Vencord/src/webpack/patchWebpack.ts
2022-11-11 12:37:37 +01:00

211 lines
9.8 KiB
TypeScript

/*
* Vencord, a modification for Discord's desktop app
* Copyright (c) 2022 Vendicated and contributors
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
import { WEBPACK_CHUNK } from "../utils/constants";
import Logger from "../utils/logger";
import { _initWebpack } from ".";
let webpackChunk: any[];
const logger = new Logger("WebpackInterceptor", "#8caaee");
Object.defineProperty(window, WEBPACK_CHUNK, {
get: () => webpackChunk,
set: v => {
if (v?.push !== Array.prototype.push) {
logger.info(`Patching ${WEBPACK_CHUNK}.push`);
_initWebpack(v);
patchPush();
// @ts-ignore
delete window[WEBPACK_CHUNK];
window[WEBPACK_CHUNK] = v;
}
webpackChunk = v;
},
configurable: true
});
function patchPush() {
function handlePush(chunk: any) {
try {
const modules = chunk[1];
const { subscriptions, listeners } = Vencord.Webpack;
const { patches } = Vencord.Plugins;
for (const id in modules) {
let mod = modules[id];
// Discords Webpack chunks for some ungodly reason contain random
// newlines. Cyn recommended this workaround and it seems to work fine,
// however this could potentially break code, so if anything goes weird,
// this is probably why.
// Additionally, `[actual newline]` is one less char than "\n", so if Discord
// ever targets newer browsers, the minifier could potentially use this trick and
// cause issues.
let code: string = mod.toString().replaceAll("\n", "");
// a very small minority of modules use function() instead of arrow functions,
// but, unnamed toplevel functions aren't valid. However 0, function() makes it a statement
if (code.startsWith("function(")) {
code = "0," + code;
}
const originalMod = mod;
const patchedBy = new Set();
const factory = modules[id] = function (module, exports, require) {
try {
mod(module, exports, require);
} catch (err) {
// Just rethrow discord errors
if (mod === originalMod) throw err;
logger.error("Error in patched chunk", err);
return void originalMod(module, exports, require);
}
// There are (at the time of writing) 11 modules exporting the window
// Make these non enumerable to improve webpack search performance
if (module.exports === window) {
Object.defineProperty(require.c, id, {
value: require.c[id],
enumerable: false,
configurable: true,
writable: true
});
return;
}
for (const callback of listeners) {
try {
callback(exports);
} catch (err) {
logger.error("Error in webpack listener", err);
}
}
for (const [filter, callback] of subscriptions) {
try {
if (filter(exports)) {
subscriptions.delete(filter);
callback(exports);
} else if (typeof exports === "object") {
if (exports.default && filter(exports.default)) {
subscriptions.delete(filter);
callback(exports.default);
}
for (const nested in exports) if (nested.length <= 3) {
if (exports[nested] && filter(exports[nested])) {
subscriptions.delete(filter);
callback(exports[nested]);
}
}
}
} catch (err) {
logger.error("Error while firing callback for webpack chunk", err);
}
}
} as any as { toString: () => string, original: any, (...args: any[]): void; };
// for some reason throws some error on which calling .toString() leads to infinite recursion
// when you force load all chunks???
try {
factory.toString = () => mod.toString();
factory.original = originalMod;
} catch { }
for (let i = 0; i < patches.length; i++) {
const patch = patches[i];
if (patch.predicate && !patch.predicate()) continue;
if (code.includes(patch.find)) {
patchedBy.add(patch.plugin);
// @ts-ignore we change all patch.replacement to array in plugins/index
for (const replacement of patch.replacement) {
const lastMod = mod;
const lastCode = code;
try {
const newCode = code.replace(replacement.match, replacement.replace);
if (newCode === code) {
logger.warn(`Patch by ${patch.plugin} had no effect (Module id is ${id}): ${replacement.match}`);
if (IS_DEV) {
logger.debug("Function Source:\n", code);
}
} else {
code = newCode;
mod = (0, eval)(`// Webpack Module ${id} - Patched by ${[...patchedBy].join(", ")}\n${newCode}\n//# sourceURL=WebpackModule${id}`);
}
} catch (err) {
logger.error(`Patch by ${patch.plugin} errored (Module id is ${id}): ${replacement.match}\n`, err);
if (IS_DEV) {
const changeSize = code.length - lastCode.length;
const match = lastCode.match(replacement.match)!;
// Use 200 surrounding characters of context
const start = Math.max(0, match.index! - 200);
const end = Math.min(lastCode.length, match.index! + match[0].length + 200);
// (changeSize may be negative)
const endPatched = end + changeSize;
const context = lastCode.slice(start, end);
const patchedContext = code.slice(start, endPatched);
// inline require to avoid including it in !IS_DEV builds
const diff = (require("diff") as typeof import("diff")).diffWordsWithSpace(context, patchedContext);
let fmt = "%c %s ";
const elements = [] as string[];
for (const d of diff) {
const color = d.removed
? "red"
: d.added
? "lime"
: "grey";
fmt += "%c%s";
elements.push("color:" + color, d.value);
}
logger.errorCustomFmt(...Logger.makeTitle("white", "Before"), context);
logger.errorCustomFmt(...Logger.makeTitle("white", "After"), context);
const [titleFmt, ...titleElements] = Logger.makeTitle("white", "Diff");
logger.errorCustomFmt(titleFmt + fmt, ...titleElements, ...elements);
}
code = lastCode;
mod = lastMod;
patchedBy.delete(patch.plugin);
}
}
if (!patch.all) patches.splice(i--, 1);
}
}
}
} catch (err) {
logger.error("Error in handlePush", err);
}
return handlePush.original.call(window[WEBPACK_CHUNK], chunk);
}
handlePush.original = window[WEBPACK_CHUNK].push;
Object.defineProperty(window[WEBPACK_CHUNK], "push", {
get: () => handlePush,
set: v => (handlePush.original = v),
configurable: true
});
}