Chromium: Add AccelerometerProviderInterface

This commit adds an interface class AccelerometerProviderInterface for
AccelerometerFileReader, to allow another mojo implementation in the
future. It also moves AccelerometerFileReader into separate source
files.

BUG=b:168434557
TEST=builds and run on kohaku

Change-Id: I6ee6e2253764a69cfe1693f792b64fa275b34a8b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2409672
Commit-Queue: Cheng-Hao Yang <chenghaoyang@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#815247}

ash/BUILD.gn

@@ -127,6 +127,8 @@ component("ash") {
     "accelerators/pre_target_accelerator_handler.h",
     "accelerators/spoken_feedback_toggler.cc",
     "accelerators/spoken_feedback_toggler.h",
+    "accelerometer/accelerometer_file_reader.cc",
+    "accelerometer/accelerometer_file_reader.h",
     "accelerometer/accelerometer_reader.cc",
     "accelerometer/accelerometer_reader.h",
     "accelerometer/accelerometer_types.cc",

ash/accelerometer/accelerometer_file_reader.h

+// Copyright 2020 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 ASH_ACCELEROMETER_ACCELEROMETER_FILE_READER_H_
+#define ASH_ACCELEROMETER_ACCELEROMETER_FILE_READER_H_
+
+#include <string>
+#include <vector>
+
+#include "ash/accelerometer/accelerometer_reader.h"
+#include "ash/public/cpp/tablet_mode_observer.h"
+#include "base/files/file_util.h"
+#include "base/observer_list_threadsafe.h"
+
+namespace ash {
+
+enum class ECLidAngleDriver { UNKNOWN, SUPPORTED, NOT_SUPPORTED };
+
+enum class State { INITIALIZING, SUCCESS, FAILED };
+
+// Work that runs on a base::TaskRunner. It determines the accelerometer
+// configuration, and reads the data. Upon a successful read it will notify
+// all observers.
+class AccelerometerFileReader : public AccelerometerProviderInterface,
+                                public TabletModeObserver {
+ public:
+  AccelerometerFileReader();
+  AccelerometerFileReader(const AccelerometerFileReader&) = delete;
+  AccelerometerFileReader& operator=(const AccelerometerFileReader&) = delete;
+
+  // AccelerometerProviderInterface:
+  void PrepareAndInitialize(
+      scoped_refptr<base::SequencedTaskRunner> sequenced_task_runner) override;
+  void AddObserver(AccelerometerReader::Observer* observer) override;
+  void RemoveObserver(AccelerometerReader::Observer* observer) override;
+  void StartListenToTabletModeController() override;
+  void StopListenToTabletModeController() override;
+  void SetEmitEvents(bool emit_events) override;
+
+  // Attempts to read the accelerometer data. Upon success, converts the raw
+  // reading to an AccelerometerUpdate and notifies observers. Triggers another
+  // read at the current sampling rate.
+  void Read();
+
+  // Controls accelerometer reading.
+  void EnableAccelerometerReading();
+  void DisableAccelerometerReading();
+
+  // Tracks if accelerometer initialization is completed.
+  void CheckInitStatus();
+
+  // With ChromeOS EC lid angle driver present, accelerometer read is cancelled
+  // in clamshell mode, and triggered when entering tablet mode.
+  void TriggerRead();
+  void CancelRead();
+
+  // TabletModeObserver:
+  void OnTabletPhysicalStateChanged() override;
+
+ private:
+  // Represents necessary information in order to read an accelerometer device.
+  struct ReadingData {
+    ReadingData();
+    ReadingData(const ReadingData&);
+    ~ReadingData();
+
+    // The full path to the accelerometer device to read.
+    base::FilePath path;
+
+    // The accelerometer sources which can be read from |path|.
+    std::vector<AccelerometerSource> sources;
+  };
+
+  // Configuration structure for accelerometer device.
+  struct ConfigurationData {
+    ConfigurationData();
+    ~ConfigurationData();
+
+    // Number of accelerometers on device.
+    size_t count;
+
+    // sysfs entry to trigger readings.
+    base::FilePath trigger_now;
+
+    // Which accelerometers are present on device.
+    bool has[ACCELEROMETER_SOURCE_COUNT];
+
+    // Scale of accelerometers (i.e. raw value * scale = m/s^2).
+    float scale[ACCELEROMETER_SOURCE_COUNT][3];
+
+    // Index of each accelerometer axis in data stream.
+    int index[ACCELEROMETER_SOURCE_COUNT][3];
+
+    // The information for each accelerometer device to be read. In kernel 3.18
+    // there is one per ACCELEROMETER_SOURCE_COUNT. On 3.14 there is only one.
+    std::vector<ReadingData> reading_data;
+  };
+
+  ~AccelerometerFileReader() override;
+
+  // Detects the accelerometer configuration.
+  // If an accelerometer is available, it triggers reads.
+  // This function MAY be called more than once.
+  // This function contains the actual initialization code to be run by the
+  // Initialize function. It is needed because on some devices the sensor hub
+  // isn't available at the time the call to Initialize is made. If the sensor
+  // is found to be missing we'll make a call to TryScheduleInitializeInternal.
+  void InitializeInternal();
+
+  // Attempt to reschedule a run of InitializeInternal(). The function will be
+  // scheduled to run again if Now() < initialization_timeout_.
+  void TryScheduleInitializeInternal();
+
+  // When accelerometers are presented as separate iio_devices this will perform
+  // the initialize for one of the devices, at the given |iio_path| and the
+  // symbolic link |name|. |location| is defined by AccelerometerSource.
+  bool InitializeAccelerometer(const base::FilePath& iio_path,
+                               const base::FilePath& name,
+                               const std::string& location);
+
+  // TODO(jonross): Separate the initialization into separate files. Add a gyp
+  // rule to have them built for the appropriate kernels. (crbug.com/525658)
+  // When accelerometers are presented as a single iio_device this will perform
+  // the initialization for both of them.
+  bool InitializeLegacyAccelerometers(const base::FilePath& iio_path,
+                                      const base::FilePath& name);
+
+  // Attempts to read the accelerometer data. Upon a success, converts the raw
+  // reading to an AccelerometerUpdate and notifies observers.
+  void ReadFileAndNotify();
+
+  void SetEmitEventsInternal(bool emit_events);
+
+  // State of ChromeOS EC lid angle driver, if SUPPORTED, it means EC can handle
+  // lid angle calculation.
+  ECLidAngleDriver ec_lid_angle_driver_ = ECLidAngleDriver::UNKNOWN;
+
+  // The current initialization state of reader.
+  State initialization_state_ = State::INITIALIZING;
+
+  // True if periodical accelerometer read is on.
+  bool accelerometer_read_on_ = false;
+
+  bool emit_events_ = true;
+
+  // The time at which initialization re-tries should stop.
+  base::TimeTicks initialization_timeout_;
+
+  // The accelerometer configuration.
+  ConfigurationData configuration_;
+
+  // The observers to notify of accelerometer updates.
+  scoped_refptr<base::ObserverListThreadSafe<AccelerometerReader::Observer>>
+      observers_;
+
+  // The task runner to use for blocking tasks.
+  scoped_refptr<base::SequencedTaskRunner> task_runner_;
+
+  // The last seen accelerometer data.
+  scoped_refptr<AccelerometerUpdate> update_;
+};
+
+}  // namespace ash
+
+#endif  // ASH_ACCELEROMETER_ACCELEROMETER_FILE_READER_H_

ash/accelerometer/accelerometer_reader.h

@@ -19,7 +19,7 @@ class SequencedTaskRunner;
 
 namespace ash {
 
-class AccelerometerFileReader;
+class AccelerometerProviderInterface;
 
 // Reads an accelerometer device and reports data back to an
 // AccelerometerDelegate.
@@ -64,11 +64,37 @@ class ASH_EXPORT AccelerometerReader {
   // Worker that will run on the base::SequencedTaskRunner provided to
   // Initialize. It will determine accelerometer configuration, read the data,
   // and notify observers.
-  scoped_refptr<AccelerometerFileReader> accelerometer_file_reader_;
+  scoped_refptr<AccelerometerProviderInterface> accelerometer_provider_;
 
   DISALLOW_COPY_AND_ASSIGN(AccelerometerReader);
 };
 
+class AccelerometerProviderInterface
+    : public base::RefCountedThreadSafe<AccelerometerProviderInterface> {
+ public:
+  // Prepare and start async initialization. SetSensorClient function
+  // contains actual code for initialization.
+  virtual void PrepareAndInitialize(
+      scoped_refptr<base::SequencedTaskRunner> sequenced_task_runner) = 0;
+
+  // Add/Remove observers.
+  virtual void AddObserver(AccelerometerReader::Observer* observer) = 0;
+  virtual void RemoveObserver(AccelerometerReader::Observer* observer) = 0;
+
+  // Start/Stop listening to tablet mode controller.
+  virtual void StartListenToTabletModeController() = 0;
+  virtual void StopListenToTabletModeController() = 0;
+
+  // Set emitting events (samples) to observers or not.
+  virtual void SetEmitEvents(bool emit_events) = 0;
+
+ protected:
+  virtual ~AccelerometerProviderInterface() = default;
+
+ private:
+  friend class base::RefCountedThreadSafe<AccelerometerProviderInterface>;
+};
+
 }  // namespace ash
 
 #endif  // ASH_ACCELEROMETER_ACCELEROMETER_READER_H_