Dreamview: small refactor of SendData (#1702)

modules/dreamview/backend/simulation_world/simulation_world_updater.cc

@@ -59,7 +59,7 @@ SimulationWorldUpdater::SimulationWorldUpdater(WebSocketHandler *websocket,
           response["type"] = "MapData";
           response["data"] = Json::parse(retrieved_json_string);
 
-          websocket_->SendData(response.dump(), conn);
+          websocket_->SendData(conn, response.dump());
         }
       });
 
@@ -72,7 +72,7 @@ SimulationWorldUpdater::SimulationWorldUpdater(WebSocketHandler *websocket,
         }
 
         auto response = sim_world_service_.GetUpdateAsJson(*radius);
-        websocket_->SendData(response.dump(), conn);
+        websocket_->SendData(conn, response.dump());
       });
 
   websocket_->RegisterMessageHandler(
@@ -107,7 +107,7 @@ SimulationWorldUpdater::SimulationWorldUpdater(WebSocketHandler *websocket,
           boost::shared_lock<boost::shared_mutex> reader_lock(mutex_);
           to_send = simulation_world_json_;
         }
-        websocket_->SendData(to_send, conn);
+        websocket_->SendData(conn, to_send, true);
       });
 }
 

modules/dreamview/backend/websocket/websocket.cc

@@ -67,7 +67,7 @@ bool WebSocketHandler::BroadcastData(const std::string &data) {
 
   bool all_success = true;
   for (Connection *conn : connections_to_send) {
-    if (!SendData(data, conn, true)) {
+    if (!SendData(conn, data, true)) {
       all_success = false;
     }
   }
@@ -75,8 +75,8 @@ bool WebSocketHandler::BroadcastData(const std::string &data) {
   return all_success;
 }
 
-bool WebSocketHandler::SendData(const std::string &data, Connection *conn,
-                                bool is_broadcast) {
+bool WebSocketHandler::SendData(Connection *conn, const std::string &data,
+                                bool skippable) {
   std::shared_ptr<std::mutex> connection_lock;
   {
     std::unique_lock<std::mutex> lock(mutex_);
@@ -92,9 +92,10 @@ bool WebSocketHandler::SendData(const std::string &data, Connection *conn,
   // Lock the connection while sending.
   if (!connection_lock->try_lock()) {
     // Skip sending data if:
-    // 1. This is a broadcast and there's higher priority data being sent.
+    // 1. Data is skippable according to sender and there's higher priority data
+    // being sent.
     // 2. The connection has been closed.
-    if (is_broadcast) {
+    if (skippable) {
       return false;
     } else {
       connection_lock->lock();  // Block to acquire the lock.

modules/dreamview/backend/websocket/websocket.h

@@ -104,12 +104,14 @@ class WebSocketHandler : public CivetWebSocketHandler {
 
   /**
    * @brief Sends the provided data to a specific connected client.
-   * @param data The message string to be sent.
+   *
    * @param conn The connection to send to.
-   * @param is_broadcast whether this is a broadcast send.
+   * @param data The message string to be sent.
+   * @param skippable whether the data is allowed to be skipped if some other is
+   * being sent to this connection.
    */
-  bool SendData(const std::string &data, Connection *conn,
-                bool is_broadcast = false);
+  bool SendData(Connection *conn, const std::string &data,
+                bool skippable = false);
 
   /**
    * @brief Add a new message handler for a message type.