Added comment and fixed typo

PrismJS · Jan 29, 2021 · 5af096e · 5af096e
1 parent 159ad50
commit 5af096e
Showing 1 changed file with 5 additions and 2 deletions.
diff --git a/components/prism-docker.js b/components/prism-docker.js
@@ -1,9 +1,12 @@
 (function (Prism) {
 
-	var spaceAfterBaskSlash = /\\[\r\n](?:\s|\\[\r\n]|#.*(?!.))*(?![\s#]|\\[\r\n])/.source;
+	// Many of the following regexes will contain negated lookaheads like `[ \t]+(?![ \t])`. This is a trick to ensure
+	// that quantifiers behave *atomically*. Atomic quantifiers are necessary to prevent exponential backtracking.
+
+	var spaceAfterBackSlash = /\\[\r\n](?:\s|\\[\r\n]|#.*(?!.))*(?![\s#]|\\[\r\n])/.source;
 	// At least one space, comment, or line break
 	var space = /(?:[ \t]+(?![ \t])(?:<SP_BS>)?|<SP_BS>)/.source
-		.replace(/<SP_BS>/g, function () { return spaceAfterBaskSlash; });
+		.replace(/<SP_BS>/g, function () { return spaceAfterBackSlash; });
 
 	var string = /"(?:[^"\\\r\n]|\\(?:\r\n|[\s\S]))*"|'(?:[^'\\\r\n]|\\(?:\r\n|[\s\S]))*'/.source;
 	var option = /--[\w-]+=(?:<STR>|(?!["'])(?:[^\s\\]|\\.)+)/.source.replace(/<STR>/g, function () { return string; });