Merge pull request #63 from georgestagg/null-lsp

src/Components/Editor.tsx

@@ -6,6 +6,7 @@
 import * as fileio from "../fileio";
 import { createUri } from "../language-server/client";
 import { LSPClient } from "../language-server/lsp-client";
+import { ensureNullClient } from "../language-server/null-client";
 import { ensurePyrightClient } from "../language-server/pyright-client";
 import { inferFiletype, modKeySymbol, stringToUint8Array } from "../utils";
 import type { AppEngine, UtilityMethods } from "./App";
@@ -97,7 +98,9 @@ export default function Editor({
   // lsp-extensions.ts, and useTabbedCodeMirror.tsx, there are explicit checks
   // that files are python files in order to enable LS features, and they should
   // not be necessary at this level.
-  const lspClient: LSPClient = ensurePyrightClient();
+  const lspClient: LSPClient = appEngine === 'python'
+    ? ensurePyrightClient()
+    : ensureNullClient();
 
   // A unique ID for this instance of the Editor. At some point it might make
   // sense to hoist this up into the App component, if we need unique IDs for

src/language-server/null-client.ts

@@ -0,0 +1,46 @@
+import { createUri, LanguageServerClient } from "./client";
+import { LSPClient } from "./lsp-client";
+import {
+  AbstractMessageReader,
+  AbstractMessageWriter,
+  createMessageConnection,
+} from "vscode-jsonrpc";
+
+let nullClient: NullClient | null = null;
+
+/**
+ * This returns a NullClient object. If this is called multiple times, it
+ * will return the same object each time.
+ */
+export function ensureNullClient(): NullClient {
+  if (!nullClient) {
+    nullClient = new NullClient();
+  }
+  return nullClient;
+}
+
+export class NullMessageReader extends AbstractMessageReader {
+  public listen() {
+    return { dispose: () => {} };
+  }
+}
+
+export class NullMessageWriter extends AbstractMessageWriter {
+  public async write() {}
+  public end(): void {}
+}
+
+/**
+ * A "null" LSP client that listens for messages but does nothing.
+ */
+export class NullClient extends LSPClient {
+  constructor() {
+    const conn = createMessageConnection(
+      new NullMessageReader(),
+      new NullMessageWriter()
+    );
+    conn.listen();
+    const client = new LanguageServerClient(conn, "en", createUri(""));
+    super(client);
+  }
+}