add LSP support in Zed extension

Author: XiNiHa

.zed/settings.json

@@ -0,0 +1,10 @@
+{
+	"lsp": {
+		"isograph": {
+			"settings": {
+				"rootDirectory": "./demos/pet-demo",
+				"pathToIso": "scripts/start-debug-cli.js"
+			}
+		}
+	}
+}

scripts/start-debug-cli.js

@@ -0,0 +1,10 @@
+'use strict';
+
+var path = require('path');
+var spawn = require('child_process').spawn;
+
+var input = process.argv.slice(2);
+
+spawn(path.join(__dirname, '../target/debug/isograph_cli'), input, {
+  stdio: 'inherit',
+}).on('exit', process.exit);

zed-extension/extension.toml

@@ -12,3 +12,8 @@ repository = "https://github.com/XiNiHa/isograph"
 # TODO: switch to some valid commit
 rev = "tree-sitter"
 path = "tree-sitter"
+
+[language_servers.isograph]
+name = "Isograph"
+language = "Isograph"
+languages = ["JavaScript", "JSX", "TypeScript", "TSX"]

zed-extension/src/lib.rs

@@ -1,11 +1,138 @@
-use zed_extension_api as zed;
+use std::{env, fs, path::PathBuf};
+
+use zed_extension_api::{self as zed, Worktree};
+
+const SERVER_PATH: &str = "node_modules/.bin/iso";
+const PACKAGE_NAME: &str = "@isograph/compiler";
 
 struct IsographExtension;
 
+impl IsographExtension {
+    fn server_exists(&self) -> bool {
+        fs::metadata(SERVER_PATH).is_ok_and(|metadata| metadata.is_file())
+    }
+
+    fn server_script_path(
+        &mut self,
+        language_server_id: &zed::LanguageServerId,
+        path_to_iso: Option<String>,
+        worktree: &Worktree,
+    ) -> zed::Result<String> {
+        if let Some(path) = path_to_iso {
+            println!(
+                "You've manually specified 'pathToIso'. We cannot confirm this version of the Isograph Compiler is supported by this version of the extension. I hope you know what you're doing."
+            );
+            return Ok(PathBuf::from(worktree.root_path())
+                .join(path)
+                .to_string_lossy()
+                .to_string());
+        }
+
+        let server_path = env::current_dir()
+            .unwrap()
+            .join(SERVER_PATH)
+            .to_string_lossy()
+            .to_string();
+        let server_exists = self.server_exists();
+        if server_exists {
+            return Ok(server_path);
+        }
+
+        zed::set_language_server_installation_status(
+            language_server_id,
+            &zed::LanguageServerInstallationStatus::CheckingForUpdate,
+        );
+        let version = zed::npm_package_latest_version(PACKAGE_NAME)?;
+
+        if !server_exists
+            || zed::npm_package_installed_version(PACKAGE_NAME)?.as_ref() != Some(&version)
+        {
+            zed::set_language_server_installation_status(
+                language_server_id,
+                &zed::LanguageServerInstallationStatus::Downloading,
+            );
+            let result = zed::npm_install_package(PACKAGE_NAME, &version);
+            match result {
+                Ok(()) => {
+                    if !self.server_exists() {
+                        Err(format!(
+                            "installed package '{PACKAGE_NAME}' did not contain expected path '{SERVER_PATH}'",
+                        ))?;
+                    }
+                }
+                Err(error) => {
+                    if !self.server_exists() {
+                        Err(error)?;
+                    }
+                }
+            }
+        }
+
+        Ok(server_path)
+    }
+}
+
 impl zed::Extension for IsographExtension {
     fn new() -> Self {
-        IsographExtension
+        Self
+    }
+
+    fn language_server_command(
+        &mut self,
+        language_server_id: &zed::LanguageServerId,
+        worktree: &zed::Worktree,
+    ) -> zed::Result<zed::Command> {
+        let settings = Settings::from_lsp_settings(zed::settings::LspSettings::for_worktree(
+            language_server_id.as_ref(),
+            worktree,
+        )?);
+        let server_path =
+            self.server_script_path(language_server_id, settings.path_to_iso, worktree)?;
+
+        let args = vec![server_path, "lsp".to_string()];
+
+        let working_directory = settings
+            .root_directory
+            .unwrap_or_else(|| worktree.root_path());
+
+        Ok(zed::Command {
+            command: "/bin/sh".to_string(),
+            args: vec![
+                "-c".to_string(),
+                format!(
+                    r#"cd {}; "{}" {}"#,
+                    working_directory,
+                    zed::node_binary_path()?,
+                    args.into_iter()
+                        .map(|arg| format!(r#""{}""#, arg))
+                        .collect::<Vec<_>>()
+                        .join(" ")
+                ),
+            ],
+            env: Vec::new(),
+        })
     }
 }
 
+struct Settings {
+    root_directory: Option<String>,
+    path_to_iso: Option<String>,
+}
+
+impl Settings {
+    fn from_lsp_settings(settings: zed::settings::LspSettings) -> Self {
+        Settings {
+            root_directory: settings.settings.as_ref().and_then(|s| {
+                s.get("rootDirectory")
+                    .and_then(|v| v.as_str())
+                    .map(|v| v.to_string())
+            }),
+            path_to_iso: settings.settings.as_ref().and_then(|s| {
+                s.get("pathToIso")
+                    .and_then(|v| v.as_str())
+                    .map(|v| v.to_string())
+            }),
+        }
+    }
+}
 zed::register_extension!(IsographExtension);