[pango/speed-up-format-filtering: 2/7] fc: Only do filtering by format once

[Matthias Clasen <matthiasc src gnome org>]

commit a1885724266ee310a2cedfdaea0fb959abc32bcc
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Aug 16 08:17:50 2020 -0400

    fc: Only do filtering by format once
    
    The fontconfig configuration changes rarely, so we can avoid
    unnecessary work by only doing the filtering by supported formats
    once, and keeping the result.

 pango/pangofc-fontmap.c | 80 +++++++++++++++++++++++++++++++++++++------------
 1 file changed, 61 insertions(+), 19 deletions(-)
---
diff --git a/pango/pangofc-fontmap.c b/pango/pangofc-fontmap.c
index 4c2aa094..ca46f184 100644
--- a/pango/pangofc-fontmap.c
+++ b/pango/pangofc-fontmap.c
@@ -157,6 +157,7 @@ struct _PangoFcFontMapPrivate
   guint closed : 1;
 
   FcConfig *config;
+  FcFontSet *fonts[2];
 };
 
 struct _PangoFcFontFaceData
@@ -837,12 +838,18 @@ pango_fc_is_supported_font_format (FcPattern* pattern)
   return FALSE;
 }
 
+static FcFontSet **pango_fc_font_map_get_config_fonts (PangoFcFontMap *fcfontmap,
+                                                       int            *nsets);
+
 static FcFontSet *
 filter_fontset_by_format (FcFontSet *fontset)
 {
   FcFontSet *result;
   int i;
 
+  if (!fontset)
+    return NULL;
+
   result = FcFontSetCreate ();
 
   for (i = 0; i < fontset->nfont; i++)
@@ -863,34 +870,40 @@ pango_fc_patterns_get_font_pattern (PangoFcPatterns *pats, int i, gboolean *prep
   if (i == 0)
     {
       FcResult result;
+
       if (!pats->match && !pats->fontset)
-       pats->match = FcFontMatch (pats->fontmap->priv->config, pats->pattern, &result);
+        {
+          FcFontSet **sets;
+          int nsets;
 
-      if (pats->match && pango_fc_is_supported_font_format (pats->match))
-       {
-         *prepare = FALSE;
-         return pats->match;
-       }
-    }
+          sets = pango_fc_font_map_get_config_fonts (pats->fontmap, &nsets);
 
-  if (!pats->fontset)
-    {
-      FcResult result;
-      FcFontSet *filtered[2] = { NULL, };
-      int i, n = 0;
+          pats->match = FcFontSetMatch (pats->fontmap->priv->config,
+                                        sets, nsets,
+                                        pats->pattern,
+                                        &result);
+        }
 
-      for (i = 0; i < 2; i++)
+      if (pats->match)
         {
-          FcFontSet *fonts = FcConfigGetFonts (pats->fontmap->priv->config, i);
-          if (fonts)
-            filtered[n++] = filter_fontset_by_format (fonts);
+          *prepare = FALSE;
+          return pats->match;
         }
+    }
 
-      pats->fontset = FcFontSetSort (pats->fontmap->priv->config, filtered, n, pats->pattern, FcTrue, NULL, 
&result);
+  if (!pats->fontset)
+    {
+      FcResult result;
+      FcFontSet **sets;
+      int nsets;
 
-      for (i = 0; i < n; i++)
-        FcFontSetDestroy (filtered[i]);
+      sets = pango_fc_font_map_get_config_fonts (pats->fontmap, &nsets);
 
+      pats->fontset = FcFontSetSort (pats->fontmap->priv->config,
+                                     sets, nsets,
+                                     pats->pattern,
+                                     FcTrue, NULL,
+                                     &result);
 
       if (pats->match)
         {
@@ -1214,6 +1227,9 @@ pango_fc_font_map_fini (PangoFcFontMap *fcfontmap)
   PangoFcFontMapPrivate *priv = fcfontmap->priv;
   int i;
 
+  for (i = 0; i < 2; i++)
+    g_clear_pointer (&priv->fonts[i], FcFontSetDestroy);
+
   g_queue_free (priv->fontset_cache);
   priv->fontset_cache = NULL;
 
@@ -2055,6 +2071,7 @@ pango_fc_font_map_set_config (PangoFcFontMap *fcfontmap,
                              FcConfig       *fcconfig)
 {
   FcConfig *oldconfig;
+  int i;
 
   g_return_if_fail (PANGO_IS_FC_FONT_MAP (fcfontmap));
 
@@ -2065,6 +2082,9 @@ pango_fc_font_map_set_config (PangoFcFontMap *fcfontmap,
 
   fcfontmap->priv->config = fcconfig;
 
+  for (i = 0; i < 2; i++)
+    g_clear_pointer (&fcfontmap->priv->fonts[i], FcFontSetDestroy);
+
   if (oldconfig != fcconfig)
     pango_fc_font_map_config_changed (fcfontmap);
 
@@ -2093,6 +2113,28 @@ pango_fc_font_map_get_config (PangoFcFontMap *fcfontmap)
   return fcfontmap->priv->config;
 }
 
+static FcFontSet **
+pango_fc_font_map_get_config_fonts (PangoFcFontMap *fcfontmap,
+                                    int            *nsets)
+{
+  if (fcfontmap->priv->fonts[0] == NULL &&
+      fcfontmap->priv->fonts[1] == NULL)
+    {
+      int set;
+
+      for (set = 0; set < 2; set++)
+        {
+          FcFontSet *fonts;
+
+          fonts = FcConfigGetFonts (fcfontmap->priv->config, set);
+          fcfontmap->priv->fonts[set] = filter_fontset_by_format (fonts);
+        }
+    }
+
+  *nsets = 2;
+  return fcfontmap->priv->fonts;
+}
+
 static PangoFcFontFaceData *
 pango_fc_font_map_get_font_face_data (PangoFcFontMap *fcfontmap,
                                      FcPattern      *font_pattern)