From d3561a63b11be8b1ad598cef52c37ff03525ffd6 Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Fri, 17 Apr 2015 21:25:31 +0900
Subject: [PATCH] nghttp: Depend on "leader" anchor if js is linked inside head
 element

---
 src/HtmlParser.cc | 24 ++++++++++++++++++++----
 src/HtmlParser.h  |  3 +++
 src/nghttp.cc     |  1 +
 3 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/src/HtmlParser.cc b/src/HtmlParser.cc
index 26559cce..51f6a12b 100644
--- a/src/HtmlParser.cc
+++ b/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");
@@ -90,8 +94,20 @@ 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.
-    add_link(parser_data, src_attr, REQ_UNBLOCK_JS);
+    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
diff --git a/src/HtmlParser.h b/src/HtmlParser.h
index 6d438212..694b6c9b 100644
--- a/src/HtmlParser.h
+++ b/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);
 };
 
diff --git a/src/nghttp.cc b/src/nghttp.cc
index 8f27e9a8..d4b02c3c 100644
--- a/src/nghttp.cc
+++ b/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;