Allow exclusive dependency to stream 0

lib/includes/nghttp2/nghttp2.h

@@ -2105,8 +2105,6 @@ void nghttp2_priority_spec_default_init(nghttp2_priority_spec *pri_spec);
  * @function
  *
  * Returns nonzero if the |pri_spec| is filled with default values.
- * `pri_spec->exclusive` is ignored since it is irrelevant when
- * `pri_spec->stream_id == 0`.
  */
 int nghttp2_priority_spec_check_default(const nghttp2_priority_spec *pri_spec);
 

lib/nghttp2_priority_spec.c

@@ -42,7 +42,7 @@ void nghttp2_priority_spec_default_init(nghttp2_priority_spec *pri_spec)
 
 int nghttp2_priority_spec_check_default(const nghttp2_priority_spec *pri_spec)
 {
-  /* Ignore exclusive flag */
   return pri_spec->stream_id == 0 &&
-    pri_spec->weight == NGHTTP2_DEFAULT_WEIGHT;
+    pri_spec->weight == NGHTTP2_DEFAULT_WEIGHT &&
+    pri_spec->exclusive == 0;
 }

lib/nghttp2_session.c

@@ -280,6 +280,8 @@ static int nghttp2_session_new(nghttp2_session **session_ptr,
     goto fail_map;
   }
 
+  nghttp2_stream_roots_init(&(*session_ptr)->roots);
+
   (*session_ptr)->next_seq = 0;
 
   (*session_ptr)->remote_window_size = NGHTTP2_INITIAL_CONNECTION_WINDOW_SIZE;
@@ -436,6 +438,8 @@ void nghttp2_session_del(nghttp2_session *session)
   }
   free(session->inflight_iv);
 
+  nghttp2_stream_roots_free(&session->roots);
+
   /* Have to free streams first, so that we can check
      stream->data_item->queued */
   nghttp2_map_each_free(&session->streams, nghttp2_free_streams, NULL);
@@ -470,14 +474,21 @@ int nghttp2_session_reprioritize_stream
     /* We have to update weight after removing stream from tree */
     stream->weight = pri_spec->weight;
 
-    rv = nghttp2_stream_dep_make_root(stream, &session->ob_pq);
+    if(pri_spec->exclusive &&
+       session->roots.num_streams <= NGHTTP2_MAX_DEP_TREE_LENGTH) {
+
+      rv = nghttp2_stream_dep_all_your_stream_are_belong_to_us
+        (stream, &session->ob_pq);
+    } else {
+      rv = nghttp2_stream_dep_make_root(stream, &session->ob_pq);
+    }
 
     return rv;
   }
 
   dep_stream = nghttp2_session_get_stream_raw(session, pri_spec->stream_id);
 
-  if(dep_stream == NULL) {
+  if(!dep_stream || !nghttp2_stream_in_dep_tree(dep_stream)) {
     return 0;
   }
 
@@ -711,7 +722,7 @@ nghttp2_stream* nghttp2_session_open_stream(nghttp2_session *session,
   }
 
   nghttp2_stream_init(stream, stream_id, flags, initial_state,
-                      pri_spec->weight,
+                      pri_spec->weight, &session->roots,
                       session->remote_settings
                       [NGHTTP2_SETTINGS_INITIAL_WINDOW_SIZE],
                       session->local_settings
@@ -747,9 +758,29 @@ nghttp2_stream* nghttp2_session_open_stream(nghttp2_session *session,
     return stream;
   }
 
+  if(pri_spec->stream_id == 0) {
+
+    ++session->roots.num_streams;
+
+    if(pri_spec->exclusive &&
+       session->roots.num_streams <= NGHTTP2_MAX_DEP_TREE_LENGTH) {
+      rv = nghttp2_stream_dep_all_your_stream_are_belong_to_us
+        (stream, &session->ob_pq);
+
+      /* Since no dpri is changed in dependency tree, the above
+         function call never fail. */
+      assert(rv == 0);
+    } else {
+      nghttp2_stream_roots_add(&session->roots, stream);
+    }
+
+    return stream;
+  }
+
   dep_stream = nghttp2_session_get_stream_raw(session, pri_spec->stream_id);
 
-  if(!dep_stream) {
+  /* If dep_stream is not part of dependency tree, we don't use it. */
+  if(!dep_stream || !nghttp2_stream_in_dep_tree(dep_stream)) {
     return stream;
   }
 
@@ -831,7 +862,9 @@ int nghttp2_session_close_stream(nghttp2_session *session, int32_t stream_id,
   /* Closes both directions just in case they are not closed yet */
   stream->flags |= NGHTTP2_STREAM_FLAG_CLOSED;
 
-  if(session->server && !nghttp2_session_is_my_stream_id(session, stream_id)) {
+  if(session->server &&
+     nghttp2_stream_in_dep_tree(stream) &&
+     !nghttp2_session_is_my_stream_id(session, stream_id)) {
     /* On server side, retain incoming stream object at most
        MAX_CONCURRENT_STREAMS combined with the current active streams
        to make dependency tree work better. */

lib/nghttp2_session.h

@@ -117,6 +117,7 @@ typedef enum {
 
 struct nghttp2_session {
   nghttp2_map /* <nghttp2_stream*> */ streams;
+  nghttp2_stream_roots roots;
   /* Queue for outbound frames other than stream-creating HEADERS */
   nghttp2_pq /* <nghttp2_outbound_item*> */ ob_pq;
   /* Queue for outbound stream-creating HEADERS frame */

lib/nghttp2_stream.c

@@ -33,6 +33,7 @@ void nghttp2_stream_init(nghttp2_stream *stream, int32_t stream_id,
                          uint8_t flags,
                          nghttp2_stream_state initial_state,
                          int32_t weight,
+                         nghttp2_stream_roots *roots,
                          int32_t remote_initial_window_size,
                          int32_t local_initial_window_size,
                          void *stream_user_data)
@@ -61,6 +62,10 @@ void nghttp2_stream_init(nghttp2_stream *stream, int32_t stream_id,
   stream->weight = weight;
   stream->effective_weight = stream->weight;
   stream->sum_dep_weight = 0;
+
+  stream->roots = roots;
+  stream->root_prev = NULL;
+  stream->root_next = NULL;
 }
 
 void nghttp2_stream_free(nghttp2_stream *stream)
@@ -474,6 +479,8 @@ void nghttp2_stream_dep_insert(nghttp2_stream *dep_stream,
 
   stream_update_dep_length(dep_stream, 1);
   stream_update_dep_effective_weight(dep_stream);
+
+  ++stream->roots->num_streams;
 }
 
 void nghttp2_stream_dep_add(nghttp2_stream *dep_stream,
@@ -502,6 +509,8 @@ void nghttp2_stream_dep_add(nghttp2_stream *dep_stream,
   }
 
   stream_update_dep_effective_weight(dep_stream);
+
+  ++stream->roots->num_streams;
 }
 
 void nghttp2_stream_dep_remove(nghttp2_stream *stream)
@@ -568,6 +577,8 @@ void nghttp2_stream_dep_remove(nghttp2_stream *stream)
       dep_next = NULL;
     }
   } else {
+    nghttp2_stream_roots_remove(stream->roots, stream);
+
     dep_next = NULL;
 
     /* stream is a root of tree.  Removing stream makes its
@@ -583,6 +594,8 @@ void nghttp2_stream_dep_remove(nghttp2_stream *stream)
       /* We already distributed weight of |stream| to this. */
       si->effective_weight = si->weight;
 
+      nghttp2_stream_roots_add(si->roots, si);
+
       si = next;
     }
   }
@@ -606,6 +619,8 @@ void nghttp2_stream_dep_remove(nghttp2_stream *stream)
   stream->dep_next = NULL;
   stream->sib_prev = NULL;
   stream->sib_next = NULL;
+
+  --stream->roots->num_streams;
 }
 
 int nghttp2_stream_dep_insert_subtree(nghttp2_stream *dep_stream,
@@ -748,6 +763,8 @@ void nghttp2_stream_dep_remove_subtree(nghttp2_stream *stream)
     }
 
   } else {
+    nghttp2_stream_roots_remove(stream->roots, stream);
+
     dep_prev = NULL;
   }
 
@@ -771,6 +788,8 @@ int nghttp2_stream_dep_make_root(nghttp2_stream *stream, nghttp2_pq *pq)
   DEBUGF(fprintf(stderr, "stream: dep_make_root stream(%p)=%d\n",
                  stream, stream->stream_id));
 
+  nghttp2_stream_roots_add(stream->roots, stream);
+
   stream_update_dep_set_rest(stream);
 
   stream->effective_weight = stream->weight;
@@ -785,3 +804,141 @@ int nghttp2_stream_dep_make_root(nghttp2_stream *stream, nghttp2_pq *pq)
 
   return 0;
 }
+
+int nghttp2_stream_dep_all_your_stream_are_belong_to_us
+(nghttp2_stream *stream, nghttp2_pq *pq)
+{
+  nghttp2_stream *first, *si;
+
+  DEBUGF(fprintf(stderr, "stream: ALL YOUR STREAM ARE BELONG TO US "
+                 "stream(%p)=%d\n",
+                 stream, stream->stream_id));
+
+  first = stream->roots->head;
+
+  /* stream must not be include in stream->roots->head list */
+  assert(first != stream);
+
+  if(first) {
+    nghttp2_stream *prev;
+
+    prev = first;
+
+    DEBUGF(fprintf(stderr, "stream: root stream(%p)=%d\n",
+                   first, first->stream_id));
+
+    stream->sum_dep_weight += first->weight;
+    stream->num_substreams += first->num_substreams;
+
+    for(si = first->root_next; si; si = si->root_next) {
+
+      assert(si != stream);
+
+      DEBUGF(fprintf(stderr, "stream: root stream(%p)=%d\n",
+                     si, si->stream_id));
+
+      fprintf(stderr, "w=%d, sum=%d\n",
+              si->weight, stream->sum_dep_weight);
+      stream->sum_dep_weight += si->weight;
+      stream->num_substreams += si->num_substreams;
+
+      si->sib_prev = prev;
+      prev->sib_next = si;
+
+      prev = si;
+    }
+
+    if(stream->dep_next) {
+      nghttp2_stream *last_sib;
+
+      last_sib = stream_last_sib(stream->dep_next);
+
+      last_sib->sib_next = first;
+      first->sib_prev = last_sib;
+    } else {
+      stream->dep_next = first;
+      first->dep_prev = stream;
+    }
+  }
+
+  nghttp2_stream_roots_remove_all(stream->roots);
+
+  return nghttp2_stream_dep_make_root(stream, pq);
+}
+
+int nghttp2_stream_in_dep_tree(nghttp2_stream *stream)
+{
+  return stream->dep_prev || stream->dep_next ||
+    stream->sib_prev || stream->sib_next ||
+    stream->root_next || stream->root_prev ||
+    stream->roots->head == stream;
+}
+
+void nghttp2_stream_roots_init(nghttp2_stream_roots *roots)
+{
+  roots->head = NULL;
+  roots->num_streams = 0;
+}
+
+void nghttp2_stream_roots_free(nghttp2_stream_roots *roots)
+{}
+
+void nghttp2_stream_roots_add(nghttp2_stream_roots *roots,
+                              nghttp2_stream *stream)
+{
+  if(roots->head) {
+    nghttp2_stream *si;
+    for(si = roots->head; si; si = si->root_next) {
+      if(si == stream) {
+        assert(0);
+      }
+    }
+
+    stream->root_next = roots->head;
+    roots->head->root_prev = stream;
+  }
+
+  roots->head = stream;
+}
+
+void nghttp2_stream_roots_remove(nghttp2_stream_roots *roots,
+                                 nghttp2_stream *stream)
+{
+  nghttp2_stream *root_prev, *root_next;
+
+  root_prev = stream->root_prev;
+  root_next = stream->root_next;
+
+  if(root_prev) {
+    root_prev->root_next = root_next;
+
+    if(root_next) {
+      root_next->root_prev = root_prev;
+    }
+  } else {
+    if(root_next) {
+      root_next->root_prev = NULL;
+    }
+
+    roots->head = root_next;
+  }
+
+  stream->root_prev = NULL;
+  stream->root_next = NULL;
+}
+
+void nghttp2_stream_roots_remove_all(nghttp2_stream_roots *roots)
+{
+  nghttp2_stream *si, *next;
+
+  for(si = roots->head; si;) {
+    next = si->root_next;
+
+    si->root_prev = NULL;
+    si->root_next = NULL;
+
+    si = next;
+  }
+
+  roots->head = NULL;
+}

lib/nghttp2_stream.h

@@ -102,6 +102,10 @@ typedef enum {
   NGHTTP2_STREAM_DPRI_REST = 0x04
 } nghttp2_stream_dpri;
 
+struct nghttp2_stream_roots;
+
+typedef struct nghttp2_stream_roots nghttp2_stream_roots;
+
 struct nghttp2_stream;
 
 typedef struct nghttp2_stream nghttp2_stream;
@@ -118,11 +122,17 @@ struct nghttp2_stream {
      dep_prev and sib_prev are NULL. */
   nghttp2_stream *dep_prev, *dep_next;
   nghttp2_stream *sib_prev, *sib_next;
+  /* pointers to track dependency tree root streams.  This is
+     doubly-linked list and first element is pointed by
+     roots->head. */
+  nghttp2_stream *root_prev, *root_next;
   /* When stream is kept after closure, it may be kept in single
      linked list pointed by nghttp2_session closed_stream_head.
      closed_next points to the next stream object if it is the element
      of the list. */
   nghttp2_stream *closed_next;
+  /* pointer to roots, which tracks dependency tree roots */
+  nghttp2_stream_roots *roots;
   /* The arbitrary data provided by user for this stream. */
   void *stream_user_data;
   /* DATA frame item */
@@ -165,6 +175,7 @@ void nghttp2_stream_init(nghttp2_stream *stream, int32_t stream_id,
                          uint8_t flags,
                          nghttp2_stream_state initial_state,
                          int32_t weight,
+                         nghttp2_stream_roots *roots,
                          int32_t remote_initial_window_size,
                          int32_t local_initial_window_size,
                          void *stream_user_data);
@@ -380,4 +391,40 @@ void nghttp2_stream_dep_remove_subtree(nghttp2_stream *stream);
  */
 int nghttp2_stream_dep_make_root(nghttp2_stream *stream, nghttp2_pq *pq);
 
+/*
+ * Makes the |stream| as root and all existing root streams become
+ * direct children of |stream|.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGHTTP2_ERR_NOMEM
+ *     Out of memory
+ */
+int nghttp2_stream_dep_all_your_stream_are_belong_to_us
+(nghttp2_stream *stream, nghttp2_pq *pq);
+
+/*
+ * Returns nonzero if |stream| is in any dependency tree.
+ */
+int nghttp2_stream_in_dep_tree(nghttp2_stream *stream);
+
+struct nghttp2_stream_roots {
+  nghttp2_stream *head;
+
+  int32_t num_streams;
+};
+
+void nghttp2_stream_roots_init(nghttp2_stream_roots *roots);
+
+void nghttp2_stream_roots_free(nghttp2_stream_roots *roots);
+
+void nghttp2_stream_roots_add(nghttp2_stream_roots *roots,
+                              nghttp2_stream *stream);
+
+void nghttp2_stream_roots_remove(nghttp2_stream_roots *roots,
+                                 nghttp2_stream *stream);
+
+void nghttp2_stream_roots_remove_all(nghttp2_stream_roots *roots);
+
 #endif /* NGHTTP2_STREAM */

lib/nghttp2_submit.c

@@ -103,10 +103,6 @@ static int nghttp2_submit_headers_shared
 
 static void adjust_priority_spec_weight(nghttp2_priority_spec *pri_spec)
 {
-  if(pri_spec->stream_id == 0) {
-    pri_spec->exclusive = 0;
-  }
-
   if(pri_spec->weight < NGHTTP2_MIN_WEIGHT) {
     pri_spec->weight = NGHTTP2_MIN_WEIGHT;
   } else if(pri_spec->weight > NGHTTP2_MAX_WEIGHT) {

tests/main.c

@@ -222,6 +222,8 @@ int main(int argc, char* argv[])
                    test_nghttp2_session_stream_dep_add_subtree) ||
       !CU_add_test(pSuite, "session_stream_dep_remove_subtree",
                    test_nghttp2_session_stream_dep_remove_subtree) ||
+      !CU_add_test(pSuite, "session_stream_dep_all_your_stream_are_belong_to_us",
+                   test_nghttp2_session_stream_dep_all_your_stream_are_belong_to_us) ||
       !CU_add_test(pSuite, "session_stream_attach_data",
                    test_nghttp2_session_stream_attach_data) ||
       !CU_add_test(pSuite, "session_stream_attach_data_subtree",

tests/nghttp2_session_test.c

@@ -4873,6 +4873,10 @@ void test_nghttp2_session_stream_dep_add(void)
   check_stream_dep_sib(c, NULL, d, b, NULL);
   check_stream_dep_sib(d, c, NULL, NULL, NULL);
 
+  CU_ASSERT(4 == session->roots.num_streams);
+  CU_ASSERT(a == session->roots.head);
+  CU_ASSERT(NULL == a->root_next);
+
   e = open_stream_with_dep_excl(session, 9, a);
 
   /* a
@@ -4902,6 +4906,10 @@ void test_nghttp2_session_stream_dep_add(void)
   check_stream_dep_sib(c, NULL, d, b, NULL);
   check_stream_dep_sib(d, c, NULL, NULL, NULL);
 
+  CU_ASSERT(5 == session->roots.num_streams);
+  CU_ASSERT(a == session->roots.head);
+  CU_ASSERT(NULL == a->root_next);
+
   nghttp2_session_del(session);
 }
 
@@ -4951,6 +4959,11 @@ void test_nghttp2_session_stream_dep_remove(void)
   check_stream_dep_sib(c, NULL, d, NULL, NULL);
   check_stream_dep_sib(d, c, NULL, NULL, NULL);
 
+  CU_ASSERT(3 == session->roots.num_streams);
+  CU_ASSERT(c == session->roots.head);
+  CU_ASSERT(b == c->root_next);
+  CU_ASSERT(NULL == b->root_next);
+
   nghttp2_session_del(session);
 
   /* Remove left most stream */
@@ -4993,6 +5006,10 @@ void test_nghttp2_session_stream_dep_remove(void)
   check_stream_dep_sib(c, a, d, NULL, NULL);
   check_stream_dep_sib(d, c, NULL, NULL, NULL);
 
+  CU_ASSERT(3 == session->roots.num_streams);
+  CU_ASSERT(a == session->roots.head);
+  CU_ASSERT(NULL == a->root_next);
+
   nghttp2_session_del(session);
 
   /* Remove right most stream */
@@ -5348,6 +5365,131 @@ void test_nghttp2_session_stream_dep_remove_subtree(void)
   nghttp2_session_del(session);
 }
 
+void test_nghttp2_session_stream_dep_all_your_stream_are_belong_to_us(void)
+{
+  nghttp2_session *session;
+  nghttp2_session_callbacks callbacks;
+  nghttp2_stream *a, *b, *c, *d;
+
+  memset(&callbacks, 0, sizeof(callbacks));
+
+  nghttp2_session_server_new(&session, &callbacks, NULL);
+
+  a = open_stream(session, 1);
+  b = open_stream_with_dep(session, 3, a);
+
+  c = open_stream(session, 5);
+
+  /* a     c
+   * |
+   * b
+   */
+
+  nghttp2_stream_dep_remove_subtree(c);
+  CU_ASSERT(0 == nghttp2_stream_dep_all_your_stream_are_belong_to_us
+            (c, &session->ob_pq));
+
+  /*
+   * c
+   * |
+   * a
+   * |
+   * b
+   */
+
+  CU_ASSERT(3 == c->num_substreams);
+  CU_ASSERT(2 == a->num_substreams);
+  CU_ASSERT(1 == b->num_substreams);
+
+  CU_ASSERT(NGHTTP2_DEFAULT_WEIGHT == c->sum_dep_weight);
+  CU_ASSERT(NGHTTP2_DEFAULT_WEIGHT == a->sum_dep_weight);
+  CU_ASSERT(0 == b->sum_dep_weight);
+
+  check_stream_dep_sib(c, NULL, a, NULL, NULL);
+  check_stream_dep_sib(a, c, b, NULL, NULL);
+  check_stream_dep_sib(b, a, NULL, NULL, NULL);
+
+  nghttp2_session_del(session);
+
+  nghttp2_session_server_new(&session, &callbacks, NULL);
+
+  a = open_stream(session, 1);
+
+  b = open_stream(session, 3);
+
+  c = open_stream(session, 5);
+
+  /*
+   * a  b   c
+   */
+
+  nghttp2_stream_dep_remove_subtree(c);
+  CU_ASSERT(0 == nghttp2_stream_dep_all_your_stream_are_belong_to_us
+            (c, &session->ob_pq));
+
+  /*
+   * c
+   * |
+   * b--a
+   */
+
+  CU_ASSERT(3 == c->num_substreams);
+  CU_ASSERT(1 == a->num_substreams);
+  CU_ASSERT(1 == b->num_substreams);
+
+  CU_ASSERT(NGHTTP2_DEFAULT_WEIGHT * 2 == c->sum_dep_weight);
+  CU_ASSERT(0 == b->sum_dep_weight);
+  CU_ASSERT(0 == a->sum_dep_weight);
+
+  check_stream_dep_sib(c, NULL, b, NULL, NULL);
+  check_stream_dep_sib(b, c, NULL, NULL, a);
+  check_stream_dep_sib(a, NULL, NULL, b, NULL);
+
+  nghttp2_session_del(session);
+
+  nghttp2_session_server_new(&session, &callbacks, NULL);
+
+  a = open_stream(session, 1);
+  b = open_stream_with_dep(session, 3, a);
+
+  c = open_stream(session, 5);
+  d = open_stream_with_dep(session, 7, c);
+
+  /* a     c
+   * |     |
+   * b     d
+   */
+
+  nghttp2_stream_dep_remove_subtree(c);
+  CU_ASSERT(0 == nghttp2_stream_dep_all_your_stream_are_belong_to_us
+            (c, &session->ob_pq));
+
+  /*
+   * c
+   * |
+   * d--a
+   *    |
+   *    b
+   */
+
+  CU_ASSERT(4 == c->num_substreams);
+  CU_ASSERT(1 == d->num_substreams);
+  CU_ASSERT(2 == a->num_substreams);
+  CU_ASSERT(1 == b->num_substreams);
+
+  CU_ASSERT(NGHTTP2_DEFAULT_WEIGHT * 2 == c->sum_dep_weight);
+  CU_ASSERT(0 == d->sum_dep_weight);
+  CU_ASSERT(NGHTTP2_DEFAULT_WEIGHT == a->sum_dep_weight);
+  CU_ASSERT(0 == b->sum_dep_weight);
+
+  check_stream_dep_sib(c, NULL, d, NULL, NULL);
+  check_stream_dep_sib(d, c, NULL, NULL, a);
+  check_stream_dep_sib(a, NULL, b, d, NULL);
+  check_stream_dep_sib(b, a, NULL, NULL, NULL);
+
+  nghttp2_session_del(session);
+}
+
 static nghttp2_outbound_item* create_data_ob_item(void)
 {
   nghttp2_outbound_item *item;
@@ -5488,6 +5630,7 @@ void test_nghttp2_session_stream_attach_data_subtree(void)
 
   /* Insert subtree e under a */
 
+  nghttp2_stream_dep_remove_subtree(e);
   nghttp2_stream_dep_insert_subtree(a, e, &session->ob_pq);
 
   /*
@@ -5570,6 +5713,7 @@ void test_nghttp2_session_stream_attach_data_subtree(void)
 
   /* Add subtree c to a */
 
+  nghttp2_stream_dep_remove_subtree(c);
   nghttp2_stream_dep_add_subtree(a, c, &session->ob_pq);
 
   /*
@@ -5589,6 +5733,7 @@ void test_nghttp2_session_stream_attach_data_subtree(void)
 
   /* Insert b under a */
 
+  nghttp2_stream_dep_remove_subtree(b);
   nghttp2_stream_dep_insert_subtree(a, b, &session->ob_pq);
 
   /*
@@ -5608,21 +5753,10 @@ void test_nghttp2_session_stream_attach_data_subtree(void)
   CU_ASSERT(NGHTTP2_STREAM_DPRI_REST == e->dpri);
   CU_ASSERT(NGHTTP2_STREAM_DPRI_NO_DATA == f->dpri);
 
-  nghttp2_stream_dep_make_root(a, &session->ob_pq);
-
-  /*
-   * a
-   * |
-   * b
-   * |
-   * e--c
-   * |  |
-   * f  d
-   */
-
   /* Remove subtree b */
 
   nghttp2_stream_dep_remove_subtree(b);
+  nghttp2_stream_dep_make_root(b, &session->ob_pq);
 
   /*
    * b       a
@@ -5870,6 +6004,58 @@ void test_nghttp2_session_stream_dep_effective_weight(void)
   CU_ASSERT(16 * 4 / 20 == d->effective_weight);
 
   nghttp2_session_del(session);
+
+  nghttp2_session_server_new(&session, &callbacks, NULL);
+
+  a = open_stream(session, 1);
+  b = open_stream_with_dep_weight(session, 3, 8, a);
+  c = open_stream_with_dep_weight(session, 5, 4, a);
+  d = open_stream_with_dep_weight(session, 7, 1, c);
+
+  e = open_stream(session, 9);
+  f = open_stream_with_dep_weight(session, 11, 12, e);
+
+  /* a      e
+   * |      |
+   * b--c   f
+   *    |
+   *    d
+   */
+
+  CU_ASSERT(e->roots->head == e);
+  CU_ASSERT(a == e->root_next);
+
+  /* Insert e under stream 0 */
+  nghttp2_stream_dep_remove_subtree(e);
+
+  CU_ASSERT(a == e->roots->head);
+
+  CU_ASSERT(0 == nghttp2_stream_dep_all_your_stream_are_belong_to_us
+            (e, &session->ob_pq));
+
+  /* e
+   * |
+   * f--a
+   *    |
+   *    b--c
+   *       |
+   *       d
+   */
+
+  CU_ASSERT(6 == e->num_substreams);
+  CU_ASSERT(28 == e->sum_dep_weight);
+
+  CU_ASSERT(16 == e->effective_weight);
+
+  CU_ASSERT(16 * 16 / 28 == a->effective_weight);
+  CU_ASSERT(16 * 12 / 28 == f->effective_weight);
+
+  CU_ASSERT((16 * 16 / 28) * 8 / 12 == b->effective_weight);
+  CU_ASSERT((16 * 16 / 28) * 4 / 12 == c->effective_weight);
+
+  CU_ASSERT((16 * 16 / 28) * 4 / 12 == d->effective_weight);
+
+  nghttp2_session_del(session);
 }
 
 void test_nghttp2_session_keep_closed_stream(void)

tests/nghttp2_session_test.h

@@ -103,6 +103,7 @@ void test_nghttp2_session_stream_dep_add(void);
 void test_nghttp2_session_stream_dep_remove(void);
 void test_nghttp2_session_stream_dep_add_subtree(void);
 void test_nghttp2_session_stream_dep_remove_subtree(void);
+void test_nghttp2_session_stream_dep_all_your_stream_are_belong_to_us(void);
 void test_nghttp2_session_stream_attach_data(void);
 void test_nghttp2_session_stream_attach_data_subtree(void);
 void test_nghttp2_session_stream_dep_effective_weight(void);