters/

[flackr, 2014/03/27 15:21:07]

Done.

+  void OnInitialized(bool success);
+
+  // Triggers an asynchronous read from the accelerometer, signalling
+  // OnDataRead with the result of the read.
+  void TriggerRead();
+
+  // Triggers the accelerometer and reads the sampled values. Returns true if
+  // successful, in which case base_accelerometer_ and lid_accelerometer_
+  // contain the current values.
+  bool ReadAccelerometer();
+
+  // If |success|, notifies the delegate_ with the new readings. Triggers

[Daniel Erat, 2014/03/26 22:26:14]

nit: s/delegate_/|delegate_|/ (also in other comments in this file -- i think
that i've usually seen both arguments and class members get the pipe treatment)

[flackr, 2014/03/27 15:21:07]

Done.

+  // another read from the accelerometer at the current sampling rate.
+  void OnDataRead(bool success);
+
+  // A weak pointer to the delegate to send accelerometer readings to.
+  AccelerometerDelegate* delegate_;
+
+  // True after Initialize has run if an accelerometer sensor exists.
+  bool has_accelerometer_;
+
+  // The index of each axis of each accelerometer.
+  std::vector<unsigned int> accelerometer_index_;
+
+  // The scale of the base and lid accelerometers.
+  unsigned int accelerometer_base_scale_;
+  unsigned int accelerometer_lid_scale_;
+
+  // The last reading from the base accelerometer.
+  gfx::Vector3dF base_accelerometer_;

[Daniel Erat, 2014/03/26 22:26:14]

nit: base_reading_? base_value_?

[flackr, 2014/03/27 15:21:07]

Done.

+
+  // The last reading from the lid accelerometer.
+  gfx::Vector3dF lid_accelerometer_;

[Daniel Erat, 2014/03/26 22:26:14]

nit: lid_reading_? lid_value_?

[flackr, 2014/03/27 15:21:07]

Done.

+
+  base::WeakPtrFactory<AccelerometerReader> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(AccelerometerReader);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_ACCELEROMETER_ACCELEROMETER_READER_H_