feat(lsp): handle CLI args for different communication channels

Implement handling of the common CLI arguments that define how to
establish the client/server communication channel.

The options are defined, but not all are supported as of yet.

Cargo.toml

@@ -22,6 +22,7 @@ all = "deny"
 pedantic = "warn"
 
 [workspace.dependencies]
+clap = { version = "4.4.10", features = ["derive", "wrap_help"] }
 color-eyre = { version = "0.6.2", default-features = false }
 glob = "0.3.1"
 indoc = "2.0.4"

crates/stef-cli/Cargo.toml

@@ -14,7 +14,7 @@ name = "stef"
 path = "src/main.rs"
 
 [dependencies]
-clap = { version = "4.4.10", features = ["derive", "wrap_help"] }
+clap.workspace = true
 color-eyre.workspace = true
 glob.workspace = true
 miette = { workspace = true, features = ["fancy-no-backtrace"] }

crates/stef-go/Cargo.toml

@@ -10,7 +10,7 @@ repository.workspace = true
 license.workspace = true
 
 [dependencies]
-clap = { version = "4.4.10", features = ["derive"] }
+clap.workspace = true
 heck = "0.4.1"
 miette = { workspace = true, features = ["fancy-no-backtrace"] }
 stef-compiler = { path = "../stef-compiler" }

crates/stef-lsp/Cargo.toml

@@ -10,6 +10,7 @@ repository.workspace = true
 license.workspace = true
 
 [dependencies]
+clap.workspace = true
 directories = "5.0.1"
 ouroboros = "0.18.0"
 stef-compiler = { path = "../stef-compiler" }

crates/stef-lsp/src/cli.rs

@@ -0,0 +1,46 @@
+use std::path::PathBuf;
+
+use clap::{Parser, ValueHint};
+
+#[derive(Parser)]
+#[command(about, author, version)]
+pub struct Cli {
+    /// Use standard I/O as the communication channel.
+    #[arg(long, conflicts_with_all = ["pipe", "socket"])]
+    pub stdio: bool,
+    /// Use pipes (Windows) or socket files (Linux, Mac) as the communication channel.
+    #[arg(
+        long,
+        conflicts_with_all = ["socket"],
+        value_name = "FILE",
+        value_hint = ValueHint::FilePath,
+    )]
+    pub pipe: Option<PathBuf>,
+    /// Use a socket as the communication channel.
+    #[arg(long, exclusive = true, value_name = "PORT")]
+    pub socket: Option<u16>,
+    /// Process ID of the editor that started this server.
+    ///
+    /// To support the case that the editor starting a server crashes an editor should also pass
+    /// its process id to the server. This allows the server to monitor the editor process and to
+    /// shutdown itself if the editor process dies.
+    #[arg(long = "clientProcessId", value_name = "ID")]
+    pub client_process_id: Option<i32>,
+}
+
+impl Cli {
+    pub fn parse() -> Self {
+        <Self as Parser>::parse()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Cli;
+
+    #[test]
+    fn verify_cli() {
+        use clap::CommandFactory;
+        Cli::command().debug_assert();
+    }
+}

crates/stef-lsp/src/main.rs

@@ -19,6 +19,9 @@ use tower_lsp::{
 use tracing::{debug, Level};
 use tracing_subscriber::{filter::Targets, fmt::MakeWriter, prelude::*};
 
+use self::cli::Cli;
+
+mod cli;
 mod compile;
 mod utf16;
 
@@ -120,6 +123,8 @@ impl LanguageServer for Backend {
 
 #[tokio::main]
 async fn main() {
+    let cli = Cli::parse();
+
     let dirs = ProjectDirs::from("rocks", "dnaka91", env!("CARGO_PKG_NAME")).unwrap();
 
     let file_appender = tracing_appender::rolling::daily(dirs.cache_dir(), "log");
@@ -147,8 +152,21 @@ async fn main() {
         }
     });
 
-    let (stdin, stdout) = (tokio::io::stdin(), tokio::io::stdout());
-    Server::new(stdin, stdout, socket).serve(service).await;
+    if cli.stdio {
+        let (stdin, stdout) = (tokio::io::stdin(), tokio::io::stdout());
+        Server::new(stdin, stdout, socket).serve(service).await;
+    } else if let Some(file) = cli.pipe {
+        let file = tokio::fs::File::options()
+            .read(true)
+            .write(true)
+            .open(file)
+            .await
+            .expect("failed to open provided pipe/socket");
+        let (read, write) = tokio::io::split(file);
+        Server::new(read, write, socket).serve(service).await;
+    } else if let Some(port) = cli.socket {
+        unimplemented!("open TCP connection on port {port}");
+    }
 }
 
 struct ClientLogWriter {