Mark code for stripping automatically based on attribute arguments

Question

I have made a minimalistic multiplayer game netcode framework where client and server code are located in the same classes. Instances of those classes appear on both, the server and the clients. These classes can have properties marked as to be synchronized over the network using a configurable attribute:

  [SynchronizeOverNetwork(Authority = Authority.Server)]
  public ReconcileMoveData ReconcileMoveData {
    // Code should not appear on server, but on client
    get => new ReconcileMoveData {
      Position = transform.position,
      Rotation = transform.rotation.eulerAngles.z,
      LinearVelocity = _body.velocity,
      AngularVelocity = _body.angularVelocity,
    };
    // Code should not appear on client, but on server
    set {
      transform.position = value.Position;
      transform.rotation = Quaternion.Euler(new Vector3(0, 0, value.Rotation));
      _body.velocity = value.LinearVelocity;
      _body.angularVelocity = value.AngularVelocity;
    }
  }

I find those properties in the initialization phase (when starting the game) to manage them globally and handle differently on client and server. If I have set Authority to Authority.Server the setter of that property is to be executed only on the server and the setter only on the client. If set to Authority.Client it is the other way around: Setter is called on the client, getter on the server.

To prevent code analysis (The server will never be published) and to reduce client code size I want to exclude server code on client builds and client code on server builds.

Unity has the UNITY_SERVER directive to marke code for stripping for client:

#if UNITY_SERVER
  // Server only code here
#endif

Placing that directives in every getter and setter is easy to do wrong, cumbersome and redundant.

Is it possible to have preprocessor build step (or whatever) that adds those directives when building automatically based on the attributes configuration (without changing the source code files, but the code passed to the compile) or to mark code for stripping otherwise?

score 0 · Answer 1 · answered May 15 '23 at 09:40

You can add whatever you want in case of a custom build pipeline. I mean building from the script using BuildPipeline. As it is just a method call, you can add whatever you want before starting a build, including some preprocessing.

You can find all your methods with certain attributes using Roslyn. You can find an example in this answer.

Mark code for stripping automatically based on attribute arguments

1 Answers1