feat: Stylua LSP server

Author: PolyMeilex

Cargo.lock

@@ -56,6 +56,9 @@ thiserror = "1.0.49"
 threadpool = "1.8.1"
 toml = "0.8.1"
 
+lsp-server = "0.7"
+lsp-types = "0.97"
+
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 wasm-bindgen = { version = "0.2.81", optional = true }
 

Cargo.toml

@@ -0,0 +1,105 @@
+use lsp_server::{Connection, Message, RequestId, Response};
+use lsp_types::{
+    request::{Formatting, RangeFormatting, Request},
+    DocumentFormattingParams, InitializeParams, InitializeResult, OneOf, Position, Range,
+    ServerCapabilities, TextEdit,
+};
+
+use crate::{config::ConfigResolver, opt};
+
+pub fn run(opt: opt::Opt) -> anyhow::Result<()> {
+    // Load the configuration
+    let opt_for_config_resolver = opt.clone();
+    let mut config_resolver = ConfigResolver::new(&opt_for_config_resolver)?;
+
+    let (connection, io_threads) = Connection::stdio();
+
+    // Wait for initialize request
+    let (id, params) = connection.initialize_start()?;
+    let _params = serde_json::from_value::<InitializeParams>(params)?;
+
+    let capabilities = ServerCapabilities {
+        document_formatting_provider: Some(OneOf::Left(true)),
+        ..Default::default()
+    };
+
+    let init_result = InitializeResult {
+        capabilities,
+        ..Default::default()
+    };
+
+    connection.initialize_finish(id, serde_json::to_value(init_result)?)?;
+
+    for msg in &connection.receiver {
+        match msg {
+            Message::Request(req) => {
+                if connection.handle_shutdown(&req)? {
+                    break;
+                }
+
+                match req.method.as_str() {
+                    Formatting::METHOD => {
+                        let result =
+                            match serde_json::from_value::<DocumentFormattingParams>(req.params) {
+                                Ok(params) => {
+                                    let res = handle_formatting(
+                                        req.id.clone(),
+                                        params,
+                                        &mut config_resolver,
+                                    );
+
+                                    res.unwrap_or(Response::new_ok(req.id, serde_json::Value::Null))
+                                }
+                                Err(err) => Response::new_err(req.id, 1, err.to_string()),
+                            };
+
+                        connection.sender.send(Message::Response(result))?;
+                    }
+                    RangeFormatting::METHOD => {
+                        // TODO: Would be cool to support this in the future
+                    }
+                    _ => {}
+                }
+            }
+            Message::Response(_) => {}
+            Message::Notification(_) => {}
+        }
+    }
+
+    io_threads.join()?;
+
+    Ok(())
+}
+
+fn handle_formatting(
+    id: RequestId,
+    params: DocumentFormattingParams,
+    config_resolver: &mut ConfigResolver,
+) -> Option<Response> {
+    let path = params.text_document.uri.path().as_str();
+    let src = std::fs::read_to_string(path).ok()?;
+
+    let config = config_resolver
+        .load_configuration(path.as_ref())
+        .unwrap_or_default();
+
+    let new_text =
+        stylua_lib::format_code(&src, config, None, stylua_lib::OutputVerification::None).ok()?;
+
+    if new_text == src {
+        return None;
+    }
+
+    // TODO: We can be smarter about this in the future, and update only the parts that changed
+    let edit = TextEdit {
+        range: Range {
+            start: Position::new(0, 0),
+            end: Position::new(u32::MAX, 0),
+        },
+        new_text,
+    };
+
+    let edits: Vec<TextEdit> = vec![edit];
+
+    Some(Response::new_ok(id, edits))
+}

src/cli/lsp.rs

@@ -19,6 +19,7 @@ use stylua_lib::{format_code, Config, OutputVerification, Range};
 use crate::config::find_ignore_file_path;
 
 mod config;
+mod lsp;
 mod opt;
 mod output_diff;
 
@@ -255,6 +256,11 @@ fn path_is_stylua_ignored(path: &Path, search_parent_directories: bool) -> Resul
 fn format(opt: opt::Opt) -> Result<i32> {
     debug!("resolved options: {:#?}", opt);
 
+    if opt.lsp {
+        lsp::run(opt)?;
+        return Ok(0);
+    }
+
     if opt.files.is_empty() {
         bail!("no files provided");
     }

src/cli/main.rs

@@ -108,6 +108,10 @@ pub struct Opt {
     /// Respect .styluaignore and glob matching for file paths provided directly to the tool
     #[structopt(long)]
     pub respect_ignores: bool,
+
+    /// Run Stylua LSP server
+    #[structopt(long)]
+    pub lsp: bool,
 }
 
 #[derive(ArgEnum, Clone, Copy, Debug, PartialEq, Eq)]