[subset] Remove add accelerator flag, replace with new api method.

Adds hb_subset_preprocess() which preprocesses the face and attaches accelerator data.

perf/benchmark-subset.cc

@@ -101,37 +101,9 @@ void AddGlyphs(unsigned num_glyphs_in_font,
 // the subsetting operations.
 static hb_face_t* preprocess_face(hb_face_t* face)
 {
-  hb_subset_input_t* input = hb_subset_input_create_or_fail ();
-
-  hb_set_clear (hb_subset_input_set(input, HB_SUBSET_SETS_UNICODE));
-  hb_set_invert (hb_subset_input_set(input, HB_SUBSET_SETS_UNICODE));
-
-  hb_set_clear (hb_subset_input_set(input,
-                                    HB_SUBSET_SETS_LAYOUT_FEATURE_TAG));
-  hb_set_invert (hb_subset_input_set(input,
-                                     HB_SUBSET_SETS_LAYOUT_FEATURE_TAG));
-
-  hb_set_clear (hb_subset_input_set(input,
-                                    HB_SUBSET_SETS_LAYOUT_SCRIPT_TAG));
-  hb_set_invert (hb_subset_input_set(input,
-                                     HB_SUBSET_SETS_LAYOUT_SCRIPT_TAG));
-
-  hb_set_clear (hb_subset_input_set(input,
-                                    HB_SUBSET_SETS_NAME_ID));
-  hb_set_invert (hb_subset_input_set(input,
-                                     HB_SUBSET_SETS_NAME_ID));
-
-  hb_subset_input_set_flags(input,
-                            HB_SUBSET_FLAGS_NOTDEF_OUTLINE |
-                            HB_SUBSET_FLAGS_GLYPH_NAMES |
-                            HB_SUBSET_FLAGS_RETAIN_GIDS |
-                            HB_SUBSET_FLAGS_ADD_ACCELERATOR_DATA);
-
-  hb_face_t* subset = hb_subset_or_fail (face, input);
-  hb_face_destroy (face);
-  hb_subset_input_destroy (input);
-
-  return subset;
+  hb_face_t* new_face = hb_subset_preprocess(face);
+  hb_face_destroy(face);
+  return new_face;
 }
 
 /* benchmark for subsetting a font */

src/hb-subset-input.cc

@@ -49,7 +49,7 @@ hb_subset_input_create_or_fail (void)
     set = hb_set_create ();
 
   input->axes_location = hb_hashmap_create<hb_tag_t, float> ();
-  
+
   if (!input->axes_location || input->in_error ())
   {
     hb_subset_input_destroy (input);
@@ -430,4 +430,52 @@ hb_subset_input_pin_axis_location (hb_subset_input_t  *input,
   return input->axes_location->set (axis_tag, val);
 }
 #endif
+
+/**
+ * hb_subset_preprocess
+ * @input: a #hb_face_t object.
+ *
+ * Preprocesses the face and attaches data that will be needed by the
+ * subsetter. Future subsetting operations can then use the precomputed data
+ * to speed up the subsetting operation.
+ *
+ * Since: EXPERIMENTAL
+ **/
+
+hb_face_t *
+hb_subset_preprocess (hb_face_t *source)
+{
+  hb_subset_input_t* input = hb_subset_input_create_or_fail ();
+
+  hb_set_clear (hb_subset_input_set(input, HB_SUBSET_SETS_UNICODE));
+  hb_set_invert (hb_subset_input_set(input, HB_SUBSET_SETS_UNICODE));
+
+  hb_set_clear (hb_subset_input_set(input,
+                                    HB_SUBSET_SETS_LAYOUT_FEATURE_TAG));
+  hb_set_invert (hb_subset_input_set(input,
+                                     HB_SUBSET_SETS_LAYOUT_FEATURE_TAG));
+
+  hb_set_clear (hb_subset_input_set(input,
+                                    HB_SUBSET_SETS_LAYOUT_SCRIPT_TAG));
+  hb_set_invert (hb_subset_input_set(input,
+                                     HB_SUBSET_SETS_LAYOUT_SCRIPT_TAG));
+
+  hb_set_clear (hb_subset_input_set(input,
+                                    HB_SUBSET_SETS_NAME_ID));
+  hb_set_invert (hb_subset_input_set(input,
+                                     HB_SUBSET_SETS_NAME_ID));
+
+  hb_subset_input_set_flags(input,
+                            HB_SUBSET_FLAGS_NOTDEF_OUTLINE |
+                            HB_SUBSET_FLAGS_GLYPH_NAMES |
+                            HB_SUBSET_FLAGS_RETAIN_GIDS);
+  input->attach_accelerator_data = true;
+
+  hb_face_t* new_source = hb_subset_or_fail (source, input);
+  hb_subset_input_destroy (input);
+
+  return new_source;
+}
+
+
 #endif

src/hb-subset-input.hh

@@ -59,6 +59,7 @@ struct hb_subset_input_t
   };
 
   unsigned flags;
+  bool attach_accelerator_data = false;
   hb_hashmap_t<hb_tag_t, float> *axes_location;
 
   inline unsigned num_sets () const

src/hb-subset-plan.cc

@@ -849,6 +849,8 @@ hb_subset_plan_create_or_fail (hb_face_t	 *face,
   plan->check_success (plan->hmtx_map = hb_hashmap_create<unsigned, hb_pair_t<unsigned, int>> ());
 
   void* accel = hb_face_get_user_data(face, hb_subset_accelerator_t::user_data_key());
+
+  plan->attach_accelerator_data = input->attach_accelerator_data;
   if (accel)
     plan->accelerator = (hb_subset_accelerator_t*) accel;
 

src/hb-subset-plan.hh

@@ -98,6 +98,7 @@ struct hb_subset_plan_t
 
   bool successful;
   unsigned flags;
+  bool attach_accelerator_data = false;
 
   // For each cp that we'd like to retain maps to the corresponding gid.
   hb_set_t *unicodes;

src/hb-subset.cc

@@ -598,7 +598,7 @@ hb_subset_plan_execute_or_fail (hb_subset_plan_t *plan)
     offset += num_tables;
   }
 
-  if (success && plan->flags & HB_SUBSET_FLAGS_ADD_ACCELERATOR_DATA) {
+  if (success && plan->attach_accelerator_data) {
     _attach_accelerator_data (plan, plan->dest);
   }
 

src/hb-subset.h

@@ -70,9 +70,6 @@ typedef struct hb_subset_plan_t hb_subset_plan_t;
  * in the final subset.
  * @HB_SUBSET_FLAGS_NO_PRUNE_UNICODE_RANGES: If set then the unicode ranges in
  * OS/2 will not be recalculated.
- * @HB_SUBSET_FLAGS_ADD_ACCELERATOR_DATA: If set the subsetter will append into
- * the output hb_face_t's user data, accelerator data that can be used to speedup
- * further subsetting operations on the face.
  * @HB_SUBSET_FLAGS_PATCH_MODE: If set the subsetter behaviour will be modified
  * to produce a subset that is better suited to patching. For example cmap
  * subtable format will be kept stable.
@@ -97,9 +94,8 @@ typedef enum { /*< flags >*/
   HB_SUBSET_FLAGS_NOTDEF_OUTLINE =	     0x00000040u,
   HB_SUBSET_FLAGS_GLYPH_NAMES =		     0x00000080u,
   HB_SUBSET_FLAGS_NO_PRUNE_UNICODE_RANGES =  0x00000100u,
-  HB_SUBSET_FLAGS_ADD_ACCELERATOR_DATA =     0x00000200u,
-  // Not supported yet: HB_SUBSET_FLAGS_PATCH_MODE = 0x00000400u,
-  // Not supported yet: HB_SUBSET_FLAGS_OMIT_GLYF =  0x00000800u,
+  // Not supported yet: HB_SUBSET_FLAGS_PATCH_MODE = 0x00000200u,
+  // Not supported yet: HB_SUBSET_FLAGS_OMIT_GLYF =  0x00000400u,
 } hb_subset_flags_t;
 
 /**
@@ -181,6 +177,10 @@ hb_subset_input_pin_axis_location (hb_subset_input_t  *input,
 				   hb_tag_t            axis_tag,
 				   float               axis_value);
 #endif
+
+HB_EXTERN hb_face_t *
+hb_subset_preprocess (hb_face_t *source);
+
 #endif
 
 HB_EXTERN hb_face_t *

util/hb-subset.cc

@@ -34,36 +34,11 @@
 
 static hb_face_t* preprocess_face(hb_face_t* face)
 {
-  hb_subset_input_t* input = hb_subset_input_create_or_fail ();
-
-  hb_set_clear (hb_subset_input_set(input, HB_SUBSET_SETS_UNICODE));
-  hb_set_invert (hb_subset_input_set(input, HB_SUBSET_SETS_UNICODE));
-
-  hb_set_clear (hb_subset_input_set(input,
-                                    HB_SUBSET_SETS_LAYOUT_FEATURE_TAG));
-  hb_set_invert (hb_subset_input_set(input,
-                                     HB_SUBSET_SETS_LAYOUT_FEATURE_TAG));
-
-  hb_set_clear (hb_subset_input_set(input,
-                                    HB_SUBSET_SETS_LAYOUT_SCRIPT_TAG));
-  hb_set_invert (hb_subset_input_set(input,
-                                     HB_SUBSET_SETS_LAYOUT_SCRIPT_TAG));
-
-  hb_set_clear (hb_subset_input_set(input,
-                                    HB_SUBSET_SETS_NAME_ID));
-  hb_set_invert (hb_subset_input_set(input,
-                                     HB_SUBSET_SETS_NAME_ID));
-
-  hb_subset_input_set_flags(input,
-                            HB_SUBSET_FLAGS_NOTDEF_OUTLINE |
-                            HB_SUBSET_FLAGS_GLYPH_NAMES |
-                            HB_SUBSET_FLAGS_RETAIN_GIDS |
-                            HB_SUBSET_FLAGS_ADD_ACCELERATOR_DATA);
-
-  hb_face_t* subset = hb_subset_or_fail (face, input);
-  hb_subset_input_destroy (input);
-
-  return subset;
+  #ifdef HB_EXPERIMENTAL_API
+  return hb_subset_preprocess (face);
+  #else
+  return hb_face_reference(face);
+  #endif
 }
 
 /*