1 files changed, 46 insertions, 18 deletions

diff --git a/thirdparty/harfbuzz/src/hb-serialize.hh b/thirdparty/harfbuzz/src/hb-serialize.hh
index f47cde5eb5..d5573281f1 100644
--- a/thirdparty/harfbuzz/src/hb-serialize.hh
+++ b/thirdparty/harfbuzz/src/hb-serialize.hh
@@ -194,7 +194,6 @@ struct hb_serialize_context_t
       current = current->next;
       _->fini ();
     }
-    object_pool.fini ();
   }
 
   bool in_error () const { return bool (errors); }
@@ -224,6 +223,7 @@ struct hb_serialize_context_t
     this->errors = HB_SERIALIZE_ERROR_NONE;
     this->head = this->start;
     this->tail = this->end;
+    this->zerocopy = nullptr;
     this->debug_depth = 0;
 
     fini ();
@@ -326,7 +326,8 @@ struct hb_serialize_context_t
     if (unlikely (in_error() && !only_overflow ())) return;
 
     current = current->next;
-    revert (obj->head, obj->tail);
+    revert (zerocopy ? zerocopy : obj->head, obj->tail);
+    zerocopy = nullptr;
     obj->fini ();
     object_pool.release (obj);
   }
@@ -344,8 +345,11 @@ struct hb_serialize_context_t
     current = current->next;
     obj->tail = head;
     obj->next = nullptr;
+    assert (obj->head <= obj->tail);
     unsigned len = obj->tail - obj->head;
-    head = obj->head; /* Rewind head. */
+    head = zerocopy ? zerocopy : obj->head; /* Rewind head. */
+    bool was_zerocopy = zerocopy;
+    zerocopy = nullptr;
 
     if (!len)
     {
@@ -355,9 +359,11 @@ struct hb_serialize_context_t
     }
 
     objidx_t objidx;
+    uint32_t hash = 0;
     if (share)
     {
-      objidx = packed_map.get (obj);
+      hash = hb_hash (obj);
+      objidx = packed_map.get_with_hash (obj, hash);
       if (objidx)
       {
         merge_virtual_links (obj, objidx);
@@ -367,7 +373,10 @@ struct hb_serialize_context_t
     }
 
     tail -= len;
-    memmove (tail, obj->head, len);
+    if (was_zerocopy)
+      assert (tail == obj->head);
+    else
+      memmove (tail, obj->head, len);
 
     obj->head = tail;
     obj->tail = tail + len;
@@ -385,7 +394,7 @@ struct hb_serialize_context_t
 
     objidx = packed.length - 1;
 
-    if (share) packed_map.set (obj, objidx);
+    if (share) packed_map.set_with_hash (obj, hash, objidx);
     propagate_error (packed_map);
 
     return objidx;
@@ -569,8 +578,26 @@ struct hb_serialize_context_t
     return !bool ((errors = (errors | err_type)));
   }
 
+  bool start_zerocopy (size_t size)
+  {
+    if (unlikely (in_error ())) return false;
+
+    if (unlikely (size > INT_MAX || this->tail - this->head < ptrdiff_t (size)))
+    {
+      err (HB_SERIALIZE_ERROR_OUT_OF_ROOM);
+      return false;
+    }
+
+    assert (!this->zerocopy);
+    this->zerocopy = this->head;
+
+    assert (this->current->head == this->head);
+    this->current->head = this->current->tail = this->head = this->tail - size;
+    return true;
+  }
+
   template <typename Type>
-  Type *allocate_size (size_t size)
+  Type *allocate_size (size_t size, bool clear = true)
   {
     if (unlikely (in_error ())) return nullptr;
 
@@ -579,7 +606,8 @@ struct hb_serialize_context_t
       err (HB_SERIALIZE_ERROR_OUT_OF_ROOM);
       return nullptr;
     }
-    hb_memset (this->head, 0, size);
+    if (clear)
+      hb_memset (this->head, 0, size);
     char *ret = this->head;
     this->head += size;
     return reinterpret_cast<Type *> (ret);
@@ -593,9 +621,9 @@ struct hb_serialize_context_t
   Type *embed (const Type *obj)
   {
     unsigned int size = obj->get_size ();
-    Type *ret = this->allocate_size<Type> (size);
+    Type *ret = this->allocate_size<Type> (size, false);
     if (unlikely (!ret)) return nullptr;
-    memcpy (ret, obj, size);
+    hb_memcpy (ret, obj, size);
     return ret;
   }
   template <typename Type>
@@ -616,7 +644,7 @@ struct hb_serialize_context_t
   }
 
   /* Like embed, but active: calls obj.operator=() or obj.copy() to transfer data
-   * instead of memcpy(). */
+   * instead of hb_memcpy(). */
   template <typename Type, typename ...Ts>
   Type *copy (const Type &src, Ts&&... ds)
   { return _copy (src, hb_prioritize, std::forward<Ts> (ds)...); }
@@ -634,7 +662,7 @@ struct hb_serialize_context_t
   hb_serialize_context_t& operator << (const Type &obj) & { embed (obj); return *this; }
 
   template <typename Type>
-  Type *extend_size (Type *obj, size_t size)
+  Type *extend_size (Type *obj, size_t size, bool clear = true)
   {
     if (unlikely (in_error ())) return nullptr;
 
@@ -642,12 +670,12 @@ struct hb_serialize_context_t
     assert ((char *) obj <= this->head);
     assert ((size_t) (this->head - (char *) obj) <= size);
     if (unlikely (((char *) obj + size < (char *) obj) ||
-		  !this->allocate_size<Type> (((char *) obj) + size - this->head))) return nullptr;
+		  !this->allocate_size<Type> (((char *) obj) + size - this->head, clear))) return nullptr;
     return reinterpret_cast<Type *> (obj);
   }
   template <typename Type>
-  Type *extend_size (Type &obj, size_t size)
-  { return extend_size (std::addressof (obj), size); }
+  Type *extend_size (Type &obj, size_t size, bool clear = true)
+  { return extend_size (std::addressof (obj), size, clear); }
 
   template <typename Type>
   Type *extend_min (Type *obj) { return extend_size (obj, obj->min_size); }
@@ -676,8 +704,8 @@ struct hb_serialize_context_t
     char *p = (char *) hb_malloc (len);
     if (unlikely (!p)) return hb_bytes_t ();
 
-    memcpy (p, this->start, this->head - this->start);
-    memcpy (p + (this->head - this->start), this->tail, this->end - this->tail);
+    hb_memcpy (p, this->start, this->head - this->start);
+    hb_memcpy (p + (this->head - this->start), this->tail, this->end - this->tail);
     return hb_bytes_t (p, len);
   }
   template <typename Type>
@@ -704,7 +732,7 @@ struct hb_serialize_context_t
   }
 
   public:
-  char *start, *head, *tail, *end;
+  char *start, *head, *tail, *end, *zerocopy;
   unsigned int debug_depth;
   hb_serialize_error_t errors;