Implement DeviceMotionEvent API

chromeos/accelerometer/accelerometer_reader.cc

 // 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.
 
 #include "chromeos/accelerometer/accelerometer_reader.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
@@ skipping 34 matching lines @@
 
 // The axes on each accelerometer.
 const char kAccelerometerAxes[][2] = {"y", "x", "z"};
 
 // The length required to read uint values from configuration files.
 const size_t kMaxAsciiUintLength = 21;
 
 // The size of individual values.
 const size_t kDataSize = 2;
 
-// The time to wait between reading the accelerometer.
-const int kDelayBetweenReadsMs = 100;
-
 // The mean acceleration due to gravity on Earth in m/s^2.
 const float kMeanGravity = 9.80665f;
 
 // Reads |path| to the unsigned int pointed to by |value|. Returns true on
 // success or false on failure.
 bool ReadFileToInt(const base::FilePath& path, int* value) {
   std::string s;
   DCHECK(value);
   if (!base::ReadFileToString(path, &s, kMaxAsciiUintLength)) {
     return false;
@@ skipping 94 matching lines @@
   if (bytes_read < static_cast<int>(length)) {
     LOG(ERROR) << "Read " << bytes_read << " byte(s), expected "
                << length << " bytes from accelerometer";
     return false;
   }
   return true;
 }
 
 }  // namespace
 
+const int AccelerometerReader::kDelayBetweenReadsMs = 100;
+
 AccelerometerReader::ConfigurationData::ConfigurationData()
     : count(0) {
   for (int i = 0; i < ACCELEROMETER_SOURCE_COUNT; ++i) {
     has[i] = false;
     for (int j = 0; j < 3; ++j) {
       scale[i][j] = 0;
       index[i][j] = -1;
     }
   }
 }
@@ skipping 13 matching lines @@
   // Asynchronously detect and initialize the accelerometer to avoid delaying
   // startup.
   base::PostTaskAndReplyWithResult(
       task_runner_.get(), FROM_HERE,
       base::Bind(&DetectAndReadAccelerometerConfiguration, configuration_),
       base::Bind(&AccelerometerReader::OnInitialized,
                  weak_factory_.GetWeakPtr(), configuration_));
 }
 
 void AccelerometerReader::AddObserver(Observer* observer) {
-  observers_.AddObserver(observer);
-  if (has_update_)
-    observer->OnAccelerometerUpdated(update_);
+  observers_->AddObserver(observer);
+  if (update_)
+    observer->OnAccelerometerUpdated(update_.get());
 }
 
 void AccelerometerReader::RemoveObserver(Observer* observer) {
-  observers_.RemoveObserver(observer);
+  observers_->RemoveObserver(observer);
 }
 
 AccelerometerReader::AccelerometerReader()
-    : has_update_(false),
-      configuration_(new AccelerometerReader::Configuration()),
+    : configuration_(new AccelerometerReader::Configuration()),
+      observers_(new ObserverListThreadSafe<Observer>()),
       weak_factory_(this) {
 }
 
 AccelerometerReader::~AccelerometerReader() {
 }
 
 void AccelerometerReader::OnInitialized(
     scoped_refptr<AccelerometerReader::Configuration> configuration,
     bool success) {
   if (success)
@@ skipping 13 matching lines @@
                                               weak_factory_.GetWeakPtr(),
                                               reading));
 }
 
 void AccelerometerReader::OnDataRead(
     scoped_refptr<AccelerometerReader::Reading> reading,
     bool success) {
   DCHECK(!task_runner_->RunsTasksOnCurrentThread());
 
   if (success) {
-    has_update_ = true;
+    update_ = new AccelerometerUpdate();
     for (int i = 0; i < ACCELEROMETER_SOURCE_COUNT; ++i) {
       if (!configuration_->data.has[i])
         continue;
 
       int16* values = reinterpret_cast<int16*>(reading->data);
-      update_.Set(static_cast<AccelerometerSource>(i),
-                  values[configuration_->data.index[i][0]] *
-                      configuration_->data.scale[i][0],
-                  values[configuration_->data.index[i][1]] *
-                      configuration_->data.scale[i][1],
-                  values[configuration_->data.index[i][2]] *
-                      configuration_->data.scale[i][2]);
+      update_->Set(static_cast<AccelerometerSource>(i),
+                   values[configuration_->data.index[i][0]] *
+                       configuration_->data.scale[i][0],
+                   values[configuration_->data.index[i][1]] *
+                       configuration_->data.scale[i][1],
+                   values[configuration_->data.index[i][2]] *
+                       configuration_->data.scale[i][2]);
     }
-    FOR_EACH_OBSERVER(Observer, observers_, OnAccelerometerUpdated(update_));
+    // TODO(jonross): move this to the blocking thread (crbug.com/461433)
+    observers_->Notify(FROM_HERE, &Observer::OnAccelerometerUpdated, update_);
   }
 
   // Trigger another read after the current sampling delay.
   base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&AccelerometerReader::TriggerRead,
                  weak_factory_.GetWeakPtr()),
       base::TimeDelta::FromMilliseconds(kDelayBetweenReadsMs));
 }
 
 }  // namespace chromeos