feat: add code completion using gopls

.gitignore

@@ -1,3 +1,4 @@
 .DS_Store
+logs/
 node_modules/
 *.log

Go.novaextension/Scripts/gopls.js

@@ -0,0 +1,116 @@
+let client = null;
+
+const debugAddress = "localhost:6060";
+
+// TODO: make this Disposable class
+async function start() {
+  stop();
+  console.log("initializing gopls...");
+
+  // Try to get gopls path from config
+  let goplsPath = nova.config.get("go.gopls-path");
+
+  // Try to get gopls path from PATH unless custom configuration provided
+  if (!goplsPath) {
+    goplsPath = await new Promise((resolve, reject) => {
+      const which = new Process("/usr/bin/env", {
+        args: ["which", "gopls"],
+      });
+      nova.subscriptions.add(
+        which.onDidExit((status) => {
+          if (status !== 0) reject(false);
+        })
+      );
+      nova.subscriptions.add(
+        which.onStdout((text) => {
+          resolve(text.trim());
+        })
+      );
+      which.start();
+    });
+  }
+
+  // If we can't find gopls, use the default path
+  if (!goplsPath) {
+    let gobin = nova.environment.GOBIN;
+    if (!gobin) {
+      const gopath = await new Promise((resolve, reject) => {
+        const go = new Process("/usr/bin/env", {
+          args: ["go", "env", "GOPATH"],
+        });
+        nova.subscriptions.add(
+          go.onDidExit((status) => {
+            if (status !== 0) {
+              reject(`go env GOPATH exited with status code: ${status}`);
+            }
+          })
+        );
+        nova.subscriptions.add(
+          go.onStdout((text) => {
+            resolve(text.trim());
+          })
+        );
+        go.start();
+      });
+      gobin = nova.path.join(gopath, "bin");
+    }
+    goplsPath = nova.path.join(gobin, "gopls");
+  }
+
+  console.log(`gopls path: ${goplsPath}`);
+
+  // Create the client
+  let serverOptions = {
+    type: "stdio",
+    path: goplsPath,
+    args: [],
+  };
+  if (nova.inDevMode()) {
+    console.log(`debug information will be available on ${debugAddress}`);
+
+    const logDir = nova.path.join(nova.workspace.path, "logs");
+    await new Promise((resolve, reject) => {
+      const mkdir = new Process("/usr/bin/env", {
+        args: ["mkdir", "-p", logDir],
+      });
+      nova.subscriptions.add(
+        mkdir.onDidExit((status) => {
+          if (status !== 0) {
+            reject(status);
+          }
+          resolve(status);
+        })
+      );
+
+      mkdir.start();
+    });
+    const logFile = nova.path.join(logDir, "gopls.log");
+    console.log(`gopls log file: ${logFile}`);
+
+    serverOptions.args.push("-debug", debugAddress);
+    serverOptions.args.push("-logfile", logFile);
+    serverOptions.args.push("-rpc.trace");
+    serverOptions.args.push("-v");
+    serverOptions.args.push("-vv");
+  }
+
+  client = new LanguageClient("gopls", "Go Language Server", serverOptions, {
+    syntaxes: ["go", "gomod"],
+  });
+  nova.subscriptions.add(client);
+
+  console.log("starting language client...");
+  client.start();
+}
+
+function stop() {
+  nova.subscriptions.dispose();
+
+  if (client) {
+    client.stop();
+    client = null;
+  }
+}
+
+exports.start = start;
+exports.stop = stop;

Go.novaextension/Scripts/main.js

@@ -0,0 +1,69 @@
+const gopls = require("gopls.js");
+
+exports.activate = function () {
+  console.log("activating");
+
+  (async () => {
+    await start();
+    if (nova.config.get("go.enable-gopls")) {
+      await gopls.start();
+    }
+    console.log("activation completed");
+  })().catch((err) => {
+    if (!nova.inDevMode()) return;
+    console.error("error activating:", err);
+  });
+};
+
+exports.deactivate = function () {
+  console.log("deactivating");
+  console.log("deactivation completed");
+};
+
+async function start() {
+  // Check if the go command is available
+  const isGoAvailable = await new Promise((resolve, reject) => {
+    const which = new Process("/usr/bin/env", {
+      args: ["which", "go"],
+    });
+    nova.subscriptions.add(
+      which.onDidExit((status) => {
+        if (status !== 0) {
+          reject(false);
+          return;
+        }
+        resolve(true);
+      })
+    );
+    which.start();
+  });
+  if (!isGoAvailable) {
+    throw new Error("cannot find go executable");
+  }
+
+  // Check if the go version is correct
+  const goVersion = await new Promise((resolve, reject) => {
+    const go = new Process("/usr/bin/env", {
+      args: ["go", "version"],
+    });
+    nova.subscriptions.add(
+      go.onDidExit((status) => {
+        if (status !== 0) {
+          reject(`go version exited with status code: ${status}`);
+        }
+      })
+    );
+    nova.subscriptions.add(
+      go.onStdout((text) => {
+        resolve(text.trim());
+      })
+    );
+    go.start();
+  });
+  if (!versionRegexp.exec(goVersion)) {
+    throw new Error(`${goVersion} is not compatible with this extension`);
+  }
+  console.log(goVersion);
+}
+
+const versionRegexp = /go version go1\.[\d]+(?:\.[\d])?(?:[\w\d]+)? darwin\/[\w\d]+/;

Go.novaextension/extension.json

@@ -6,6 +6,33 @@
   "version": "0.3.4",
   "min_runtime": "4.0",
   "categories": ["languages", "completions"],
+  "main": "main.js",
+  "activationEvents": [
+    "onLanguage:go",
+    "onWorkspaceContains:go.mod",
+    "onWorkspaceContains:go.sum"
+  ],
+  "entitlements": {
+    "process": true
+  },
   "bugs": "https://github.com/maku693/go-nova/issues/new",
-  "repository": "https://github.com/maku693/go-nova"
+  "repository": "https://github.com/maku693/go-nova",
+  "config": [
+    {
+      "key": "go.enable-gopls",
+      "title": "Use Language Server (gopls) (Experimental)",
+      "description": "Whether to enable code completion using gopls.\nYou should have a valid go installation to enable this option.",
+      "type": "boolean",
+      "default": false,
+      "children": [
+        {
+          "key": "go.gopls-path",
+          "title": "gopls path",
+          "description": "Path to gopls executable.\nIf empty, the extension try to infer executable path from $PATH and $GOBIN.",
+          "type": "path",
+          "default": ""
+        }
+      ]
+    }
+  ]
 }