nghttp: Depend on "leader" anchor if js is linked inside head element

src/HtmlParser.cc

@@ -30,7 +30,8 @@
 
 namespace nghttp2 {
 
-ParserData::ParserData(const std::string &base_uri) : base_uri(base_uri) {}
+ParserData::ParserData(const std::string &base_uri)
+    : base_uri(base_uri), inside_head(0) {}
 
 HtmlParser::HtmlParser(const std::string &base_uri)
     : base_uri_(base_uri), parser_ctx_(nullptr), parser_data_(base_uri) {}
@@ -68,6 +69,9 @@ namespace {
 void start_element_func(void *user_data, const xmlChar *name,
                         const xmlChar **attrs) {
   auto parser_data = static_cast<ParserData *>(user_data);
+  if (util::strieq(reinterpret_cast<const char *>(name), "head")) {
+    ++parser_data->inside_head;
+  }
   if (util::strieq(reinterpret_cast<const char *>(name), "link")) {
     auto rel_attr = get_attr(attrs, "rel");
     auto href_attr = get_attr(attrs, "href");
@@ -90,9 +94,21 @@ void start_element_func(void *user_data, const xmlChar *name,
     if (!src_attr) {
       return;
     }
-    // TODO if script is inside in head, this should be REQ_LEADERS.
+    if (parser_data->inside_head) {
+      add_link(parser_data, src_attr, REQ_JS);
+    } else {
       add_link(parser_data, src_attr, REQ_UNBLOCK_JS);
     }
+  }
+}
+} // namespace
+
+namespace {
+void end_element_func(void *user_data, const xmlChar *name) {
+  auto parser_data = static_cast<ParserData *>(user_data);
+  if (util::strieq(reinterpret_cast<const char *>(name), "head")) {
+    --parser_data->inside_head;
+  }
 }
 } // namespace
 
@@ -113,7 +129,7 @@ xmlSAXHandler saxHandler = {
     nullptr,             // startDocumentSAXFunc
     nullptr,             // endDocumentSAXFunc
     &start_element_func, // startElementSAXFunc
-    nullptr,             // endElementSAXFunc
+    &end_element_func,   // endElementSAXFunc
     nullptr,             // referenceSAXFunc
     nullptr,             // charactersSAXFunc
     nullptr,             // ignorableWhitespaceSAXFunc

src/HtmlParser.h

@@ -41,6 +41,7 @@ namespace nghttp2 {
 // Lower value has higher priority
 enum RequestPriority {
   REQ_CSS = 1,
+  REQ_JS,
   REQ_UNBLOCK_JS,
   REQ_IMG,
   REQ_OTHERS,
@@ -49,6 +50,8 @@ enum RequestPriority {
 struct ParserData {
   std::string base_uri;
   std::vector<std::pair<std::string, RequestPriority>> links;
+  // > 0 if we are inside "head" element.
+  int inside_head;
   ParserData(const std::string &base_uri);
 };
 

src/nghttp.cc

@@ -196,6 +196,7 @@ nghttp2_priority_spec Request::resolve_dep(int32_t pri) {
     int32_t weight;
     switch (pri) {
     case REQ_CSS:
+    case REQ_JS:
       anchor_id = anchors[ANCHOR_LEADERS].stream_id;
       weight = 2;
       break;