1 files changed, 39 insertions, 16 deletions

diff --git a/thirdparty/harfbuzz/src/hb-serialize.hh b/thirdparty/harfbuzz/src/hb-serialize.hh
index d22ae06087..823c0be8b5 100644
--- a/thirdparty/harfbuzz/src/hb-serialize.hh
+++ b/thirdparty/harfbuzz/src/hb-serialize.hh
@@ -65,19 +65,26 @@ struct hb_serialize_context_t
 
   struct object_t
   {
-    void fini () { links.fini (); }
+    void fini () {
+      real_links.fini ();
+      virtual_links.fini ();
+    }
 
     bool operator == (const object_t &o) const
     {
+      // Virtual links aren't considered for equality since they don't affect the functionality
+      // of the object.
       return (tail - head == o.tail - o.head)
-	  && (links.length == o.links.length)
+	  && (real_links.length == o.real_links.length)
 	  && 0 == hb_memcmp (head, o.head, tail - head)
-	  && links.as_bytes () == o.links.as_bytes ();
+	  && real_links.as_bytes () == o.real_links.as_bytes ();
     }
     uint32_t hash () const
     {
+      // Virtual links aren't considered for equality since they don't affect the functionality
+      // of the object.
       return hb_bytes_t (head, tail - head).hash () ^
-	     links.as_bytes ().hash ();
+          real_links.as_bytes ().hash ();
     }
 
     struct link_t
@@ -92,8 +99,14 @@ struct hb_serialize_context_t
 
     char *head;
     char *tail;
-    hb_vector_t<link_t> links;
+    hb_vector_t<link_t> real_links;
+    hb_vector_t<link_t> virtual_links;
     object_t *next;
+
+    auto all_links () const HB_AUTO_RETURN
+        (( hb_concat (this->real_links, this->virtual_links) ));
+    auto all_links_writer () HB_AUTO_RETURN
+        (( hb_concat (this->real_links.writer (), this->virtual_links.writer ()) ));
   };
 
   struct snapshot_t
@@ -101,12 +114,14 @@ struct hb_serialize_context_t
     char *head;
     char *tail;
     object_t *current; // Just for sanity check
-    unsigned num_links;
+    unsigned num_real_links;
+    unsigned num_virtual_links;
     hb_serialize_error_t errors;
   };
 
   snapshot_t snapshot ()
-  { return snapshot_t { head, tail, current, current->links.length, errors }; }
+  { return snapshot_t {
+      head, tail, current, current->real_links.length, current->virtual_links.length, errors }; }
 
   hb_serialize_context_t (void *start_, unsigned int size) :
     start ((char *) start_),
@@ -282,7 +297,8 @@ struct hb_serialize_context_t
 
     if (!len)
     {
-      assert (!obj->links.length);
+      assert (!obj->real_links.length);
+      assert (!obj->virtual_links.length);
       return 0;
     }
 
@@ -292,6 +308,7 @@ struct hb_serialize_context_t
       objidx = packed_map.get (obj);
       if (objidx)
       {
+        merge_virtual_links (obj, objidx);
 	obj->fini ();
 	return objidx;
       }
@@ -327,7 +344,8 @@ struct hb_serialize_context_t
     // Overflows that happened after the snapshot will be erased by the revert.
     if (unlikely (in_error () && !only_overflow ())) return;
     assert (snap.current == current);
-    current->links.shrink (snap.num_links);
+    current->real_links.shrink (snap.num_real_links);
+    current->virtual_links.shrink (snap.num_virtual_links);
     errors = snap.errors;
     revert (snap.head, snap.tail);
   }
@@ -375,8 +393,8 @@ struct hb_serialize_context_t
 
     assert (current);
 
-    auto& link = *current->links.push ();
-    if (current->links.in_error ())
+    auto& link = *current->virtual_links.push ();
+    if (current->virtual_links.in_error ())
       err (HB_SERIALIZE_ERROR_OTHER);
 
     link.width = 0;
@@ -400,8 +418,8 @@ struct hb_serialize_context_t
     assert (current);
     assert (current->head <= (const char *) &ofs);
 
-    auto& link = *current->links.push ();
-    if (current->links.in_error ())
+    auto& link = *current->real_links.push ();
+    if (current->real_links.in_error ())
       err (HB_SERIALIZE_ERROR_OTHER);
 
     link.width = sizeof (T);
@@ -440,10 +458,8 @@ struct hb_serialize_context_t
     assert (packed.length > 1);
 
     for (const object_t* parent : ++hb_iter (packed))
-      for (const object_t::link_t &link : parent->links)
+      for (const object_t::link_t &link : parent->real_links)
       {
-        if (unlikely (!link.width)) continue; // Don't need to resolve virtual offsets
-
 	const object_t* child = packed[link.objidx];
 	if (unlikely (!child)) { err (HB_SERIALIZE_ERROR_OTHER); return; }
 	unsigned offset = 0;
@@ -642,6 +658,13 @@ struct hb_serialize_context_t
 
   private:
 
+  void merge_virtual_links (const object_t* from, objidx_t to_idx) {
+    object_t* to = packed[to_idx];
+    for (const auto& l : from->virtual_links) {
+      to->virtual_links.push (l);
+    }
+  }
+
   /* Object memory pool. */
   hb_pool_t<object_t> object_pool;