avoid firefox bug with sourceMappingURL parsing

Author: evanw

code.js

@@ -101,16 +101,31 @@
  }
 
  async function finishLoadingCodeWithEmbeddedSourceMap(code, file) {
- // Check for both "//" and "/*" comments
- let match = /\/(\/)[#@] *sourceMappingURL=([^\s]+)/.exec(code);
- if (!match) match = /\/(\*)[#@] *sourceMappingURL=((?:[^\s*]|\*[^/])+)(?:[^*]|\*[^/])*\*\//.exec(code);
+ let url;
+
+ // Check for both "//" and "/*" comments. This is mostly done manually
+ // instead of doing it all with a regular expression because Firefox's
+ // regular expression engine crashes with an internal error when the
+ // match is too big.
+ for (let regex = /\/([*/])[#@] *sourceMappingURL=/g, match; match = regex.exec(code);) {
+ const start = match.index + match[0].length;
+ const n = code.length;
+ let end = start;
+ while (end < n && code.charCodeAt(end) > 32) {
+ end++;
+ }
+ if (end > start && (match[1] === '/' || code.slice(end).indexOf('*/') > 0)) {
+ url = code.slice(start, end);
+ break;
+ }
+ }
 
  // Check for a non-empty data URL payload
- if (match && match[2]) {
+ if (url) {
  let map;
  try {
  // Use "new URL" to ensure that the URL has a protocol (e.g. "data:" or "https:")
- map = await fetch(new URL(match[2])).then(r => r.text());
+ map = await fetch(new URL(url)).then(r => r.text());
  } catch (e) {
  showLoadingError(`Failed to parse the URL in the "/${match[1]}# sourceMappingURL=" comment: ${e && e.message || e}`);
  return;