[HarfBuzz] harfbuzz: Branch 'master' - 6 commits

Behdad Esfahbod behdad at kemper.freedesktop.org
Tue May 8 09:48:34 UTC 2018


 src/dump-emoji.cc                  |   10 ++---
 src/dump-fon.cc                    |   17 ++++-----
 src/hb-aat-layout.cc               |   12 +++----
 src/hb-blob-private.hh             |   11 ++++++
 src/hb-face.cc                     |    9 ++---
 src/hb-object-private.hh           |   36 ++++++++++++++++-----
 src/hb-open-type-private.hh        |   63 +++++--------------------------------
 src/hb-ot-cmap-table.hh            |    6 +--
 src/hb-ot-color-cbdt-table.hh      |    4 +-
 src/hb-ot-color-sbix-table.hh      |    2 -
 src/hb-ot-color-svg-table.hh       |    2 -
 src/hb-ot-color.cc                 |    4 +-
 src/hb-ot-glyf-table.hh            |    6 +--
 src/hb-ot-hmtx-table.hh            |    8 ++--
 src/hb-ot-kern-table.hh            |    2 -
 src/hb-ot-layout-common-private.hh |   13 +++++--
 src/hb-ot-layout.cc                |   28 ++++++++--------
 src/hb-ot-math.cc                  |    4 +-
 src/hb-ot-post-table.hh            |   18 +++++-----
 src/hb-ot-var.cc                   |    6 +--
 src/hb-private.hh                  |   43 +++++++++++++++++++++----
 src/hb-string-array.hh             |    6 +--
 src/hb-subset.cc                   |    6 +--
 src/main.cc                        |    4 +-
 24 files changed, 172 insertions(+), 148 deletions(-)

New commits:
commit eba1c16a604d1be774f22541bf3e417f27a27c68
Author: Behdad Esfahbod <behdad at behdad.org>
Date:   Tue May 8 02:47:42 2018 -0700

    Always lock blob in sanitize. Remove blob->lock_as() in favor of blob->lock()

diff --git a/src/dump-emoji.cc b/src/dump-emoji.cc
index 47c6c98b..63af4a6a 100644
--- a/src/dump-emoji.cc
+++ b/src/dump-emoji.cc
@@ -240,11 +240,11 @@ int main (int argc, char **argv)
 
   OT::Sanitizer<OT::COLR> sanitizerCOLR;
   hb_blob_t* colr_blob = sanitizerCOLR.sanitize (face->reference_table (HB_OT_TAG_COLR));
-  const OT::COLR *colr = colr_blob->lock_as<OT::COLR> ();
+  const OT::COLR *colr = colr_blob->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 = cpal_blob->lock_as<OT::CPAL> ();
+  const OT::CPAL *cpal = cpal_blob->as<OT::CPAL> ();
 
   cairo_font_face_t *cairo_face;
   {
diff --git a/src/dump-fon.cc b/src/dump-fon.cc
index dc45d9c4..81525f42 100644
--- a/src/dump-fon.cc
+++ b/src/dump-fon.cc
@@ -542,7 +542,7 @@ int main (int argc, char** argv) {
 
   OT::Sanitizer<LE_IMAGE_DOS_HEADER> sanitizer;
   hb_blob_t *font_blob = sanitizer.sanitize (blob);
-  const LE_IMAGE_DOS_HEADER* dos_header = font_blob->lock_as<LE_IMAGE_DOS_HEADER> ();
+  const LE_IMAGE_DOS_HEADER* dos_header = font_blob->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 e6efaab4..7784fae3 100644
--- a/src/hb-aat-layout.cc
+++ b/src/hb-aat-layout.cc
@@ -118,11 +118,11 @@ _get_trak (hb_face_t *face, hb_blob_t **blob = nullptr)
 //   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));
-//   morx_blob->lock_as<AAT::morx> ();
+//   morx_blob->as<AAT::morx> ();
 
 //   if (0)
 //   {
-//     morx_blob->lock_as<AAT::Lookup<OT::GlyphID> > ()->get_value (1, face->get_num_glyphs ());
+//     morx_blob->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 f564351a..b72fa721 100644
--- a/src/hb-blob-private.hh
+++ b/src/hb-blob-private.hh
@@ -69,12 +69,6 @@ struct hb_blob_t
   {
     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;
diff --git a/src/hb-face.cc b/src/hb-face.cc
index 9fc40d48..01271413 100644
--- a/src/hb-face.cc
+++ b/src/hb-face.cc
@@ -135,7 +135,7 @@ _hb_face_for_data_reference_table (hb_face_t *face HB_UNUSED, hb_tag_t tag, void
   if (tag == HB_TAG_NONE)
     return hb_blob_reference (data->blob);
 
-  const OT::OpenTypeFontFile &ot_file = *data->blob->lock_as<OT::OpenTypeFontFile> ();
+  const OT::OpenTypeFontFile &ot_file = *data->blob->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);
@@ -426,7 +426,7 @@ void
 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 = head_blob->lock_as<OT::head> ();
+  const OT::head *head_table = head_blob->as<OT::head> ();
   upem = head_table->get_upem ();
   hb_blob_destroy (head_blob);
 }
@@ -470,7 +470,7 @@ void
 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 = maxp_blob->lock_as<OT::maxp> ();
+  const OT::maxp *maxp_table = maxp_blob->as<OT::maxp> ();
   num_glyphs = maxp_table->get_num_glyphs ();
   hb_blob_destroy (maxp_blob);
 }
@@ -500,7 +500,7 @@ hb_face_get_table_tags (hb_face_t    *face,
 
   hb_face_for_data_closure_t *data = (hb_face_for_data_closure_t *) face->user_data;
 
-  const OT::OpenTypeFontFile &ot_file = *data->blob->lock_as<OT::OpenTypeFontFile> ();
+  const OT::OpenTypeFontFile &ot_file = *data->blob->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 9f07b3f5..8bc74169 100644
--- a/src/hb-open-type-private.hh
+++ b/src/hb-open-type-private.hh
@@ -344,8 +344,12 @@ struct Sanitizer
 
     DEBUG_MSG_FUNC (SANITIZE, c->start, sane ? "PASSED" : "FAILED");
     if (sane)
+    {
+      blob->lock ();
       return blob;
-    else {
+    }
+    else
+    {
       hb_blob_destroy (blob);
       return hb_blob_get_empty ();
     }
@@ -1250,7 +1254,7 @@ struct hb_lazy_table_loader_t
     if (unlikely (!p))
     {
       hb_blob_t *blob_ = OT::Sanitizer<T>().sanitize (face->reference_table (T::tableTag));
-      p = const_cast<T *>(blob_->lock_as<T> ());
+      p = const_cast<T *>(blob_->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 438063e0..950a0ee1 100644
--- a/src/hb-ot-cmap-table.hh
+++ b/src/hb-ot-cmap-table.hh
@@ -661,7 +661,7 @@ struct cmap
     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 = this->blob->lock_as<OT::cmap> ();
+      const OT::cmap *cmap = this->blob->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 52364ff7..f4207f2d 100644
--- a/src/hb-ot-color-cbdt-table.hh
+++ b/src/hb-ot-color-cbdt-table.hh
@@ -403,8 +403,8 @@ struct CBDT
 	cbdt = nullptr;
 	return;  /* Not a bitmap font. */
       }
-      cblc = cblc_blob->lock_as<CBLC> ();
-      cbdt = cbdt_blob->lock_as<CBDT> ();
+      cblc = cblc_blob->as<CBLC> ();
+      cbdt = cbdt_blob->as<CBDT> ();
 
     }
 
diff --git a/src/hb-ot-color-sbix-table.hh b/src/hb-ot-color-sbix-table.hh
index 17d6c730..09a9517c 100644
--- a/src/hb-ot-color-sbix-table.hh
+++ b/src/hb-ot-color-sbix-table.hh
@@ -102,7 +102,7 @@ struct sbix
       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 = sbix_blob->lock_as<OT::sbix> ();
+      sbix_table = sbix_blob->as<OT::sbix> ();
 
     }
 
diff --git a/src/hb-ot-color-svg-table.hh b/src/hb-ot-color-svg-table.hh
index ccf4b9c4..ed6cf970 100644
--- a/src/hb-ot-color-svg-table.hh
+++ b/src/hb-ot-color-svg-table.hh
@@ -99,7 +99,7 @@ struct SVG
       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 = svg_blob->lock_as<OT::SVG> ();
+      svg = svg_blob->as<OT::SVG> ();
 
     }
 
diff --git a/src/hb-ot-glyf-table.hh b/src/hb-ot-glyf-table.hh
index 07169687..8c2bfd09 100644
--- a/src/hb-ot-glyf-table.hh
+++ b/src/hb-ot-glyf-table.hh
@@ -237,7 +237,7 @@ struct glyf
       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 = head_blob->lock_as<head> ();
+      const head *head_table = head_blob->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 @@ struct glyf
       hb_blob_destroy (head_blob);
 
       loca_blob = Sanitizer<loca>().sanitize (face->reference_table (HB_OT_TAG_loca));
-      loca_table = loca_blob->lock_as<loca> ();
+      loca_table = loca_blob->as<loca> ();
       glyf_blob = Sanitizer<glyf>().sanitize (face->reference_table (HB_OT_TAG_glyf));
-      glyf_table = glyf_blob->lock_as<glyf> ();
+      glyf_table = glyf_blob->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 02419a88..c07763e6 100644
--- a/src/hb-ot-hmtx-table.hh
+++ b/src/hb-ot-hmtx-table.hh
@@ -196,7 +196,7 @@ struct hmtxvmtx
       if (T::os2Tag)
       {
 	hb_blob_t *os2_blob = Sanitizer<os2> ().sanitize (face->reference_table (T::os2Tag));
-	const os2 *os2_table = os2_blob->lock_as<os2> ();
+	const os2 *os2_table = os2_blob->as<os2> ();
 #define USE_TYPO_METRICS (1u<<7)
 	if (0 != (os2_table->fsSelection & USE_TYPO_METRICS))
 	{
@@ -209,7 +209,7 @@ struct hmtxvmtx
       }
 
       hb_blob_t *_hea_blob = Sanitizer<H> ().sanitize (face->reference_table (H::tableTag));
-      const H *_hea_table = _hea_blob->lock_as<H> ();
+      const H *_hea_table = _hea_blob->as<H> ();
       num_advances = _hea_table->numberOfLongMetrics;
       if (!got_font_extents)
       {
@@ -238,10 +238,10 @@ struct hmtxvmtx
 	hb_blob_destroy (blob);
 	blob = hb_blob_get_empty ();
       }
-      table = blob->lock_as<hmtxvmtx> ();
+      table = blob->as<hmtxvmtx> ();
 
       var_blob = Sanitizer<HVARVVAR> ().sanitize (face->reference_table (T::variationsTag));
-      var_table = var_blob->lock_as<HVARVVAR> ();
+      var_table = var_blob->as<HVARVVAR> ();
     }
 
     inline void fini (void)
diff --git a/src/hb-ot-kern-table.hh b/src/hb-ot-kern-table.hh
index 71b368a8..9366dbf4 100644
--- a/src/hb-ot-kern-table.hh
+++ b/src/hb-ot-kern-table.hh
@@ -363,7 +363,7 @@ struct kern
     inline void init (hb_face_t *face)
     {
       blob = Sanitizer<kern>().sanitize (face->reference_table (HB_OT_TAG_kern));
-      table = blob->lock_as<kern> ();
+      table = blob->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 a4673fc5..d5efde29 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -59,13 +59,13 @@ _hb_ot_layout_create (hb_face_t *face)
     return nullptr;
 
   layout->gdef_blob = OT::Sanitizer<OT::GDEF>().sanitize (face->reference_table (HB_OT_TAG_GDEF));
-  layout->gdef = layout->gdef_blob->lock_as<OT::GDEF> ();
+  layout->gdef = layout->gdef_blob->as<OT::GDEF> ();
 
   layout->gsub_blob = OT::Sanitizer<OT::GSUB>().sanitize (face->reference_table (HB_OT_TAG_GSUB));
-  layout->gsub = layout->gsub_blob->lock_as<OT::GSUB> ();
+  layout->gsub = layout->gsub_blob->as<OT::GSUB> ();
 
   layout->gpos_blob = OT::Sanitizer<OT::GPOS>().sanitize (face->reference_table (HB_OT_TAG_GPOS));
-  layout->gpos = layout->gpos_blob->lock_as<OT::GPOS> ();
+  layout->gpos = layout->gpos_blob->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 d1793d35..bb5f9b31 100644
--- a/src/hb-ot-post-table.hh
+++ b/src/hb-ot-post-table.hh
@@ -110,7 +110,7 @@ struct post
     inline void init (hb_face_t *face)
     {
       blob = Sanitizer<post>().sanitize (face->reference_table (HB_OT_TAG_post));
-      const post *table = blob->lock_as<post> ();
+      const post *table = blob->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 bca56770..d6295a48 100644
--- a/src/hb-subset.cc
+++ b/src/hb-subset.cc
@@ -87,7 +87,7 @@ _subset (hb_subset_plan_t *plan)
   OT::Sanitizer<TableType> sanitizer;
 
   hb_blob_t *source_blob = sanitizer.sanitize (plan->source->reference_table (TableType::tableTag));
-  const TableType *table = source_blob->lock_as<TableType> ();
+  const TableType *table = source_blob->as<TableType> ();
 
   hb_tag_t tag = TableType::tableTag;
   hb_bool_t result = false;
diff --git a/src/main.cc b/src/main.cc
index 2976c895..9a187366 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -56,7 +56,7 @@ main (int argc, char **argv)
 
   Sanitizer<OpenTypeFontFile> sanitizer;
   hb_blob_t *font_blob = sanitizer.sanitize (blob);
-  const OpenTypeFontFile* sanitized = font_blob->lock_as<OpenTypeFontFile> ();
+  const OpenTypeFontFile* sanitized = font_blob->as<OpenTypeFontFile> ();
   if (sanitized == &Null (OpenTypeFontFile))
   {
     printf ("Sanitization of the file wasn't successful. Exit");
commit b4fa50501414b7471e840f2ee6b9dfe87080b078
Author: Behdad Esfahbod <behdad at behdad.org>
Date:   Tue May 8 02:45:08 2018 -0700

    Move Sanitizer::lock_instance<>() to blob->lock_as<>().

diff --git a/src/dump-emoji.cc b/src/dump-emoji.cc
index 19c06183..47c6c98b 100644
--- a/src/dump-emoji.cc
+++ b/src/dump-emoji.cc
@@ -240,11 +240,11 @@ int main (int argc, char **argv)
 
   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 7e1fef61..dc45d9c4 100644
--- a/src/dump-fon.cc
+++ b/src/dump-fon.cc
@@ -542,8 +542,7 @@ int main (int argc, char** argv) {
 
   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 18743e3c..e6efaab4 100644
--- a/src/hb-aat-layout.cc
+++ b/src/hb-aat-layout.cc
@@ -118,11 +118,11 @@ _get_trak (hb_face_t *face, hb_blob_t **blob = nullptr)
 //   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 0d567c28..f564351a 100644
--- a/src/hb-blob-private.hh
+++ b/src/hb-blob-private.hh
@@ -59,6 +59,23 @@ struct hb_blob_t
   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 d8af8c1f..9fc40d48 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 @@ _hb_face_for_data_reference_table (hb_face_t *face HB_UNUSED, hb_tag_t tag, void
   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 @@ void
 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 @@ void
 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_get_table_tags (hb_face_t    *face,
 
   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 68e0e410..9f07b3f5 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 @@ struct Sanitizer
     }
   }
 
-  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 @@ struct hb_lazy_table_loader_t
     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 caffda35..438063e0 100644
--- a/src/hb-ot-cmap-table.hh
+++ b/src/hb-ot-cmap-table.hh
@@ -661,7 +661,7 @@ struct cmap
     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 528d144a..52364ff7 100644
--- a/src/hb-ot-color-cbdt-table.hh
+++ b/src/hb-ot-color-cbdt-table.hh
@@ -403,8 +403,8 @@ struct CBDT
 	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 09d0cc57..17d6c730 100644
--- a/src/hb-ot-color-sbix-table.hh
+++ b/src/hb-ot-color-sbix-table.hh
@@ -102,7 +102,7 @@ struct sbix
       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 47b3292b..ccf4b9c4 100644
--- a/src/hb-ot-color-svg-table.hh
+++ b/src/hb-ot-color-svg-table.hh
@@ -99,7 +99,7 @@ struct SVG
       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 4b02153c..07169687 100644
--- a/src/hb-ot-glyf-table.hh
+++ b/src/hb-ot-glyf-table.hh
@@ -237,7 +237,7 @@ struct glyf
       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 @@ struct glyf
       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 5944688a..02419a88 100644
--- a/src/hb-ot-hmtx-table.hh
+++ b/src/hb-ot-hmtx-table.hh
@@ -196,7 +196,7 @@ struct hmtxvmtx
       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 @@ struct hmtxvmtx
       }
 
       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 @@ struct hmtxvmtx
 	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 ec331698..71b368a8 100644
--- a/src/hb-ot-kern-table.hh
+++ b/src/hb-ot-kern-table.hh
@@ -363,7 +363,7 @@ struct kern
     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 5ee03dc8..a4673fc5 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -59,13 +59,13 @@ _hb_ot_layout_create (hb_face_t *face)
     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 63aa83ad..d1793d35 100644
--- a/src/hb-ot-post-table.hh
+++ b/src/hb-ot-post-table.hh
@@ -110,7 +110,7 @@ struct post
     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 6c3d7591..bca56770 100644
--- a/src/hb-subset.cc
+++ b/src/hb-subset.cc
@@ -87,7 +87,7 @@ _subset (hb_subset_plan_t *plan)
   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 0436c85f..2976c895 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -56,7 +56,7 @@ main (int argc, char **argv)
 
   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");
commit abc12f7b8157c3981216d82ead60627db31a6c14
Author: Behdad Esfahbod <behdad at behdad.org>
Date:   Tue May 8 02:23:36 2018 -0700

    Move null pool to hb-private

diff --git a/src/dump-emoji.cc b/src/dump-emoji.cc
index e173a5ee..19c06183 100644
--- a/src/dump-emoji.cc
+++ b/src/dump-emoji.cc
@@ -47,7 +47,7 @@
 #include <stdio.h>
 
 #ifndef HB_NO_VISIBILITY
-const void * const OT::_hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
+const void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 #endif
 
 void cbdt_callback (const uint8_t* data, unsigned int length,
@@ -91,7 +91,7 @@ void svg_callback (const uint8_t* data, unsigned int length,
 void colr_cpal_rendering (cairo_font_face_t *cairo_face, unsigned int upem, unsigned int num_glyphs,
 			  const OT::COLR *colr, const OT::CPAL *cpal)
 {
-  for (int i = 0; i < num_glyphs; ++i)
+  for (unsigned int i = 0; i < num_glyphs; ++i)
   {
     unsigned int first_layer_index, num_layers;
     if (colr->get_base_glyph_record (i, &first_layer_index, &num_layers))
@@ -171,7 +171,7 @@ void dump_glyphs (cairo_font_face_t *cairo_face, unsigned int upem, unsigned int
 {
   // Dump every glyph available on the font
   return; // disabled for now
-  for (int i = 0; i < num_glyphs; ++i)
+  for (unsigned int i = 0; i < num_glyphs; ++i)
   {
     cairo_text_extents_t extents;
     cairo_glyph_t glyph = {0};
diff --git a/src/dump-fon.cc b/src/dump-fon.cc
index 1d18983c..7e1fef61 100644
--- a/src/dump-fon.cc
+++ b/src/dump-fon.cc
@@ -27,7 +27,7 @@
 #include "hb-open-type-private.hh"
 
 #ifndef HB_NO_VISIBILITY
-const void * const OT::_hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
+const void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 #endif
 
 template <typename Type, int Bytes> struct LEInt;
@@ -344,7 +344,7 @@ struct NE_TYPEINFO
   {
     const NE_TYPEINFO& next = OT::StructAfter<NE_TYPEINFO> (*this);
     if (type_id == 0)
-      return OT::Null (NE_TYPEINFO);
+      return Null (NE_TYPEINFO);
     return next;
   }
 
@@ -352,7 +352,7 @@ struct NE_TYPEINFO
   {
     if (idx < count)
       return resources[idx].get_font (base, shift);
-    return OT::Null (LE_FONTINFO16);
+    return Null (LE_FONTINFO16);
   }
 
   inline unsigned int get_count () const
@@ -401,7 +401,7 @@ struct NE_RESOURCE_TABLE
       return_trace (false);
 
     const NE_TYPEINFO* n = &chain;
-    while (n != &OT::Null (NE_TYPEINFO) && c->check_struct (n) && n->get_type_id () != 0)
+    while (n != &Null (NE_TYPEINFO) && c->check_struct (n) && n->get_type_id () != 0)
     {
       if (n->get_type_id () == NE_TYPEINFO::FONT)
 	return_trace (n->sanitize (c, base, alignmentShiftCount));
@@ -418,13 +418,13 @@ struct NE_RESOURCE_TABLE
   inline const NE_TYPEINFO& get_fonts_entry () const
   {
     const NE_TYPEINFO* n = &chain;
-    while (n != &OT::Null (NE_TYPEINFO) && n->get_type_id () != 0)
+    while (n != &Null (NE_TYPEINFO) && n->get_type_id () != 0)
     {
       if (n->get_type_id () == NE_TYPEINFO::FONT)
 	return *n;
       n = &n->next();
     }
-    return OT::Null (NE_TYPEINFO);
+    return Null (NE_TYPEINFO);
   }
 
   protected:
@@ -447,7 +447,7 @@ struct LE_IMAGE_OS2_HEADER
   inline const NE_RESOURCE_TABLE& get_resource_table () const
   {
     if (magic != 0x454E) // Only NE containers are support for now, NE == 0x454E
-      return OT::Null (NE_RESOURCE_TABLE);
+      return Null (NE_RESOURCE_TABLE);
     return this+rsrctab;
   }
 
diff --git a/src/hb-aat-layout.cc b/src/hb-aat-layout.cc
index 7bd60272..18743e3c 100644
--- a/src/hb-aat-layout.cc
+++ b/src/hb-aat-layout.cc
@@ -52,7 +52,7 @@ _get_ankr (hb_face_t *face, hb_blob_t **blob = nullptr)
   {
     if (blob)
       *blob = hb_blob_get_empty ();
-    return OT::Null(AAT::ankr);
+    return Null(AAT::ankr);
   }
   hb_ot_layout_t * layout = hb_ot_layout_from_face (face);
   const AAT::ankr& ankr = *(layout->ankr.get ());
@@ -68,7 +68,7 @@ _get_kerx (hb_face_t *face, hb_blob_t **blob = nullptr)
   {
     if (blob)
       *blob = hb_blob_get_empty ();
-    return OT::Null(AAT::kerx);
+    return Null(AAT::kerx);
   }
   hb_ot_layout_t * layout = hb_ot_layout_from_face (face);
   /* XXX this doesn't call set_num_glyphs on sanitizer. */
@@ -85,7 +85,7 @@ _get_morx (hb_face_t *face, hb_blob_t **blob = nullptr)
   {
     if (blob)
       *blob = hb_blob_get_empty ();
-    return OT::Null(AAT::morx);
+    return Null(AAT::morx);
   }
   hb_ot_layout_t * layout = hb_ot_layout_from_face (face);
   /* XXX this doesn't call set_num_glyphs on sanitizer. */
@@ -102,7 +102,7 @@ _get_trak (hb_face_t *face, hb_blob_t **blob = nullptr)
   {
     if (blob)
       *blob = hb_blob_get_empty ();
-    return OT::Null(AAT::trak);
+    return Null(AAT::trak);
   }
   hb_ot_layout_t * layout = hb_ot_layout_from_face (face);
   const AAT::trak& trak = *(layout->trak.get ());
diff --git a/src/hb-open-type-private.hh b/src/hb-open-type-private.hh
index 1f22b182..68e0e410 100644
--- a/src/hb-open-type-private.hh
+++ b/src/hb-open-type-private.hh
@@ -127,46 +127,6 @@ static inline Type& StructAfter(TObject &X)
 
 
 /*
- * Null objects
- */
-
-/* Global nul-content Null pool.  Enlarge as necessary. */
-
-#define HB_NULL_POOL_SIZE 264
-static_assert (HB_NULL_POOL_SIZE % sizeof (void *) == 0, "Align HB_NULL_POOL_SIZE.");
-
-#ifdef HB_NO_VISIBILITY
-static
-#else
-extern HB_INTERNAL
-#endif
-const void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)]
-#ifdef HB_NO_VISIBILITY
-= {}
-#endif
-;
-
-/* Generic nul-content Null objects. */
-template <typename Type>
-static inline const Type& Null (void) {
-  static_assert (sizeof (Type) <= HB_NULL_POOL_SIZE, "Increase HB_NULL_POOL_SIZE.");
-  return *CastP<Type> (_hb_NullPool);
-}
-
-/* Specializaiton for arbitrary-content arbitrary-sized Null objects. */
-#define DEFINE_NULL_DATA(Type, data) \
-static const char _Null##Type[sizeof (Type) + 1] = data; /* +1 is for nul-termination in data */ \
-template <> \
-/*static*/ inline const Type& Null<Type> (void) { \
-  return *CastP<Type> (_Null##Type); \
-} /* The following line really exists such that we end in a place needing semicolon */ \
-static_assert (Type::min_size + 1 <= sizeof (_Null##Type), "Null pool too small.  Enlarge.")
-
-/* Accessor macro. */
-#define Null(Type) Null<Type>()
-
-
-/*
  * Dispatch
  */
 
@@ -726,7 +686,6 @@ struct Tag : HBUINT32
   public:
   DEFINE_SIZE_STATIC (4);
 };
-DEFINE_NULL_DATA (Tag, "    ");
 
 /* Glyph index number, same as uint16 (length = 16 bits) */
 typedef HBUINT16 GlyphID;
@@ -738,7 +697,6 @@ typedef HBUINT16 NameID;
 struct Index : HBUINT16 {
   static const unsigned int NOT_FOUND_INDEX = 0xFFFFu;
 };
-DEFINE_NULL_DATA (Index, "\xff\xff");
 
 /* Offset, Null offset = 0 */
 template <typename Type>
@@ -1236,7 +1194,7 @@ struct hb_lazy_loader_t
 
   inline void fini (void)
   {
-    if (instance && instance != &OT::Null(T))
+    if (instance && instance != &Null(T))
     {
       instance->fini();
       free (instance);
@@ -1251,12 +1209,12 @@ struct hb_lazy_loader_t
     {
       p = (T *) calloc (1, sizeof (T));
       if (unlikely (!p))
-        p = const_cast<T *> (&OT::Null(T));
+        p = const_cast<T *> (&Null(T));
       else
 	p->init (face);
       if (unlikely (!hb_atomic_ptr_cmpexch (const_cast<T **>(&instance), nullptr, p)))
       {
-	if (p != &OT::Null(T))
+	if (p != &Null(T))
 	  p->fini ();
 	goto retry;
       }
diff --git a/src/hb-ot-cmap-table.hh b/src/hb-ot-cmap-table.hh
index 83a0b519..caffda35 100644
--- a/src/hb-ot-cmap-table.hh
+++ b/src/hb-ot-cmap-table.hh
@@ -682,7 +682,7 @@ struct cmap
 	if (subtable) symbol = true;
       }
       /* Meh. */
-      if (!subtable) subtable = &OT::Null(OT::CmapSubtable);
+      if (!subtable) subtable = &Null(OT::CmapSubtable);
 
       /* UVS subtable. */
       if (!subtable_uvs)
@@ -692,7 +692,7 @@ struct cmap
 	  subtable_uvs = &st->u.format14;
       }
       /* Meh. */
-      if (!subtable_uvs) subtable_uvs = &OT::Null(OT::CmapSubtableFormat14);
+      if (!subtable_uvs) subtable_uvs = &Null(OT::CmapSubtableFormat14);
 
       this->uvs_table = subtable_uvs;
 
diff --git a/src/hb-ot-color.cc b/src/hb-ot-color.cc
index ceebe0b7..86171c63 100644
--- a/src/hb-ot-color.cc
+++ b/src/hb-ot-color.cc
@@ -44,7 +44,7 @@ HB_MARK_AS_FLAG_T (hb_ot_color_palette_flags_t)
 static inline const OT::COLR&
 _get_colr (hb_face_t *face)
 {
-  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::COLR);
+  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return Null(OT::COLR);
   hb_ot_layout_t * layout = hb_ot_layout_from_face (face);
   return *(layout->colr.get ());
 }
@@ -52,7 +52,7 @@ _get_colr (hb_face_t *face)
 static inline const OT::CPAL&
 _get_cpal (hb_face_t *face)
 {
-  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::CPAL);
+  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return Null(OT::CPAL);
   hb_ot_layout_t * layout = hb_ot_layout_from_face (face);
   return *(layout->cpal.get ());
 }
diff --git a/src/hb-ot-layout-common-private.hh b/src/hb-ot-layout-common-private.hh
index bd193f9d..bec694e1 100644
--- a/src/hb-ot-layout-common-private.hh
+++ b/src/hb-ot-layout-common-private.hh
@@ -165,7 +165,6 @@ struct RangeRecord
   public:
   DEFINE_SIZE_STATIC (6);
 };
-DEFINE_NULL_DATA (RangeRecord, "\000\001");
 
 
 struct IndexArray : ArrayOf<Index>
@@ -225,7 +224,6 @@ struct LangSys
   public:
   DEFINE_SIZE_ARRAY (6, featureIndex);
 };
-DEFINE_NULL_DATA (LangSys, "\0\0\xFF\xFF");
 
 
 struct Script
@@ -247,7 +245,16 @@ struct Script
   { return langSys.find_index (tag, index); }
 
   inline bool has_default_lang_sys (void) const { return defaultLangSys != 0; }
-  inline const LangSys& get_default_lang_sys (void) const { return this+defaultLangSys; }
+  inline const LangSys& get_default_lang_sys (void) const
+  {
+    if (!defaultLangSys)
+    {
+      /* This is the ONLY place where our null data is not all zeros.
+       * So, return special data instead of using the null pool. */
+      return *reinterpret_cast<const LangSys *> ("\0\0\xFF\xFF");
+    }
+    return this+defaultLangSys;
+  }
 
   inline bool sanitize (hb_sanitize_context_t *c,
 			const Record<Script>::sanitize_closure_t * = nullptr) const
diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc
index f7e49648..5ee03dc8 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -47,7 +47,7 @@
 
 
 #ifndef HB_NO_VISIBILITY
-const void * const OT::_hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
+const void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 #endif
 
 
@@ -102,7 +102,7 @@ _hb_ot_layout_create (hb_face_t *face)
        * https://lists.freedesktop.org/archives/harfbuzz/2016-February/005489.html
        */
      if (3 == layout->gdef->get_glyph_class (5))
-       layout->gdef = &OT::Null(OT::GDEF);
+       layout->gdef = &Null(OT::GDEF);
     }
     else if (0
       /* sha1sum:96eda93f7d33e79962451c6c39a6b51ee893ce8c  tahoma.ttf from Windows 8 */
@@ -174,7 +174,7 @@ _hb_ot_layout_create (hb_face_t *face)
        *     https://bugzilla.mozilla.org/show_bug.cgi?id=1279693
        *     https://bugzilla.mozilla.org/show_bug.cgi?id=1279875
        */
-      layout->gdef = &OT::Null(OT::GDEF);
+      layout->gdef = &Null(OT::GDEF);
     }
   }
 
@@ -226,7 +226,7 @@ _hb_ot_layout_destroy (hb_ot_layout_t *layout)
 // static inline const OT::BASE&
 // _get_base (hb_face_t *face)
 // {
-//   if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::BASE);
+//   if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return Null(OT::BASE);
 //   hb_ot_layout_t * layout = hb_ot_layout_from_face (face);
 //   return *(layout->base.get ());
 // }
@@ -234,19 +234,19 @@ _hb_ot_layout_destroy (hb_ot_layout_t *layout)
 static inline const OT::GDEF&
 _get_gdef (hb_face_t *face)
 {
-  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::GDEF);
+  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return Null(OT::GDEF);
   return *hb_ot_layout_from_face (face)->gdef;
 }
 static inline const OT::GSUB&
 _get_gsub (hb_face_t *face)
 {
-  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::GSUB);
+  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return Null(OT::GSUB);
   return *hb_ot_layout_from_face (face)->gsub;
 }
 static inline const OT::GPOS&
 _get_gpos (hb_face_t *face)
 {
-  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::GPOS);
+  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return Null(OT::GPOS);
   return *hb_ot_layout_from_face (face)->gpos;
 }
 
@@ -318,7 +318,7 @@ get_gsubgpos_table (hb_face_t *face,
   switch (table_tag) {
     case HB_OT_TAG_GSUB: return _get_gsub (face);
     case HB_OT_TAG_GPOS: return _get_gpos (face);
-    default:             return OT::Null(OT::GSUBGPOS);
+    default:             return Null(OT::GSUBGPOS);
   }
 }
 
@@ -898,7 +898,7 @@ hb_ot_layout_feature_with_variations_get_lookups (hb_face_t    *face,
 hb_bool_t
 hb_ot_layout_has_substitution (hb_face_t *face)
 {
-  return &_get_gsub (face) != &OT::Null(OT::GSUB);
+  return &_get_gsub (face) != &Null(OT::GSUB);
 }
 
 /**
@@ -962,7 +962,7 @@ hb_ot_layout_lookup_substitute_closure (hb_face_t    *face,
 hb_bool_t
 hb_ot_layout_has_positioning (hb_face_t *face)
 {
-  return &_get_gpos (face) != &OT::Null(OT::GPOS);
+  return &_get_gpos (face) != &Null(OT::GPOS);
 }
 
 void
@@ -1298,5 +1298,5 @@ hb_ot_layout_substitute_lookup (OT::hb_ot_apply_context_t *c,
 // hb_bool_t
 // hb_ot_base_has_data (hb_face_t *face)
 // {
-//   return &_get_base (face) != &OT::Null(OT::BASE);
+//   return &_get_base (face) != &Null(OT::BASE);
 // }
diff --git a/src/hb-ot-math.cc b/src/hb-ot-math.cc
index f82a0735..1667a7da 100644
--- a/src/hb-ot-math.cc
+++ b/src/hb-ot-math.cc
@@ -32,7 +32,7 @@
 static inline const OT::MATH&
 _get_math (hb_face_t *face)
 {
-  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::MATH);
+  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return Null(OT::MATH);
   hb_ot_layout_t * layout = hb_ot_layout_from_face (face);
   return *(layout->math.get ());
 }
@@ -55,7 +55,7 @@ _get_math (hb_face_t *face)
 hb_bool_t
 hb_ot_math_has_data (hb_face_t *face)
 {
-  return &_get_math (face) != &OT::Null(OT::MATH);
+  return &_get_math (face) != &Null(OT::MATH);
 }
 
 /**
diff --git a/src/hb-ot-var.cc b/src/hb-ot-var.cc
index 90ba0bd0..f0612a61 100644
--- a/src/hb-ot-var.cc
+++ b/src/hb-ot-var.cc
@@ -39,14 +39,14 @@
 static inline const OT::fvar&
 _get_fvar (hb_face_t *face)
 {
-  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::fvar);
+  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return Null(OT::fvar);
   hb_ot_layout_t * layout = hb_ot_layout_from_face (face);
   return *(layout->fvar.get ());
 }
 static inline const OT::avar&
 _get_avar (hb_face_t *face)
 {
-  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::avar);
+  if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return Null(OT::avar);
   hb_ot_layout_t * layout = hb_ot_layout_from_face (face);
   return *(layout->avar.get ());
 }
@@ -65,7 +65,7 @@ _get_avar (hb_face_t *face)
 hb_bool_t
 hb_ot_var_has_data (hb_face_t *face)
 {
-  return &_get_fvar (face) != &OT::Null(OT::fvar);
+  return &_get_fvar (face) != &Null(OT::fvar);
 }
 
 /**
diff --git a/src/hb-private.hh b/src/hb-private.hh
index 21561ce4..9e075a31 100644
--- a/src/hb-private.hh
+++ b/src/hb-private.hh
@@ -1089,4 +1089,33 @@ round (double x)
 #endif
 
 
+/*
+ * Null objects
+ */
+
+/* Global nul-content Null pool.  Enlarge as necessary. */
+
+#define HB_NULL_POOL_SIZE 264
+static_assert (HB_NULL_POOL_SIZE % sizeof (void *) == 0, "Align HB_NULL_POOL_SIZE.");
+
+#ifdef HB_NO_VISIBILITY
+static
+#else
+extern HB_INTERNAL
+#endif
+const void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)]
+#ifdef HB_NO_VISIBILITY
+= {}
+#endif
+;
+
+/* Generic nul-content Null objects. */
+template <typename Type>
+static inline const Type& Null (void) {
+  static_assert (sizeof (Type) <= HB_NULL_POOL_SIZE, "Increase HB_NULL_POOL_SIZE.");
+  return *reinterpret_cast<const Type *> (_hb_NullPool);
+}
+#define Null(Type) Null<Type>()
+
+
 #endif /* HB_PRIVATE_HH */
diff --git a/src/hb-subset.cc b/src/hb-subset.cc
index 35fe0ef8..6c3d7591 100644
--- a/src/hb-subset.cc
+++ b/src/hb-subset.cc
@@ -45,7 +45,7 @@
 
 
 #if !defined(HB_NO_VISIBILITY) && !defined(HB_SUBSET_BUILTIN)
-const void * const OT::_hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
+const void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 #endif
 
 
@@ -91,7 +91,7 @@ _subset (hb_subset_plan_t *plan)
 
   hb_tag_t tag = TableType::tableTag;
   hb_bool_t result = false;
-  if (table != &OT::Null(TableType))
+  if (table != &Null(TableType))
   {
     result = table->subset(plan);
   } else {
diff --git a/src/main.cc b/src/main.cc
index 935fa392..0436c85f 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -38,7 +38,7 @@
 using namespace OT;
 
 #ifndef HB_NO_VISIBILITY
-const void * const OT::_hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
+const void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 #endif
 
 int
commit 08e280fd84384f73d395918646ee044a5bbfee45
Author: Behdad Esfahbod <behdad at behdad.org>
Date:   Tue May 8 01:57:27 2018 -0700

    Rename hb_string_t to hb_bytes_t

diff --git a/src/hb-ot-post-table.hh b/src/hb-ot-post-table.hh
index 0cd97fa2..63aa83ad 100644
--- a/src/hb-ot-post-table.hh
+++ b/src/hb-ot-post-table.hh
@@ -141,7 +141,7 @@ struct post
     inline bool get_glyph_name (hb_codepoint_t glyph,
 				char *buf, unsigned int buf_len) const
     {
-      hb_string_t s = find_glyph_name (glyph);
+      hb_bytes_t s = find_glyph_name (glyph);
       if (!s.len)
         return false;
       if (!buf_len)
@@ -185,7 +185,7 @@ struct post
 	}
       }
 
-      hb_string_t st (name, len);
+      hb_bytes_t st (name, len);
       const uint16_t *gid = (const uint16_t *) hb_bsearch_r (&st, gids, count, sizeof (gids[0]), cmp_key, (void *) this);
       if (gid)
       {
@@ -220,23 +220,23 @@ struct post
     static inline int cmp_key (const void *pk, const void *po, void *arg)
     {
       const accelerator_t *thiz = (const accelerator_t *) arg;
-      const hb_string_t *key = (const hb_string_t *) pk;
+      const hb_bytes_t *key = (const hb_bytes_t *) pk;
       uint16_t o = * (const uint16_t *) po;
       return thiz->find_glyph_name (o).cmp (*key);
     }
 
-    inline hb_string_t find_glyph_name (hb_codepoint_t glyph) const
+    inline hb_bytes_t find_glyph_name (hb_codepoint_t glyph) const
     {
       if (version == 0x00010000)
       {
 	if (glyph >= NUM_FORMAT1_NAMES)
-	  return hb_string_t ();
+	  return hb_bytes_t ();
 
 	return format1_names (glyph);
       }
 
       if (version != 0x00020000 || glyph >= glyphNameIndex->len)
-	return hb_string_t ();
+	return hb_bytes_t ();
 
       unsigned int index = glyphNameIndex->array[glyph];
       if (index < NUM_FORMAT1_NAMES)
@@ -244,14 +244,14 @@ struct post
       index -= NUM_FORMAT1_NAMES;
 
       if (index >= index_to_offset.len)
-	return hb_string_t ();
+	return hb_bytes_t ();
       unsigned int offset = index_to_offset.array[index];
 
       const uint8_t *data = pool + offset;
       unsigned int name_length = *data;
       data++;
 
-      return hb_string_t ((const char *) data, name_length);
+      return hb_bytes_t ((const char *) data, name_length);
     }
 
     private:
diff --git a/src/hb-private.hh b/src/hb-private.hh
index 1b1e83f4..21561ce4 100644
--- a/src/hb-private.hh
+++ b/src/hb-private.hh
@@ -1052,12 +1052,12 @@ hb_options (void)
 
 /* String type. */
 
-struct hb_string_t
+struct hb_bytes_t
 {
-  inline hb_string_t (void) : bytes (nullptr), len (0) {}
-  inline hb_string_t (const char *bytes_, unsigned int len_) : bytes (bytes_), len (len_) {}
+  inline hb_bytes_t (void) : bytes (nullptr), len (0) {}
+  inline hb_bytes_t (const char *bytes_, unsigned int len_) : bytes (bytes_), len (len_) {}
 
-  inline int cmp (const hb_string_t &a) const
+  inline int cmp (const hb_bytes_t &a) const
   {
     if (len != a.len)
       return (int) a.len - (int) len;
@@ -1066,8 +1066,8 @@ struct hb_string_t
   }
   static inline int cmp (const void *pa, const void *pb)
   {
-    hb_string_t *a = (hb_string_t *) pa;
-    hb_string_t *b = (hb_string_t *) pb;
+    hb_bytes_t *a = (hb_bytes_t *) pa;
+    hb_bytes_t *b = (hb_bytes_t *) pb;
     return b->cmp (*a);
   }
 
diff --git a/src/hb-string-array.hh b/src/hb-string-array.hh
index d83553dd..679841c8 100644
--- a/src/hb-string-array.hh
+++ b/src/hb-string-array.hh
@@ -66,12 +66,12 @@ static const unsigned int HB_STRING_ARRAY_OFFS_NAME[] =
   sizeof (HB_STRING_ARRAY_TYPE_NAME)
 };
 
-static inline hb_string_t
+static inline hb_bytes_t
 HB_STRING_ARRAY_NAME (unsigned int i)
 {
   assert (i < ARRAY_LENGTH (HB_STRING_ARRAY_OFFS_NAME) - 1);
-  return hb_string_t (HB_STRING_ARRAY_POOL_NAME.str + HB_STRING_ARRAY_OFFS_NAME[i],
-		      HB_STRING_ARRAY_OFFS_NAME[i + 1] - HB_STRING_ARRAY_OFFS_NAME[i] - 1);
+  return hb_bytes_t (HB_STRING_ARRAY_POOL_NAME.str + HB_STRING_ARRAY_OFFS_NAME[i],
+		     HB_STRING_ARRAY_OFFS_NAME[i + 1] - HB_STRING_ARRAY_OFFS_NAME[i] - 1);
 }
 
 #undef HB_STRING_ARRAY_TYPE_NAME
commit bd021a67203aa5b07c31c02d63e6154da0c05d31
Author: Behdad Esfahbod <behdad at behdad.org>
Date:   Tue May 8 01:50:30 2018 -0700

    Minor

diff --git a/src/hb-private.hh b/src/hb-private.hh
index d7c8fef8..1b1e83f4 100644
--- a/src/hb-private.hh
+++ b/src/hb-private.hh
@@ -829,7 +829,7 @@ static inline unsigned char TOLOWER (unsigned char c)
  * light-weight) to be enabled, then HB_DEBUG can be defined to disable
  * the costlier checks. */
 #ifdef NDEBUG
-#define HB_NDEBUG
+#define HB_NDEBUG 1
 #endif
 
 
commit 16e4ccf7b417f021948643012cbe7641ba02c039
Author: Behdad Esfahbod <behdad at behdad.org>
Date:   Tue May 8 01:47:05 2018 -0700

    Allocate user-data-array on the heap
    
    This saves each object allocation 72 bytes.  Now object overhead is just
    16 bytes (on x86) instead of 88 bytes. Neat.

diff --git a/src/hb-object-private.hh b/src/hb-object-private.hh
index 75a72f4b..1f61dcea 100644
--- a/src/hb-object-private.hh
+++ b/src/hb-object-private.hh
@@ -62,7 +62,6 @@ struct hb_reference_count_t
 
 /* user_data */
 
-#define HB_USER_DATA_ARRAY_INIT {HB_MUTEX_INIT, HB_LOCKABLE_SET_INIT}
 struct hb_user_data_array_t
 {
   struct hb_user_data_item_t {
@@ -97,9 +96,9 @@ struct hb_user_data_array_t
 struct hb_object_header_t
 {
   hb_reference_count_t ref_count;
-  hb_user_data_array_t user_data;
+  hb_user_data_array_t *user_data;
 
-#define HB_OBJECT_HEADER_STATIC {HB_REFERENCE_COUNT_INIT, HB_USER_DATA_ARRAY_INIT}
+#define HB_OBJECT_HEADER_STATIC {HB_REFERENCE_COUNT_INIT, nullptr}
 
   private:
   ASSERT_POD ();
@@ -133,7 +132,7 @@ template <typename Type>
 static inline void hb_object_init (Type *obj)
 {
   obj->header.ref_count.init (1);
-  obj->header.user_data.init ();
+  obj->header.user_data = nullptr;
 }
 template <typename Type>
 static inline bool hb_object_is_inert (const Type *obj)
@@ -172,7 +171,11 @@ template <typename Type>
 static inline void hb_object_fini (Type *obj)
 {
   obj->header.ref_count.fini (); /* Do this before user_data */
-  obj->header.user_data.fini ();
+  if (obj->header.user_data)
+  {
+    obj->header.user_data->fini ();
+    free (obj->header.user_data);
+  }
 }
 template <typename Type>
 static inline bool hb_object_set_user_data (Type               *obj,
@@ -184,17 +187,34 @@ static inline bool hb_object_set_user_data (Type               *obj,
   if (unlikely (!obj || hb_object_is_inert (obj)))
     return false;
   assert (hb_object_is_valid (obj));
-  return obj->header.user_data.set (key, data, destroy, replace);
+
+retry:
+  hb_user_data_array_t *user_data = (hb_user_data_array_t *) hb_atomic_ptr_get (&obj->header.user_data);
+  if (unlikely (!user_data))
+  {
+    user_data = (hb_user_data_array_t *) calloc (sizeof (hb_user_data_array_t), 1);
+    if (unlikely (!user_data))
+      return false;
+    user_data->init ();
+    if (unlikely (!hb_atomic_ptr_cmpexch (&obj->header.user_data, nullptr, user_data)))
+    {
+      user_data->fini ();
+      free (user_data);
+      goto retry;
+    }
+  }
+
+  return user_data->set (key, data, destroy, replace);
 }
 
 template <typename Type>
 static inline void *hb_object_get_user_data (Type               *obj,
 					     hb_user_data_key_t *key)
 {
-  if (unlikely (!obj || hb_object_is_inert (obj)))
+  if (unlikely (!obj || hb_object_is_inert (obj) || !obj->header.user_data))
     return nullptr;
   assert (hb_object_is_valid (obj));
-  return obj->header.user_data.get (key);
+  return obj->header.user_data->get (key);
 }
 
 


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