From c31be5af4d0bc2a4aceb173da9d802e4f8e20f49 Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Sat, 8 Nov 2014 16:12:13 +0900
Subject: [PATCH] Assign default priority if dep_stream in PRIORITY does not
 exist

---
 lib/nghttp2_session.c        | 19 ++++++++++++-------
 tests/nghttp2_session_test.c |  4 ++--
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/lib/nghttp2_session.c b/lib/nghttp2_session.c
index 9a8d24b5..0b86b455 100644
--- a/lib/nghttp2_session.c
+++ b/lib/nghttp2_session.c
@@ -567,11 +567,13 @@ void nghttp2_session_del(nghttp2_session *session)
 
 int nghttp2_session_reprioritize_stream
 (nghttp2_session *session, nghttp2_stream *stream,
- const nghttp2_priority_spec *pri_spec)
+ const nghttp2_priority_spec *pri_spec_in)
 {
   int rv;
   nghttp2_stream *dep_stream;
   nghttp2_stream *root_stream;
+  nghttp2_priority_spec pri_spec_default;
+  const nghttp2_priority_spec *pri_spec = pri_spec_in;
 
   if(!nghttp2_stream_in_dep_tree(stream)) {
     return 0;
@@ -582,6 +584,15 @@ int nghttp2_session_reprioritize_stream
       (session, NGHTTP2_PROTOCOL_ERROR, "depend on itself");
   }
 
+  if(pri_spec->stream_id != 0) {
+    dep_stream = nghttp2_session_get_stream_raw(session, pri_spec->stream_id);
+
+    if(!dep_stream || !nghttp2_stream_in_dep_tree(dep_stream)) {
+      nghttp2_priority_spec_default_init(&pri_spec_default);
+      pri_spec = &pri_spec_default;
+    }
+  }
+
   if(pri_spec->stream_id == 0) {
     nghttp2_stream_dep_remove_subtree(stream);
 
@@ -602,12 +613,6 @@ int nghttp2_session_reprioritize_stream
     return rv;
   }
 
-  dep_stream = nghttp2_session_get_stream_raw(session, pri_spec->stream_id);
-
-  if(!dep_stream || !nghttp2_stream_in_dep_tree(dep_stream)) {
-    return 0;
-  }
-
   if(nghttp2_stream_dep_subtree_find(stream, dep_stream)) {
     DEBUGF(fprintf(stderr,
                    "stream: cycle detected, dep_stream(%p)=%d "
diff --git a/tests/nghttp2_session_test.c b/tests/nghttp2_session_test.c
index ac263563..49351db3 100644
--- a/tests/nghttp2_session_test.c
+++ b/tests/nghttp2_session_test.c
@@ -3074,13 +3074,13 @@ void test_nghttp2_session_reprioritize_stream(void)
   CU_ASSERT(10 == stream->weight);
   CU_ASSERT(NULL == stream->dep_prev);
 
-  /* dep_stream does not exist */
+  /* If dep_stream does not exist, default priority is assigned. */
 
   nghttp2_priority_spec_init(&pri_spec, 3, 99, 0);
 
   nghttp2_session_reprioritize_stream(session, stream, &pri_spec);
 
-  CU_ASSERT(10 == stream->weight);
+  CU_ASSERT(NGHTTP2_DEFAULT_WEIGHT == stream->weight);
   CU_ASSERT(NULL == stream->dep_prev);
 
   dep_stream = open_stream(session, 3);