Implement shape_plan caching

Should give us some performance boost.

TODO

@@ -1,6 +1,10 @@
 General fixes:
 =============
 
+- mask propagation (when ligation, "or" the masks).
+
+- fail_shaper that always fails.
+
 - Make map in setup_masks() const, etc.
 
 - Warn at compile time (and runtime with HB_DEBUG?) if no Unicode / font

src/hb-buffer-private.hh

@@ -40,14 +40,44 @@
 ASSERT_STATIC (sizeof (hb_glyph_info_t) == 20);
 ASSERT_STATIC (sizeof (hb_glyph_info_t) == sizeof (hb_glyph_position_t));
 
+
+/*
+ * hb_segment_properties_t
+ */
+
 typedef struct hb_segment_properties_t {
     hb_direction_t      direction;
     hb_script_t         script;
     hb_language_t       language;
     ASSERT_POD ();
 } hb_segment_properties_t;
+
 #define _HB_BUFFER_PROPS_DEFAULT { HB_DIRECTION_INVALID, HB_SCRIPT_INVALID, HB_LANGUAGE_INVALID }
 
+static inline hb_bool_t
+hb_segment_properties_equal (const hb_segment_properties_t *a,
+			     const hb_segment_properties_t *b)
+{
+  return a->direction == b->direction &&
+	 a->script    == b->script    &&
+	 a->language  == b->language;
+}
+
+
+static inline long
+hb_segment_properties_hash (const hb_segment_properties_t *p)
+{
+  /* TODO improve */
+  return (long) p->direction +
+	 (long) p->script +
+	 (long) p->language;
+}
+
+
+
+/*
+ * hb_buffer_t
+ */
 
 struct hb_buffer_t {
   hb_object_header_t header;

src/hb-font-private.hh

@@ -34,6 +34,7 @@
 #include "hb-font.h"
 #include "hb-object-private.hh"
 #include "hb-shaper-private.hh"
+#include "hb-shape-plan-private.hh"
 
 
 
@@ -101,6 +102,11 @@ struct hb_face_t {
   unsigned int upem;
 
   struct hb_shaper_data_t shaper_data;
+
+  struct plan_node_t {
+    hb_shape_plan_t *shape_plan;
+    plan_node_t *next;
+  } *shape_plans;
 };
 
 #define HB_SHAPER_DATA_CREATE_FUNC_EXTRA_ARGS

src/hb-font.cc

@@ -596,7 +596,9 @@ static const hb_face_t _hb_face_nil = {
 #define HB_SHAPER_IMPLEMENT(shaper) HB_SHAPER_DATA_INVALID,
 #include "hb-shaper-list.hh"
 #undef HB_SHAPER_IMPLEMENT
-  }
+  },
+
+  NULL, /* shape_plans */
 };
 
 
@@ -709,6 +711,17 @@ hb_face_destroy (hb_face_t *face)
 {
   if (!hb_object_destroy (face)) return;
 
+  /* The cached shape_plans think they have a reference on us, and
+   * try to release it.  Make sure that doesn't mess up. */
+  face->header.ref_count.ref_count = HB_REFERENCE_COUNT_INVALID_VALUE;
+  for (hb_face_t::plan_node_t *node = face->shape_plans; node; )
+  {
+    hb_face_t::plan_node_t *next = node->next;
+    hb_shape_plan_destroy (node->shape_plan);
+    free (node);
+    node = next;
+  }
+
 #define HB_SHAPER_IMPLEMENT(shaper) HB_SHAPER_DATA_DESTROY(shaper, face);
 #include "hb-shaper-list.hh"
 #undef HB_SHAPER_IMPLEMENT

src/hb-shape-plan.cc

@@ -179,3 +179,103 @@ hb_shape_plan_execute (hb_shape_plan      *shape_plan,
 
   return false;
 }
+
+
+/*
+ * caching
+ */
+
+#if 0
+static long
+hb_shape_plan_hash (const hb_shape_plan_t *shape_plan)
+{
+  return hb_segment_properties_hash (&shape_plan->props) +
+	 shape_plan->default_shaper_list ? 0 : (long) shape_plan->shaper_func;
+}
+#endif
+
+/* TODO no user-feature caching for now. */
+struct hb_shape_plan_proposal_t
+{
+  const hb_segment_properties_t  props;
+  const char * const            *shaper_list;
+  hb_shape_func_t               *shaper_func;
+};
+
+static hb_bool_t
+hb_shape_plan_matches (const hb_shape_plan_t          *shape_plan,
+		       const hb_shape_plan_proposal_t *proposal)
+{
+  return hb_segment_properties_equal (&shape_plan->props, &proposal->props) &&
+	 ((shape_plan->default_shaper_list && proposal->shaper_list == NULL) ||
+	  (shape_plan->shaper_func == proposal->shaper_func));
+}
+
+hb_shape_plan_t *
+hb_shape_plan_create_cached (hb_face_t                     *face,
+			     const hb_segment_properties_t *props,
+			     const hb_feature_t            *user_features,
+			     unsigned int                   num_user_features,
+			     const char * const            *shaper_list)
+{
+  if (num_user_features)
+    return hb_shape_plan_create (face, props, user_features, num_user_features, shaper_list);
+
+  hb_shape_plan_proposal_t proposal = {
+    *props,
+    shaper_list,
+    NULL
+  };
+
+  if (shaper_list) {
+    /* Choose shaper.  Adapted from hb_shape_plan_plan(). */
+#define HB_SHAPER_PLAN(shaper) \
+	  HB_STMT_START { \
+	    if (hb_##shaper##_shaper_face_data_ensure (face)) \
+	      proposal.shaper_func = _hb_##shaper##_shape; \
+	  } HB_STMT_END
+
+    for (const char * const *shaper_item = shaper_list; *shaper_item; shaper_item++)
+      if (0)
+	;
+#define HB_SHAPER_IMPLEMENT(shaper) \
+      else if (0 == strcmp (*shaper_item, #shaper)) \
+	HB_SHAPER_PLAN (shaper);
+#include "hb-shaper-list.hh"
+#undef HB_SHAPER_IMPLEMENT
+
+#undef HB_SHAPER_PLAN
+
+    if (unlikely (!proposal.shaper_list))
+      return hb_shape_plan_get_empty ();
+  }
+
+
+retry:
+  hb_face_t::plan_node_t *cached_plan_nodes = (hb_face_t::plan_node_t *) hb_atomic_ptr_get (&face->shape_plans);
+  for (hb_face_t::plan_node_t *node = cached_plan_nodes; node; node = node->next)
+    if (hb_shape_plan_matches (node->shape_plan, &proposal))
+      return hb_shape_plan_reference (node->shape_plan);
+
+  /* Not found. */
+
+  hb_shape_plan_t *shape_plan = hb_shape_plan_create (face, props, user_features, num_user_features, shaper_list);
+
+  hb_face_t::plan_node_t *node = (hb_face_t::plan_node_t *) calloc (1, sizeof (hb_face_t::plan_node_t));
+  if (unlikely (!node))
+    return shape_plan;
+
+  node->shape_plan = shape_plan;
+  node->next = cached_plan_nodes;
+
+  if (!hb_atomic_ptr_cmpexch (&face->shape_plans, cached_plan_nodes, node)) {
+    hb_shape_plan_destroy (shape_plan);
+    free (node);
+    goto retry;
+  }
+
+  /* Release our reference on face. */
+  hb_face_destroy (face);
+
+  return hb_shape_plan_reference (shape_plan);
+}

src/hb-shape-plan.h

@@ -47,6 +47,13 @@ hb_shape_plan_create (hb_face_t                     *face,
 		      unsigned int                   num_user_features,
 		      const char * const            *shaper_list);
 
+hb_shape_plan_t *
+hb_shape_plan_create_cached (hb_face_t                     *face,
+			     const hb_segment_properties_t *props,
+			     const hb_feature_t            *user_features,
+			     unsigned int                   num_user_features,
+			     const char * const            *shaper_list);
+
 HB_INTERNAL hb_shape_plan_t *
 hb_shape_plan_get_empty (void);
 

src/hb-shape.cc

@@ -87,7 +87,7 @@ hb_shape_full (hb_font_t          *font,
 
   buffer->guess_properties ();
 
-  hb_shape_plan_t *shape_plan = hb_shape_plan_create (font->face, &buffer->props, features, num_features, shaper_list);
+  hb_shape_plan_t *shape_plan = hb_shape_plan_create_cached (font->face, &buffer->props, features, num_features, shaper_list);
   hb_bool_t res = hb_shape_plan_execute (shape_plan, font, buffer, features, num_features);
   hb_shape_plan_destroy (shape_plan);
   return res;