tan_lsp_server 0.4.0

use lsp_server::{Connection, ExtractError, Message, Request, RequestId, Response};
use lsp_types::{
    request::{GotoDefinition, References},
    GotoDefinitionResponse, InitializeParams, OneOf, ServerCapabilities,
};
use tracing::{info, trace};
use tracing_subscriber::util::SubscriberInitExt;

fn cast<R>(req: Request) -> Result<(RequestId, R::Params), ExtractError<Request>>
where
    R: lsp_types::request::Request,
    R::Params: serde::de::DeserializeOwned,
{
    req.extract(R::METHOD)
}

fn run(connection: Connection, params: serde_json::Value) -> anyhow::Result<()> {
    let _params: InitializeParams = serde_json::from_value(params).unwrap();

    for msg in &connection.receiver {
        trace!("got msg: {:?}", msg);
        match msg {
            Message::Request(req) => {
                if connection.handle_shutdown(&req)? {
                    return Ok(());
                }
                trace!("got request: {:?}", req);
                match cast::<GotoDefinition>(req.clone()) {
                    Ok((id, params)) => {
                        eprintln!("got gotoDefinition request #{}: {:?}", id, params);
                        let result = Some(GotoDefinitionResponse::Array(Vec::new()));
                        let result = serde_json::to_value(&result).unwrap();
                        let resp = Response {
                            id,
                            result: Some(result),
                            error: None,
                        };
                        connection.sender.send(Message::Response(resp))?;
                        continue;
                    }
                    Err(err @ ExtractError::JsonError { .. }) => panic!("{:?}", err),
                    Err(ExtractError::MethodMismatch(req)) => req,
                };
                match cast::<References>(req.clone()) {
                    Ok((id, params)) => {
                        eprintln!("got references request #{}: {:?}", id, params);
                        let result = Some(Vec::<String>::new());
                        let result = serde_json::to_value(&result).unwrap();
                        let resp = Response {
                            id,
                            result: Some(result),
                            error: None,
                        };
                        connection.sender.send(Message::Response(resp))?;
                        continue;
                    }
                    Err(err @ ExtractError::JsonError { .. }) => panic!("{:?}", err),
                    Err(ExtractError::MethodMismatch(req)) => req,
                };
                // ...
            }
            Message::Response(resp) => {
                trace!("got response: {:?}", resp);
            }
            Message::Notification(not) => {
                trace!("got notification: {:?}", not);
            }
        }
    }
    Ok(())
}

fn main() -> anyhow::Result<()> {
    tracing_subscriber::fmt()
        .with_writer(std::io::stderr)
        .finish()
        .init();

    info!("starting LSP server");

    // Create the transport. Includes the stdio (stdin and stdout) versions but this could
    // also be implemented to use sockets or HTTP.
    let (connection, io_threads) = Connection::stdio();

    // Run the server and wait for the two threads to end (typically by trigger LSP Exit event).
    let server_capabilities = serde_json::to_value(&ServerCapabilities {
        definition_provider: Some(OneOf::Left(true)),
        references_provider: Some(OneOf::Left(true)),
        ..Default::default()
    })
    .unwrap();

    let initialization_params = connection.initialize(server_capabilities)?;
    run(connection, initialization_params)?;
    io_threads.join()?;

    info!("shutting down server");

    Ok(())
}