[sensors] Generic Sensors Framework blink side

third_party/WebKit/Source/modules/sensor/SensorProxy.cpp

+// Copyright 2016 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 "modules/sensor/SensorProxy.h"
+
+#include "core/frame/LocalFrame.h"
+#include "modules/sensor/SensorProviderProxy.h"
+#include "platform/mojo/MojoHelper.h"
+
+using namespace device::mojom::blink;
+
+namespace blink {
+
+SensorProxy::SensorProxy(SensorType sensorType, SensorProviderProxy* provider)
+    : m_type(sensorType)
+    , m_mode(ReportingMode::CONTINUOUS)
+    , m_provider(provider)
+    , m_clientBinding(this)
+    , m_state(SensorProxy::Uninitialized)
+    , m_reading()
+{
+}
+
+SensorProxy::~SensorProxy()
+{
+}
+
+void SensorProxy::dispose()
+{
+    m_clientBinding.Close();
+}
+
+DEFINE_TRACE(SensorProxy)
+{
+    visitor->trace(m_observers);
+    visitor->trace(m_provider);
+}
+
+void SensorProxy::addObserver(Observer* observer)
+{
+    if (!m_observers.contains(observer))
+        m_observers.add(observer);
+}
+
+void SensorProxy::removeObserver(Observer* observer)
+{
+    if (m_observers.contains(observer))
+        m_observers.remove(observer);
+
+    if (m_observers.isEmpty())
+        m_provider->removeSensor(this);
+}
+
+void SensorProxy::initialize()
+{
+    if (m_state != Uninitialized)
+        return;
+    m_state = Initializing;
+    auto callback = convertToBaseCallback(WTF::bind(&SensorProxy::onSensorCreated, wrapWeakPersistent(this)));
+    m_provider->sensorProvider()->GetSensor(m_type, mojo::GetProxy(&m_sensor), callback);
+}
+
+void SensorProxy::addConfiguration(SensorConfigurationPtr configuration, std::unique_ptr<Function<void(bool)>> callback)
+{
+    DCHECK(isInitialized());
+    m_sensor->AddConfiguration(std::move(configuration), convertToBaseCallback(std::move(callback)));
+}
+
+void SensorProxy::removeConfiguration(SensorConfigurationPtr configuration, std::unique_ptr<Function<void(bool)>> callback)
+{
+    DCHECK(isInitialized());
+    m_sensor->RemoveConfiguration(std::move(configuration), convertToBaseCallback(std::move(callback)));
+}
+
+void SensorProxy::suspend()
+{
+    DCHECK(isInitialized());
+    m_sensor->Suspend();
+}
+
+void SensorProxy::resume()
+{
+    DCHECK(isInitialized());
+    m_sensor->Resume();
+}
+
+void SensorProxy::updateReading()
+{
+    DCHECK(isInitialized());
+    Reading* reading = static_cast<Reading*>(m_sharedBuffer.get());
+    m_reading = *reading;
+}
+
+void SensorProxy::RaiseError()
+{
+    handleSensorError();
+}
+
+void SensorProxy::SensorReadingChanged()
+{
+    for (Observer* observer : m_observers)
+        observer->onSensorReadingChanged();
+}
+
+void SensorProxy::handleSensorError()
+{
+    m_state = Uninitialized;
+
+    ObserversSet observersCopy(m_observers);
+    for (Observer* observer : observersCopy)
+        observer->onSensorError();
+
+    m_observers.clear();
+    m_provider->removeSensor(this);
+}
+
+void SensorProxy::onSensorCreated(SensorReadBufferPtr buffer, SensorClientRequest clientRequest)
+{
+    DCHECK_EQ(Initializing, m_state);
+    if (!buffer) {
+        handleSensorError();
+        return;
+    }
+
+    if (buffer->offset % SensorReadBuffer::kReadBufferSize != 0) {
+        NOTREACHED();
+        handleSensorError();
+        return;
+    }
+
+    m_mode = buffer->mode;
+
+    m_clientBinding.Bind(std::move(clientRequest));
+    m_sensor.set_connection_error_handler(convertToBaseCallback(WTF::bind(&SensorProxy::handleSensorError, wrapWeakPersistent(this))));
+
+    m_sharedBufferHandle = std::move(buffer->memory);
+    DCHECK(!m_sharedBuffer);
+    m_sharedBuffer = m_sharedBufferHandle->MapAtOffset(buffer->offset, SensorReadBuffer::kReadBufferSize);
+
+    if (!m_sharedBuffer) {
+        handleSensorError();
+        return;
+    }
+
+    auto callback = convertToBaseCallback(WTF::bind(&SensorProxy::onDefaultConfiguration, wrapWeakPersistent(this)));
+    m_sensor->GetDefaultConfiguration(callback);

[timvolodine, 2016/09/01 19:02:06]

why is this needed? i.e. wouldn't a sensor always have a config, and if not
could it just be returned in onSensorCreated(), like e.g. buffer?

[Mikhail, 2016/09/02 08:23:43]

It is better to know the default config beforehand: if the user gave some
parameters but missed others than the sensor implementation could assign the
missing parameters to the default ones.

[timvolodine, 2016/09/02 19:41:28]

In that case I think my question still stands: why not return this in
OnSensorCreated()? that way avoiding extra IPC and extra asynchronous callback.

How is the default config used in this patch? What happens for example if
AddConfiguration() is invoked before onDefaultConfiguration() callback (or some
other race condition)?

If it's not used anywhere I think it would be better to add it in a separate
patch instead.

[Mikhail, 2016/09/05 10:26:27]

Oh sorry, I probably misunderstood your comment. It would also work if default
configuration is passed in OnSensorCreated().
Sensor proxy is initialized only after default configuration is obtained.
I agree that it's better to make a separate patch (as it might require mojo
interfaces changes).

+}
+
+void SensorProxy::onDefaultConfiguration(device::mojom::blink::SensorConfigurationPtr config)
+{
+    DCHECK_EQ(Initializing, m_state);
+    if (!config) {
+        handleSensorError();
+        return;
+    }
+    m_defaultConfiguration = std::move(config);

[timvolodine, 2016/09/02 19:41:28]

Is m_defaultConfiguration used anywhere? looks like extra functionality and
could be added in a separate patch?

+
+    m_state = Initialized;
+    for (Observer* observer : m_observers)
+        observer->onSensorInitialized();
+}
+
+} // namespace blink