Add version support via protobuf

Author: Erimelowo

README.md

@@ -58,6 +58,6 @@ To update vcpkg packages set the vcpkg registry submodule to a newer commit and
 
 ### Updating protobuf messages
 
-You can modify the protobuf messages for communication between the server and this driver at [src\bridge\ProtobufMessages.proto](src\bridge\ProtobufMessages.proto)
+You can modify the protobuf messages for communication between the server and this driver in [src\bridge\ProtobufMessages.proto](src\bridge\ProtobufMessages.proto). Please update PROTOCOL_VERSION in [src\bridge\BridgeClient.hpp](src\bridge\BridgeClient.hpp)
 
 To update the protobuf messages on the server, you will need to install [protoc](https://protobuf.dev/installation/) (we use version 4.31.1), then make sure that your SlimeVR-Server and SlimeVR-OpenVR-Driver repositories are in the same parent directory and run `protobuf_update.bat` located at `SlimeVR-Server\server\desktop`

src/bridge/BridgeClient.cpp

@@ -40,6 +40,7 @@ void BridgeClient::CreateConnection() {
         logger_->Log("[{}] connected", path);
         connected_ = true;
         last_error_ = std::nullopt;
+        SendVersion();
     });
     connection_handle_->on<uvw::end_event>([this, path](const uvw::end_event&, uvw::pipe_handle&) {
         logger_->Log("[{}] disconnected", path);
@@ -79,3 +80,12 @@ void BridgeClient::CloseConnectionHandles() {
     if (reconnect_timeout_) reconnect_timeout_->close();
     connected_ = false;
 }
+
+void BridgeClient::SendVersion() {
+    messages::ProtobufMessage* message = google::protobuf::Arena::CreateMessage<messages::ProtobufMessage>(&arena_);
+    messages::Version* version = google::protobuf::Arena::CreateMessage<messages::Version>(&arena_);
+    message->set_allocated_version(version);
+    version->set_protocol_version(PROTOCOL_VERSION);
+    SendBridgeMessage(*message);
+    arena_.Reset();
+}

src/bridge/BridgeClient.hpp

@@ -28,6 +28,8 @@
 
 #include "BridgeTransport.hpp"
 
+#define PROTOCOL_VERSION 1
+
 /**
  * @brief Client implementation for communication with SlimeVR Server using pipes or unix sockets.
  * 
@@ -49,8 +51,11 @@ class BridgeClient: public BridgeTransport {
     void ResetConnection() override;
     void CloseConnectionHandles() override;
     void Reconnect();
+    void SendVersion();
 
     std::optional<std::string> last_error_;
     std::optional<std::string> last_path_;
     std::shared_ptr<uvw::timer_handle> reconnect_timeout_;
+
+    google::protobuf::Arena arena_;
 };

src/bridge/ProtobufMessages.proto

@@ -54,6 +54,10 @@ option optimize_for = LITE_RUNTIME;
 message PingPong {
 }
 
+message Version {
+  int32 protocol_version = 1;
+}
+
 message Position {
     int32 tracker_id = 1;
     optional float x = 2;
@@ -117,5 +121,6 @@ message ProtobufMessage {
         TrackerAdded tracker_added = 3;
         TrackerStatus tracker_status = 4;
         Battery battery = 5;
+        Version version = 6;
     }
 }