Implements part of Device Motion in the Renderer

content/browser/device_orientation/motion_message_filter.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/motion_message_filter.h"
+
+#include "base/memory/scoped_ptr.h"
+#include "content/browser/device_orientation/motion.h"
+#include "content/browser/device_orientation/provider.h"
+#include "content/browser/renderer_host/render_view_host_impl.h"
+#include "content/common/device_motion_messages.h"
+#include "content/public/browser/browser_thread.h"
+
+using content::BrowserThread;
+
+namespace device_orientation {
+
+MotionMessageFilter::MotionMessageFilter() : provider_(NULL) {
+}
+
+MotionMessageFilter::~MotionMessageFilter() {
+}
+
+class MotionMessageFilter::MotionObserverDelegate
+    : public base::RefCounted<MotionObserverDelegate>,
+      public Provider::MotionObserver {
+ public:
+    // Create MotionObserverDelegate that observes provider and forwards
+    // updates to render_view_id in process_id.
+    // Will stop observing provider when destructed.
+    MotionObserverDelegate(Provider* provider, int render_view_id,
+                           IPC::Sender* sender);
+
+    // From Provider::MotionObserver.
+    virtual void OnMotionUpdate(const Motion& motion);
+
+ private:
+  friend class base::RefCounted<MotionObserverDelegate>;
+  virtual ~MotionObserverDelegate();
+
+  scoped_refptr<Provider> provider_;
+  int render_view_id_;
+  IPC::Sender* sender_;  // Weak pointer.

[bulach, 2012/07/02 12:47:56]

not sure how is this a weak pointer in this context?

[aousterh, 2012/07/04 13:31:55]

The sender isn't owned by the MotionMessageFilter (I think it's owned by the
Channel Proxy, which keeps a scoped pointer to it), so this pointer doesn't
effect its lifetime.

+
+  DISALLOW_COPY_AND_ASSIGN(MotionObserverDelegate);
+};
+
+MotionMessageFilter::MotionObserverDelegate::MotionObserverDelegate(
+    Provider* provider, int render_view_id, IPC::Sender* sender)
+    : provider_(provider),
+      render_view_id_(render_view_id),
+      sender_(sender) {
+  provider_->AddMotionObserver(this);
+}
+
+MotionMessageFilter::MotionObserverDelegate::~MotionObserverDelegate() {
+  provider_->RemoveMotionObserver(this);
+}
+
+void MotionMessageFilter::MotionObserverDelegate::OnMotionUpdate(
+    const Motion& motion) {
+  DeviceMotionMsg_Updated_Params params;
+
+  params.can_provide_acceleration_x = motion.canProvideAccelerationX();
+  params.acceleration_x = motion.accelerationX();
+  params.can_provide_acceleration_y = motion.canProvideAccelerationY();
+  params.acceleration_y = motion.accelerationY();
+  params.can_provide_acceleration_z = motion.canProvideAccelerationZ();
+  params.acceleration_z = motion.accelerationZ();
+
+  params.can_provide_acceleration_including_gravity_x =
+    motion.canProvideAccelerationIncludingGravityX();
+  params.acceleration_including_gravity_x =
+    motion.accelerationIncludingGravityX();
+  params.can_provide_acceleration_including_gravity_y =
+    motion.canProvideAccelerationIncludingGravityY();
+  params.acceleration_including_gravity_y =
+    motion.accelerationIncludingGravityY();
+  params.can_provide_acceleration_including_gravity_z =
+    motion.canProvideAccelerationIncludingGravityZ();
+  params.acceleration_including_gravity_z =
+    motion.accelerationIncludingGravityZ();
+
+  params.can_provide_rotation_rate_alpha =
+    motion.canProvideRotationRateAlpha();
+  params.rotation_rate_alpha = motion.rotationRateAlpha();
+  params.can_provide_rotation_rate_beta =
+    motion.canProvideRotationRateBeta();
+  params.rotation_rate_beta = motion.rotationRateBeta();
+  params.can_provide_rotation_rate_gamma =
+    motion.canProvideRotationRateGamma();

[bulach, 2012/07/02 12:47:56]

nit: from 72-91, need an extra indent for the continuation lines..

[aousterh, 2012/07/04 13:31:55]

Done.

+  params.rotation_rate_gamma = motion.rotationRateGamma();
+
+  params.can_provide_interval = motion.canProvideInterval();
+  params.interval = motion.interval();
+
+  sender_->Send(new DeviceMotionMsg_Updated(render_view_id_, params));
+}
+
+bool MotionMessageFilter::OnMessageReceived(const IPC::Message& message,
+                                            bool* message_was_ok) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP_EX(MotionMessageFilter, message, *message_was_ok)
+    IPC_MESSAGE_HANDLER(DeviceMotionHostMsg_StartUpdating, OnStartUpdating)
+    IPC_MESSAGE_HANDLER(DeviceMotionHostMsg_StopUpdating, OnStopUpdating)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+void MotionMessageFilter::OnStartUpdating(int render_view_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  if (!provider_)
+    provider_ = Provider::GetInstance();
+
+  observers_map_[render_view_id] = new MotionObserverDelegate(provider_,
+                                                        render_view_id,
+                                                        this);

[bulach, 2012/07/02 12:47:56]

nit: move this line to 119, and indent it just by 4..

[aousterh, 2012/07/04 13:31:55]

Done.

+}
+
+void MotionMessageFilter::OnStopUpdating(int render_view_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  observers_map_.erase(render_view_id);
+}
+
+}  // namespace device_motion