Add hb_blob_ptr_t

Use in a couple of places.  Push to bots to see how many unhappy before
I convert the rest.

src/hb-blob.hh

@@ -80,4 +80,27 @@ struct hb_blob_t
 DECLARE_NULL_INSTANCE (hb_blob_t);
 
 
+/*
+ * hb_blob_ptr_t
+ */
+
+template <typename P>
+struct hb_blob_ptr_t
+{
+  typedef typename hb_remove_pointer<P>::value T;
+
+  inline hb_blob_ptr_t (hb_blob_t *b_ = nullptr) : b (b_) {}
+  inline hb_blob_t * operator = (hb_blob_t *b_) { return b = b_; }
+  inline const T * operator -> (void) const { return get (); }
+  inline const T & operator * (void) const { return *get (); }
+  template <typename C> inline operator const C * (void) const { return get (); }
+  inline operator const char * (void) const { return (const char *) get (); }
+  inline const T * get (void) const { return b->as<T> (); }
+  inline hb_blob_t * get_blob (void) const { return b.get_raw (); }
+  inline unsigned int get_length (void) const { return get_blob ()->length; }
+
+  hb_nonnull_ptr_t<hb_blob_t> b;
+};
+
+
 #endif /* HB_BLOB_HH */

src/hb-ot-layout-gdef-table.hh

@@ -412,11 +412,10 @@ struct GDEF
 
     inline void fini (void)
     {
-      hb_blob_destroy (this->blob);
+      hb_blob_destroy (this->table.get_blob ());
     }
 
-    hb_blob_t *blob;
-    hb_nonnull_ptr_t<const GDEF> table;
+    hb_blob_ptr_t<GDEF> table;
   };
 
   inline unsigned int get_size (void) const

src/hb-ot-layout-gsubgpos.hh

@@ -2752,8 +2752,7 @@ struct GSUBGPOS
   {
     inline void init (hb_face_t *face)
     {
-      this->blob = hb_sanitize_context_t().reference_table<T> (face);
-      table = this->blob->template as<T> ();
+      this->table = hb_sanitize_context_t().reference_table<T> (face);
 
       this->lookup_count = table->get_lookup_count ();
 
@@ -2770,11 +2769,10 @@ struct GSUBGPOS
       for (unsigned int i = 0; i < this->lookup_count; i++)
 	this->accels[i].fini ();
       free (this->accels);
-      hb_blob_destroy (this->blob);
+      hb_blob_destroy (this->table.get_blob ());
     }
 
-    hb_blob_t *blob;
-    hb_nonnull_ptr_t<const T> table;
+    hb_blob_ptr_t<T> table;
     unsigned int lookup_count;
     hb_ot_layout_lookup_accelerator_t *accels;
   };

src/hb-ot-layout.cc

@@ -194,17 +194,15 @@ _hb_ot_blacklist_gdef (unsigned int gdef_len,
 void
 OT::GDEF::accelerator_t::init (hb_face_t *face)
 {
-  this->blob = hb_sanitize_context_t().reference_table<GDEF> (face);
+  this->table = hb_sanitize_context_t().reference_table<GDEF> (face);
 
-  if (unlikely (_hb_ot_blacklist_gdef (this->blob->length,
-				       face->table.GSUB->blob->length,
-				       face->table.GPOS->blob->length)))
+  if (unlikely (_hb_ot_blacklist_gdef (this->table.get_length (),
+				       face->table.GSUB->table.get_length (),
+				       face->table.GPOS->table.get_length ())))
   {
-    hb_blob_destroy (this->blob);
-    this->blob = hb_blob_get_empty ();
+    hb_blob_destroy (this->table.get_blob ());
+    this->table = hb_blob_get_empty ();
   }
-
-  table = this->blob->as<GDEF> ();
 }
 
 static void

src/hb-ot-name-table.hh

@@ -179,11 +179,10 @@ struct name
   {
     inline void init (hb_face_t *face)
     {
-      this->blob = hb_sanitize_context_t().reference_table<name> (face);
-      this->table = this->blob->as<name> ();
-      assert (this->blob->length >= this->table->stringOffset);
+      this->table = hb_sanitize_context_t().reference_table<name> (face);
+      assert (this->table.get_length () >= this->table->stringOffset);
       this->pool = (this->table+this->table->stringOffset).arrayZ;
-      this->pool_len = this->blob->length - this->table->stringOffset;
+      this->pool_len = this->table.get_length () - this->table->stringOffset;
       const hb_array_t<const NameRecord> all_names (this->table->nameRecordZ.arrayZ,
 						    this->table->count);
 
@@ -221,7 +220,7 @@ struct name
     inline void fini (void)
     {
       this->names.fini ();
-      hb_blob_destroy (this->blob);
+      hb_blob_destroy (this->table.get_blob ());
     }
 
     inline int get_index (hb_ot_name_id_t   name_id,
@@ -253,11 +252,10 @@ struct name
     }
 
     private:
-    hb_blob_t *blob;
     const void *pool;
     unsigned int pool_len;
     public:
-    hb_nonnull_ptr_t<const name> table;
+    hb_blob_ptr_t<name> table;
     hb_vector_t<hb_ot_name_entry_t> names;
   };