src/java.desktop/share/native/libfontmanager/harfbuzz/hb-coretext.cc
changeset 47216 71c04702a3d5
parent 43232 8e39ad39979f
child 48274 51772bf1fb0c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.desktop/share/native/libfontmanager/harfbuzz/hb-coretext.cc	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,1310 @@
+/*
+ * Copyright © 2012,2013  Mozilla Foundation.
+ * Copyright © 2012,2013  Google, Inc.
+ *
+ *  This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Mozilla Author(s): Jonathan Kew
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#define HB_SHAPER coretext
+#include "hb-shaper-impl-private.hh"
+
+#include "hb-coretext.h"
+
+
+#ifndef HB_DEBUG_CORETEXT
+#define HB_DEBUG_CORETEXT (HB_DEBUG+0)
+#endif
+
+
+static void
+release_table_data (void *user_data)
+{
+  CFDataRef cf_data = reinterpret_cast<CFDataRef> (user_data);
+  CFRelease(cf_data);
+}
+
+static hb_blob_t *
+reference_table  (hb_face_t *face HB_UNUSED, hb_tag_t tag, void *user_data)
+{
+  CGFontRef cg_font = reinterpret_cast<CGFontRef> (user_data);
+  CFDataRef cf_data = CGFontCopyTableForTag (cg_font, tag);
+  if (unlikely (!cf_data))
+    return NULL;
+
+  const char *data = reinterpret_cast<const char*> (CFDataGetBytePtr (cf_data));
+  const size_t length = CFDataGetLength (cf_data);
+  if (!data || !length)
+    return NULL;
+
+  return hb_blob_create (data, length, HB_MEMORY_MODE_READONLY,
+                         reinterpret_cast<void *> (const_cast<__CFData *> (cf_data)),
+                         release_table_data);
+}
+
+hb_face_t *
+hb_coretext_face_create (CGFontRef cg_font)
+{
+  return hb_face_create_for_tables (reference_table, CGFontRetain (cg_font), (hb_destroy_func_t) CGFontRelease);
+}
+
+
+HB_SHAPER_DATA_ENSURE_DECLARE(coretext, face)
+HB_SHAPER_DATA_ENSURE_DECLARE(coretext, font)
+
+
+/*
+ * shaper face data
+ */
+
+static CTFontDescriptorRef
+get_last_resort_font_desc (void)
+{
+  // TODO Handle allocation failures?
+  CTFontDescriptorRef last_resort = CTFontDescriptorCreateWithNameAndSize (CFSTR("LastResort"), 0);
+  CFArrayRef cascade_list = CFArrayCreate (kCFAllocatorDefault,
+                                           (const void **) &last_resort,
+                                           1,
+                                           &kCFTypeArrayCallBacks);
+  CFRelease (last_resort);
+  CFDictionaryRef attributes = CFDictionaryCreate (kCFAllocatorDefault,
+                                                   (const void **) &kCTFontCascadeListAttribute,
+                                                   (const void **) &cascade_list,
+                                                   1,
+                                                   &kCFTypeDictionaryKeyCallBacks,
+                                                   &kCFTypeDictionaryValueCallBacks);
+  CFRelease (cascade_list);
+
+  CTFontDescriptorRef font_desc = CTFontDescriptorCreateWithAttributes (attributes);
+  CFRelease (attributes);
+  return font_desc;
+}
+
+static void
+release_data (void *info, const void *data, size_t size)
+{
+  assert (hb_blob_get_length ((hb_blob_t *) info) == size &&
+          hb_blob_get_data ((hb_blob_t *) info, NULL) == data);
+
+  hb_blob_destroy ((hb_blob_t *) info);
+}
+
+static CGFontRef
+create_cg_font (hb_face_t *face)
+{
+  CGFontRef cg_font = NULL;
+  if (face->destroy == (hb_destroy_func_t) CGFontRelease)
+  {
+    cg_font = CGFontRetain ((CGFontRef) face->user_data);
+  }
+  else
+  {
+    hb_blob_t *blob = hb_face_reference_blob (face);
+    unsigned int blob_length;
+    const char *blob_data = hb_blob_get_data (blob, &blob_length);
+    if (unlikely (!blob_length))
+      DEBUG_MSG (CORETEXT, face, "Face has empty blob");
+
+    CGDataProviderRef provider = CGDataProviderCreateWithData (blob, blob_data, blob_length, &release_data);
+    if (likely (provider))
+    {
+      cg_font = CGFontCreateWithDataProvider (provider);
+      if (unlikely (!cg_font))
+        DEBUG_MSG (CORETEXT, face, "Face CGFontCreateWithDataProvider() failed");
+      CGDataProviderRelease (provider);
+    }
+  }
+  return cg_font;
+}
+
+static CTFontRef
+create_ct_font (CGFontRef cg_font, CGFloat font_size)
+{
+  CTFontRef ct_font = CTFontCreateWithGraphicsFont (cg_font, font_size, NULL, NULL);
+  if (unlikely (!ct_font)) {
+    DEBUG_MSG (CORETEXT, cg_font, "Font CTFontCreateWithGraphicsFont() failed");
+    return NULL;
+  }
+
+  /* crbug.com/576941 and crbug.com/625902 and the investigation in the latter
+   * bug indicate that the cascade list reconfiguration occasionally causes
+   * crashes in CoreText on OS X 10.9, thus let's skip this step on older
+   * operating system versions. Except for the emoji font, where _not_
+   * reconfiguring the cascade list causes CoreText crashes. For details, see
+   * crbug.com/549610 */
+  // 0x00070000 stands for "kCTVersionNumber10_10", see CoreText.h
+  if (&CTGetCoreTextVersion != NULL && CTGetCoreTextVersion() < 0x00070000) {
+    CFStringRef fontName = CTFontCopyPostScriptName (ct_font);
+    bool isEmojiFont = CFStringCompare (fontName, CFSTR("AppleColorEmoji"), 0) == kCFCompareEqualTo;
+    CFRelease (fontName);
+    if (!isEmojiFont)
+      return ct_font;
+  }
+
+  CFURLRef original_url = (CFURLRef)CTFontCopyAttribute(ct_font, kCTFontURLAttribute);
+
+  /* Create font copy with cascade list that has LastResort first; this speeds up CoreText
+   * font fallback which we don't need anyway. */
+  {
+    CTFontDescriptorRef last_resort_font_desc = get_last_resort_font_desc ();
+    CTFontRef new_ct_font = CTFontCreateCopyWithAttributes (ct_font, 0.0, NULL, last_resort_font_desc);
+    CFRelease (last_resort_font_desc);
+    if (new_ct_font)
+    {
+      /* The CTFontCreateCopyWithAttributes call fails to stay on the same font
+       * when reconfiguring the cascade list and may switch to a different font
+       * when there are fonts that go by the same name, since the descriptor is
+       * just name and size.
+       *
+       * Avoid reconfiguring the cascade lists if the new font is outside the
+       * system locations that we cannot access from the sandboxed renderer
+       * process in Blink. This can be detected by the new file URL location
+       * that the newly found font points to. */
+      CFURLRef new_url = (CFURLRef) CTFontCopyAttribute (new_ct_font, kCTFontURLAttribute);
+      // Keep reconfigured font if URL cannot be retrieved (seems to be the case
+      // on Mac OS 10.12 Sierra), speculative fix for crbug.com/625606
+      if (!original_url || !new_url || CFEqual (original_url, new_url)) {
+        CFRelease (ct_font);
+        ct_font = new_ct_font;
+      } else {
+        CFRelease (new_ct_font);
+        DEBUG_MSG (CORETEXT, ct_font, "Discarding reconfigured CTFont, location changed.");
+      }
+      if (new_url)
+        CFRelease (new_url);
+    }
+    else
+      DEBUG_MSG (CORETEXT, ct_font, "Font copy with empty cascade list failed");
+  }
+
+  if (original_url)
+    CFRelease (original_url);
+  return ct_font;
+}
+
+struct hb_coretext_shaper_face_data_t {
+  CGFontRef cg_font;
+  CTFontRef ct_font;
+};
+
+hb_coretext_shaper_face_data_t *
+_hb_coretext_shaper_face_data_create (hb_face_t *face)
+{
+  hb_coretext_shaper_face_data_t *data = (hb_coretext_shaper_face_data_t *) calloc (1, sizeof (hb_coretext_shaper_face_data_t));
+  if (unlikely (!data))
+    return NULL;
+
+  data->cg_font = create_cg_font (face);
+  if (unlikely (!data->cg_font))
+  {
+    DEBUG_MSG (CORETEXT, face, "CGFont creation failed..");
+    free (data);
+    return NULL;
+  }
+
+  /* We use 36pt size instead of UPEM, because CoreText implements the 'trak' table,
+   * which can make the font too tight at large sizes.  36pt should be a good semi-neutral
+   * size.
+   *
+   * Since we always create CTFont at a fixed size, our CTFont lives in face_data
+   * instead of font_data.  Which is good, because when people change scale on
+   * hb_font_t, we won't need to update our CTFont. */
+  data->ct_font = create_ct_font (data->cg_font, 36.);
+  if (unlikely (!data->ct_font))
+  {
+    DEBUG_MSG (CORETEXT, face, "CTFont creation failed.");
+    CFRelease (data->cg_font);
+    free (data);
+    return NULL;
+  }
+
+  return data;
+}
+
+void
+_hb_coretext_shaper_face_data_destroy (hb_coretext_shaper_face_data_t *data)
+{
+  CFRelease (data->ct_font);
+  CFRelease (data->cg_font);
+  free (data);
+}
+
+/*
+ * Since: 0.9.10
+ */
+CGFontRef
+hb_coretext_face_get_cg_font (hb_face_t *face)
+{
+  if (unlikely (!hb_coretext_shaper_face_data_ensure (face))) return NULL;
+  hb_coretext_shaper_face_data_t *face_data = HB_SHAPER_DATA_GET (face);
+  return face_data->cg_font;
+}
+
+
+/*
+ * shaper font data
+ */
+
+struct hb_coretext_shaper_font_data_t {};
+
+hb_coretext_shaper_font_data_t *
+_hb_coretext_shaper_font_data_create (hb_font_t *font HB_UNUSED)
+{
+  return (hb_coretext_shaper_font_data_t *) HB_SHAPER_DATA_SUCCEEDED;
+}
+
+void
+_hb_coretext_shaper_font_data_destroy (hb_coretext_shaper_font_data_t *data)
+{
+}
+
+
+/*
+ * shaper shape_plan data
+ */
+
+struct hb_coretext_shaper_shape_plan_data_t {};
+
+hb_coretext_shaper_shape_plan_data_t *
+_hb_coretext_shaper_shape_plan_data_create (hb_shape_plan_t    *shape_plan HB_UNUSED,
+                                             const hb_feature_t *user_features HB_UNUSED,
+                                             unsigned int        num_user_features HB_UNUSED,
+                                             const int          *coords HB_UNUSED,
+                                             unsigned int        num_coords HB_UNUSED)
+{
+  return (hb_coretext_shaper_shape_plan_data_t *) HB_SHAPER_DATA_SUCCEEDED;
+}
+
+void
+_hb_coretext_shaper_shape_plan_data_destroy (hb_coretext_shaper_shape_plan_data_t *data HB_UNUSED)
+{
+}
+
+CTFontRef
+hb_coretext_font_get_ct_font (hb_font_t *font)
+{
+  hb_face_t *face = font->face;
+  if (unlikely (!hb_coretext_shaper_face_data_ensure (face))) return NULL;
+  hb_coretext_shaper_face_data_t *face_data = HB_SHAPER_DATA_GET (face);
+  return face_data->ct_font;
+}
+
+
+/*
+ * shaper
+ */
+
+struct feature_record_t {
+  unsigned int feature;
+  unsigned int setting;
+};
+
+struct active_feature_t {
+  feature_record_t rec;
+  unsigned int order;
+
+  static int cmp (const active_feature_t *a, const active_feature_t *b) {
+    return a->rec.feature < b->rec.feature ? -1 : a->rec.feature > b->rec.feature ? 1 :
+           a->order < b->order ? -1 : a->order > b->order ? 1 :
+           a->rec.setting < b->rec.setting ? -1 : a->rec.setting > b->rec.setting ? 1 :
+           0;
+  }
+  bool operator== (const active_feature_t *f) {
+    return cmp (this, f) == 0;
+  }
+};
+
+struct feature_event_t {
+  unsigned int index;
+  bool start;
+  active_feature_t feature;
+
+  static int cmp (const feature_event_t *a, const feature_event_t *b) {
+    return a->index < b->index ? -1 : a->index > b->index ? 1 :
+           a->start < b->start ? -1 : a->start > b->start ? 1 :
+           active_feature_t::cmp (&a->feature, &b->feature);
+  }
+};
+
+struct range_record_t {
+  CTFontRef font;
+  unsigned int index_first; /* == start */
+  unsigned int index_last;  /* == end - 1 */
+};
+
+
+/* The following enum members are added in OS X 10.8. */
+#define kAltHalfWidthTextSelector               6
+#define kAltProportionalTextSelector            5
+#define kAlternateHorizKanaOffSelector          1
+#define kAlternateHorizKanaOnSelector           0
+#define kAlternateKanaType                      34
+#define kAlternateVertKanaOffSelector           3
+#define kAlternateVertKanaOnSelector            2
+#define kCaseSensitiveLayoutOffSelector         1
+#define kCaseSensitiveLayoutOnSelector          0
+#define kCaseSensitiveLayoutType                33
+#define kCaseSensitiveSpacingOffSelector        3
+#define kCaseSensitiveSpacingOnSelector         2
+#define kContextualAlternatesOffSelector        1
+#define kContextualAlternatesOnSelector         0
+#define kContextualAlternatesType               36
+#define kContextualLigaturesOffSelector         19
+#define kContextualLigaturesOnSelector          18
+#define kContextualSwashAlternatesOffSelector   5
+#define kContextualSwashAlternatesOnSelector    4
+#define kDefaultLowerCaseSelector               0
+#define kDefaultUpperCaseSelector               0
+#define kHistoricalLigaturesOffSelector         21
+#define kHistoricalLigaturesOnSelector          20
+#define kHojoCharactersSelector                 12
+#define kJIS2004CharactersSelector              11
+#define kLowerCasePetiteCapsSelector            2
+#define kLowerCaseSmallCapsSelector             1
+#define kLowerCaseType                          37
+#define kMathematicalGreekOffSelector           11
+#define kMathematicalGreekOnSelector            10
+#define kNLCCharactersSelector                  13
+#define kQuarterWidthTextSelector               4
+#define kScientificInferiorsSelector            4
+#define kStylisticAltEightOffSelector           17
+#define kStylisticAltEightOnSelector            16
+#define kStylisticAltEighteenOffSelector        37
+#define kStylisticAltEighteenOnSelector         36
+#define kStylisticAltElevenOffSelector          23
+#define kStylisticAltElevenOnSelector           22
+#define kStylisticAltFifteenOffSelector         31
+#define kStylisticAltFifteenOnSelector          30
+#define kStylisticAltFiveOffSelector            11
+#define kStylisticAltFiveOnSelector             10
+#define kStylisticAltFourOffSelector            9
+#define kStylisticAltFourOnSelector             8
+#define kStylisticAltFourteenOffSelector        29
+#define kStylisticAltFourteenOnSelector         28
+#define kStylisticAltNineOffSelector            19
+#define kStylisticAltNineOnSelector             18
+#define kStylisticAltNineteenOffSelector        39
+#define kStylisticAltNineteenOnSelector         38
+#define kStylisticAltOneOffSelector             3
+#define kStylisticAltOneOnSelector              2
+#define kStylisticAltSevenOffSelector           15
+#define kStylisticAltSevenOnSelector            14
+#define kStylisticAltSeventeenOffSelector       35
+#define kStylisticAltSeventeenOnSelector        34
+#define kStylisticAltSixOffSelector             13
+#define kStylisticAltSixOnSelector              12
+#define kStylisticAltSixteenOffSelector         33
+#define kStylisticAltSixteenOnSelector          32
+#define kStylisticAltTenOffSelector             21
+#define kStylisticAltTenOnSelector              20
+#define kStylisticAltThirteenOffSelector        27
+#define kStylisticAltThirteenOnSelector         26
+#define kStylisticAltThreeOffSelector           7
+#define kStylisticAltThreeOnSelector            6
+#define kStylisticAltTwelveOffSelector          25
+#define kStylisticAltTwelveOnSelector           24
+#define kStylisticAltTwentyOffSelector          41
+#define kStylisticAltTwentyOnSelector           40
+#define kStylisticAltTwoOffSelector             5
+#define kStylisticAltTwoOnSelector              4
+#define kStylisticAlternativesType              35
+#define kSwashAlternatesOffSelector             3
+#define kSwashAlternatesOnSelector              2
+#define kThirdWidthTextSelector                 3
+#define kTraditionalNamesCharactersSelector     14
+#define kUpperCasePetiteCapsSelector            2
+#define kUpperCaseSmallCapsSelector             1
+#define kUpperCaseType                          38
+
+/* Table data courtesy of Apple. */
+static const struct feature_mapping_t {
+    FourCharCode otFeatureTag;
+    uint16_t aatFeatureType;
+    uint16_t selectorToEnable;
+    uint16_t selectorToDisable;
+} feature_mappings[] = {
+    { 'c2pc',   kUpperCaseType,             kUpperCasePetiteCapsSelector,           kDefaultUpperCaseSelector },
+    { 'c2sc',   kUpperCaseType,             kUpperCaseSmallCapsSelector,            kDefaultUpperCaseSelector },
+    { 'calt',   kContextualAlternatesType,  kContextualAlternatesOnSelector,        kContextualAlternatesOffSelector },
+    { 'case',   kCaseSensitiveLayoutType,   kCaseSensitiveLayoutOnSelector,         kCaseSensitiveLayoutOffSelector },
+    { 'clig',   kLigaturesType,             kContextualLigaturesOnSelector,         kContextualLigaturesOffSelector },
+    { 'cpsp',   kCaseSensitiveLayoutType,   kCaseSensitiveSpacingOnSelector,        kCaseSensitiveSpacingOffSelector },
+    { 'cswh',   kContextualAlternatesType,  kContextualSwashAlternatesOnSelector,   kContextualSwashAlternatesOffSelector },
+    { 'dlig',   kLigaturesType,             kRareLigaturesOnSelector,               kRareLigaturesOffSelector },
+    { 'expt',   kCharacterShapeType,        kExpertCharactersSelector,              16 },
+    { 'frac',   kFractionsType,             kDiagonalFractionsSelector,             kNoFractionsSelector },
+    { 'fwid',   kTextSpacingType,           kMonospacedTextSelector,                7 },
+    { 'halt',   kTextSpacingType,           kAltHalfWidthTextSelector,              7 },
+    { 'hist',   kLigaturesType,             kHistoricalLigaturesOnSelector,         kHistoricalLigaturesOffSelector },
+    { 'hkna',   kAlternateKanaType,         kAlternateHorizKanaOnSelector,          kAlternateHorizKanaOffSelector, },
+    { 'hlig',   kLigaturesType,             kHistoricalLigaturesOnSelector,         kHistoricalLigaturesOffSelector },
+    { 'hngl',   kTransliterationType,       kHanjaToHangulSelector,                 kNoTransliterationSelector },
+    { 'hojo',   kCharacterShapeType,        kHojoCharactersSelector,                16 },
+    { 'hwid',   kTextSpacingType,           kHalfWidthTextSelector,                 7 },
+    { 'ital',   kItalicCJKRomanType,        kCJKItalicRomanOnSelector,              kCJKItalicRomanOffSelector },
+    { 'jp04',   kCharacterShapeType,        kJIS2004CharactersSelector,             16 },
+    { 'jp78',   kCharacterShapeType,        kJIS1978CharactersSelector,             16 },
+    { 'jp83',   kCharacterShapeType,        kJIS1983CharactersSelector,             16 },
+    { 'jp90',   kCharacterShapeType,        kJIS1990CharactersSelector,             16 },
+    { 'liga',   kLigaturesType,             kCommonLigaturesOnSelector,             kCommonLigaturesOffSelector },
+    { 'lnum',   kNumberCaseType,            kUpperCaseNumbersSelector,              2 },
+    { 'mgrk',   kMathematicalExtrasType,    kMathematicalGreekOnSelector,           kMathematicalGreekOffSelector },
+    { 'nlck',   kCharacterShapeType,        kNLCCharactersSelector,                 16 },
+    { 'onum',   kNumberCaseType,            kLowerCaseNumbersSelector,              2 },
+    { 'ordn',   kVerticalPositionType,      kOrdinalsSelector,                      kNormalPositionSelector },
+    { 'palt',   kTextSpacingType,           kAltProportionalTextSelector,           7 },
+    { 'pcap',   kLowerCaseType,             kLowerCasePetiteCapsSelector,           kDefaultLowerCaseSelector },
+    { 'pkna',   kTextSpacingType,           kProportionalTextSelector,              7 },
+    { 'pnum',   kNumberSpacingType,         kProportionalNumbersSelector,           4 },
+    { 'pwid',   kTextSpacingType,           kProportionalTextSelector,              7 },
+    { 'qwid',   kTextSpacingType,           kQuarterWidthTextSelector,              7 },
+    { 'ruby',   kRubyKanaType,              kRubyKanaOnSelector,                    kRubyKanaOffSelector },
+    { 'sinf',   kVerticalPositionType,      kScientificInferiorsSelector,           kNormalPositionSelector },
+    { 'smcp',   kLowerCaseType,             kLowerCaseSmallCapsSelector,            kDefaultLowerCaseSelector },
+    { 'smpl',   kCharacterShapeType,        kSimplifiedCharactersSelector,          16 },
+    { 'ss01',   kStylisticAlternativesType, kStylisticAltOneOnSelector,             kStylisticAltOneOffSelector },
+    { 'ss02',   kStylisticAlternativesType, kStylisticAltTwoOnSelector,             kStylisticAltTwoOffSelector },
+    { 'ss03',   kStylisticAlternativesType, kStylisticAltThreeOnSelector,           kStylisticAltThreeOffSelector },
+    { 'ss04',   kStylisticAlternativesType, kStylisticAltFourOnSelector,            kStylisticAltFourOffSelector },
+    { 'ss05',   kStylisticAlternativesType, kStylisticAltFiveOnSelector,            kStylisticAltFiveOffSelector },
+    { 'ss06',   kStylisticAlternativesType, kStylisticAltSixOnSelector,             kStylisticAltSixOffSelector },
+    { 'ss07',   kStylisticAlternativesType, kStylisticAltSevenOnSelector,           kStylisticAltSevenOffSelector },
+    { 'ss08',   kStylisticAlternativesType, kStylisticAltEightOnSelector,           kStylisticAltEightOffSelector },
+    { 'ss09',   kStylisticAlternativesType, kStylisticAltNineOnSelector,            kStylisticAltNineOffSelector },
+    { 'ss10',   kStylisticAlternativesType, kStylisticAltTenOnSelector,             kStylisticAltTenOffSelector },
+    { 'ss11',   kStylisticAlternativesType, kStylisticAltElevenOnSelector,          kStylisticAltElevenOffSelector },
+    { 'ss12',   kStylisticAlternativesType, kStylisticAltTwelveOnSelector,          kStylisticAltTwelveOffSelector },
+    { 'ss13',   kStylisticAlternativesType, kStylisticAltThirteenOnSelector,        kStylisticAltThirteenOffSelector },
+    { 'ss14',   kStylisticAlternativesType, kStylisticAltFourteenOnSelector,        kStylisticAltFourteenOffSelector },
+    { 'ss15',   kStylisticAlternativesType, kStylisticAltFifteenOnSelector,         kStylisticAltFifteenOffSelector },
+    { 'ss16',   kStylisticAlternativesType, kStylisticAltSixteenOnSelector,         kStylisticAltSixteenOffSelector },
+    { 'ss17',   kStylisticAlternativesType, kStylisticAltSeventeenOnSelector,       kStylisticAltSeventeenOffSelector },
+    { 'ss18',   kStylisticAlternativesType, kStylisticAltEighteenOnSelector,        kStylisticAltEighteenOffSelector },
+    { 'ss19',   kStylisticAlternativesType, kStylisticAltNineteenOnSelector,        kStylisticAltNineteenOffSelector },
+    { 'ss20',   kStylisticAlternativesType, kStylisticAltTwentyOnSelector,          kStylisticAltTwentyOffSelector },
+    { 'subs',   kVerticalPositionType,      kInferiorsSelector,                     kNormalPositionSelector },
+    { 'sups',   kVerticalPositionType,      kSuperiorsSelector,                     kNormalPositionSelector },
+    { 'swsh',   kContextualAlternatesType,  kSwashAlternatesOnSelector,             kSwashAlternatesOffSelector },
+    { 'titl',   kStyleOptionsType,          kTitlingCapsSelector,                   kNoStyleOptionsSelector },
+    { 'tnam',   kCharacterShapeType,        kTraditionalNamesCharactersSelector,    16 },
+    { 'tnum',   kNumberSpacingType,         kMonospacedNumbersSelector,             4 },
+    { 'trad',   kCharacterShapeType,        kTraditionalCharactersSelector,         16 },
+    { 'twid',   kTextSpacingType,           kThirdWidthTextSelector,                7 },
+    { 'unic',   kLetterCaseType,            14,                                     15 },
+    { 'valt',   kTextSpacingType,           kAltProportionalTextSelector,           7 },
+    { 'vert',   kVerticalSubstitutionType,  kSubstituteVerticalFormsOnSelector,     kSubstituteVerticalFormsOffSelector },
+    { 'vhal',   kTextSpacingType,           kAltHalfWidthTextSelector,              7 },
+    { 'vkna',   kAlternateKanaType,         kAlternateVertKanaOnSelector,           kAlternateVertKanaOffSelector },
+    { 'vpal',   kTextSpacingType,           kAltProportionalTextSelector,           7 },
+    { 'vrt2',   kVerticalSubstitutionType,  kSubstituteVerticalFormsOnSelector,     kSubstituteVerticalFormsOffSelector },
+    { 'zero',   kTypographicExtrasType,     kSlashedZeroOnSelector,                 kSlashedZeroOffSelector },
+};
+
+static int
+_hb_feature_mapping_cmp (const void *key_, const void *entry_)
+{
+  unsigned int key = * (unsigned int *) key_;
+  const feature_mapping_t * entry = (const feature_mapping_t *) entry_;
+  return key < entry->otFeatureTag ? -1 :
+         key > entry->otFeatureTag ? 1 :
+         0;
+}
+
+hb_bool_t
+_hb_coretext_shape (hb_shape_plan_t    *shape_plan,
+                    hb_font_t          *font,
+                    hb_buffer_t        *buffer,
+                    const hb_feature_t *features,
+                    unsigned int        num_features)
+{
+  hb_face_t *face = font->face;
+  hb_coretext_shaper_face_data_t *face_data = HB_SHAPER_DATA_GET (face);
+
+  CGFloat ct_font_size = CTFontGetSize (face_data->ct_font);
+  CGFloat x_mult = (CGFloat) font->x_scale / ct_font_size;
+  CGFloat y_mult = (CGFloat) font->y_scale / ct_font_size;
+
+  /* Attach marks to their bases, to match the 'ot' shaper.
+   * Adapted from hb-ot-shape:hb_form_clusters().
+   * Note that this only makes us be closer to the 'ot' shaper,
+   * but by no means the same.  For example, if there's
+   * B1 M1 B2 M2, and B1-B2 form a ligature, M2's cluster will
+   * continue pointing to B2 even though B2 was merged into B1's
+   * cluster... */
+  if (buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES)
+  {
+    hb_unicode_funcs_t *unicode = buffer->unicode;
+    unsigned int count = buffer->len;
+    hb_glyph_info_t *info = buffer->info;
+    for (unsigned int i = 1; i < count; i++)
+      if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (unicode->general_category (info[i].codepoint)))
+        buffer->merge_clusters (i - 1, i + 1);
+  }
+
+  hb_auto_array_t<feature_record_t> feature_records;
+  hb_auto_array_t<range_record_t> range_records;
+
+  /*
+   * Set up features.
+   * (copied + modified from code from hb-uniscribe.cc)
+   */
+  if (num_features)
+  {
+    /* Sort features by start/end events. */
+    hb_auto_array_t<feature_event_t> feature_events;
+    for (unsigned int i = 0; i < num_features; i++)
+    {
+      const feature_mapping_t * mapping = (const feature_mapping_t *) bsearch (&features[i].tag,
+                                                                               feature_mappings,
+                                                                               ARRAY_LENGTH (feature_mappings),
+                                                                               sizeof (feature_mappings[0]),
+                                                                               _hb_feature_mapping_cmp);
+      if (!mapping)
+        continue;
+
+      active_feature_t feature;
+      feature.rec.feature = mapping->aatFeatureType;
+      feature.rec.setting = features[i].value ? mapping->selectorToEnable : mapping->selectorToDisable;
+      feature.order = i;
+
+      feature_event_t *event;
+
+      event = feature_events.push ();
+      if (unlikely (!event))
+        goto fail_features;
+      event->index = features[i].start;
+      event->start = true;
+      event->feature = feature;
+
+      event = feature_events.push ();
+      if (unlikely (!event))
+        goto fail_features;
+      event->index = features[i].end;
+      event->start = false;
+      event->feature = feature;
+    }
+    feature_events.qsort ();
+    /* Add a strategic final event. */
+    {
+      active_feature_t feature;
+      feature.rec.feature = HB_TAG_NONE;
+      feature.rec.setting = 0;
+      feature.order = num_features + 1;
+
+      feature_event_t *event = feature_events.push ();
+      if (unlikely (!event))
+        goto fail_features;
+      event->index = 0; /* This value does magic. */
+      event->start = false;
+      event->feature = feature;
+    }
+
+    /* Scan events and save features for each range. */
+    hb_auto_array_t<active_feature_t> active_features;
+    unsigned int last_index = 0;
+    for (unsigned int i = 0; i < feature_events.len; i++)
+    {
+      feature_event_t *event = &feature_events[i];
+
+      if (event->index != last_index)
+      {
+        /* Save a snapshot of active features and the range. */
+        range_record_t *range = range_records.push ();
+        if (unlikely (!range))
+          goto fail_features;
+
+        if (active_features.len)
+        {
+          CFMutableArrayRef features_array = CFArrayCreateMutable(kCFAllocatorDefault, 0, &kCFTypeArrayCallBacks);
+
+          /* TODO sort and resolve conflicting features? */
+          /* active_features.qsort (); */
+          for (unsigned int j = 0; j < active_features.len; j++)
+          {
+            CFStringRef keys[2] = {
+              kCTFontFeatureTypeIdentifierKey,
+              kCTFontFeatureSelectorIdentifierKey
+            };
+            CFNumberRef values[2] = {
+              CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &active_features[j].rec.feature),
+              CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &active_features[j].rec.setting)
+            };
+            CFDictionaryRef dict = CFDictionaryCreate (kCFAllocatorDefault,
+                                                       (const void **) keys,
+                                                       (const void **) values,
+                                                       2,
+                                                       &kCFTypeDictionaryKeyCallBacks,
+                                                       &kCFTypeDictionaryValueCallBacks);
+            CFRelease (values[0]);
+            CFRelease (values[1]);
+
+            CFArrayAppendValue (features_array, dict);
+            CFRelease (dict);
+
+          }
+
+          CFDictionaryRef attributes = CFDictionaryCreate (kCFAllocatorDefault,
+                                                           (const void **) &kCTFontFeatureSettingsAttribute,
+                                                           (const void **) &features_array,
+                                                           1,
+                                                           &kCFTypeDictionaryKeyCallBacks,
+                                                           &kCFTypeDictionaryValueCallBacks);
+          CFRelease (features_array);
+
+          CTFontDescriptorRef font_desc = CTFontDescriptorCreateWithAttributes (attributes);
+          CFRelease (attributes);
+
+          range->font = CTFontCreateCopyWithAttributes (face_data->ct_font, 0.0, NULL, font_desc);
+          CFRelease (font_desc);
+        }
+        else
+        {
+          range->font = NULL;
+        }
+
+        range->index_first = last_index;
+        range->index_last  = event->index - 1;
+
+        last_index = event->index;
+      }
+
+      if (event->start) {
+        active_feature_t *feature = active_features.push ();
+        if (unlikely (!feature))
+          goto fail_features;
+        *feature = event->feature;
+      } else {
+        active_feature_t *feature = active_features.find (&event->feature);
+        if (feature)
+          active_features.remove (feature - active_features.array);
+      }
+    }
+
+    if (!range_records.len) /* No active feature found. */
+      goto fail_features;
+  }
+  else
+  {
+  fail_features:
+    num_features = 0;
+  }
+
+  unsigned int scratch_size;
+  hb_buffer_t::scratch_buffer_t *scratch = buffer->get_scratch_buffer (&scratch_size);
+
+#define ALLOCATE_ARRAY(Type, name, len, on_no_room) \
+  Type *name = (Type *) scratch; \
+  { \
+    unsigned int _consumed = DIV_CEIL ((len) * sizeof (Type), sizeof (*scratch)); \
+    if (unlikely (_consumed > scratch_size)) \
+    { \
+      on_no_room; \
+      assert (0); \
+    } \
+    scratch += _consumed; \
+    scratch_size -= _consumed; \
+  }
+
+  ALLOCATE_ARRAY (UniChar, pchars, buffer->len * 2, /*nothing*/);
+  unsigned int chars_len = 0;
+  for (unsigned int i = 0; i < buffer->len; i++) {
+    hb_codepoint_t c = buffer->info[i].codepoint;
+    if (likely (c <= 0xFFFFu))
+      pchars[chars_len++] = c;
+    else if (unlikely (c > 0x10FFFFu))
+      pchars[chars_len++] = 0xFFFDu;
+    else {
+      pchars[chars_len++] = 0xD800u + ((c - 0x10000u) >> 10);
+      pchars[chars_len++] = 0xDC00u + ((c - 0x10000u) & ((1u << 10) - 1));
+    }
+  }
+
+  ALLOCATE_ARRAY (unsigned int, log_clusters, chars_len, /*nothing*/);
+  chars_len = 0;
+  for (unsigned int i = 0; i < buffer->len; i++)
+  {
+    hb_codepoint_t c = buffer->info[i].codepoint;
+    unsigned int cluster = buffer->info[i].cluster;
+    log_clusters[chars_len++] = cluster;
+    if (hb_in_range (c, 0x10000u, 0x10FFFFu))
+      log_clusters[chars_len++] = cluster; /* Surrogates. */
+  }
+
+#define FAIL(...) \
+  HB_STMT_START { \
+    DEBUG_MSG (CORETEXT, NULL, __VA_ARGS__); \
+    ret = false; \
+    goto fail; \
+  } HB_STMT_END;
+
+  bool ret = true;
+  CFStringRef string_ref = NULL;
+  CTLineRef line = NULL;
+
+  if (0)
+  {
+resize_and_retry:
+    DEBUG_MSG (CORETEXT, buffer, "Buffer resize");
+    /* string_ref uses the scratch-buffer for backing store, and line references
+     * string_ref (via attr_string).  We must release those before resizing buffer. */
+    assert (string_ref);
+    assert (line);
+    CFRelease (string_ref);
+    CFRelease (line);
+    string_ref = NULL;
+    line = NULL;
+
+    /* Get previous start-of-scratch-area, that we use later for readjusting
+     * our existing scratch arrays. */
+    unsigned int old_scratch_used;
+    hb_buffer_t::scratch_buffer_t *old_scratch;
+    old_scratch = buffer->get_scratch_buffer (&old_scratch_used);
+    old_scratch_used = scratch - old_scratch;
+
+    if (unlikely (!buffer->ensure (buffer->allocated * 2)))
+      FAIL ("Buffer resize failed");
+
+    /* Adjust scratch, pchars, and log_cluster arrays.  This is ugly, but really the
+     * cleanest way to do without completely restructuring the rest of this shaper. */
+    scratch = buffer->get_scratch_buffer (&scratch_size);
+    pchars = reinterpret_cast<UniChar *> (((char *) scratch + ((char *) pchars - (char *) old_scratch)));
+    log_clusters = reinterpret_cast<unsigned int *> (((char *) scratch + ((char *) log_clusters - (char *) old_scratch)));
+    scratch += old_scratch_used;
+    scratch_size -= old_scratch_used;
+  }
+  {
+    string_ref = CFStringCreateWithCharactersNoCopy (NULL,
+                                                     pchars, chars_len,
+                                                     kCFAllocatorNull);
+    if (unlikely (!string_ref))
+      FAIL ("CFStringCreateWithCharactersNoCopy failed");
+
+    /* Create an attributed string, populate it, and create a line from it, then release attributed string. */
+    {
+      CFMutableAttributedStringRef attr_string = CFAttributedStringCreateMutable (kCFAllocatorDefault,
+                                                                                  chars_len);
+      if (unlikely (!attr_string))
+        FAIL ("CFAttributedStringCreateMutable failed");
+      CFAttributedStringReplaceString (attr_string, CFRangeMake (0, 0), string_ref);
+      if (HB_DIRECTION_IS_VERTICAL (buffer->props.direction))
+      {
+        CFAttributedStringSetAttribute (attr_string, CFRangeMake (0, chars_len),
+                                        kCTVerticalFormsAttributeName, kCFBooleanTrue);
+      }
+
+      if (buffer->props.language)
+      {
+/* What's the iOS equivalent of this check?
+ * The symbols was introduced in iOS 7.0.
+ * At any rate, our fallback is safe and works fine. */
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 1090
+#  define kCTLanguageAttributeName CFSTR ("NSLanguage")
+#endif
+        CFStringRef lang = CFStringCreateWithCStringNoCopy (kCFAllocatorDefault,
+                                                            hb_language_to_string (buffer->props.language),
+                                                            kCFStringEncodingUTF8,
+                                                            kCFAllocatorNull);
+        if (unlikely (!lang))
+          FAIL ("CFStringCreateWithCStringNoCopy failed");
+        CFAttributedStringSetAttribute (attr_string, CFRangeMake (0, chars_len),
+                                        kCTLanguageAttributeName, lang);
+        CFRelease (lang);
+      }
+      CFAttributedStringSetAttribute (attr_string, CFRangeMake (0, chars_len),
+                                      kCTFontAttributeName, face_data->ct_font);
+
+      if (num_features)
+      {
+        unsigned int start = 0;
+        range_record_t *last_range = &range_records[0];
+        for (unsigned int k = 0; k < chars_len; k++)
+        {
+          range_record_t *range = last_range;
+          while (log_clusters[k] < range->index_first)
+            range--;
+          while (log_clusters[k] > range->index_last)
+            range++;
+          if (range != last_range)
+          {
+            if (last_range->font)
+              CFAttributedStringSetAttribute (attr_string, CFRangeMake (start, k - start),
+                                              kCTFontAttributeName, last_range->font);
+
+            start = k;
+          }
+
+          last_range = range;
+        }
+        if (start != chars_len && last_range->font)
+          CFAttributedStringSetAttribute (attr_string, CFRangeMake (start, chars_len - start),
+                                          kCTFontAttributeName, last_range->font);
+      }
+
+      int level = HB_DIRECTION_IS_FORWARD (buffer->props.direction) ? 0 : 1;
+      CFNumberRef level_number = CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &level);
+      CFDictionaryRef options = CFDictionaryCreate (kCFAllocatorDefault,
+                                                    (const void **) &kCTTypesetterOptionForcedEmbeddingLevel,
+                                                    (const void **) &level_number,
+                                                    1,
+                                                    &kCFTypeDictionaryKeyCallBacks,
+                                                    &kCFTypeDictionaryValueCallBacks);
+      if (unlikely (!options))
+        FAIL ("CFDictionaryCreate failed");
+
+      CTTypesetterRef typesetter = CTTypesetterCreateWithAttributedStringAndOptions (attr_string, options);
+      CFRelease (options);
+      CFRelease (attr_string);
+      if (unlikely (!typesetter))
+        FAIL ("CTTypesetterCreateWithAttributedStringAndOptions failed");
+
+      line = CTTypesetterCreateLine (typesetter, CFRangeMake(0, 0));
+      CFRelease (typesetter);
+      if (unlikely (!line))
+        FAIL ("CTTypesetterCreateLine failed");
+    }
+
+    CFArrayRef glyph_runs = CTLineGetGlyphRuns (line);
+    unsigned int num_runs = CFArrayGetCount (glyph_runs);
+    DEBUG_MSG (CORETEXT, NULL, "Num runs: %d", num_runs);
+
+    buffer->len = 0;
+    uint32_t status_and = ~0, status_or = 0;
+    double advances_so_far = 0;
+    /* For right-to-left runs, CoreText returns the glyphs positioned such that
+     * any trailing whitespace is to the left of (0,0).  Adjust coordinate system
+     * to fix for that.  Test with any RTL string with trailing spaces.
+     * https://code.google.com/p/chromium/issues/detail?id=469028
+     */
+    if (HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
+    {
+      advances_so_far -= CTLineGetTrailingWhitespaceWidth (line);
+      if (HB_DIRECTION_IS_VERTICAL (buffer->props.direction))
+          advances_so_far = -advances_so_far;
+    }
+
+    const CFRange range_all = CFRangeMake (0, 0);
+
+    for (unsigned int i = 0; i < num_runs; i++)
+    {
+      CTRunRef run = static_cast<CTRunRef>(CFArrayGetValueAtIndex (glyph_runs, i));
+      CTRunStatus run_status = CTRunGetStatus (run);
+      status_or  |= run_status;
+      status_and &= run_status;
+      DEBUG_MSG (CORETEXT, run, "CTRunStatus: %x", run_status);
+      double run_advance = CTRunGetTypographicBounds (run, range_all, NULL, NULL, NULL);
+      if (HB_DIRECTION_IS_VERTICAL (buffer->props.direction))
+          run_advance = -run_advance;
+      DEBUG_MSG (CORETEXT, run, "Run advance: %g", run_advance);
+
+      /* CoreText does automatic font fallback (AKA "cascading") for  characters
+       * not supported by the requested font, and provides no way to turn it off,
+       * so we must detect if the returned run uses a font other than the requested
+       * one and fill in the buffer with .notdef glyphs instead of random glyph
+       * indices from a different font.
+       */
+      CFDictionaryRef attributes = CTRunGetAttributes (run);
+      CTFontRef run_ct_font = static_cast<CTFontRef>(CFDictionaryGetValue (attributes, kCTFontAttributeName));
+      if (!CFEqual (run_ct_font, face_data->ct_font))
+      {
+        /* The run doesn't use our main font instance.  We have to figure out
+         * whether font fallback happened, or this is just CoreText giving us
+         * another CTFont using the same underlying CGFont.  CoreText seems
+         * to do that in a variety of situations, one of which being vertical
+         * text, but also perhaps for caching reasons.
+         *
+         * First, see if it uses any of our subfonts created to set font features...
+         *
+         * Next, compare the CGFont to the one we used to create our fonts.
+         * Even this doesn't work all the time.
+         *
+         * Finally, we compare PS names, which I don't think are unique...
+         *
+         * Looks like if we really want to be sure here we have to modify the
+         * font to change the name table, similar to what we do in the uniscribe
+         * backend.
+         *
+         * However, even that wouldn't work if we were passed in the CGFont to
+         * construct a hb_face to begin with.
+         *
+         * See: http://github.com/behdad/harfbuzz/pull/36
+         *
+         * Also see: https://bugs.chromium.org/p/chromium/issues/detail?id=597098
+         */
+        bool matched = false;
+        for (unsigned int i = 0; i < range_records.len; i++)
+          if (range_records[i].font && CFEqual (run_ct_font, range_records[i].font))
+          {
+            matched = true;
+            break;
+          }
+        if (!matched)
+        {
+          CGFontRef run_cg_font = CTFontCopyGraphicsFont (run_ct_font, 0);
+          if (run_cg_font)
+          {
+            matched = CFEqual (run_cg_font, face_data->cg_font);
+            CFRelease (run_cg_font);
+          }
+        }
+        if (!matched)
+        {
+          CFStringRef font_ps_name = CTFontCopyName (face_data->ct_font, kCTFontPostScriptNameKey);
+          CFStringRef run_ps_name = CTFontCopyName (run_ct_font, kCTFontPostScriptNameKey);
+          CFComparisonResult result = CFStringCompare (run_ps_name, font_ps_name, 0);
+          CFRelease (run_ps_name);
+          CFRelease (font_ps_name);
+          if (result == kCFCompareEqualTo)
+            matched = true;
+        }
+        if (!matched)
+        {
+          CFRange range = CTRunGetStringRange (run);
+          DEBUG_MSG (CORETEXT, run, "Run used fallback font: %ld..%ld",
+                     range.location, range.location + range.length);
+          if (!buffer->ensure_inplace (buffer->len + range.length))
+            goto resize_and_retry;
+          hb_glyph_info_t *info = buffer->info + buffer->len;
+
+          hb_codepoint_t notdef = 0;
+          hb_direction_t dir = buffer->props.direction;
+          hb_position_t x_advance, y_advance, x_offset, y_offset;
+          hb_font_get_glyph_advance_for_direction (font, notdef, dir, &x_advance, &y_advance);
+          hb_font_get_glyph_origin_for_direction (font, notdef, dir, &x_offset, &y_offset);
+          hb_position_t advance = x_advance + y_advance;
+          x_offset = -x_offset;
+          y_offset = -y_offset;
+
+          unsigned int old_len = buffer->len;
+          for (CFIndex j = range.location; j < range.location + range.length; j++)
+          {
+              UniChar ch = CFStringGetCharacterAtIndex (string_ref, j);
+              if (hb_in_range<UniChar> (ch, 0xDC00u, 0xDFFFu) && range.location < j)
+              {
+                ch = CFStringGetCharacterAtIndex (string_ref, j - 1);
+                if (hb_in_range<UniChar> (ch, 0xD800u, 0xDBFFu))
+                  /* This is the second of a surrogate pair.  Don't need .notdef
+                   * for this one. */
+                  continue;
+              }
+              if (buffer->unicode->is_default_ignorable (ch))
+                continue;
+
+              info->codepoint = notdef;
+              info->cluster = log_clusters[j];
+
+              info->mask = advance;
+              info->var1.i32 = x_offset;
+              info->var2.i32 = y_offset;
+
+              info++;
+              buffer->len++;
+          }
+          if (HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
+            buffer->reverse_range (old_len, buffer->len);
+          advances_so_far += run_advance;
+          continue;
+        }
+      }
+
+      unsigned int num_glyphs = CTRunGetGlyphCount (run);
+      if (num_glyphs == 0)
+        continue;
+
+      if (!buffer->ensure_inplace (buffer->len + num_glyphs))
+        goto resize_and_retry;
+
+      hb_glyph_info_t *run_info = buffer->info + buffer->len;
+
+      /* Testing used to indicate that CTRunGetGlyphsPtr, etc (almost?) always
+       * succeed, and so copying data to our own buffer will be rare.  Reports
+       * have it that this changed in OS X 10.10 Yosemite, and NULL is returned
+       * frequently.  At any rate, we can test that codepath by setting USE_PTR
+       * to false. */
+
+#define USE_PTR true
+
+#define SCRATCH_SAVE() \
+  unsigned int scratch_size_saved = scratch_size; \
+  hb_buffer_t::scratch_buffer_t *scratch_saved = scratch
+
+#define SCRATCH_RESTORE() \
+  scratch_size = scratch_size_saved; \
+  scratch = scratch_saved;
+
+      { /* Setup glyphs */
+        SCRATCH_SAVE();
+        const CGGlyph* glyphs = USE_PTR ? CTRunGetGlyphsPtr (run) : NULL;
+        if (!glyphs) {
+          ALLOCATE_ARRAY (CGGlyph, glyph_buf, num_glyphs, goto resize_and_retry);
+          CTRunGetGlyphs (run, range_all, glyph_buf);
+          glyphs = glyph_buf;
+        }
+        const CFIndex* string_indices = USE_PTR ? CTRunGetStringIndicesPtr (run) : NULL;
+        if (!string_indices) {
+          ALLOCATE_ARRAY (CFIndex, index_buf, num_glyphs, goto resize_and_retry);
+          CTRunGetStringIndices (run, range_all, index_buf);
+          string_indices = index_buf;
+        }
+        hb_glyph_info_t *info = run_info;
+        for (unsigned int j = 0; j < num_glyphs; j++)
+        {
+          info->codepoint = glyphs[j];
+          info->cluster = log_clusters[string_indices[j]];
+          info++;
+        }
+        SCRATCH_RESTORE();
+      }
+      {
+        /* Setup positions.
+         * Note that CoreText does not return advances for glyphs.  As such,
+         * for all but last glyph, we use the delta position to next glyph as
+         * advance (in the advance direction only), and for last glyph we set
+         * whatever is needed to make the whole run's advance add up. */
+        SCRATCH_SAVE();
+        const CGPoint* positions = USE_PTR ? CTRunGetPositionsPtr (run) : NULL;
+        if (!positions) {
+          ALLOCATE_ARRAY (CGPoint, position_buf, num_glyphs, goto resize_and_retry);
+          CTRunGetPositions (run, range_all, position_buf);
+          positions = position_buf;
+        }
+        hb_glyph_info_t *info = run_info;
+        if (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction))
+        {
+          hb_position_t x_offset = (positions[0].x - advances_so_far) * x_mult;
+          for (unsigned int j = 0; j < num_glyphs; j++)
+          {
+            double advance;
+            if (likely (j + 1 < num_glyphs))
+              advance = positions[j + 1].x - positions[j].x;
+            else /* last glyph */
+              advance = run_advance - (positions[j].x - positions[0].x);
+            info->mask = advance * x_mult;
+            info->var1.i32 = x_offset;
+            info->var2.i32 = positions[j].y * y_mult;
+            info++;
+          }
+        }
+        else
+        {
+          hb_position_t y_offset = (positions[0].y - advances_so_far) * y_mult;
+          for (unsigned int j = 0; j < num_glyphs; j++)
+          {
+            double advance;
+            if (likely (j + 1 < num_glyphs))
+              advance = positions[j + 1].y - positions[j].y;
+            else /* last glyph */
+              advance = run_advance - (positions[j].y - positions[0].y);
+            info->mask = advance * y_mult;
+            info->var1.i32 = positions[j].x * x_mult;
+            info->var2.i32 = y_offset;
+            info++;
+          }
+        }
+        SCRATCH_RESTORE();
+        advances_so_far += run_advance;
+      }
+#undef SCRATCH_RESTORE
+#undef SCRATCH_SAVE
+#undef USE_PTR
+#undef ALLOCATE_ARRAY
+
+      buffer->len += num_glyphs;
+    }
+
+    /* Mac OS 10.6 doesn't have kCTTypesetterOptionForcedEmbeddingLevel,
+     * or if it does, it doesn't resepct it.  So we get runs with wrong
+     * directions.  As such, disable the assert...  It wouldn't crash, but
+     * cursoring will be off...
+     *
+     * http://crbug.com/419769
+     */
+    if (0)
+    {
+      /* Make sure all runs had the expected direction. */
+      bool backward = HB_DIRECTION_IS_BACKWARD (buffer->props.direction);
+      assert (bool (status_and & kCTRunStatusRightToLeft) == backward);
+      assert (bool (status_or  & kCTRunStatusRightToLeft) == backward);
+    }
+
+    buffer->clear_positions ();
+
+    unsigned int count = buffer->len;
+    hb_glyph_info_t *info = buffer->info;
+    hb_glyph_position_t *pos = buffer->pos;
+    if (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction))
+      for (unsigned int i = 0; i < count; i++)
+      {
+        pos->x_advance = info->mask;
+        pos->x_offset = info->var1.i32;
+        pos->y_offset = info->var2.i32;
+        info++, pos++;
+      }
+    else
+      for (unsigned int i = 0; i < count; i++)
+      {
+        pos->y_advance = info->mask;
+        pos->x_offset = info->var1.i32;
+        pos->y_offset = info->var2.i32;
+        info++, pos++;
+      }
+
+    /* Fix up clusters so that we never return out-of-order indices;
+     * if core text has reordered glyphs, we'll merge them to the
+     * beginning of the reordered cluster.  CoreText is nice enough
+     * to tell us whenever it has produced nonmonotonic results...
+     * Note that we assume the input clusters were nonmonotonic to
+     * begin with.
+     *
+     * This does *not* mean we'll form the same clusters as Uniscribe
+     * or the native OT backend, only that the cluster indices will be
+     * monotonic in the output buffer. */
+    if (count > 1 && (status_or & kCTRunStatusNonMonotonic))
+    {
+      hb_glyph_info_t *info = buffer->info;
+      if (HB_DIRECTION_IS_FORWARD (buffer->props.direction))
+      {
+        unsigned int cluster = info[count - 1].cluster;
+        for (unsigned int i = count - 1; i > 0; i--)
+        {
+          cluster = MIN (cluster, info[i - 1].cluster);
+          info[i - 1].cluster = cluster;
+        }
+      }
+      else
+      {
+        unsigned int cluster = info[0].cluster;
+        for (unsigned int i = 1; i < count; i++)
+        {
+          cluster = MIN (cluster, info[i].cluster);
+          info[i].cluster = cluster;
+        }
+      }
+    }
+  }
+
+#undef FAIL
+
+fail:
+  if (string_ref)
+    CFRelease (string_ref);
+  if (line)
+    CFRelease (line);
+
+  for (unsigned int i = 0; i < range_records.len; i++)
+    if (range_records[i].font)
+      CFRelease (range_records[i].font);
+
+  return ret;
+}
+
+
+/*
+ * AAT shaper
+ */
+
+/*
+ * shaper face data
+ */
+
+struct hb_coretext_aat_shaper_face_data_t {};
+
+hb_coretext_aat_shaper_face_data_t *
+_hb_coretext_aat_shaper_face_data_create (hb_face_t *face)
+{
+  hb_blob_t *mort_blob = face->reference_table (HB_CORETEXT_TAG_MORT);
+  /* Umm, we just reference the table to check whether it exists.
+   * Maybe add better API for this? */
+  if (!hb_blob_get_length (mort_blob))
+  {
+    hb_blob_destroy (mort_blob);
+    mort_blob = face->reference_table (HB_CORETEXT_TAG_MORX);
+    if (!hb_blob_get_length (mort_blob))
+    {
+      hb_blob_destroy (mort_blob);
+      return NULL;
+    }
+  }
+  hb_blob_destroy (mort_blob);
+
+  return hb_coretext_shaper_face_data_ensure (face) ? (hb_coretext_aat_shaper_face_data_t *) HB_SHAPER_DATA_SUCCEEDED : NULL;
+}
+
+void
+_hb_coretext_aat_shaper_face_data_destroy (hb_coretext_aat_shaper_face_data_t *data HB_UNUSED)
+{
+}
+
+
+/*
+ * shaper font data
+ */
+
+struct hb_coretext_aat_shaper_font_data_t {};
+
+hb_coretext_aat_shaper_font_data_t *
+_hb_coretext_aat_shaper_font_data_create (hb_font_t *font)
+{
+  return hb_coretext_shaper_font_data_ensure (font) ? (hb_coretext_aat_shaper_font_data_t *) HB_SHAPER_DATA_SUCCEEDED : NULL;
+}
+
+void
+_hb_coretext_aat_shaper_font_data_destroy (hb_coretext_aat_shaper_font_data_t *data HB_UNUSED)
+{
+}
+
+
+/*
+ * shaper shape_plan data
+ */
+
+struct hb_coretext_aat_shaper_shape_plan_data_t {};
+
+hb_coretext_aat_shaper_shape_plan_data_t *
+_hb_coretext_aat_shaper_shape_plan_data_create (hb_shape_plan_t    *shape_plan HB_UNUSED,
+                                             const hb_feature_t *user_features HB_UNUSED,
+                                             unsigned int        num_user_features HB_UNUSED,
+                                             const int          *coords HB_UNUSED,
+                                             unsigned int        num_coords HB_UNUSED)
+{
+  return (hb_coretext_aat_shaper_shape_plan_data_t *) HB_SHAPER_DATA_SUCCEEDED;
+}
+
+void
+_hb_coretext_aat_shaper_shape_plan_data_destroy (hb_coretext_aat_shaper_shape_plan_data_t *data HB_UNUSED)
+{
+}
+
+
+/*
+ * shaper
+ */
+
+hb_bool_t
+_hb_coretext_aat_shape (hb_shape_plan_t    *shape_plan,
+                        hb_font_t          *font,
+                        hb_buffer_t        *buffer,
+                        const hb_feature_t *features,
+                        unsigned int        num_features)
+{
+  return _hb_coretext_shape (shape_plan, font, buffer, features, num_features);
+}