http: simplify checkIsHttpToken()

Replace code optimized for older versions of V8 with more
straightforward code in checkIsHttpToken().

PR-URL: #17399
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>

lib/_http_common.js

@@ -233,70 +233,14 @@ function httpSocketSetup(socket) {
   socket.on('drain', ondrain);
 }
 
+const tokenRegExp = /^[\^_`a-zA-Z\-0-9!#$%&'*+.|~]+$/;
 /**
  * Verifies that the given val is a valid HTTP token
  * per the rules defined in RFC 7230
  * See https://tools.ietf.org/html/rfc7230#section-3.2.6
- *
- * Allowed characters in an HTTP token:
- * ^_`a-z  94-122
- * A-Z     65-90
- * -       45
- * 0-9     48-57
- * !       33
- * #$%&'   35-39
- * *+      42-43
- * .       46
- * |       124
- * ~       126
- *
- * This implementation of checkIsHttpToken() loops over the string instead of
- * using a regular expression since the former is up to 180% faster with v8 4.9
- * depending on the string length (the shorter the string, the larger the
- * performance difference)
- *
- * Additionally, checkIsHttpToken() is currently designed to be inlinable by v8,
- * so take care when making changes to the implementation so that the source
- * code size does not exceed v8's default max_inlined_source_size setting.
- **/
-var validTokens = [
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0 - 15
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 16 - 31
-  0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, // 32 - 47
-  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, // 48 - 63
-  0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 64 - 79
-  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, // 80 - 95
-  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 96 - 111
-  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, // 112 - 127
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 128 ...
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0  // ... 255
-];
+**/
 function checkIsHttpToken(val) {
-  if (!validTokens[val.charCodeAt(0)])
-    return false;
-  if (val.length < 2)
-    return true;
-  if (!validTokens[val.charCodeAt(1)])
-    return false;
-  if (val.length < 3)
-    return true;
-  if (!validTokens[val.charCodeAt(2)])
-    return false;
-  if (val.length < 4)
-    return true;
-  if (!validTokens[val.charCodeAt(3)])
-    return false;
-  for (var i = 4; i < val.length; ++i) {
-    if (!validTokens[val.charCodeAt(i)])
-      return false;
-  }
-  return true;
+  return tokenRegExp.test(val);
 }
 
 /**