http: cleanup parser properties

Cleanup constructor and freeParser to manage all existing parser
properties, not just some.

PR-URL: nodejs#20126
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

lib/_http_client.js

@@ -606,7 +606,6 @@ function tickOnSocket(req, socket) {
   req.connection = socket;
   parser.reinitialize(HTTPParser.RESPONSE);
   parser.socket = socket;
-  parser.incoming = null;
   parser.outgoing = req;
   req.parser = parser;
 
@@ -619,9 +618,6 @@ function tickOnSocket(req, socket) {
   // Propagate headers limit from request object to parser
   if (typeof req.maxHeadersCount === 'number') {
     parser.maxHeaderPairs = req.maxHeadersCount << 1;
-  } else {
-    // Set default value because parser may be reused from FreeList
-    parser.maxHeaderPairs = 2000;
   }
 
   parser.onIncoming = parserOnIncomingClient;

lib/_http_common.js

@@ -41,6 +41,8 @@ const kOnBody = HTTPParser.kOnBody | 0;
 const kOnMessageComplete = HTTPParser.kOnMessageComplete | 0;
 const kOnExecute = HTTPParser.kOnExecute | 0;
 
+const MAX_HEADER_PAIRS = 2000;
+
 // Only called in the slow case where slow means
 // that the request headers were either fragmented
 // across multiple TCP packets or too large to be
@@ -159,6 +161,9 @@ const parsers = new FreeList('parsers', 1000, function() {
   parser.incoming = null;
   parser.outgoing = null;
 
+  parser.maxHeaderPairs = MAX_HEADER_PAIRS;
+
+  parser.onIncoming = null;
   parser[kOnHeaders] = parserOnHeaders;
   parser[kOnHeadersComplete] = parserOnHeadersComplete;
   parser[kOnBody] = parserOnBody;
@@ -180,6 +185,8 @@ function closeParserInstance(parser) { parser.close(); }
 function freeParser(parser, req, socket) {
   if (parser) {
     parser._headers = [];
+    parser._url = '';
+    parser.maxHeaderPairs = MAX_HEADER_PAIRS;
     parser.onIncoming = null;
     if (parser._consumed)
       parser.unconsume();

lib/_http_server.js

@@ -342,14 +342,10 @@ function connectionListenerInternal(server, socket) {
   parser.reinitialize(HTTPParser.REQUEST);
   parser.socket = socket;
   socket.parser = parser;
-  parser.incoming = null;
 
   // Propagate headers limit from server instance to parser
   if (typeof server.maxHeadersCount === 'number') {
     parser.maxHeaderPairs = server.maxHeadersCount << 1;
-  } else {
-    // Set default value because parser may be reused from FreeList
-    parser.maxHeaderPairs = 2000;
   }
 
   var state = {