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

chromeos/accelerometer/accelerometer_reader.h

Index: chromeos/accelerometer/accelerometer_reader.h
diff --git a/chromeos/accelerometer/accelerometer_reader.h b/chromeos/accelerometer/accelerometer_reader.h
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index 0000000000000000000000000000000000000000..e2b85bcd4d8c4ca0768cc224b79eccb68057400e
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+++ b/chromeos/accelerometer/accelerometer_reader.h
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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/gfx/geometry/vector3d_f.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 HandleAccelerometerReading(const gfx::Vector3dF& base,
+                                            const gfx::Vector3dF& lid) = 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 a pair of Vector3dF
+  // values 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 accelerometer configuration.
+  scoped_refptr<Configuration> configuration_;
+
+  base::WeakPtrFactory<AccelerometerReader> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(AccelerometerReader);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_ACCELEROMETER_ACCELEROMETER_READER_H_