Merge pull request #57563 from bruvzg/hb331

1 files changed, 191 insertions, 113 deletions

diff --git a/thirdparty/harfbuzz/src/hb-ot-layout-gsubgpos.hh b/thirdparty/harfbuzz/src/hb-ot-layout-gsubgpos.hh
index 191d3bebc5..65de131f85 100644
--- a/thirdparty/harfbuzz/src/hb-ot-layout-gsubgpos.hh
+++ b/thirdparty/harfbuzz/src/hb-ot-layout-gsubgpos.hh
@@ -125,24 +125,31 @@ struct hb_closure_context_t :
     hb_set_t *covered_glyph_set = done_lookups_glyph_set->get (lookup_index);
     if (unlikely (covered_glyph_set->in_error ()))
       return true;
-    if (parent_active_glyphs ()->is_subset (*covered_glyph_set))
+    if (parent_active_glyphs ().is_subset (*covered_glyph_set))
       return true;
 
-    hb_set_union (covered_glyph_set, parent_active_glyphs ());
+    covered_glyph_set->union_ (parent_active_glyphs ());
     return false;
   }
 
-  hb_set_t* parent_active_glyphs ()
+  const hb_set_t& previous_parent_active_glyphs () {
+    if (active_glyphs_stack.length <= 1)
+      return *glyphs;
+
+    return active_glyphs_stack[active_glyphs_stack.length - 2];
+  }
+
+  const hb_set_t& parent_active_glyphs ()
   {
-    if (active_glyphs_stack.length < 1)
-      return glyphs;
+    if (!active_glyphs_stack)
+      return *glyphs;
 
     return active_glyphs_stack.tail ();
   }
 
-  void push_cur_active_glyphs (hb_set_t* cur_active_glyph_set)
+  hb_set_t& push_cur_active_glyphs ()
   {
-    active_glyphs_stack.push (cur_active_glyph_set);
+    return *active_glyphs_stack.push ();
   }
 
   bool pop_cur_done_glyphs ()
@@ -156,29 +163,24 @@ struct hb_closure_context_t :
 
   hb_face_t *face;
   hb_set_t *glyphs;
-  hb_set_t *cur_intersected_glyphs;
   hb_set_t output[1];
-  hb_vector_t<hb_set_t *> active_glyphs_stack;
+  hb_vector_t<hb_set_t> active_glyphs_stack;
   recurse_func_t recurse_func;
   unsigned int nesting_level_left;
 
   hb_closure_context_t (hb_face_t *face_,
 			hb_set_t *glyphs_,
-			hb_set_t *cur_intersected_glyphs_,
 			hb_map_t *done_lookups_glyph_count_,
 			hb_hashmap_t<unsigned, hb_set_t *> *done_lookups_glyph_set_,
 			unsigned int nesting_level_left_ = HB_MAX_NESTING_LEVEL) :
 			  face (face_),
 			  glyphs (glyphs_),
-			  cur_intersected_glyphs (cur_intersected_glyphs_),
 			  recurse_func (nullptr),
 			  nesting_level_left (nesting_level_left_),
 			  done_lookups_glyph_count (done_lookups_glyph_count_),
 			  done_lookups_glyph_set (done_lookups_glyph_set_),
 			  lookup_count (0)
-  {
-    push_cur_active_glyphs (glyphs_);
-  }
+  {}
 
   ~hb_closure_context_t () { flush (); }
 
@@ -186,11 +188,11 @@ struct hb_closure_context_t :
 
   void flush ()
   {
-    hb_set_del_range (output, face->get_num_glyphs (), HB_SET_VALUE_INVALID);	/* Remove invalid glyphs. */
-    hb_set_union (glyphs, output);
-    hb_set_clear (output);
+    output->del_range (face->get_num_glyphs (), HB_SET_VALUE_INVALID);	/* Remove invalid glyphs. */
+    glyphs->union_ (*output);
+    output->clear ();
     active_glyphs_stack.pop ();
-    active_glyphs_stack.fini ();
+    active_glyphs_stack.reset ();
   }
 
   private:
@@ -520,7 +522,7 @@ struct hb_ot_apply_context_t :
     may_skip (const hb_glyph_info_t &info) const
     { return matcher.may_skip (c, info); }
 
-    bool next ()
+    bool next (unsigned *unsafe_to = nullptr)
     {
       assert (num_items > 0);
       while (idx + num_items < end)
@@ -543,11 +545,17 @@ struct hb_ot_apply_context_t :
 	}
 
 	if (skip == matcher_t::SKIP_NO)
+	{
+	  if (unsafe_to)
+	    *unsafe_to = idx + 1;
 	  return false;
+	}
       }
+      if (unsafe_to)
+        *unsafe_to = end;
       return false;
     }
-    bool prev ()
+    bool prev (unsigned *unsafe_from = nullptr)
     {
       assert (num_items > 0);
       while (idx > num_items - 1)
@@ -570,8 +578,14 @@ struct hb_ot_apply_context_t :
 	}
 
 	if (skip == matcher_t::SKIP_NO)
+	{
+	  if (unsafe_from)
+	    *unsafe_from = hb_max (1u, idx) - 1u;
 	  return false;
+	}
       }
+      if (unsafe_from)
+        *unsafe_from = 0;
       return false;
     }
 
@@ -712,53 +726,60 @@ struct hb_ot_apply_context_t :
     return true;
   }
 
-  void _set_glyph_props (hb_codepoint_t glyph_index,
+  void _set_glyph_class (hb_codepoint_t glyph_index,
 			  unsigned int class_guess = 0,
 			  bool ligature = false,
 			  bool component = false) const
   {
-    unsigned int add_in = _hb_glyph_info_get_glyph_props (&buffer->cur()) &
-			  HB_OT_LAYOUT_GLYPH_PROPS_PRESERVE;
-    add_in |= HB_OT_LAYOUT_GLYPH_PROPS_SUBSTITUTED;
+    unsigned int props = _hb_glyph_info_get_glyph_props (&buffer->cur());
+    props |= HB_OT_LAYOUT_GLYPH_PROPS_SUBSTITUTED;
     if (ligature)
     {
-      add_in |= HB_OT_LAYOUT_GLYPH_PROPS_LIGATED;
+      props |= HB_OT_LAYOUT_GLYPH_PROPS_LIGATED;
       /* In the only place that the MULTIPLIED bit is used, Uniscribe
        * seems to only care about the "last" transformation between
        * Ligature and Multiple substitutions.  Ie. if you ligate, expand,
        * and ligate again, it forgives the multiplication and acts as
        * if only ligation happened.  As such, clear MULTIPLIED bit.
        */
-      add_in &= ~HB_OT_LAYOUT_GLYPH_PROPS_MULTIPLIED;
+      props &= ~HB_OT_LAYOUT_GLYPH_PROPS_MULTIPLIED;
     }
     if (component)
-      add_in |= HB_OT_LAYOUT_GLYPH_PROPS_MULTIPLIED;
+      props |= HB_OT_LAYOUT_GLYPH_PROPS_MULTIPLIED;
     if (likely (has_glyph_classes))
-      _hb_glyph_info_set_glyph_props (&buffer->cur(), add_in | gdef.get_glyph_props (glyph_index));
+    {
+      props &= HB_OT_LAYOUT_GLYPH_PROPS_PRESERVE;
+      _hb_glyph_info_set_glyph_props (&buffer->cur(), props | gdef.get_glyph_props (glyph_index));
+    }
     else if (class_guess)
-      _hb_glyph_info_set_glyph_props (&buffer->cur(), add_in | class_guess);
+    {
+      props &= HB_OT_LAYOUT_GLYPH_PROPS_PRESERVE;
+      _hb_glyph_info_set_glyph_props (&buffer->cur(), props | class_guess);
+    }
+    else
+      _hb_glyph_info_set_glyph_props (&buffer->cur(), props);
   }
 
   void replace_glyph (hb_codepoint_t glyph_index) const
   {
-    _set_glyph_props (glyph_index);
+    _set_glyph_class (glyph_index);
     (void) buffer->replace_glyph (glyph_index);
   }
   void replace_glyph_inplace (hb_codepoint_t glyph_index) const
   {
-    _set_glyph_props (glyph_index);
+    _set_glyph_class (glyph_index);
     buffer->cur().codepoint = glyph_index;
   }
   void replace_glyph_with_ligature (hb_codepoint_t glyph_index,
 				    unsigned int class_guess) const
   {
-    _set_glyph_props (glyph_index, class_guess, true);
+    _set_glyph_class (glyph_index, class_guess, true);
     (void) buffer->replace_glyph (glyph_index);
   }
   void output_glyph_for_component (hb_codepoint_t glyph_index,
 				   unsigned int class_guess) const
   {
-    _set_glyph_props (glyph_index, class_guess, false, true);
+    _set_glyph_class (glyph_index, class_guess, false, true);
     (void) buffer->output_glyph (glyph_index);
   }
 };
@@ -948,7 +969,7 @@ static inline bool match_input (hb_ot_apply_context_t *c,
 				const HBUINT16 input[], /* Array of input values--start with second glyph */
 				match_func_t match_func,
 				const void *match_data,
-				unsigned int *end_offset,
+				unsigned int *end_position,
 				unsigned int match_positions[HB_MAX_CONTEXT_LENGTH],
 				unsigned int *p_total_component_count = nullptr)
 {
@@ -1001,7 +1022,12 @@ static inline bool match_input (hb_ot_apply_context_t *c,
   match_positions[0] = buffer->idx;
   for (unsigned int i = 1; i < count; i++)
   {
-    if (!skippy_iter.next ()) return_trace (false);
+    unsigned unsafe_to;
+    if (!skippy_iter.next (&unsafe_to))
+    {
+      *end_position = unsafe_to;
+      return_trace (false);
+    }
 
     match_positions[i] = skippy_iter.idx;
 
@@ -1055,7 +1081,7 @@ static inline bool match_input (hb_ot_apply_context_t *c,
     total_component_count += _hb_glyph_info_get_lig_num_comps (&buffer->info[skippy_iter.idx]);
   }
 
-  *end_offset = skippy_iter.idx - buffer->idx + 1;
+  *end_position = skippy_iter.idx + 1;
 
   if (p_total_component_count)
     *p_total_component_count = total_component_count;
@@ -1065,7 +1091,7 @@ static inline bool match_input (hb_ot_apply_context_t *c,
 static inline bool ligate_input (hb_ot_apply_context_t *c,
 				 unsigned int count, /* Including the first glyph */
 				 const unsigned int match_positions[HB_MAX_CONTEXT_LENGTH], /* Including the first glyph */
-				 unsigned int match_length,
+				 unsigned int match_end,
 				 hb_codepoint_t lig_glyph,
 				 unsigned int total_component_count)
 {
@@ -1073,7 +1099,7 @@ static inline bool ligate_input (hb_ot_apply_context_t *c,
 
   hb_buffer_t *buffer = c->buffer;
 
-  buffer->merge_clusters (buffer->idx, buffer->idx + match_length);
+  buffer->merge_clusters (buffer->idx, match_end);
 
   /* - If a base and one or more marks ligate, consider that as a base, NOT
    *   ligature, such that all following marks can still attach to it.
@@ -1190,11 +1216,16 @@ static inline bool match_backtrack (hb_ot_apply_context_t *c,
   skippy_iter.set_match_func (match_func, match_data, backtrack);
 
   for (unsigned int i = 0; i < count; i++)
-    if (!skippy_iter.prev ())
+  {
+    unsigned unsafe_from;
+    if (!skippy_iter.prev (&unsafe_from))
+    {
+      *match_start = unsafe_from;
       return_trace (false);
+    }
+  }
 
   *match_start = skippy_iter.idx;
-
   return_trace (true);
 }
 
@@ -1203,21 +1234,26 @@ static inline bool match_lookahead (hb_ot_apply_context_t *c,
 				    const HBUINT16 lookahead[],
 				    match_func_t match_func,
 				    const void *match_data,
-				    unsigned int offset,
+				    unsigned int start_index,
 				    unsigned int *end_index)
 {
   TRACE_APPLY (nullptr);
 
   hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_context;
-  skippy_iter.reset (c->buffer->idx + offset - 1, count);
+  skippy_iter.reset (start_index - 1, count);
   skippy_iter.set_match_func (match_func, match_data, lookahead);
 
   for (unsigned int i = 0; i < count; i++)
-    if (!skippy_iter.next ())
+  {
+    unsigned unsafe_to;
+    if (!skippy_iter.next (&unsafe_to))
+    {
+      *end_index = unsafe_to;
       return_trace (false);
+    }
+  }
 
   *end_index = skippy_iter.idx + 1;
-
   return_trace (true);
 }
 
@@ -1284,22 +1320,23 @@ static void context_closure_recurse_lookups (hb_closure_context_t *c,
     unsigned seqIndex = lookupRecord[i].sequenceIndex;
     if (seqIndex >= inputCount) continue;
 
-    hb_set_t *pos_glyphs = nullptr;
+    bool has_pos_glyphs = false;
+    hb_set_t pos_glyphs;
 
     if (hb_set_is_empty (covered_seq_indicies) || !hb_set_has (covered_seq_indicies, seqIndex))
     {
-      pos_glyphs = hb_set_create ();
+      has_pos_glyphs = true;
       if (seqIndex == 0)
       {
         switch (context_format) {
         case ContextFormat::SimpleContext:
-          pos_glyphs->add (value);
+          pos_glyphs.add (value);
           break;
         case ContextFormat::ClassBasedContext:
-          intersected_glyphs_func (c->cur_intersected_glyphs, data, value, pos_glyphs);
+          intersected_glyphs_func (&c->parent_active_glyphs (), data, value, &pos_glyphs);
           break;
         case ContextFormat::CoverageBasedContext:
-          hb_set_set (pos_glyphs, c->cur_intersected_glyphs);
+          pos_glyphs.set (c->parent_active_glyphs ());
           break;
         }
       }
@@ -1313,12 +1350,16 @@ static void context_closure_recurse_lookups (hb_closure_context_t *c,
           input_value = input[seqIndex - 1];
         }
 
-        intersected_glyphs_func (c->glyphs, input_data, input_value, pos_glyphs);
+        intersected_glyphs_func (c->glyphs, input_data, input_value, &pos_glyphs);
       }
     }
 
-    hb_set_add (covered_seq_indicies, seqIndex);
-    c->push_cur_active_glyphs (pos_glyphs ? pos_glyphs : c->glyphs);
+    covered_seq_indicies->add (seqIndex);
+    if (has_pos_glyphs) {
+      c->push_cur_active_glyphs () = pos_glyphs;
+    } else {
+      c->push_cur_active_glyphs ().set (*c->glyphs);
+    }
 
     unsigned endIndex = inputCount;
     if (context_format == ContextFormat::CoverageBasedContext)
@@ -1327,8 +1368,6 @@ static void context_closure_recurse_lookups (hb_closure_context_t *c,
     c->recurse (lookupRecord[i].lookupListIndex, covered_seq_indicies, seqIndex, endIndex);
 
     c->pop_cur_done_glyphs ();
-    if (pos_glyphs)
-      hb_set_destroy (pos_glyphs);
   }
 
   hb_set_destroy (covered_seq_indicies);
@@ -1343,15 +1382,13 @@ static inline void recurse_lookups (context_t *c,
     c->recurse (lookupRecord[i].lookupListIndex);
 }
 
-static inline bool apply_lookup (hb_ot_apply_context_t *c,
+static inline void apply_lookup (hb_ot_apply_context_t *c,
 				 unsigned int count, /* Including the first glyph */
 				 unsigned int match_positions[HB_MAX_CONTEXT_LENGTH], /* Including the first glyph */
 				 unsigned int lookupCount,
 				 const LookupRecord lookupRecord[], /* Array of LookupRecords--in design order */
-				 unsigned int match_length)
+				 unsigned int match_end)
 {
-  TRACE_APPLY (nullptr);
-
   hb_buffer_t *buffer = c->buffer;
   int end;
 
@@ -1359,7 +1396,7 @@ static inline bool apply_lookup (hb_ot_apply_context_t *c,
    * Adjust. */
   {
     unsigned int bl = buffer->backtrack_len ();
-    end = bl + match_length;
+    end = bl + match_end - buffer->idx;
 
     int delta = bl - buffer->idx;
     /* Convert positions to new indexing. */
@@ -1461,8 +1498,6 @@ static inline bool apply_lookup (hb_ot_apply_context_t *c,
   }
 
   (void) buffer->move_to (end);
-
-  return_trace (true);
 }
 
 
@@ -1550,17 +1585,25 @@ static inline bool context_apply_lookup (hb_ot_apply_context_t *c,
 					 const LookupRecord lookupRecord[],
 					 ContextApplyLookupContext &lookup_context)
 {
-  unsigned int match_length = 0;
-  unsigned int match_positions[HB_MAX_CONTEXT_LENGTH];
-  return match_input (c,
-		      inputCount, input,
-		      lookup_context.funcs.match, lookup_context.match_data,
-		      &match_length, match_positions)
-      && (c->buffer->unsafe_to_break (c->buffer->idx, c->buffer->idx + match_length),
-	  apply_lookup (c,
-		       inputCount, match_positions,
-		       lookupCount, lookupRecord,
-		       match_length));
+  unsigned match_end = 0;
+  unsigned match_positions[HB_MAX_CONTEXT_LENGTH];
+  if (match_input (c,
+		   inputCount, input,
+		   lookup_context.funcs.match, lookup_context.match_data,
+		   &match_end, match_positions))
+  {
+    c->buffer->unsafe_to_break (c->buffer->idx, match_end);
+    apply_lookup (c,
+		  inputCount, match_positions,
+		  lookupCount, lookupRecord,
+		  match_end);
+    return true;
+  }
+  else
+  {
+    c->buffer->unsafe_to_concat (c->buffer->idx, match_end);
+    return false;
+  }
 }
 
 struct Rule
@@ -1828,8 +1871,9 @@ struct ContextFormat1
 
   void closure (hb_closure_context_t *c) const
   {
-    c->cur_intersected_glyphs->clear ();
-    get_coverage ().intersected_coverage_glyphs (c->parent_active_glyphs (), c->cur_intersected_glyphs);
+    hb_set_t* cur_active_glyphs = &c->push_cur_active_glyphs ();
+    get_coverage ().intersected_coverage_glyphs (&c->previous_parent_active_glyphs (),
+                                                 cur_active_glyphs);
 
     struct ContextClosureLookupContext lookup_context = {
       {intersects_glyph, intersected_glyph},
@@ -1838,10 +1882,14 @@ struct ContextFormat1
     };
 
     + hb_zip (this+coverage, hb_range ((unsigned) ruleSet.len))
-    | hb_filter (c->parent_active_glyphs (), hb_first)
+    | hb_filter ([&] (hb_codepoint_t _) {
+      return c->previous_parent_active_glyphs ().has (_);
+    }, hb_first)
     | hb_map ([&](const hb_pair_t<hb_codepoint_t, unsigned> _) { return hb_pair_t<unsigned, const RuleSet&> (_.first, this+ruleSet[_.second]); })
     | hb_apply ([&] (const hb_pair_t<unsigned, const RuleSet&>& _) { _.second.closure (c, _.first, lookup_context); })
     ;
+
+    c->pop_cur_done_glyphs ();
   }
 
   void closure_lookups (hb_closure_lookups_context_t *c) const
@@ -1989,8 +2037,9 @@ struct ContextFormat2
     if (!(this+coverage).intersects (c->glyphs))
       return;
 
-    c->cur_intersected_glyphs->clear ();
-    get_coverage ().intersected_coverage_glyphs (c->parent_active_glyphs (), c->cur_intersected_glyphs);
+    hb_set_t* cur_active_glyphs = &c->push_cur_active_glyphs ();
+    get_coverage ().intersected_coverage_glyphs (&c->previous_parent_active_glyphs (),
+                                                 cur_active_glyphs);
 
     const ClassDef &class_def = this+classDef;
 
@@ -2000,10 +2049,9 @@ struct ContextFormat2
       &class_def
     };
 
-    return
     + hb_enumerate (ruleSet)
     | hb_filter ([&] (unsigned _)
-		 { return class_def.intersects_class (c->cur_intersected_glyphs, _); },
+    { return class_def.intersects_class (&c->parent_active_glyphs (), _); },
 		 hb_first)
     | hb_apply ([&] (const hb_pair_t<unsigned, const Offset16To<RuleSet>&> _)
                 {
@@ -2011,6 +2059,8 @@ struct ContextFormat2
                   rule_set.closure (c, _.first, lookup_context);
                 })
     ;
+
+    c->pop_cur_done_glyphs ();
   }
 
   void closure_lookups (hb_closure_lookups_context_t *c) const
@@ -2183,8 +2233,10 @@ struct ContextFormat3
     if (!(this+coverageZ[0]).intersects (c->glyphs))
       return;
 
-    c->cur_intersected_glyphs->clear ();
-    get_coverage ().intersected_coverage_glyphs (c->parent_active_glyphs (), c->cur_intersected_glyphs);
+    hb_set_t* cur_active_glyphs = &c->push_cur_active_glyphs ();
+    get_coverage ().intersected_coverage_glyphs (&c->previous_parent_active_glyphs (),
+                                                 cur_active_glyphs);
+
 
     const LookupRecord *lookupRecord = &StructAfter<LookupRecord> (coverageZ.as_array (glyphCount));
     struct ContextClosureLookupContext lookup_context = {
@@ -2196,6 +2248,8 @@ struct ContextFormat3
 			    glyphCount, (const HBUINT16 *) (coverageZ.arrayZ + 1),
 			    lookupCount, lookupRecord,
 			    0, lookup_context);
+
+    c->pop_cur_done_glyphs ();
   }
 
   void closure_lookups (hb_closure_lookups_context_t *c) const
@@ -2452,25 +2506,38 @@ static inline bool chain_context_apply_lookup (hb_ot_apply_context_t *c,
 					       const LookupRecord lookupRecord[],
 					       ChainContextApplyLookupContext &lookup_context)
 {
-  unsigned int start_index = 0, match_length = 0, end_index = 0;
-  unsigned int match_positions[HB_MAX_CONTEXT_LENGTH];
-  return match_input (c,
-		      inputCount, input,
-		      lookup_context.funcs.match, lookup_context.match_data[1],
-		      &match_length, match_positions)
-      && match_backtrack (c,
-			  backtrackCount, backtrack,
-			  lookup_context.funcs.match, lookup_context.match_data[0],
-			  &start_index)
-      && match_lookahead (c,
-			  lookaheadCount, lookahead,
-			  lookup_context.funcs.match, lookup_context.match_data[2],
-			  match_length, &end_index)
-      && (c->buffer->unsafe_to_break_from_outbuffer (start_index, end_index),
-	  apply_lookup (c,
-			inputCount, match_positions,
-			lookupCount, lookupRecord,
-			match_length));
+  unsigned end_index = c->buffer->idx;
+  unsigned match_end = 0;
+  unsigned match_positions[HB_MAX_CONTEXT_LENGTH];
+  if (!(match_input (c,
+		     inputCount, input,
+		     lookup_context.funcs.match, lookup_context.match_data[1],
+		     &match_end, match_positions) && (end_index = match_end)
+       && match_lookahead (c,
+			   lookaheadCount, lookahead,
+			   lookup_context.funcs.match, lookup_context.match_data[2],
+			   match_end, &end_index)))
+  {
+    c->buffer->unsafe_to_concat (c->buffer->idx, end_index);
+    return false;
+  }
+
+  unsigned start_index = c->buffer->out_len;
+  if (!match_backtrack (c,
+			backtrackCount, backtrack,
+			lookup_context.funcs.match, lookup_context.match_data[0],
+			&start_index))
+  {
+    c->buffer->unsafe_to_concat_from_outbuffer (start_index, end_index);
+    return false;
+  }
+
+  c->buffer->unsafe_to_break_from_outbuffer (start_index, end_index);
+  apply_lookup (c,
+		inputCount, match_positions,
+		lookupCount, lookupRecord,
+		match_end);
+  return true;
 }
 
 struct ChainRule
@@ -2802,8 +2869,9 @@ struct ChainContextFormat1
 
   void closure (hb_closure_context_t *c) const
   {
-    c->cur_intersected_glyphs->clear ();
-    get_coverage ().intersected_coverage_glyphs (c->parent_active_glyphs (), c->cur_intersected_glyphs);
+    hb_set_t* cur_active_glyphs = &c->push_cur_active_glyphs ();
+    get_coverage ().intersected_coverage_glyphs (&c->previous_parent_active_glyphs (),
+                                                 cur_active_glyphs);
 
     struct ChainContextClosureLookupContext lookup_context = {
       {intersects_glyph, intersected_glyph},
@@ -2812,10 +2880,14 @@ struct ChainContextFormat1
     };
 
     + hb_zip (this+coverage, hb_range ((unsigned) ruleSet.len))
-    | hb_filter (c->parent_active_glyphs (), hb_first)
+    | hb_filter ([&] (hb_codepoint_t _) {
+      return c->previous_parent_active_glyphs ().has (_);
+    }, hb_first)
     | hb_map ([&](const hb_pair_t<hb_codepoint_t, unsigned> _) { return hb_pair_t<unsigned, const ChainRuleSet&> (_.first, this+ruleSet[_.second]); })
     | hb_apply ([&] (const hb_pair_t<unsigned, const ChainRuleSet&>& _) { _.second.closure (c, _.first, lookup_context); })
     ;
+
+    c->pop_cur_done_glyphs ();
   }
 
   void closure_lookups (hb_closure_lookups_context_t *c) const
@@ -2964,8 +3036,10 @@ struct ChainContextFormat2
     if (!(this+coverage).intersects (c->glyphs))
       return;
 
-    c->cur_intersected_glyphs->clear ();
-    get_coverage ().intersected_coverage_glyphs (c->parent_active_glyphs (), c->cur_intersected_glyphs);
+    hb_set_t* cur_active_glyphs = &c->push_cur_active_glyphs ();
+    get_coverage ().intersected_coverage_glyphs (&c->previous_parent_active_glyphs (),
+                                                 cur_active_glyphs);
+
 
     const ClassDef &backtrack_class_def = this+backtrackClassDef;
     const ClassDef &input_class_def = this+inputClassDef;
@@ -2979,10 +3053,9 @@ struct ChainContextFormat2
        &lookahead_class_def}
     };
 
-    return
     + hb_enumerate (ruleSet)
     | hb_filter ([&] (unsigned _)
-		 { return input_class_def.intersects_class (c->cur_intersected_glyphs, _); },
+    { return input_class_def.intersects_class (&c->parent_active_glyphs (), _); },
 		 hb_first)
     | hb_apply ([&] (const hb_pair_t<unsigned, const Offset16To<ChainRuleSet>&> _)
                 {
@@ -2990,6 +3063,8 @@ struct ChainContextFormat2
                   chainrule_set.closure (c, _.first, lookup_context);
                 })
     ;
+
+    c->pop_cur_done_glyphs ();
   }
 
   void closure_lookups (hb_closure_lookups_context_t *c) const
@@ -3216,8 +3291,10 @@ struct ChainContextFormat3
     if (!(this+input[0]).intersects (c->glyphs))
       return;
 
-    c->cur_intersected_glyphs->clear ();
-    get_coverage ().intersected_coverage_glyphs (c->parent_active_glyphs (), c->cur_intersected_glyphs);
+    hb_set_t* cur_active_glyphs = &c->push_cur_active_glyphs ();
+    get_coverage ().intersected_coverage_glyphs (&c->previous_parent_active_glyphs (),
+                                                 cur_active_glyphs);
+
 
     const Array16OfOffset16To<Coverage> &lookahead = StructAfter<Array16OfOffset16To<Coverage>> (input);
     const Array16Of<LookupRecord> &lookup = StructAfter<Array16Of<LookupRecord>> (lookahead);
@@ -3232,6 +3309,8 @@ struct ChainContextFormat3
 				  lookahead.len, (const HBUINT16 *) lookahead.arrayZ,
 				  lookup.len, lookup.arrayZ,
 				  0, lookup_context);
+
+    c->pop_cur_done_glyphs ();
   }
 
   void closure_lookups (hb_closure_lookups_context_t *c) const
@@ -3706,7 +3785,7 @@ struct GSUBGPOS
     for (unsigned i : feature_indices->iter ())
     {
       hb_tag_t t = get_feature_tag (i);
-      if (t == unique_features.INVALID_KEY) continue;
+      if (t == HB_MAP_VALUE_INVALID) continue;
       if (!unique_features.has (t))
       {
         hb_set_t* indices = hb_set_create ();
@@ -3839,7 +3918,7 @@ struct GSUBGPOS
   template <typename T>
   struct accelerator_t
   {
-    void init (hb_face_t *face)
+    accelerator_t (hb_face_t *face)
     {
       this->table = hb_sanitize_context_t ().reference_table<T> (face);
       if (unlikely (this->table->is_blocklisted (this->table.get_blob (), face)))
@@ -3861,8 +3940,7 @@ struct GSUBGPOS
       for (unsigned int i = 0; i < this->lookup_count; i++)
 	this->accels[i].init (table->get_lookup (i));
     }
-
-    void fini ()
+    ~accelerator_t ()
     {
       for (unsigned int i = 0; i < this->lookup_count; i++)
 	this->accels[i].fini ();