Avoid match looping in sourceMappingURL tag detection by using negative lookahead

lib/internal/source_map/source_map_cache.js

@@ -5,9 +5,12 @@
   JSONParse,
   ObjectFreeze,
   RegExpPrototypeExec,
+  RegExpPrototypeSymbolMatch,
   SafeMap,
   StringPrototypeCodePointAt,
+  StringPrototypeIndexOf,
   StringPrototypeSplit,
+  StringPrototypeSubstring,
 } = primordials;
 
 // See https://tc39.es/ecma426/ for SourceMap V3 specification.
@@ -37,8 +40,8 @@
 // source url magic comments.
 const generatedSourceMapCache = new SafeMap();
 const kLeadingProtocol = /^\w+:\/\//;
-const kSourceMappingURLMagicComment = /\/[*/]#\s+sourceMappingURL=(?<sourceMappingURL>[^\s]+)/g;
-const kSourceURLMagicComment = /\/[*/]#\s+sourceURL=(?<sourceURL>[^\s]+)/g;
+const kSourceMappingURLMagicComment = /\/[*/]#\s+sourceMappingURL=[^\s]+/g;
+const kSourceURLMagicComment = /\/[*/]#\s+sourceURL=[^\s]+/g;
 
 const { isAbsolute } = require('path');
 const { fileURLToPath, pathToFileURL, URL, URLParse } = require('internal/url');
@@ -99,17 +102,12 @@
  * @returns {string | null} source url or null if not present
  */
 function extractSourceURLMagicComment(content) {
-  let match;
-  let matchSourceURL;
-  // A while loop is used here to get the last occurrence of sourceURL.
-  // This is needed so that we don't match sourceURL in string literals.
-  while ((match = RegExpPrototypeExec(kSourceURLMagicComment, content))) {
-    matchSourceURL = match;
-  }
-  if (matchSourceURL == null) {
+  const matches = RegExpPrototypeSymbolMatch(kSourceURLMagicComment, content);
+  if (matches == null || matches.length === 0) {
     return null;
   }
-  let sourceURL = matchSourceURL.groups.sourceURL;
+  const match = matches[matches.length - 1];
+  let sourceURL = StringPrototypeSubstring(match, StringPrototypeIndexOf(match, '=') + 1);
   if (sourceURL != null && RegExpPrototypeExec(kLeadingProtocol, sourceURL) === null) {
     sourceURL = pathToFileURL(sourceURL).href;
   }
@@ -125,17 +123,12 @@
  * @returns {string | null} source map url or null if not present
  */
 function extractSourceMapURLMagicComment(content) {
-  let match;
-  let lastMatch;
-  // A while loop is used here to get the last occurrence of sourceMappingURL.
-  // This is needed so that we don't match sourceMappingURL in string literals.
-  while ((match = RegExpPrototypeExec(kSourceMappingURLMagicComment, content))) {
-    lastMatch = match;
-  }
-  if (lastMatch == null) {
+  const matches = RegExpPrototypeSymbolMatch(kSourceMappingURLMagicComment, content);
+  if (matches == null || matches.length === 0) {
     return null;
   }
-  return lastMatch.groups.sourceMappingURL;
+  const match = matches[matches.length - 1];
+  return StringPrototypeSubstring(match, StringPrototypeIndexOf(match, '=') + 1);
 }
 
 /**

test/fixtures/source-map/output/source_map_eval.snapshot

@@ -1,10 +1,10 @@
-*/synthesized/workspace/tabs-source-url.coffee:26
+*/synthesized/workspace/tabs-source-url.coffee:32
 	alert "I knew it!"
 	^
 
 
 ReferenceError: alert is not defined
-    at Object.eval (*/synthesized/workspace/tabs-source-url.coffee:26:2)
+    at Object.eval (*/synthesized/workspace/tabs-source-url.coffee:32:2)
     at eval (*/synthesized/workspace/tabs-source-url.coffee:1:14)
     at Object.<anonymous> (*/test/fixtures/source-map/output/source_map_eval.js:11:1)
 

test/fixtures/source-map/tabs-source-url.coffee

@@ -21,6 +21,12 @@ math =
 race = (winner, runners...) ->
 	print winner, runners
 
+# Multiple sourceMappingURL comments
+## sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJmaWxlIjoidGFicy1zb3VyY2UtdXJsLmpzIiwic
+
+# sourceMappingURL inside strings
+sourceMappingURL = "//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJmaWxlIjoidGFicy1zb3VyY2UtdXJsLmpzIiwic"
+
 # Existence:
 if true
 	alert "I knew it!"