Include code cache for preload bundle

Co-authored-by: Scott Nonnenberg <scott@signal.org>

preload.wrapper.ts

@@ -0,0 +1,126 @@
+// Copyright 2024 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+// Based on:
+// https://github.com/zertosh/v8-compile-cache/blob/b6bc035d337fbda0e6e3ec7936499048fc9deafc/v8-compile-cache.js
+
+import { Module } from 'node:module';
+import { readFileSync } from 'node:fs';
+import { join, dirname } from 'node:path';
+import { Script } from 'node:vm';
+
+const srcPath = join(__dirname, 'preload.bundle.js');
+const cachePath = join(__dirname, 'preload.bundle.cache');
+
+let cachedData: Buffer | undefined;
+try {
+  cachedData = readFileSync(cachePath);
+} catch (error) {
+  // No cache - no big deal
+  if (error.code !== 'ENOENT') {
+    throw error;
+  }
+}
+
+function compile(
+  filename: string,
+  content: string
+): (..._args: Array<unknown>) => void {
+  // https://github.com/nodejs/node/blob/v7.5.0/lib/module.js#L511
+
+  // create wrapper function
+  const wrapper = Module.wrap(content);
+
+  const script = new Script(wrapper, {
+    filename,
+    lineOffset: 0,
+    cachedData,
+  });
+
+  const compiledWrapper = script.runInThisContext({
+    filename,
+    lineOffset: 0,
+    columnOffset: 0,
+    displayErrors: true,
+  });
+
+  return compiledWrapper;
+}
+
+const ModuleInternals = Module as unknown as {
+  prototype: {
+    _compile(
+      this: typeof ModuleInternals,
+      content: string,
+      filename: string
+    ): unknown;
+  };
+  require(id: string): unknown;
+  exports: unknown;
+  _resolveFilename(
+    request: unknown,
+    mod: unknown,
+    _: false,
+    options: unknown
+  ): unknown;
+  _resolveLookupPaths(request: unknown, mod: unknown, _: true): unknown;
+  _cache: unknown;
+  _extensions: unknown;
+};
+
+const previousModuleCompile = ModuleInternals.prototype._compile;
+ModuleInternals.prototype._compile = function _compile(
+  content: string,
+  filename: string
+) {
+  if (filename !== srcPath) {
+    throw new Error(`Unexpected filename: ${filename}`);
+  }
+
+  // Immediately restore
+  ModuleInternals.prototype._compile = previousModuleCompile;
+
+  const require = (id: string) => {
+    return this.require(id);
+  };
+
+  // https://github.com/nodejs/node/blob/v10.15.3/lib/internal/modules/cjs/helpers.js#L28
+  const resolve = (request: unknown, options: unknown) => {
+    return ModuleInternals._resolveFilename(request, this, false, options);
+  };
+  require.resolve = resolve;
+
+  resolve.paths = (request: unknown) => {
+    return ModuleInternals._resolveLookupPaths(request, this, true);
+  };
+
+  require.main = process.mainModule;
+
+  // Enable support to add extra extension types
+  require.extensions = ModuleInternals._extensions;
+  require.cache = ModuleInternals._cache;
+
+  const dir = dirname(filename);
+
+  const compiledWrapper = compile(filename, content);
+
+  // We skip the debugger setup because by the time we run, node has already
+  // done that itself.
+
+  // `Buffer` is included for Electron.
+  // See https://github.com/zertosh/v8-compile-cache/pull/10#issuecomment-518042543
+  const args = [
+    this.exports,
+    require,
+    this,
+    filename,
+    dir,
+    process,
+    global,
+    Buffer,
+  ];
+  return compiledWrapper.apply(this.exports, args);
+};
+
+// eslint-disable-next-line import/no-dynamic-require
+require(srcPath);