uORB move to PX4 platform layer

platforms/common/uORB/Subscription.cpp

@@ -0,0 +1,113 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2012-2019 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the name PX4 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.
+ *
+ ****************************************************************************/
+
+/**
+ * @file Subscription.cpp
+ *
+ */
+
+#include "Subscription.hpp"
+#include <px4_platform_common/defines.h>
+
+namespace uORB
+{
+
+bool Subscription::subscribe()
+{
+	// check if already subscribed
+	if (_node != nullptr) {
+		return true;
+	}
+
+	if (_orb_id != ORB_ID::INVALID) {
+
+		DeviceMaster *device_master = uORB::Manager::get_instance()->get_device_master();
+
+		if (device_master != nullptr) {
+
+			if (!device_master->deviceNodeExists(_orb_id, _instance)) {
+				return false;
+			}
+
+			uORB::DeviceNode *node = device_master->getDeviceNode(get_topic(), _instance);
+
+			if (node != nullptr) {
+				_node = node;
+				_node->add_internal_subscriber();
+
+				_last_generation = _node->get_initial_generation();
+
+				return true;
+			}
+		}
+	}
+
+	return false;
+}
+
+void Subscription::unsubscribe()
+{
+	if (_node != nullptr) {
+		_node->remove_internal_subscriber();
+	}
+
+	_node = nullptr;
+	_last_generation = 0;
+}
+
+bool Subscription::ChangeInstance(uint8_t instance)
+{
+	if (instance != _instance) {
+		DeviceMaster *device_master = uORB::Manager::get_instance()->get_device_master();
+
+		if (device_master != nullptr) {
+			if (!device_master->deviceNodeExists(_orb_id, _instance)) {
+				return false;
+			}
+
+			// if desired new instance exists, unsubscribe from current
+			unsubscribe();
+			_instance = instance;
+			subscribe();
+			return true;
+		}
+
+	} else {
+		// already on desired index
+		return true;
+	}
+
+	return false;
+}
+
+} // namespace uORB