Roll HarfBuzz to 0.9.32

third_party/harfbuzz-ng/src/hb-ot-shape-complex-arabic.cc

Index: third_party/harfbuzz-ng/src/hb-ot-shape-complex-arabic.cc
diff --git a/third_party/harfbuzz-ng/src/hb-ot-shape-complex-arabic.cc b/third_party/harfbuzz-ng/src/hb-ot-shape-complex-arabic.cc
index ea6d85c1e6c1f282dc5c9bc392752aac76a4d17b..9870ba3da05376de77301c2fc7d3a65505570a94 100644
--- a/third_party/harfbuzz-ng/src/hb-ot-shape-complex-arabic.cc
+++ b/third_party/harfbuzz-ng/src/hb-ot-shape-complex-arabic.cc
@@ -57,68 +57,41 @@ enum {
 
 static unsigned int get_joining_type (hb_codepoint_t u, hb_unicode_general_category_t gen_cat)
 {
-  if (likely (hb_in_range<hb_codepoint_t> (u, JOINING_TABLE_FIRST, JOINING_TABLE_LAST))) {
-    unsigned int j_type = joining_table[u - JOINING_TABLE_FIRST];
-    if (likely (j_type != JOINING_TYPE_X))
-      return j_type;
-  }
-
-  /* Mongolian joining data is not in ArabicJoining.txt yet. */
-  if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x1800, 0x18AF)))
-  {
-    if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x1880, 0x1886)))
-      return JOINING_TYPE_U;
-
-    /* All letters, SIBE SYLLABLE BOUNDARY MARKER, and NIRUGU are D */
-    if ((FLAG(gen_cat) & (FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER) |
-			  FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_LETTER)))
-	|| u == 0x1807 || u == 0x180A)
-      return JOINING_TYPE_D;
-  }
-
-  /* 'Phags-pa joining data is not in ArabicJoining.txt yet. */
-  if (unlikely (hb_in_range<hb_codepoint_t> (u, 0xA840, 0xA872)))
-  {
-      if (unlikely (u == 0xA872))
-	return JOINING_TYPE_L;
-
-      return JOINING_TYPE_D;
-  }
-
-  if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x200C, 0x200D)))
-  {
-    return u == 0x200C ? JOINING_TYPE_U : JOINING_TYPE_C;
-  }
-
-  return (FLAG(gen_cat) & (FLAG(HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) | FLAG(HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) | FLAG(HB_UNICODE_GENERAL_CATEGORY_FORMAT))) ?
-	 JOINING_TYPE_T : JOINING_TYPE_U;
+  unsigned int j_type = joining_type(u);
+  if (likely (j_type != JOINING_TYPE_X))
+    return j_type;
+
+  return (FLAG(gen_cat) &
+	  (FLAG(HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) |
+	   FLAG(HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) |
+	   FLAG(HB_UNICODE_GENERAL_CATEGORY_FORMAT))
+	 ) ?  JOINING_TYPE_T : JOINING_TYPE_U;
 }
 
+#define FEATURE_IS_SYRIAC(tag) hb_in_range<unsigned char> ((unsigned char) (tag), '2', '3')
+
 static const hb_tag_t arabic_features[] =
 {
-  HB_TAG('i','n','i','t'),
-  HB_TAG('m','e','d','i'),
-  HB_TAG('f','i','n','a'),
   HB_TAG('i','s','o','l'),
-  /* Syriac */
-  HB_TAG('m','e','d','2'),
+  HB_TAG('f','i','n','a'),
   HB_TAG('f','i','n','2'),
   HB_TAG('f','i','n','3'),
+  HB_TAG('m','e','d','i'),
+  HB_TAG('m','e','d','2'),
+  HB_TAG('i','n','i','t'),
   HB_TAG_NONE
 };
 
 
 /* Same order as the feature array */
 enum {
-  INIT,
-  MEDI,
-  FINA,
   ISOL,
-
-  /* Syriac */
-  MED2,
+  FINA,
   FIN2,
   FIN3,
+  MEDI,
+  MED2,
+  INIT,
 
   NONE,
 
@@ -171,14 +144,23 @@ collect_features_arabic (hb_ot_shape_planner_t *plan)
 {
   hb_ot_map_builder_t *map = &plan->map;
 
-  /* For Language forms (in ArabicOT speak), we do the iso/fina/medi/init together,
-   * then rlig and calt each in their own stage.  This makes IranNastaliq's ALLAH
-   * ligature work correctly. It's unfortunate though...
+  /* We apply features according to the Arabic spec, with pauses
+   * in between most.
    *
-   * This also makes Arial Bold in Windows7 work.  See:
+   * The pause between init/medi/... and rlig is required.  See eg:
    * https://bugzilla.mozilla.org/show_bug.cgi?id=644184
    *
-   * TODO: Add test cases for these two.
+   * The pauses between init/medi/... themselves are not necessarily
+   * needed as only one of those features is applied to any character.
+   * The only difference it makes is when fonts have contextual
+   * substitutions.  We now follow the order of the spec, which makes
+   * for better experience if that's what Uniscribe is doing.
+   *
+   * At least for Arabic, looks like Uniscribe has a pause between
+   * rlig and calt.  Otherwise the IranNastaliq's ALLAH ligature won't
+   * work.  However, testing shows that rlig and calt are applied
+   * together for Mongolian in Uniscribe.  As such, we only add a
+   * pause for Arabic, not other scripts.
    */
 
   map->add_gsub_pause (nuke_joiners);
@@ -189,16 +171,28 @@ collect_features_arabic (hb_ot_shape_planner_t *plan)
   map->add_gsub_pause (NULL);
 
   for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++)
-    map->add_feature (arabic_features[i], 1, i < 4 ? F_HAS_FALLBACK : F_NONE); /* The first four features have fallback. */
-
-  map->add_gsub_pause (NULL);
+  {
+    bool has_fallback = plan->props.script == HB_SCRIPT_ARABIC && !FEATURE_IS_SYRIAC (arabic_features[i]);
+    map->add_feature (arabic_features[i], 1, has_fallback ? F_HAS_FALLBACK : F_NONE);
+    map->add_gsub_pause (NULL);
+  }
 
   map->add_feature (HB_TAG('r','l','i','g'), 1, F_GLOBAL|F_HAS_FALLBACK);
-  map->add_gsub_pause (arabic_fallback_shape);
+  if (plan->props.script == HB_SCRIPT_ARABIC)
+    map->add_gsub_pause (arabic_fallback_shape);
 
   map->add_global_bool_feature (HB_TAG('c','a','l','t'));
   map->add_gsub_pause (NULL);
 
+  /* The spec includes 'cswh'.  Earlier versions of Windows
+   * used to enable this by default, but testing suggests
+   * that Windows 8 and later do not enable it by default,
+   * and spec now says 'Off by default'.
+   * We disabled this in ae23c24c32.
+   * Note that IranNastaliq uses this feature extensively
+   * to fixup broken glyph sequences.  Oh well...
+   * Test case: U+0643,U+0640,U+0631. */
+  //map->add_global_bool_feature (HB_TAG('c','s','w','h'));
   map->add_global_bool_feature (HB_TAG('m','s','e','t'));
 }
 
@@ -228,8 +222,9 @@ data_create_arabic (const hb_ot_shape_plan_t *plan)
   arabic_plan->do_fallback = plan->props.script == HB_SCRIPT_ARABIC;
   for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++) {
     arabic_plan->mask_array[i] = plan->map.get_1_mask (arabic_features[i]);
-    if (i < 4)
-      arabic_plan->do_fallback = arabic_plan->do_fallback && plan->map.needs_fallback (arabic_features[i]);
+    arabic_plan->do_fallback = arabic_plan->do_fallback &&
+			       !FEATURE_IS_SYRIAC (arabic_features[i]) &&
+			       plan->map.needs_fallback (arabic_features[i]);
   }
 
   return arabic_plan;
@@ -249,10 +244,9 @@ static void
 arabic_joining (hb_buffer_t *buffer)
 {
   unsigned int count = buffer->len;
+  hb_glyph_info_t *info = buffer->info;
   unsigned int prev = (unsigned int) -1, state = 0;
 
-  HB_BUFFER_ALLOCATE_VAR (buffer, arabic_shaping_action);
-
   /* Check pre-context */
   if (!(buffer->flags & HB_BUFFER_FLAG_BOT))
     for (unsigned int i = 0; i < buffer->context_len[0]; i++)
@@ -269,20 +263,19 @@ arabic_joining (hb_buffer_t *buffer)
 
   for (unsigned int i = 0; i < count; i++)
   {
-    unsigned int this_type = get_joining_type (buffer->info[i].codepoint, _hb_glyph_info_get_general_category (&buffer->info[i]));
+    unsigned int this_type = get_joining_type (info[i].codepoint, _hb_glyph_info_get_general_category (&info[i]));
 
     if (unlikely (this_type == JOINING_TYPE_T)) {
-      buffer->info[i].arabic_shaping_action() = NONE;
+      info[i].arabic_shaping_action() = NONE;
       continue;
     }
 
     const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
 
     if (entry->prev_action != NONE && prev != (unsigned int) -1)
-      for (; prev < i; prev++)
-	buffer->info[prev].arabic_shaping_action() = entry->prev_action;
+      info[prev].arabic_shaping_action() = entry->prev_action;
 
-    buffer->info[i].arabic_shaping_action() = entry->curr_action;
+    info[i].arabic_shaping_action() = entry->curr_action;
 
     prev = i;
     state = entry->next_state;
@@ -298,12 +291,20 @@ arabic_joining (hb_buffer_t *buffer)
 
       const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
       if (entry->prev_action != NONE && prev != (unsigned int) -1)
-	buffer->info[prev].arabic_shaping_action() = entry->prev_action;
+	info[prev].arabic_shaping_action() = entry->prev_action;
       break;
     }
+}
 
-
-  HB_BUFFER_DEALLOCATE_VAR (buffer, arabic_shaping_action);
+static void
+mongolian_variation_selectors (hb_buffer_t *buffer)
+{
+  /* Copy arabic_shaping_action() from base to Mongolian variation selectors. */
+  unsigned int count = buffer->len;
+  hb_glyph_info_t *info = buffer->info;
+  for (unsigned int i = 1; i < count; i++)
+    if (unlikely (hb_in_range (info[i].codepoint, 0x180Bu, 0x180Du)))
+      info[i].arabic_shaping_action() = info[i - 1].arabic_shaping_action();
 }
 
 static void
@@ -311,12 +312,20 @@ setup_masks_arabic (const hb_ot_shape_plan_t *plan,
 		    hb_buffer_t              *buffer,
 		    hb_font_t                *font HB_UNUSED)
 {
+  HB_BUFFER_ALLOCATE_VAR (buffer, arabic_shaping_action);
+
   const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data;
 
   arabic_joining (buffer);
+  if (plan->props.script == HB_SCRIPT_MONGOLIAN)
+    mongolian_variation_selectors (buffer);
+
   unsigned int count = buffer->len;
+  hb_glyph_info_t *info = buffer->info;
   for (unsigned int i = 0; i < count; i++)
-    buffer->info[i].mask |= arabic_plan->mask_array[buffer->info[i].arabic_shaping_action()];
+    info[i].mask |= arabic_plan->mask_array[info[i].arabic_shaping_action()];
+
+  HB_BUFFER_DEALLOCATE_VAR (buffer, arabic_shaping_action);
 }
 
 
@@ -326,9 +335,10 @@ nuke_joiners (const hb_ot_shape_plan_t *plan HB_UNUSED,
 	      hb_buffer_t *buffer)
 {
   unsigned int count = buffer->len;
+  hb_glyph_info_t *info = buffer->info;
   for (unsigned int i = 0; i < count; i++)
-    if (_hb_glyph_info_is_zwj (&buffer->info[i]))
-      _hb_glyph_info_flip_joiners (&buffer->info[i]);
+    if (_hb_glyph_info_is_zwj (&info[i]))
+      _hb_glyph_info_flip_joiners (&info[i]);
 }
 
 static void