Implement Android shared memory data fetcher for Device Motion.

content/browser/device_orientation/data_fetcher_impl_android.cc

 // Copyright (c) 2012 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 "content/browser/device_orientation/data_fetcher_impl_android.h"
 
+#include <string.h>
 #include "base/android/jni_android.h"
 #include "base/logging.h"
 #include "content/browser/device_orientation/orientation.h"
 #include "jni/DeviceMotionAndOrientation_jni.h"
 
 using base::android::AttachCurrentThread;
 
 namespace content {
 
 namespace {
 
 // This should match ProviderImpl::kDesiredSamplingIntervalMs.
 // TODO(husky): Make that constant public so we can use it directly.
 const int kPeriodInMilliseconds = 100;
 
 }  // namespace
 
-DataFetcherImplAndroid::DataFetcherImplAndroid() {
+DataFetcherImplAndroid::DataFetcherImplAndroid()
+    : device_motion_buffer_(NULL),
+      is_buffer_ready_(false) {
+  memset(received_motion_data_, 0, sizeof(received_motion_data_));
   device_orientation_.Reset(
       Java_DeviceMotionAndOrientation_getInstance(AttachCurrentThread()));
 }
 
-void DataFetcherImplAndroid::Init(JNIEnv* env) {
+void DataFetcherImplAndroid::Register(JNIEnv* env) {
   bool result = RegisterNativesImpl(env);
   DCHECK(result);
 }
 
-// TODO(timvolodine): Modify this method to be able to distinguish
-// device motion from orientation.
+DataFetcherImplAndroid* DataFetcherImplAndroid::instance() {
+  CR_DEFINE_STATIC_LOCAL(DataFetcherImplAndroid, s_data_fetcher, ());
+  return &s_data_fetcher;
+}
+
+// TODO(timvolodine): Remove this method once orientation also switches to
+// shared memory implementation.
 DataFetcher* DataFetcherImplAndroid::Create() {
-  scoped_ptr<DataFetcherImplAndroid> fetcher(new DataFetcherImplAndroid);
+  DataFetcherImplAndroid* fetcher = DataFetcherImplAndroid::instance();
   if (fetcher->Start(DeviceData::kTypeOrientation, kPeriodInMilliseconds))
-    return fetcher.release();
+    return fetcher;
 
-  LOG(ERROR) << "DataFetcherImplAndroid::Start failed!";
+  DVLOG(2) << "DataFetcherImplAndroid::Start failed!";
   return NULL;
 }
 
 DataFetcherImplAndroid::~DataFetcherImplAndroid() {

[bulach, 2013/07/09 09:03:29]

question: the destructor will never be called since this is relying on
CR_DEFINE_STATIC_LOCAL, right? should this be NOTREACHED() ?

[timvolodine, 2013/07/09 18:59:56]

hmm, very good point. This is actually a bug.

The CR_DEFINE_STATIC_LOCAL apparently uses new to allocate on heap, so the
destructor is never called. To add to the complexity the provider_impl.cc (for
device orientation) does not know that the fetcher is a singleton now, and tries
to destroy the fetcher because it thinks it owns it in a scoped_ptr :/.
I've modified provider_impl.cc slightly and also added instance to all ports
(mac and windows). Also added some code to properly shutdown sensors on exit.

-  // TODO(timvolodine): Support device motion as well. Only stop
-  // the active event type(s).
   Stop(DeviceData::kTypeOrientation);
+  Stop(DeviceData::kTypeMotion);
 }
 
 const DeviceData* DataFetcherImplAndroid::GetDeviceData(
     DeviceData::Type type) {
   if (type != DeviceData::kTypeOrientation)
     return NULL;
   return GetOrientation();
 }
 
 const Orientation* DataFetcherImplAndroid::GetOrientation() {
@@ skipping 16 matching lines @@
   Orientation* orientation = new Orientation();
   orientation->set_alpha(alpha);
   orientation->set_beta(beta);
   orientation->set_gamma(gamma);
   orientation->set_absolute(true);
   next_orientation_ = orientation;
 }
 
 void DataFetcherImplAndroid::GotAcceleration(
     JNIEnv*, jobject, double x, double y, double z) {
-  NOTIMPLEMENTED();
+  device_motion_buffer_->seqlock.WriteBegin();
+  device_motion_buffer_->data.accelerationX = x;
+  device_motion_buffer_->data.hasAccelerationX = true;
+  device_motion_buffer_->data.accelerationY = y;
+  device_motion_buffer_->data.hasAccelerationY = true;
+  device_motion_buffer_->data.accelerationZ = z;
+  device_motion_buffer_->data.hasAccelerationZ = true;
+  device_motion_buffer_->seqlock.WriteEnd();
+
+  if (!is_buffer_ready_) {
+    received_motion_data_[DATA_ACCELERATION] = 1;
+    CheckBufferReadyToRead();
+  }
 }
 
 void DataFetcherImplAndroid::GotAccelerationIncludingGravity(
     JNIEnv*, jobject, double x, double y, double z) {
-  NOTIMPLEMENTED();
+  device_motion_buffer_->seqlock.WriteBegin();
+  device_motion_buffer_->data.accelerationIncludingGravityX = x;
+  device_motion_buffer_->data.hasAccelerationIncludingGravityX = true;
+  device_motion_buffer_->data.accelerationIncludingGravityY = y;
+  device_motion_buffer_->data.hasAccelerationIncludingGravityY = true;
+  device_motion_buffer_->data.accelerationIncludingGravityZ = z;
+  device_motion_buffer_->data.hasAccelerationIncludingGravityZ = true;
+  device_motion_buffer_->seqlock.WriteEnd();
+
+  if (!is_buffer_ready_) {
+    received_motion_data_[DATA_ACCELERATION_INCLUDING_GRAVITY] = 1;
+    CheckBufferReadyToRead();
+  }
 }
 
 void DataFetcherImplAndroid::GotRotationRate(
     JNIEnv*, jobject, double alpha, double beta, double gamma) {
-  NOTIMPLEMENTED();
+  device_motion_buffer_->seqlock.WriteBegin();
+  device_motion_buffer_->data.rotationRateAlpha = alpha;
+  device_motion_buffer_->data.hasRotationRateAlpha = true;
+  device_motion_buffer_->data.rotationRateBeta = beta;
+  device_motion_buffer_->data.hasRotationRateBeta = true;
+  device_motion_buffer_->data.rotationRateGamma = gamma;
+  device_motion_buffer_->data.hasRotationRateGamma = true;
+  device_motion_buffer_->seqlock.WriteEnd();
+
+  if (!is_buffer_ready_) {
+    received_motion_data_[DATA_ROTATION_RATE] = 1;
+    CheckBufferReadyToRead();
+  }
 }
 
 bool DataFetcherImplAndroid::Start(
     DeviceData::Type event_type, int rate_in_milliseconds) {
   DCHECK(!device_orientation_.is_null());
   return Java_DeviceMotionAndOrientation_start(
       AttachCurrentThread(), device_orientation_.obj(),
       reinterpret_cast<jint>(this), static_cast<jint>(event_type),
       rate_in_milliseconds);
 }
 
 void DataFetcherImplAndroid::Stop(DeviceData::Type event_type) {
   DCHECK(!device_orientation_.is_null());
   Java_DeviceMotionAndOrientation_stop(
       AttachCurrentThread(), device_orientation_.obj(),
       static_cast<jint>(event_type));
 }
 
 int DataFetcherImplAndroid::GetNumberActiveDeviceMotionSensors() {
   DCHECK(!device_orientation_.is_null());
   return Java_DeviceMotionAndOrientation_getNumberActiveDeviceMotionSensors(
       AttachCurrentThread(), device_orientation_.obj());
 }
 
+
+// ----- New shared memory API methods
+
+bool DataFetcherImplAndroid::FetchDeviceMotionDataIntoBuffer() {
+  // This method should not be called because it is a push based fetcher.
+  DCHECK(NeedsPolling());

[bulach, 2013/07/09 09:03:29]

would NOTREACHED(); be better?

[timvolodine, 2013/07/09 18:59:56]

Done.

+  return false;
+}
+
+void DataFetcherImplAndroid::CheckBufferReadyToRead() {
+  if (received_motion_data_[DATA_ACCELERATION]
+      + received_motion_data_[DATA_ACCELERATION_INCLUDING_GRAVITY]

[bulach, 2013/07/09 09:03:29]

nit: + and == always at the end of the previous line

[timvolodine, 2013/07/09 18:59:56]

Done.

+      + received_motion_data_[DATA_ROTATION_RATE]
+      == number_active_device_motion_sensors_) {
+    SetBufferReadyStatus(true);
+  }
+}
+
+void DataFetcherImplAndroid::SetBufferReadyStatus(bool ready) {
+  device_motion_buffer_->seqlock.WriteBegin();
+  device_motion_buffer_->data.allAvailableSensorsAreActive = ready;
+  device_motion_buffer_->seqlock.WriteEnd();
+  is_buffer_ready_ = ready;
+}
+
+bool DataFetcherImplAndroid::StartFetchingDeviceMotionData(
+    DeviceMotionHardwareBuffer* buffer) {
+  device_motion_buffer_ = buffer;
+  memset(received_motion_data_, 0, sizeof(received_motion_data_));

[bulach, 2013/07/09 09:03:29]

192-194 is the same as 207-209, perhaps "ClearInternalBuffers()" would help?

[timvolodine, 2013/07/09 18:59:56]

Done.

+  number_active_device_motion_sensors_ = 0;
+  SetBufferReadyStatus(false);
+  bool success = Start(DeviceData::kTypeMotion, kPeriodInMilliseconds);
+
+  // If no motion data can ever be provided, the number of active device motion
+  // sensors will be zero. In that case flag the shared memory buffer
+  // as ready to read, as it will not change anyway.
+  number_active_device_motion_sensors_ = GetNumberActiveDeviceMotionSensors();
+  CheckBufferReadyToRead();
+  return success;
+}
+
+void DataFetcherImplAndroid::StopFetchingDeviceMotionData() {
+  Stop(DeviceData::kTypeMotion);
+  number_active_device_motion_sensors_ = 0;
+  memset(received_motion_data_, 0, sizeof(received_motion_data_));
+  SetBufferReadyStatus(false);
+}
+
 }  // namespace content