Implement the Blink part of the Device Motion API.

Source/modules/device_orientation/WebDeviceMotionDispatcher.cpp

+/*
+ * Copyright (C) 2013 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "WebDeviceMotionDispatcher.h"
+
+#include <public/Platform.h>
+#include <public/WebDeviceMotionData.h>
+#include <public/WebDeviceMotionHandler.h>
+#include "modules/device_orientation/DeviceMotionController.h"
+#include "modules/device_orientation/DeviceMotionData.h"
+
+using WebCore::DeviceMotionData;
+
+namespace WebKit {

[abarth-chromium, 2013/05/07 16:43:47]

s/WebKit/WebCore/

[timvolodine, 2013/05/07 19:02:30]

Done.

+
+// static
+WebDeviceMotionDispatcher& WebDeviceMotionDispatcher::shared()
+{
+    DEFINE_STATIC_LOCAL(WebDeviceMotionDispatcher, webDeviceMotionDispatcher, ());
+    return webDeviceMotionDispatcher;
+}
+
+WebDeviceMotionDispatcher::WebDeviceMotionDispatcher() : m_lastDeviceMotionData(0)

[abarth-chromium, 2013/05/07 16:43:47]

There's no need for this initializer.  RefPtr automatically initializes to 0.

[timvolodine, 2013/05/07 19:02:30]

Done.

+{
+}
+
+void WebDeviceMotionDispatcher::addController(WebCore::DeviceMotionController* controller)
+{
+    bool wasEmpty = m_controllers.isEmpty();
+    m_controllers.add(controller);
+    if (wasEmpty)
+        startListening();
+}
+
+void WebDeviceMotionDispatcher::removeController(WebCore::DeviceMotionController* controller)
+{
+    m_controllers.remove(controller);
+    if (m_controllers.isEmpty())
+        stopListening();
+}
+
+void WebDeviceMotionDispatcher::startListening()
+{
+    if (WebDeviceMotionHandler* handler = WebKit::Platform::current()->deviceMotionHandler())
+        handler->startListeningToDeviceMotion(this);
+}
+
+void WebDeviceMotionDispatcher::stopListening()
+{
+    if (WebDeviceMotionHandler* handler = WebKit::Platform::current()->deviceMotionHandler())
+        handler->stopListeningToDeviceMotion();
+}
+
+void WebDeviceMotionDispatcher::didChangeDeviceMotion(WebDeviceMotionData& motion)
+{
+    m_lastDeviceMotionData = convertToDeviceMotionData(motion);
+
+    Vector<RefPtr<WebCore::DeviceMotionController> > listenerVector;
+    copyToVector(m_controllers, listenerVector);
+    for (size_t i = 0; i<listenerVector.size(); ++i)
+        listenerVector[i]->didChangeDeviceMotion(m_lastDeviceMotionData.get());

[abarth-chromium, 2013/05/07 16:43:47]

This pattern isn't secure.  If listenerVector was really keeping any of the
controllers alive, you'd still have a use-after-free vulnerability because the
controllers have a raw pointer to m_document.

nit: Please add spaces around the " < " operator.

It's not clear to me how to do this iteration securely...

I think the way to do this is to make removeController zero out the entry in
m_controllers rather than removing it.  After we're done iterating
m_controllers, we can compact it by removing all the zero entries.

[timvolodine, 2013/05/07 19:02:30]

once the controllers are not ref-counted anymore this should not be a problem
right? maybe I am missing a concurrency issue here.

+}
+
+PassRefPtr<DeviceMotionData> WebDeviceMotionDispatcher::convertToDeviceMotionData(WebDeviceMotionData& motion)
+{
+    return DeviceMotionData::create(
+        DeviceMotionData::Acceleration::create(
+            motion.hasAccelerationX(), motion.accelerationX(),
+            motion.hasAccelerationY(), motion.accelerationY(),
+            motion.hasAccelerationZ(), motion.accelerationZ()),
+        DeviceMotionData::Acceleration::create(
+            motion.hasAccelerationIncludingGravityX(), motion.accelerationIncludingGravityX(),
+            motion.hasAccelerationIncludingGravityY(), motion.accelerationIncludingGravityY(),
+            motion.hasAccelerationIncludingGravityZ(), motion.accelerationIncludingGravityZ()),
+        DeviceMotionData::RotationRate::create(
+            motion.hasRotationRateAlpha(), motion.rotationRateAlpha(),
+            motion.hasRotationRateBeta(), motion.rotationRateBeta(),
+            motion.hasRotationRateGamma(), motion.rotationRateGamma()),
+        true, motion.interval());
+}
+
+WebCore::DeviceMotionData* WebDeviceMotionDispatcher::latestDeviceMotionData()
+{
+    return m_lastDeviceMotionData.get();
+}
+
+WebDeviceMotionDispatcher::~WebDeviceMotionDispatcher()
+{
+}
+
+}  // namespace WebKit