src/athena/system/orientation_controller.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "athena/screen/public/screen_manager.h"
   6 #include "athena/system/orientation_controller.h"
   7 #include "base/bind.h"
   8 #include "base/file_util.h"
   9 #include "base/files/file_path_watcher.h"
  10 #include "base/message_loop/message_loop.h"
  11 #include "base/task_runner.h"
  12
  13 namespace athena {
  14
  15 namespace {
  16
  17 // Path of the socket which the sensor daemon creates.
  18 const char kSocketPath[] = "/dev/sensors/orientation";
  19
  20 // Threshold after which to rotate in a given direction.
  21 const int kGravityThreshold = 6.0f;
  22
  23 // Minimum delay before triggering another orientation change.
  24 const int kOrientationChangeDelayNS = 500000000;
  25
  26 enum SensorType {
  27   SENSOR_ACCELEROMETER,
  28   SENSOR_LIGHT,
  29   SENSOR_PROXIMITY
  30 };
  31
  32 // A sensor event from the device.
  33 struct DeviceSensorEvent {
  34   // The type of event from the SensorType enum above.
  35   int32_t type;
  36
  37   // The time in nanoseconds at which the event happened.
  38   int64_t timestamp;
  39
  40   union {
  41     // Accelerometer X,Y,Z values in SI units (m/s^2) including gravity.
  42     // The orientation is described at
  43     // http://www.html5rocks.com/en/tutorials/device/orientation/.
  44     float data[3];
  45
  46     // Ambient (room) temperature in degrees Celcius.
  47     float temperature;
  48
  49     // Proximity sensor distance in centimeters.
  50     float distance;
  51
  52     // Ambient light level in SI lux units.
  53     float light;
  54   };
  55 };
  56
  57 }  // namespace
  58
  59 OrientationController::OrientationController(
  60     scoped_refptr<base::TaskRunner> io_task_runner)
  61     : DeviceSocketListener(kSocketPath, sizeof(DeviceSensorEvent)),
  62       last_orientation_change_time_(0),
  63       weak_factory_(this) {
  64   CHECK(base::MessageLoopForUI::current());
  65   ui_task_runner_ = base::MessageLoopForUI::current()->task_runner();
  66   io_task_runner->PostTask(FROM_HERE, base::Bind(
  67       &OrientationController::WatchForSocketPathOnIO,
  68       make_scoped_refptr<OrientationController>(this)));
  69 }
  70
  71 OrientationController::~OrientationController() {
  72 }
  73
  74 void OrientationController::WatchForSocketPathOnIO() {
  75   CHECK(base::MessageLoopForIO::current());
  76   if (base::PathExists(base::FilePath(kSocketPath))) {
  77     ui_task_runner_->PostTask(FROM_HERE,
  78         base::Bind(&OrientationController::StartListening,
  79                    make_scoped_refptr<OrientationController>(this)));
  80   } else {
  81     watcher_.reset(new base::FilePathWatcher);
  82     watcher_->Watch(
  83         base::FilePath(kSocketPath), false,
  84         base::Bind(&OrientationController::OnFilePathChangedOnIO,
  85                    make_scoped_refptr<OrientationController>(this)));
  86   }
  87 }
  88
  89 void OrientationController::OnFilePathChangedOnIO(const base::FilePath& path,
  90                                                   bool error) {
  91   watcher_.reset();
  92   if (error)
  93     return;
  94
  95   ui_task_runner_->PostTask(FROM_HERE,
  96       base::Bind(&OrientationController::StartListening,
  97                  make_scoped_refptr<OrientationController>(this)));
  98 }
  99
 100 void OrientationController::OnDataAvailableOnIO(const void* data) {
 101   const DeviceSensorEvent* event =
 102       static_cast<const DeviceSensorEvent*>(data);
 103   if (event->type != SENSOR_ACCELEROMETER)
 104     return;
 105
 106   float gravity_x = event->data[0];
 107   float gravity_y = event->data[1];
 108   gfx::Display::Rotation rotation;
 109   if (gravity_x < -kGravityThreshold) {
 110     rotation = gfx::Display::ROTATE_270;
 111   } else if (gravity_x > kGravityThreshold) {
 112     rotation = gfx::Display::ROTATE_90;
 113   } else if (gravity_y < -kGravityThreshold) {
 114     rotation = gfx::Display::ROTATE_180;
 115   } else if (gravity_y > kGravityThreshold) {
 116     rotation = gfx::Display::ROTATE_0;
 117   } else {
 118     // No rotation as gravity threshold was not hit.
 119     return;
 120   }
 121
 122   if (rotation == current_rotation_ ||
 123       event->timestamp - last_orientation_change_time_ <
 124           kOrientationChangeDelayNS) {
 125     return;
 126   }
 127
 128   last_orientation_change_time_ = event->timestamp;
 129   current_rotation_ = rotation;
 130   ui_task_runner_->PostTask(FROM_HERE,
 131       base::Bind(&OrientationController::RotateOnUI,
 132                  make_scoped_refptr<OrientationController>(this), rotation));
 133 }
 134
 135 void OrientationController::RotateOnUI(gfx::Display::Rotation rotation) {
 136   ScreenManager* screen_manager = ScreenManager::Get();
 137   // Since this is called from the IO thread, the screen manager may no longer
 138   // exist.
 139   if (screen_manager)
 140     screen_manager->SetRotation(rotation);
 141 }
 142
 143 }  // namespace athena