[pango/preferred-languages: 2/3] pangofc: Add pango_fc_font_get_languages

[Matthias Clasen <matthiasc src gnome org>]

commit 9b6d9faddede30d2e1f2b2cbf413b776790e48a6
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Sep 8 14:25:42 2020 -0400

    pangofc: Add pango_fc_font_get_languages
    
    This really belongs into PangoFont, but we're out of
    room in the PangoFontClass struct for vfuncs, so this
    will have to remain backend-specific functionality
    for now.

 docs/pango-sections.txt |  1 +
 pango/pangofc-font.c    | 30 ++++++++++++++++++++++++++
 pango/pangofc-font.h    |  4 ++++
 pango/pangofc-fontmap.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++-
 pango/pangofc-private.h |  3 +++
 5 files changed, 93 insertions(+), 1 deletion(-)
---
diff --git a/docs/pango-sections.txt b/docs/pango-sections.txt
index 56ca9ecf..062b1bb4 100644
--- a/docs/pango-sections.txt
+++ b/docs/pango-sections.txt
@@ -1011,6 +1011,7 @@ pango_fc_font_has_char
 pango_fc_font_get_glyph
 pango_fc_font_get_unknown_glyph
 pango_fc_font_kern_glyphs
+pango_fc_font_get_languages
 <SUBSECTION Standard>
 PANGO_FC_FONT
 PANGO_IS_FC_FONT
diff --git a/pango/pangofc-font.c b/pango/pangofc-font.c
index 7456cd9e..96be3dc1 100644
--- a/pango/pangofc-font.c
+++ b/pango/pangofc-font.c
@@ -1035,3 +1035,33 @@ pango_fc_font_create_hb_font (PangoFont *font)
 done:
   return hb_font;
 }
+
+/**
+ * pango_fc_font_get_languages:
+ * @font: a #PangoFcFont
+ *
+ * Returns the languages that are supported by @font.
+ *
+ * This is the FC_LANG member of the FcPattern.
+ *
+ * The returned array is only valid as long as the font
+ * and its fontmap are valid.
+ *
+ * Returns: (transfer none) (nullable): a %NULL-terminated
+ *    array of PangoLanguage*
+ */
+PangoLanguage **
+pango_fc_font_get_languages (PangoFcFont *font)
+{
+  PangoFcFontMap *fontmap;
+  PangoLanguage **languages;
+
+  fontmap = g_weak_ref_get ((GWeakRef *) &font->fontmap);
+  if (!fontmap)
+    return NULL;
+
+  languages  = _pango_fc_font_map_get_languages (fontmap, font);
+  g_object_unref (fontmap);
+
+  return languages;
+}
diff --git a/pango/pangofc-font.h b/pango/pangofc-font.h
index 25a0277c..aa4fd3b0 100644
--- a/pango/pangofc-font.h
+++ b/pango/pangofc-font.h
@@ -94,6 +94,10 @@ gboolean   pango_fc_font_has_char          (PangoFcFont      *font,
 PANGO_AVAILABLE_IN_1_4
 guint      pango_fc_font_get_glyph         (PangoFcFont      *font,
                                             gunichar          wc);
+PANGO_AVAILABLE_IN_1_48
+PangoLanguage **
+           pango_fc_font_get_languages     (PangoFcFont      *font);
+
 PANGO_DEPRECATED_FOR(PANGO_GET_UNKNOWN_GLYPH)
 PangoGlyph pango_fc_font_get_unknown_glyph (PangoFcFont      *font,
                                             gunichar          wc);
diff --git a/pango/pangofc-fontmap.c b/pango/pangofc-fontmap.c
index eed0960a..bd15bf2a 100644
--- a/pango/pangofc-fontmap.c
+++ b/pango/pangofc-fontmap.c
@@ -166,8 +166,9 @@ struct _PangoFcFontFaceData
   int id;            /* needed to handle TTC files with multiple faces */
 
   /* Data */
-  FcPattern *pattern;  /* Referenced pattern that owns filename */
+  FcPattern *pattern;  /* Referenced pattern that owns filename */
   PangoCoverage *coverage;
+  PangoLanguage **languages;
 
   hb_face_t *hb_face;
 };
@@ -307,6 +308,8 @@ pango_fc_font_face_data_free (PangoFcFontFaceData *data)
   if (data->coverage)
     pango_coverage_unref (data->coverage);
 
+  g_free (data->languages);
+
   hb_face_destroy (data->hb_face);
 
   g_slice_free (PangoFcFontFaceData, data);
@@ -2245,6 +2248,57 @@ _pango_fc_font_map_fc_to_coverage (FcCharSet *charset)
   return (PangoCoverage *)coverage;
 }
 
+static PangoLanguage **
+_pango_fc_font_map_fc_to_languages (FcLangSet *langset)
+{
+  FcStrSet *strset;
+  FcStrList *list;
+  FcChar8 *s;
+  GArray *langs;
+
+  langs = g_array_new (TRUE, FALSE, sizeof (PangoLanguage *));
+
+  strset = FcLangSetGetLangs (langset);
+  list = FcStrListCreate (strset);
+
+  FcStrListFirst (list);
+  while ((s = FcStrListNext (list)))
+    {
+      PangoLanguage *l = pango_language_from_string ((const char *)s);
+      g_array_append_val (langs, l);
+    }
+
+  FcStrListDone (list);
+  FcStrSetDestroy (strset);
+
+  return (PangoLanguage **) g_array_free (langs, FALSE);
+}
+
+PangoLanguage **
+_pango_fc_font_map_get_languages (PangoFcFontMap *fcfontmap,
+                                  PangoFcFont    *fcfont)
+{
+  PangoFcFontFaceData *data;
+  FcLangSet *langset;
+
+  data = pango_fc_font_map_get_font_face_data (fcfontmap, fcfont->font_pattern);
+  if (G_UNLIKELY (!data))
+    return NULL;
+
+  if (G_UNLIKELY (data->languages == NULL))
+    {
+      /*
+       * Pull the languages out of the pattern, this
+       * doesn't require loading the font
+       */
+      if (FcPatternGetLangSet (fcfont->font_pattern, FC_LANG, 0, &langset) != FcResultMatch)
+        return NULL;
+
+      data->languages = _pango_fc_font_map_fc_to_languages (langset);
+    }
+
+  return data->languages;
+}
 /**
  * pango_fc_font_map_create_context:
  * @fcfontmap: a #PangoFcFontMap
diff --git a/pango/pangofc-private.h b/pango/pangofc-private.h
index 27b96df4..7e216ed9 100644
--- a/pango/pangofc-private.h
+++ b/pango/pangofc-private.h
@@ -78,6 +78,9 @@ _PANGO_EXTERN
 PangoFontMetrics *pango_fc_font_create_base_metrics_for_context (PangoFcFont   *font,
                                                                 PangoContext  *context);
 
+PangoLanguage **_pango_fc_font_map_get_languages (PangoFcFontMap *fcfontmap,
+                                                  PangoFcFont    *fcfont);
+
 G_END_DECLS
 
 #endif /* __PANGOFC_PRIVATE_H__ */