first step at implementing the native sensor support

in this commit:
- implemented the C stub
- implemented the binder interfaces involved
- implemented most of the C++ client side

missing:
- SensorManager cannot connect to the SensorServer yet
(because there is no SensorServer yet)

Change-Id: I75010cbeef31c98d6fa62fd5d388dcef87c2636b
diff --git a/libs/gui/SensorEventQueue.cpp b/libs/gui/SensorEventQueue.cpp
new file mode 100644
index 0000000..f922ac4
--- /dev/null
+++ b/libs/gui/SensorEventQueue.cpp
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+#include <utils/RefBase.h>
+
+#include <gui/Sensor.h>
+#include <gui/SensorChannel.h>
+#include <gui/SensorEventQueue.h>
+#include <gui/ISensorEventConnection.h>
+
+#include <android/sensor.h>
+
+// ----------------------------------------------------------------------------
+namespace android {
+// ----------------------------------------------------------------------------
+
+SensorEventQueue::SensorEventQueue(const sp<ISensorEventConnection>& connection)
+    : mSensorEventConnection(connection)
+{
+}
+
+SensorEventQueue::~SensorEventQueue()
+{
+}
+
+void SensorEventQueue::onFirstRef()
+{
+    mSensorChannel = mSensorEventConnection->getSensorChannel();
+}
+
+int SensorEventQueue::getFd() const
+{
+    return mSensorChannel->getFd();
+}
+
+ssize_t SensorEventQueue::write(ASensorEvent const* events, size_t numEvents)
+{
+    ssize_t size = mSensorChannel->write(events, numEvents * sizeof(events[0]));
+    if (size >= 0) {
+        if (size % sizeof(events[0])) {
+            // partial write!!! should never happen.
+            return -EINVAL;
+        }
+        // returns number of events written
+        size /= sizeof(events[0]);
+    }
+    return size;
+}
+
+ssize_t SensorEventQueue::read(ASensorEvent* events, size_t numEvents)
+{
+    ssize_t size = mSensorChannel->read(events, numEvents*sizeof(events[0]));
+    if (size >= 0) {
+        if (size % sizeof(events[0])) {
+            // partial write!!! should never happen.
+            return -EINVAL;
+        }
+        // returns number of events read
+        size /= sizeof(events[0]);
+    }
+    return size;
+}
+
+status_t SensorEventQueue::enableSensor(Sensor const* sensor) const
+{
+    return mSensorEventConnection->enableDisable(sensor->getHandle(), true);
+}
+
+status_t SensorEventQueue::disableSensor(Sensor const* sensor) const
+{
+    return mSensorEventConnection->enableDisable(sensor->getHandle(), false);
+}
+
+status_t SensorEventQueue::setEventRate(Sensor const* sensor, nsecs_t ns) const
+{
+    return mSensorEventConnection->setEventRate(sensor->getHandle(), ns);
+}
+
+// ----------------------------------------------------------------------------
+}; // namespace android
+