allow extra ? at the beginning of a query_string.

fixes joyent/http-parser issue #25

http_parser.c

@@ -535,30 +535,15 @@ parse_url_char(enum state s, const char ch)
       break;
 
     case s_req_query_string_start:
-      if (IS_URL_CHAR(ch)) {
-        return s_req_query_string;
-      }
-
-      switch (ch) {
-        case '?':
-          /* XXX ignore extra '?' ... is this right? */
-          return s;
-
-        case '#':
-          return s_req_fragment_start;
-      }
-
-      break;
-
     case s_req_query_string:
       if (IS_URL_CHAR(ch)) {
-        return s;
+        return s_req_query_string;
       }
 
       switch (ch) {
         case '?':
           /* allow extra '?' in query string */
-          return s;
+          return s_req_query_string;
 
         case '#':
           return s_req_fragment_start;

test.c

@@ -1985,6 +1985,24 @@ const struct url_test url_tests[] =
   ,.rv=0
   }
 
+, {.name="extra ? in query string"
+  ,.url="http://a.tbcdn.cn/p/fp/2010c/??fp-header-min.css,fp-base-min.css,fp-channel-min.css,fp-product-min.css,fp-mall-min.css,fp-category-min.css,fp-sub-min.css,fp-gdp4p-min.css,fp-css3-min.css,fp-misc-min.css?t=20101022.css"
+  ,.is_connect=0
+  ,.u=
+    {.field_set=(1<<UF_SCHEMA) | (1<<UF_HOST) | (1<<UF_PATH) | (1<<UF_QUERY)
+    ,.port=0
+    ,.field_data=
+      {{  0,  4 } /* UF_SCHEMA */
+      ,{  7, 10 } /* UF_HOST */
+      ,{  0,  0 } /* UF_PORT */
+      ,{ 17, 12 } /* UF_PATH */
+      ,{ 30,187 } /* UF_QUERY */
+      ,{  0,  0 } /* UF_FRAGMENT */
+      }
+    }
+  ,.rv=0
+  }
+
 , {.name="proxy empty host"
   ,.url="http://:443/"
   ,.is_connect=1