Refactored the mission message exclusion logic.

The existing logic for filtering out MISSION* messages that don't apply to this instance of QGC wasn't clear and exactly correct. This refactoring reorganizes the code to be more clear and makes it explicit when the messages should be ignored by this instance of QGC.
Additionally a few more status messages are translated to be helpful to our non-English speaking devs/users.

src/uas/UAS.cc

@@ -1111,58 +1111,100 @@ void UAS::receiveMessage(LinkInterface* link, mavlink_message_t message)
             break;
         case MAVLINK_MSG_ID_MISSION_COUNT:
         {
-            mavlink_mission_count_t wpc;
-            mavlink_msg_mission_count_decode(&message, &wpc);
-            if(wpc.target_system == mavlink->getSystemId() || wpc.target_system == 0)
+            mavlink_mission_count_t mc;
+            mavlink_msg_mission_count_decode(&message, &mc);
+
+            // Special case a 0 for the target system or component, it means that anyone is the target, so we should process this.
+            if (mc.target_system == 0) {
+                mc.target_system = mavlink->getSystemId();
+            }
+            if (mc.target_component == 0) {
+                mc.target_component = mavlink->getComponentId();
+            }
+
+            // Check that this message applies to the UAS.
+            if(mc.target_system == mavlink->getSystemId() && mc.target_component == mavlink->getComponentId())
             {
-                waypointManager.handleWaypointCount(message.sysid, message.compid, wpc.count);
+                waypointManager.handleWaypointCount(message.sysid, message.compid, mc.count);
             }
             else
             {
-                qDebug() << "Got waypoint message, but was wrong system id" << wpc.target_system;
+                qDebug() << tr("Received mission count message, but was wrong system id. Expected %1, received %2").arg(mavlink->getSystemId()).arg(mc.target_system);
             }
         }
             break;
 
         case MAVLINK_MSG_ID_MISSION_ITEM:
         {
-            mavlink_mission_item_t wp;
-            mavlink_msg_mission_item_decode(&message, &wp);
-            //qDebug() << "got waypoint (" << wp.seq << ") from ID " << message.sysid << " x=" << wp.x << " y=" << wp.y << " z=" << wp.z;
-            if(wp.target_system == mavlink->getSystemId() || wp.target_system == 0)
+            mavlink_mission_item_t mi;
+            mavlink_msg_mission_item_decode(&message, &mi);
+
+            // Special case a 0 for the target system or component, it means that anyone is the target, so we should process this.
+            if (mi.target_system == 0) {
+                mi.target_system = mavlink->getSystemId();
+            }
+            if (mi.target_component == 0) {
+                mi.target_component = mavlink->getComponentId();
+            }
+
+            // Check that the item pertains to this UAS.
+            if(mi.target_system == mavlink->getSystemId() && mi.target_component == mavlink->getComponentId())
             {
-                waypointManager.handleWaypoint(message.sysid, message.compid, &wp);
+                waypointManager.handleWaypoint(message.sysid, message.compid, &mi);
             }
             else
             {
-                qDebug() << "Got waypoint message, but was wrong system id" << wp.target_system;
+                qDebug() << tr("Received mission item message, but was wrong system id. Expected %1, received %2").arg(mavlink->getSystemId()).arg(mi.target_system);
             }
         }
             break;
 
         case MAVLINK_MSG_ID_MISSION_ACK:
         {
-            mavlink_mission_ack_t wpa;
-            mavlink_msg_mission_ack_decode(&message, &wpa);
-            if((wpa.target_system == mavlink->getSystemId() || wpa.target_system == 0) &&
-                    (wpa.target_component == mavlink->getComponentId() || wpa.target_component == 0))
+            mavlink_mission_ack_t ma;
+            mavlink_msg_mission_ack_decode(&message, &ma);
+
+            // Special case a 0 for the target system or component, it means that anyone is the target, so we should process this.
+            if (ma.target_system == 0) {
+                ma.target_system = mavlink->getSystemId();
+            }
+            if (ma.target_component == 0) {
+                ma.target_component = mavlink->getComponentId();
+            }
+
+            // Check that the ack pertains to this UAS.
+            if(ma.target_system == mavlink->getSystemId() && ma.target_component == mavlink->getComponentId())
+            {
+                waypointManager.handleWaypointAck(message.sysid, message.compid, &ma);
+            }
+            else
             {
-                waypointManager.handleWaypointAck(message.sysid, message.compid, &wpa);
+                qDebug() << tr("Received mission ack message, but was wrong system id. Expected %1, received %2").arg(mavlink->getSystemId()).arg(ma.target_system);
             }
         }
             break;
 
         case MAVLINK_MSG_ID_MISSION_REQUEST:
         {
-            mavlink_mission_request_t wpr;
-            mavlink_msg_mission_request_decode(&message, &wpr);
-            if(wpr.target_system == mavlink->getSystemId() || wpr.target_system == 0)
+            mavlink_mission_request_t mr;
+            mavlink_msg_mission_request_decode(&message, &mr);
+
+            // Special case a 0 for the target system or component, it means that anyone is the target, so we should process this.
+            if (mr.target_system == 0) {
+                mr.target_system = mavlink->getSystemId();
+            }
+            if (mr.target_component == 0) {
+                mr.target_component = mavlink->getComponentId();
+            }
+
+            // Check that the request pertains to this UAS.
+            if(mr.target_system == mavlink->getSystemId() && mr.target_component == mavlink->getComponentId())
             {
-                waypointManager.handleWaypointRequest(message.sysid, message.compid, &wpr);
+                waypointManager.handleWaypointRequest(message.sysid, message.compid, &mr);
             }
             else
             {
-                qDebug() << "Got waypoint message, but was wrong system id" << wpr.target_system;
+                qDebug() << tr("Received mission request message, but was wrong system id. Expected %1, received %2").arg(mavlink->getSystemId()).arg(mr.target_system);
             }
         }
             break;