[pango/kill-ft-face: 15/24] Add api to get a hb_font_t

[Matthias Clasen <matthiasc src gnome org>]

commit 72dc560dbe0f1d5c5e9e192bbf07e5094c5da6c0
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Oct 15 16:34:01 2018 -0400

    Add api to get a hb_font_t
    
    Add pango_font_get_hb_font, which will make it easier
    access harfbuzz features.

 docs/pango-sections.txt    |  1 +
 pango/fonts.c              | 50 +++++++++++++++++++++++++++++++++++++++++++++-
 pango/pango-font-private.h |  6 +-----
 pango/pango-font.h         |  3 +++
 pango/pangofc-font.c       | 39 ++++++++++++++++++++++++++++++++++++
 pango/pangofc-fontmap.c    | 25 +++++++++++++++++++++++
 pango/pangofc-fontmap.h    |  6 +++++-
 7 files changed, 123 insertions(+), 7 deletions(-)
---
diff --git a/docs/pango-sections.txt b/docs/pango-sections.txt
index 7df0dbc9..4373fb9d 100644
--- a/docs/pango-sections.txt
+++ b/docs/pango-sections.txt
@@ -248,6 +248,7 @@ pango_font_get_glyph_extents
 pango_font_get_metrics
 pango_font_get_font_map
 pango_font_get_features
+pango_font_get_hb_font
 <SUBSECTION>
 PangoFontFamily
 PANGO_TYPE_FONT_FAMILY
diff --git a/pango/fonts.c b/pango/fonts.c
index b04eb497..efea09e5 100644
--- a/pango/fonts.c
+++ b/pango/fonts.c
@@ -1617,11 +1617,29 @@ pango_parse_stretch (const char   *str,
  * PangoFont
  */
 
-G_DEFINE_ABSTRACT_TYPE (PangoFont, pango_font, G_TYPE_OBJECT)
+typedef struct {
+  hb_font_t *hb_font;
+} PangoFontPrivate;
+
+G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE (PangoFont, pango_font, G_TYPE_OBJECT)
+
+static void
+pango_font_finalize (GObject *object)
+{
+  PangoFont *font = PANGO_FONT (object);
+  PangoFontPrivate *priv = pango_font_get_instance_private (font);
+
+  hb_font_destroy (priv->hb_font);
+
+  G_OBJECT_CLASS (pango_font_parent_class)->finalize (object);
+}
 
 static void
 pango_font_class_init (PangoFontClass *class G_GNUC_UNUSED)
 {
+  GObjectClass *object_class = G_OBJECT_CLASS (class);
+
+  object_class->finalize = pango_font_finalize;
 }
 
 static void
@@ -1838,6 +1856,36 @@ pango_font_get_font_map (PangoFont *font)
     return NULL;
 }
 
+/**
+ * pango_font_get_hb_font:
+ * @font: a #PangoFont
+ *
+ * Get a hb_font_t object backing this font.
+ *
+ * Returns: (transfer none) (nullable): the hb_font_t object backing the
+ *          font, or %NULL if the font does not have one
+ *
+ * Since: 1.44
+ */
+hb_font_t *
+pango_font_get_hb_font (PangoFont *font)
+{
+  PangoFontPrivate *priv = pango_font_get_instance_private (font);
+
+  if (G_UNLIKELY (!font))
+    return NULL;
+
+  if (priv->hb_font)
+    return priv->hb_font;
+  else if (PANGO_FONT_GET_CLASS (font)->create_hb_font)
+    {
+      priv->hb_font = PANGO_FONT_GET_CLASS (font)->create_hb_font (font);
+      return priv->hb_font;
+    }
+
+  return NULL;
+}
+
 G_DEFINE_BOXED_TYPE (PangoFontMetrics, pango_font_metrics,
                      pango_font_metrics_ref,
                      pango_font_metrics_unref);
diff --git a/pango/pango-font-private.h b/pango/pango-font-private.h
index be399d7d..029bef99 100644
--- a/pango/pango-font-private.h
+++ b/pango/pango-font-private.h
@@ -179,11 +179,7 @@ struct _PangoFontClass
                                                hb_feature_t   *features,
                                                guint           len,
                                                guint          *num_features);
-
-  /*< private >*/
-
-  /* Padding for future expansion */
-  void (*_pango_reserved1) (void);
+  hb_font_t *           (*create_hb_font)     (PangoFont      *font);
 };
 
 /* used for very rare and miserable situtations that we cannot even
diff --git a/pango/pango-font.h b/pango/pango-font.h
index fd5d7df4..b26c5ece 100644
--- a/pango/pango-font.h
+++ b/pango/pango-font.h
@@ -26,6 +26,7 @@
 #include <pango/pango-types.h>
 
 #include <glib-object.h>
+#include <hb.h>
 
 G_BEGIN_DECLS
 
@@ -492,6 +493,8 @@ void                  pango_font_get_features      (PangoFont        *font,
                                                     hb_feature_t     *features,
                                                     guint             len,
                                                     guint            *num_features);
+PANGO_AVAILABLE_IN_1_44
+hb_font_t *           pango_font_get_hb_font       (PangoFont        *font);
 
 
 /**
diff --git a/pango/pangofc-font.c b/pango/pangofc-font.c
index 335cde42..a314de73 100644
--- a/pango/pangofc-font.c
+++ b/pango/pangofc-font.c
@@ -93,6 +93,7 @@ static void                  pango_fc_font_get_features (PangoFont        *font,
                                                          hb_feature_t     *features,
                                                          guint             len,
                                                          guint            *num_features);
+static hb_font_t *           pango_fc_font_create_hb_font (PangoFont        *font);
 
 #define PANGO_FC_FONT_LOCK_FACE(font)  (PANGO_FC_FONT_GET_CLASS (font)->lock_face (font))
 #define PANGO_FC_FONT_UNLOCK_FACE(font)        (PANGO_FC_FONT_GET_CLASS (font)->unlock_face (font))
@@ -120,6 +121,8 @@ pango_fc_font_class_init (PangoFcFontClass *class)
   font_class->get_metrics = pango_fc_font_get_metrics;
   font_class->get_font_map = pango_fc_font_get_font_map;
   font_class->get_features = pango_fc_font_get_features;
+  font_class->create_hb_font = pango_fc_font_create_hb_font;
+  font_class->get_features = pango_fc_font_get_features;
 
   g_object_class_install_property (object_class, PROP_PATTERN,
                                   g_param_spec_pointer ("pattern",
@@ -1038,6 +1041,42 @@ pango_fc_font_get_raw_extents (PangoFcFont    *fcfont,
   PANGO_FC_FONT_UNLOCK_FACE (fcfont);
 }
 
+static void
+pango_fc_font_get_features (PangoFont    *font,
+                            hb_feature_t *features,
+                            guint         len,
+                            guint        *num_features)
+{
+  /* Setup features from fontconfig pattern. */
+  PangoFcFont *fc_font = PANGO_FC_FONT (font);
+  if (fc_font->font_pattern)
+    {
+      char *s;
+      while (*num_features < len &&
+             FcResultMatch == FcPatternGetString (fc_font->font_pattern,
+                                                  PANGO_FC_FONT_FEATURES,
+                                                  *num_features,
+                                                  (FcChar8 **) &s))
+        {
+          gboolean ret = hb_feature_from_string (s, -1, &features[*num_features]);
+          features[*num_features].start = 0;
+          features[*num_features].end   = (unsigned int) -1;
+          if (ret)
+            (*num_features)++;
+        }
+    }
+
+static hb_font_t *
+pango_fc_font_create_hb_font (PangoFont *font)
+{
+  PangoFcFont *fcfont = PANGO_FC_FONT (font);
+  hb_face_t *hb_face;
+
+  hb_face = pango_fc_font_map_get_hb_face (PANGO_FC_FONT_MAP (fcfont->fontmap), fcfont);
+
+  return hb_font_create (hb_face);
+}
+
 static void
 pango_fc_font_get_features (PangoFont    *font,
                             hb_feature_t *features,
diff --git a/pango/pangofc-fontmap.c b/pango/pangofc-fontmap.c
index 20ef6c04..21277044 100644
--- a/pango/pangofc-fontmap.c
+++ b/pango/pangofc-fontmap.c
@@ -52,6 +52,7 @@
 #include "pango-impl-utils.h"
 #include "pango-enum-types.h"
 #include "pango-coverage-private.h"
+#include <hb-ft.h>
 
 
 /* Overview:
@@ -166,6 +167,8 @@ struct _PangoFcFontFaceData
   FcPattern *pattern;  /* Referenced pattern that owns filename */
   PangoCoverage *coverage;
   PangoFcCmapCache *cmap_cache;
+
+  hb_face_t *hb_face;
 };
 
 struct _PangoFcFace
@@ -297,6 +300,8 @@ pango_fc_font_face_data_free (PangoFcFontFaceData *data)
   if (data->cmap_cache)
     _pango_fc_cmap_cache_unref (data->cmap_cache);
 
+  hb_face_destroy (data->hb_face);
+
   g_slice_free (PangoFcFontFaceData, data);
 }
 
@@ -2726,3 +2731,23 @@ pango_fc_family_init (PangoFcFamily *fcfamily)
 {
   fcfamily->n_faces = -1;
 }
+
+hb_face_t *
+pango_fc_font_map_get_hb_face (PangoFcFontMap *fcfontmap,
+                               PangoFcFont    *fcfont)
+{
+  PangoFcFontFaceData *data;
+
+  data = pango_fc_font_map_get_font_face_data (fcfontmap, fcfont->font_pattern);
+  
+  if (!data->hb_face)
+    {
+      hb_blob_t *blob;
+
+      blob = hb_blob_create_from_file (data->filename);
+      data->hb_face = hb_face_create (blob, data->id);
+      hb_blob_destroy (blob);
+    }
+
+  return data->hb_face;
+}
diff --git a/pango/pangofc-fontmap.h b/pango/pangofc-fontmap.h
index 5195d761..495adc52 100644
--- a/pango/pangofc-fontmap.h
+++ b/pango/pangofc-fontmap.h
@@ -26,6 +26,7 @@
 #include <fontconfig/fontconfig.h>
 #include <pango/pangofc-decoder.h>
 #include <pango/pangofc-font.h>
+#include <hb.h>
 
 G_BEGIN_DECLS
 
@@ -42,7 +43,6 @@ typedef struct _PangoFcFontMap        PangoFcFontMap;
 typedef struct _PangoFcFontMapClass   PangoFcFontMapClass;
 typedef struct _PangoFcFontMapPrivate PangoFcFontMapPrivate;
 
-
 PANGO_AVAILABLE_IN_ALL
 GType pango_fc_font_map_get_type (void) G_GNUC_CONST;
 
@@ -87,6 +87,10 @@ PANGO_AVAILABLE_IN_1_4
 PangoFontDescription *pango_fc_font_description_from_pattern (FcPattern *pattern,
                                                              gboolean   include_size);
 
+PANGO_AVAILABLE_IN_1_44
+hb_face_t * pango_fc_font_map_get_hb_face (PangoFcFontMap *fcfontmap,
+                                           PangoFcFont    *fcfont);
+
 /**
  * PANGO_FC_GRAVITY:
  *