[pango/hb-getters: 3/3] Implement hb font getter for fontconfig

[Matthias Clasen <matthiasc src gnome org>]

commit 539d8f6ad0c2d7987d9e1132ce6e5a1528172de4
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Oct 15 17:46:54 2018 -0400

    Implement hb font getter for fontconfig
    
    We cache a hb_face_t object along with the font data
    we already cache, and create a hb_font_t object from
    it as needed.

 pango/pangofc-font.c    | 16 +++++++++++++++-
 pango/pangofc-fontmap.c | 26 ++++++++++++++++++++++++++
 pango/pangofc-fontmap.h |  7 +++++++
 3 files changed, 48 insertions(+), 1 deletion(-)
---
diff --git a/pango/pangofc-font.c b/pango/pangofc-font.c
index 5a48e782..d26a11e3 100644
--- a/pango/pangofc-font.c
+++ b/pango/pangofc-font.c
@@ -89,7 +89,7 @@ static PangoFontMetrics *    pango_fc_font_get_metrics  (PangoFont        *font,
 static PangoFontMap *        pango_fc_font_get_font_map (PangoFont        *font);
 static PangoFontDescription *pango_fc_font_describe     (PangoFont        *font);
 static PangoFontDescription *pango_fc_font_describe_absolute (PangoFont        *font);
-
+static hb_font_t *           pango_fc_font_get_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))
@@ -116,6 +116,7 @@ pango_fc_font_class_init (PangoFcFontClass *class)
   font_class->get_coverage = pango_fc_font_get_coverage;
   font_class->get_metrics = pango_fc_font_get_metrics;
   font_class->get_font_map = pango_fc_font_get_font_map;
+  font_class->get_hb_font = pango_fc_font_get_hb_font;
 
   g_object_class_install_property (object_class, PROP_PATTERN,
                                   g_param_spec_pointer ("pattern",
@@ -1067,3 +1068,16 @@ pango_fc_font_get_raw_extents (PangoFcFont    *fcfont,
   PANGO_FC_FONT_UNLOCK_FACE (fcfont);
 }
 
+static hb_font_t *
+pango_fc_font_get_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);
+
+  if (hb_face)
+    return hb_font_create (hb_face);
+
+  return NULL;
+}
diff --git a/pango/pangofc-fontmap.c b/pango/pangofc-fontmap.c
index 8b41018b..5a9389a8 100644
--- a/pango/pangofc-fontmap.c
+++ b/pango/pangofc-fontmap.c
@@ -50,6 +50,7 @@
 #include "pangofc-private.h"
 #include "pango-impl-utils.h"
 #include "pango-enum-types.h"
+#include <hb-ft.h>
 
 
 /* Overview:
@@ -164,6 +165,8 @@ struct _PangoFcFontFaceData
   FcPattern *pattern;  /* Referenced pattern that owns filename */
   PangoCoverage *coverage;
   PangoFcCmapCache *cmap_cache;
+
+  hb_face_t *hb_face;
 };
 
 struct _PangoFcFace
@@ -294,6 +297,9 @@ pango_fc_font_face_data_free (PangoFcFontFaceData *data)
   if (data->cmap_cache)
     _pango_fc_cmap_cache_unref (data->cmap_cache);
 
+  if (data->hb_face)
+    hb_face_destroy (data->hb_face);
+
   g_slice_free (PangoFcFontFaceData, data);
 }
 
@@ -2656,3 +2662,23 @@ 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 bff288b6..afa402df 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
 
@@ -187,6 +188,7 @@ struct _PangoFcFontMapClass
                                      FcPattern                  *pattern);
   PangoFcFont  *(*create_font)       (PangoFcFontMap             *fontmap,
                                      PangoFcFontKey             *fontkey);
+
   /*< private >*/
 
   /* Padding for future expansion */
@@ -249,6 +251,11 @@ 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:
  *