Merge pull request #3429 from harfbuzz/external_plan

[subset] expose subset plan in public subsetting API

src/hb-subset-plan.cc

@@ -458,7 +458,7 @@ _nameid_closure (hb_face_t *face,
 }
 
 /**
- * hb_subset_plan_create:
+ * hb_subset_plan_create_or_fail:
  * @face: font face to create the plan for.
  * @input: a #hb_subset_input_t input.
  *
@@ -467,17 +467,18 @@ _nameid_closure (hb_face_t *face,
  * which tables and glyphs should be retained.
  *
  * Return value: (transfer full): New subset plan. Destroy with
- * hb_subset_plan_destroy().
+ * hb_subset_plan_destroy(). If there is a failure creating the plan
+ * nullptr will be returned.
  *
- * Since: 1.7.5
+ * Since: REPLACEME
  **/
 hb_subset_plan_t *
-hb_subset_plan_create (hb_face_t	 *face,
+hb_subset_plan_create_or_fail (hb_face_t	 *face,
                                const hb_subset_input_t *input)
 {
   hb_subset_plan_t *plan;
   if (unlikely (!(plan = hb_object_create<hb_subset_plan_t> ())))
-    return const_cast<hb_subset_plan_t *> (&Null (hb_subset_plan_t));
+    return nullptr;
 
   plan->successful = true;
   plan->flags = input->flags;
@@ -514,8 +515,9 @@ hb_subset_plan_create (hb_face_t	 *face,
   plan->layout_variation_indices = hb_set_create ();
   plan->layout_variation_idx_map = hb_map_create ();
 
-  if (plan->in_error ()) {
+  if (unlikely (plan->in_error ())) {
-    return plan;
+    hb_subset_plan_destroy (plan);
+    return nullptr;
   }
 
   _populate_unicodes_to_retain (input->sets.unicodes, input->sets.glyphs, plan);
@@ -532,6 +534,10 @@ hb_subset_plan_create (hb_face_t	 *face,
 				  plan->reverse_glyph_map,
 				  &plan->_num_output_glyphs);
 
+  if (unlikely (plan->in_error ())) {
+    hb_subset_plan_destroy (plan);
+    return nullptr;
+  }
   return plan;
 }
 
@@ -542,7 +548,7 @@ hb_subset_plan_create (hb_face_t	 *face,
  * Decreases the reference count on @plan, and if it reaches zero, destroys
  * @plan, freeing all memory.
  *
- * Since: 1.7.5
+ * Since: REPLACEME
  **/
 void
 hb_subset_plan_destroy (hb_subset_plan_t *plan)
@@ -596,3 +602,108 @@ hb_subset_plan_destroy (hb_subset_plan_t *plan)
 
   hb_free (plan);
 }
+
+/**
+ * hb_subset_plan_old_to_new_glyph_mapping:
+ * @plan: a subsetting plan.
+ *
+ * Return value:
+ * the mapping between glyphs in the original font to glyphs
+ * in the subset that will be produced by @plan.
+ *
+ * Since: REPLACEME
+ **/
+const hb_map_t*
+hb_subset_plan_old_to_new_glyph_mapping (const hb_subset_plan_t *plan)
+{
+  return plan->glyph_map;
+}
+
+/**
+ * hb_subset_plan_old_to_new_glyph_mapping:
+ * @plan: a subsetting plan.
+ *
+ * Returns the mapping between glyphs in the subset that will be produced by
+ * @plan and the glyph in the original font.
+ *
+ * Since: REPLACEME
+ **/
+const hb_map_t*
+hb_subset_plan_new_to_old_glyph_mapping (const hb_subset_plan_t *plan)
+{
+  return plan->reverse_glyph_map;
+}
+
+/**
+ * hb_subset_plan_old_to_new_glyph_mapping:
+ * @plan: a subsetting plan.
+ *
+ * Returns the mapping between codepoints in the original font and the
+ * associated glyph id in the original font.
+ *
+ * Since: REPLACEME
+ **/
+const hb_map_t*
+hb_subset_plan_codepoint_to_old_glyph_mapping (const hb_subset_plan_t *plan)
+{
+  return plan->codepoint_to_glyph;
+}
+
+/**
+ * hb_subset_plan_reference: (skip)
+ * @plan: a #hb_subset_plan_t object.
+ *
+ * Increases the reference count on @plan.
+ *
+ * Return value: @plan.
+ *
+ * Since: REPLACEME
+ **/
+hb_subset_plan_t *
+hb_subset_plan_reference (hb_subset_plan_t *plan)
+{
+  return hb_object_reference (plan);
+}
+
+/**
+ * hb_subset_plan_set_user_data: (skip)
+ * @plan: a #hb_subset_plan_t object.
+ * @key: The user-data key to set
+ * @data: A pointer to the user data
+ * @destroy: (nullable): A callback to call when @data is not needed anymore
+ * @replace: Whether to replace an existing data with the same key
+ *
+ * Attaches a user-data key/data pair to the given subset plan object.
+ *
+ * Return value: %true if success, %false otherwise
+ *
+ * Since: REPLACEME
+ **/
+hb_bool_t
+hb_subset_plan_set_user_data (hb_subset_plan_t   *plan,
+                              hb_user_data_key_t *key,
+                              void               *data,
+                              hb_destroy_func_t   destroy,
+                              hb_bool_t	          replace)
+{
+  return hb_object_set_user_data (plan, key, data, destroy, replace);
+}
+
+/**
+ * hb_subset_plan_get_user_data: (skip)
+ * @plan: a #hb_subset_plan_t object.
+ * @key: The user-data key to query
+ *
+ * Fetches the user data associated with the specified key,
+ * attached to the specified subset plan object.
+ *
+ * Return value: (transfer none): A pointer to the user data
+ *
+ * Since: REPLACEME
+ **/
+void *
+hb_subset_plan_get_user_data (const hb_subset_plan_t *plan,
+                              hb_user_data_key_t     *key)
+{
+  return hb_object_get_user_data (plan, key);
+}

src/hb-subset-plan.hh

@@ -198,13 +198,4 @@ struct hb_subset_plan_t
   }
 };
 
-typedef struct hb_subset_plan_t hb_subset_plan_t;
-
-HB_INTERNAL hb_subset_plan_t *
-hb_subset_plan_create (hb_face_t           *face,
-		       const hb_subset_input_t   *input);
-
-HB_INTERNAL void
-hb_subset_plan_destroy (hb_subset_plan_t *plan);
-
 #endif /* HB_SUBSET_PLAN_HH */

src/hb-subset.cc

@@ -343,9 +343,33 @@ hb_subset_or_fail (hb_face_t *source, const hb_subset_input_t *input)
 {
   if (unlikely (!input || !source)) return hb_face_get_empty ();
 
-  hb_subset_plan_t *plan = hb_subset_plan_create (source, input);
+  hb_subset_plan_t *plan = hb_subset_plan_create_or_fail (source, input);
-  if (unlikely (plan->in_error ())) {
+  if (unlikely (!plan)) {
+    return nullptr;
+  }
+
+  hb_face_t * result = hb_subset_plan_execute_or_fail (plan);
   hb_subset_plan_destroy (plan);
+  return result;
+}
+
+
+/**
+ * hb_subset_plan_execute_or_fail:
+ * @plan: a subsetting plan.
+ *
+ * Executes the provided subsetting @plan.
+ *
+ * Return value:
+ * on success returns a reference to generated font subset. If the subsetting operation fails
+ * returns nullptr.
+ *
+ * Since: REPLACEME
+ **/
+hb_face_t *
+hb_subset_plan_execute_or_fail (hb_subset_plan_t *plan)
+{
+  if (unlikely (!plan || plan->in_error ())) {
     return nullptr;
   }
 
@@ -353,7 +377,7 @@ hb_subset_or_fail (hb_face_t *source, const hb_subset_input_t *input)
   bool success = true;
   hb_tag_t table_tags[32];
   unsigned offset = 0, num_tables = ARRAY_LENGTH (table_tags);
-  while ((hb_face_get_table_tags (source, offset, &num_tables, table_tags), num_tables))
+  while ((hb_face_get_table_tags (plan->source, offset, &num_tables, table_tags), num_tables))
   {
     for (unsigned i = 0; i < num_tables; ++i)
     {
@@ -367,8 +391,5 @@ hb_subset_or_fail (hb_face_t *source, const hb_subset_input_t *input)
   }
 end:
 
-  hb_face_t *result = success ? hb_face_reference (plan->dest) : nullptr;
+  return success ? hb_face_reference (plan->dest) : nullptr;
-
-  hb_subset_plan_destroy (plan);
-  return result;
 }

src/hb-subset.h

@@ -39,6 +39,15 @@ HB_BEGIN_DECLS
 
 typedef struct hb_subset_input_t hb_subset_input_t;
 
+/**
+ * hb_subset_plan_t:
+ *
+ * Contains information about how the subset operation will be executed.
+ * Such as mappings from the old glyph ids to the new ones in the subset.
+ */
+
+typedef struct hb_subset_plan_t hb_subset_plan_t;
+
 /**
  * hb_subset_flags_t:
  * @HB_SUBSET_FLAGS_DEFAULT: all flags at their default value of false.
@@ -145,6 +154,41 @@ hb_subset_input_set_flags (hb_subset_input_t *input,
 HB_EXTERN hb_face_t *
 hb_subset_or_fail (hb_face_t *source, const hb_subset_input_t *input);
 
+HB_EXTERN hb_face_t *
+hb_subset_plan_execute_or_fail (hb_subset_plan_t *plan);
+
+HB_EXTERN hb_subset_plan_t *
+hb_subset_plan_create_or_fail (hb_face_t                 *face,
+                               const hb_subset_input_t   *input);
+
+HB_EXTERN void
+hb_subset_plan_destroy (hb_subset_plan_t *plan);
+
+HB_EXTERN const hb_map_t*
+hb_subset_plan_old_to_new_glyph_mapping (const hb_subset_plan_t *plan);
+
+HB_EXTERN const hb_map_t*
+hb_subset_plan_new_to_old_glyph_mapping (const hb_subset_plan_t *plan);
+
+HB_EXTERN const hb_map_t*
+hb_subset_plan_codepoint_to_old_glyph_mapping (const hb_subset_plan_t *plan);
+
+
+HB_EXTERN hb_subset_plan_t *
+hb_subset_plan_reference (hb_subset_plan_t *plan);
+
+HB_EXTERN hb_bool_t
+hb_subset_plan_set_user_data (hb_subset_plan_t   *plan,
+                              hb_user_data_key_t *key,
+                              void               *data,
+                              hb_destroy_func_t   destroy,
+                              hb_bool_t	          replace);
+
+HB_EXTERN void *
+hb_subset_plan_get_user_data (const hb_subset_plan_t *plan,
+                              hb_user_data_key_t     *key);
+
+
 HB_END_DECLS
 
 #endif /* HB_SUBSET_H */

test/api/test-subset.c

@@ -155,6 +155,44 @@ test_subset_sets (void)
   hb_subset_input_destroy (input);
 }
 
+static void
+test_subset_plan (void)
+{
+  hb_face_t *face_abc = hb_test_open_font_file ("fonts/Roboto-Regular.abc.ttf");
+  hb_face_t *face_ac = hb_test_open_font_file ("fonts/Roboto-Regular.ac.ttf");
+
+  hb_set_t *codepoints = hb_set_create();
+  hb_set_add (codepoints, 97);
+  hb_set_add (codepoints, 99);
+  hb_subset_input_t* input = hb_subset_test_create_input (codepoints);
+  hb_set_destroy (codepoints);
+
+  hb_subset_plan_t* plan = hb_subset_plan_create_or_fail (face_abc, input);
+  g_assert (plan);
+
+  const hb_map_t* mapping = hb_subset_plan_old_to_new_glyph_mapping (plan);
+  g_assert (hb_map_get (mapping, 1) == 1);
+  g_assert (hb_map_get (mapping, 3) == 2);
+
+  mapping = hb_subset_plan_new_to_old_glyph_mapping (plan);
+  g_assert (hb_map_get (mapping, 1) == 1);
+  g_assert (hb_map_get (mapping, 2) == 3);
+
+  mapping = hb_subset_plan_codepoint_to_old_glyph_mapping (plan);
+  g_assert (hb_map_get (mapping, 0x63) == 3);
+
+  hb_face_t* face_abc_subset = hb_subset_plan_execute_or_fail (plan);
+
+  hb_subset_test_check (face_ac, face_abc_subset, HB_TAG ('l','o','c', 'a'));
+  hb_subset_test_check (face_ac, face_abc_subset, HB_TAG ('g','l','y','f'));
+
+  hb_subset_input_destroy (input);
+  hb_subset_plan_destroy (plan);
+  hb_face_destroy (face_abc_subset);
+  hb_face_destroy (face_abc);
+  hb_face_destroy (face_ac);
+}
+
 int
 main (int argc, char **argv)
 {
@@ -165,6 +203,7 @@ main (int argc, char **argv)
   hb_test_add (test_subset_crash);
   hb_test_add (test_subset_set_flags);
   hb_test_add (test_subset_sets);
+  hb_test_add (test_subset_plan);
 
   return hb_test_run();
 }