Types, better-sqlite3, and worker_threads for our sqlite

ts/sql/mainWorker.ts

@@ -0,0 +1,56 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { parentPort } from 'worker_threads';
+
+import { WrappedWorkerRequest, WrappedWorkerResponse } from './main';
+import db from './Server';
+
+if (!parentPort) {
+  throw new Error('Must run as a worker thread');
+}
+
+const port = parentPort;
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+function respond(seq: number, error: Error | undefined, response?: any) {
+  const wrappedResponse: WrappedWorkerResponse = {
+    seq,
+    error: error ? error.stack : undefined,
+    response,
+  };
+  port.postMessage(wrappedResponse);
+}
+
+port.on('message', async ({ seq, request }: WrappedWorkerRequest) => {
+  try {
+    if (request.type === 'init') {
+      await db.initialize(request.options);
+
+      respond(seq, undefined, undefined);
+      return;
+    }
+
+    if (request.type === 'close') {
+      await db.close();
+
+      respond(seq, undefined, undefined);
+      process.exit(0);
+      return;
+    }
+
+    if (request.type === 'sqlCall') {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      const method = (db as any)[request.method];
+      if (typeof method !== 'function') {
+        throw new Error(`Invalid sql method: ${method}`);
+      }
+
+      respond(seq, undefined, await method.apply(db, request.args));
+    } else {
+      throw new Error('Unexpected request type');
+    }
+  } catch (error) {
+    respond(seq, error, undefined);
+  }
+});