diff --git a/src/dump-emoji.cc b/src/dump-emoji.cc
index 19c0618..47c6c98 100644
--- a/src/dump-emoji.cc
+++ b/src/dump-emoji.cc
@@ -240,11 +240,11 @@
 
   OT::Sanitizer<OT::COLR> sanitizerCOLR;
   hb_blob_t* colr_blob = sanitizerCOLR.sanitize (face->reference_table (HB_OT_TAG_COLR));
-  const OT::COLR *colr = OT::Sanitizer<OT::COLR>::lock_instance (colr_blob);
+  const OT::COLR *colr = colr_blob->lock_as<OT::COLR> ();
 
   OT::Sanitizer<OT::CPAL> sanitizerCPAL;
   hb_blob_t* cpal_blob = sanitizerCPAL.sanitize (face->reference_table (HB_OT_TAG_CPAL));
-  const OT::CPAL *cpal = OT::Sanitizer<OT::CPAL>::lock_instance (cpal_blob);
+  const OT::CPAL *cpal = cpal_blob->lock_as<OT::CPAL> ();
 
   cairo_font_face_t *cairo_face;
   {
diff --git a/src/dump-fon.cc b/src/dump-fon.cc
index 7e1fef6..dc45d9c 100644
--- a/src/dump-fon.cc
+++ b/src/dump-fon.cc
@@ -542,8 +542,7 @@
 
   OT::Sanitizer<LE_IMAGE_DOS_HEADER> sanitizer;
   hb_blob_t *font_blob = sanitizer.sanitize (blob);
-  const LE_IMAGE_DOS_HEADER* dos_header =
-    OT::Sanitizer<LE_IMAGE_DOS_HEADER>::lock_instance (font_blob);
+  const LE_IMAGE_DOS_HEADER* dos_header = font_blob->lock_as<LE_IMAGE_DOS_HEADER> ();
 
   const NE_RESOURCE_TABLE &rtable = dos_header->get_os2_header ().get_resource_table ();
   int shift = rtable.get_shift_value ();
diff --git a/src/hb-aat-layout.cc b/src/hb-aat-layout.cc
index 18743e3..e6efaab 100644
--- a/src/hb-aat-layout.cc
+++ b/src/hb-aat-layout.cc
@@ -118,11 +118,11 @@
 //   OT::Sanitizer<AAT::morx> sanitizer;
 //   sanitizer.set_num_glyphs (face->get_num_glyphs ());
 //   hb_blob_t *morx_blob = sanitizer.sanitize (face->reference_table (HB_AAT_TAG_morx));
-//   OT::Sanitizer<AAT::morx>::lock_instance (morx_blob);
+//   morx_blob->lock_as<AAT::morx> ();
 
 //   if (0)
 //   {
-//     OT::Sanitizer<AAT::Lookup<OT::GlyphID> >::lock_instance (morx_blob)->get_value (1, face->get_num_glyphs ());
+//     morx_blob->lock_as<AAT::Lookup<OT::GlyphID> > ()->get_value (1, face->get_num_glyphs ());
 //   }
 // }
 
diff --git a/src/hb-blob-private.hh b/src/hb-blob-private.hh
index 0d567c2..f564351 100644
--- a/src/hb-blob-private.hh
+++ b/src/hb-blob-private.hh
@@ -59,6 +59,23 @@
   HB_INTERNAL bool try_make_writable_inplace (void);
   HB_INTERNAL bool try_make_writable_inplace_unix (void);
 
+  inline void lock (void)
+  {
+    hb_blob_make_immutable (this);
+  }
+
+  template <typename Type>
+  inline const Type* as (void) const
+  {
+    return unlikely (!data) ? &Null(Type) : reinterpret_cast<const Type *> (data);
+  }
+  template <typename Type>
+  inline const Type* lock_as (void)
+  {
+    lock ();
+    return unlikely (!data) ? &Null(Type) : reinterpret_cast<const Type *> (data);
+  }
+
   public:
   hb_object_header_t header;
   ASSERT_POD ();
diff --git a/src/hb-face.cc b/src/hb-face.cc
index d8af8c1..9fc40d4 100644
--- a/src/hb-face.cc
+++ b/src/hb-face.cc
@@ -29,6 +29,7 @@
 #include "hb-private.hh"
 
 #include "hb-face-private.hh"
+#include "hb-blob-private.hh"
 #include "hb-open-file-private.hh"
 #include "hb-ot-head-table.hh"
 #include "hb-ot-maxp-table.hh"
@@ -134,7 +135,7 @@
   if (tag == HB_TAG_NONE)
     return hb_blob_reference (data->blob);
 
-  const OT::OpenTypeFontFile &ot_file = *OT::Sanitizer<OT::OpenTypeFontFile>::lock_instance (data->blob);
+  const OT::OpenTypeFontFile &ot_file = *data->blob->lock_as<OT::OpenTypeFontFile> ();
   const OT::OpenTypeFontFace &ot_face = ot_file.get_face (data->index);
 
   const OT::OpenTypeTable &table = ot_face.get_table_by_tag (tag);
@@ -425,7 +426,7 @@
 hb_face_t::load_upem (void) const
 {
   hb_blob_t *head_blob = OT::Sanitizer<OT::head>().sanitize (reference_table (HB_OT_TAG_head));
-  const OT::head *head_table = OT::Sanitizer<OT::head>::lock_instance (head_blob);
+  const OT::head *head_table = head_blob->lock_as<OT::head> ();
   upem = head_table->get_upem ();
   hb_blob_destroy (head_blob);
 }
@@ -469,7 +470,7 @@
 hb_face_t::load_num_glyphs (void) const
 {
   hb_blob_t *maxp_blob = OT::Sanitizer<OT::maxp>().sanitize (reference_table (HB_OT_TAG_maxp));
-  const OT::maxp *maxp_table = OT::Sanitizer<OT::maxp>::lock_instance (maxp_blob);
+  const OT::maxp *maxp_table = maxp_blob->lock_as<OT::maxp> ();
   num_glyphs = maxp_table->get_num_glyphs ();
   hb_blob_destroy (maxp_blob);
 }
@@ -499,7 +500,7 @@
 
   hb_face_for_data_closure_t *data = (hb_face_for_data_closure_t *) face->user_data;
 
-  const OT::OpenTypeFontFile &ot_file = *OT::Sanitizer<OT::OpenTypeFontFile>::lock_instance (data->blob);
+  const OT::OpenTypeFontFile &ot_file = *data->blob->lock_as<OT::OpenTypeFontFile> ();
   const OT::OpenTypeFontFace &ot_face = ot_file.get_face (data->index);
 
   return ot_face.get_table_tags (start_offset, table_count, table_tags);
diff --git a/src/hb-open-type-private.hh b/src/hb-open-type-private.hh
index 68e0e41..9f07b3f 100644
--- a/src/hb-open-type-private.hh
+++ b/src/hb-open-type-private.hh
@@ -31,6 +31,7 @@
 
 #include "hb-private.hh"
 #include "hb-debug.hh"
+#include "hb-blob-private.hh"
 #include "hb-face-private.hh"
 
 
@@ -350,12 +351,6 @@
     }
   }
 
-  static const Type* lock_instance (hb_blob_t *blob) {
-    hb_blob_make_immutable (blob);
-    const char *base = hb_blob_get_data (blob, nullptr);
-    return unlikely (!base) ? &Null(Type) : CastP<Type> (base);
-  }
-
   inline void set_num_glyphs (unsigned int num_glyphs) { c->num_glyphs = num_glyphs; }
 
   private:
@@ -1255,7 +1250,7 @@
     if (unlikely (!p))
     {
       hb_blob_t *blob_ = OT::Sanitizer<T>().sanitize (face->reference_table (T::tableTag));
-      p = const_cast<T *>(OT::Sanitizer<T>::lock_instance (blob_));
+      p = const_cast<T *>(blob_->lock_as<T> ());
       if (!hb_atomic_ptr_cmpexch (const_cast<T **>(&instance), nullptr, p))
       {
 	hb_blob_destroy (blob_);
diff --git a/src/hb-ot-cmap-table.hh b/src/hb-ot-cmap-table.hh
index caffda3..438063e 100644
--- a/src/hb-ot-cmap-table.hh
+++ b/src/hb-ot-cmap-table.hh
@@ -661,7 +661,7 @@
     inline void init (hb_face_t *face)
     {
       this->blob = OT::Sanitizer<OT::cmap>().sanitize (face->reference_table (HB_OT_TAG_cmap));
-      const OT::cmap *cmap = OT::Sanitizer<OT::cmap>::lock_instance (this->blob);
+      const OT::cmap *cmap = this->blob->lock_as<OT::cmap> ();
       const OT::CmapSubtable *subtable = nullptr;
       const OT::CmapSubtableFormat14 *subtable_uvs = nullptr;
 
diff --git a/src/hb-ot-color-cbdt-table.hh b/src/hb-ot-color-cbdt-table.hh
index 528d144..52364ff 100644
--- a/src/hb-ot-color-cbdt-table.hh
+++ b/src/hb-ot-color-cbdt-table.hh
@@ -403,8 +403,8 @@
 	cbdt = nullptr;
 	return;  /* Not a bitmap font. */
       }
-      cblc = Sanitizer<CBLC>::lock_instance (cblc_blob);
-      cbdt = Sanitizer<CBDT>::lock_instance (cbdt_blob);
+      cblc = cblc_blob->lock_as<CBLC> ();
+      cbdt = cbdt_blob->lock_as<CBDT> ();
 
     }
 
diff --git a/src/hb-ot-color-sbix-table.hh b/src/hb-ot-color-sbix-table.hh
index 09d0cc5..17d6c73 100644
--- a/src/hb-ot-color-sbix-table.hh
+++ b/src/hb-ot-color-sbix-table.hh
@@ -102,7 +102,7 @@
       sanitizer.set_num_glyphs (num_glyphs);
       sbix_blob = sanitizer.sanitize (face->reference_table (HB_OT_TAG_sbix));
       sbix_len = hb_blob_get_length (sbix_blob);
-      sbix_table = OT::Sanitizer<OT::sbix>::lock_instance (sbix_blob);
+      sbix_table = sbix_blob->lock_as<OT::sbix> ();
 
     }
 
diff --git a/src/hb-ot-color-svg-table.hh b/src/hb-ot-color-svg-table.hh
index 47b3292..ccf4b9c 100644
--- a/src/hb-ot-color-svg-table.hh
+++ b/src/hb-ot-color-svg-table.hh
@@ -99,7 +99,7 @@
       OT::Sanitizer<OT::SVG> sanitizer;
       svg_blob = sanitizer.sanitize (face->reference_table (HB_OT_TAG_SVG));
       svg_len = hb_blob_get_length (svg_blob);
-      svg = OT::Sanitizer<OT::SVG>::lock_instance (svg_blob);
+      svg = svg_blob->lock_as<OT::SVG> ();
 
     }
 
diff --git a/src/hb-ot-glyf-table.hh b/src/hb-ot-glyf-table.hh
index 4b02153..0716968 100644
--- a/src/hb-ot-glyf-table.hh
+++ b/src/hb-ot-glyf-table.hh
@@ -237,7 +237,7 @@
       memset (this, 0, sizeof (accelerator_t));
 
       hb_blob_t *head_blob = Sanitizer<head>().sanitize (face->reference_table (HB_OT_TAG_head));
-      const head *head_table = Sanitizer<head>::lock_instance (head_blob);
+      const head *head_table = head_blob->lock_as<head> ();
       if (head_table == &Null(head) || (unsigned int) head_table->indexToLocFormat > 1 || head_table->glyphDataFormat != 0)
       {
 	/* head table is not present, or in an unknown format.  Leave num_glyphs=0, that takes care of disabling us. */
@@ -248,9 +248,9 @@
       hb_blob_destroy (head_blob);
 
       loca_blob = Sanitizer<loca>().sanitize (face->reference_table (HB_OT_TAG_loca));
-      loca_table = Sanitizer<loca>::lock_instance (loca_blob);
+      loca_table = loca_blob->lock_as<loca> ();
       glyf_blob = Sanitizer<glyf>().sanitize (face->reference_table (HB_OT_TAG_glyf));
-      glyf_table = Sanitizer<glyf>::lock_instance (glyf_blob);
+      glyf_table = glyf_blob->lock_as<glyf> ();
 
       num_glyphs = MAX (1u, hb_blob_get_length (loca_blob) / (short_offset ? 2 : 4)) - 1;
       glyf_len = hb_blob_get_length (glyf_blob);
diff --git a/src/hb-ot-hmtx-table.hh b/src/hb-ot-hmtx-table.hh
index 5944688..02419a8 100644
--- a/src/hb-ot-hmtx-table.hh
+++ b/src/hb-ot-hmtx-table.hh
@@ -196,7 +196,7 @@
       if (T::os2Tag)
       {
 	hb_blob_t *os2_blob = Sanitizer<os2> ().sanitize (face->reference_table (T::os2Tag));
-	const os2 *os2_table = Sanitizer<os2>::lock_instance (os2_blob);
+	const os2 *os2_table = os2_blob->lock_as<os2> ();
 #define USE_TYPO_METRICS (1u<<7)
 	if (0 != (os2_table->fsSelection & USE_TYPO_METRICS))
 	{
@@ -209,7 +209,7 @@
       }
 
       hb_blob_t *_hea_blob = Sanitizer<H> ().sanitize (face->reference_table (H::tableTag));
-      const H *_hea_table = Sanitizer<H>::lock_instance (_hea_blob);
+      const H *_hea_table = _hea_blob->lock_as<H> ();
       num_advances = _hea_table->numberOfLongMetrics;
       if (!got_font_extents)
       {
@@ -238,10 +238,10 @@
 	hb_blob_destroy (blob);
 	blob = hb_blob_get_empty ();
       }
-      table = Sanitizer<hmtxvmtx>::lock_instance (blob);
+      table = blob->lock_as<hmtxvmtx> ();
 
       var_blob = Sanitizer<HVARVVAR> ().sanitize (face->reference_table (T::variationsTag));
-      var_table = Sanitizer<HVARVVAR>::lock_instance (var_blob);
+      var_table = var_blob->lock_as<HVARVVAR> ();
     }
 
     inline void fini (void)
diff --git a/src/hb-ot-kern-table.hh b/src/hb-ot-kern-table.hh
index ec33169..71b368a 100644
--- a/src/hb-ot-kern-table.hh
+++ b/src/hb-ot-kern-table.hh
@@ -363,7 +363,7 @@
     inline void init (hb_face_t *face)
     {
       blob = Sanitizer<kern>().sanitize (face->reference_table (HB_OT_TAG_kern));
-      table = Sanitizer<kern>::lock_instance (blob);
+      table = blob->lock_as<kern> ();
       table_length = hb_blob_get_length (blob);
     }
     inline void fini (void)
diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc
index 5ee03dc..a4673fc 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -59,13 +59,13 @@
     return nullptr;
 
   layout->gdef_blob = OT::Sanitizer<OT::GDEF>().sanitize (face->reference_table (HB_OT_TAG_GDEF));
-  layout->gdef = OT::Sanitizer<OT::GDEF>::lock_instance (layout->gdef_blob);
+  layout->gdef = layout->gdef_blob->lock_as<OT::GDEF> ();
 
   layout->gsub_blob = OT::Sanitizer<OT::GSUB>().sanitize (face->reference_table (HB_OT_TAG_GSUB));
-  layout->gsub = OT::Sanitizer<OT::GSUB>::lock_instance (layout->gsub_blob);
+  layout->gsub = layout->gsub_blob->lock_as<OT::GSUB> ();
 
   layout->gpos_blob = OT::Sanitizer<OT::GPOS>().sanitize (face->reference_table (HB_OT_TAG_GPOS));
-  layout->gpos = OT::Sanitizer<OT::GPOS>::lock_instance (layout->gpos_blob);
+  layout->gpos = layout->gpos_blob->lock_as<OT::GPOS> ();
 
   layout->math.init (face);
   layout->fvar.init (face);
diff --git a/src/hb-ot-post-table.hh b/src/hb-ot-post-table.hh
index 63aa83a..d1793d3 100644
--- a/src/hb-ot-post-table.hh
+++ b/src/hb-ot-post-table.hh
@@ -110,7 +110,7 @@
     inline void init (hb_face_t *face)
     {
       blob = Sanitizer<post>().sanitize (face->reference_table (HB_OT_TAG_post));
-      const post *table = Sanitizer<post>::lock_instance (blob);
+      const post *table = blob->lock_as<post> ();
       unsigned int table_length = hb_blob_get_length (blob);
 
       version = table->version.to_int ();
diff --git a/src/hb-subset.cc b/src/hb-subset.cc
index 6c3d759..bca5677 100644
--- a/src/hb-subset.cc
+++ b/src/hb-subset.cc
@@ -87,7 +87,7 @@
   OT::Sanitizer<TableType> sanitizer;
 
   hb_blob_t *source_blob = sanitizer.sanitize (plan->source->reference_table (TableType::tableTag));
-  const TableType *table = OT::Sanitizer<TableType>::lock_instance (source_blob);
+  const TableType *table = source_blob->lock_as<TableType> ();
 
   hb_tag_t tag = TableType::tableTag;
   hb_bool_t result = false;
diff --git a/src/main.cc b/src/main.cc
index 0436c85..2976c89 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -56,7 +56,7 @@
 
   Sanitizer<OpenTypeFontFile> sanitizer;
   hb_blob_t *font_blob = sanitizer.sanitize (blob);
-  const OpenTypeFontFile* sanitized = Sanitizer<OpenTypeFontFile>::lock_instance (font_blob);
+  const OpenTypeFontFile* sanitized = font_blob->lock_as<OpenTypeFontFile> ();
   if (sanitized == &Null (OpenTypeFontFile))
   {
     printf ("Sanitization of the file wasn't successful. Exit");