Signal-Desktop/preload.wrapper.ts

138 lines
3.5 KiB
TypeScript

// 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, writeFileSync } from 'node:fs';
import { join, dirname } from 'node:path';
import { Script } from 'node:vm';
import { ipcRenderer } from 'electron';
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;
}
}
let script: Script | undefined;
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);
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;
};
if (cachedData || process.env.GENERATE_PRELOAD_CACHE) {
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);
// See `ts/scripts/generate-preload-cache.ts`
if (script && process.env.GENERATE_PRELOAD_CACHE) {
writeFileSync(cachePath, script.createCachedData());
ipcRenderer.send('shutdown');
}