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

[Matthias Clasen <matthiasc src gnome org>]

commit c8f6f30d03d5cd24b15919434fe2479185324113
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Aug 16 08:17:50 2020 -0400

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

 pango/pangofc-fontmap.c | 87 ++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 72 insertions(+), 15 deletions(-)
---
diff --git a/pango/pangofc-fontmap.c b/pango/pangofc-fontmap.c
index 4c2aa094c..b2a6285e9 100644
--- a/pango/pangofc-fontmap.c
+++ b/pango/pangofc-fontmap.c
@@ -157,6 +157,8 @@ struct _PangoFcFontMapPrivate
   guint closed : 1;
 
   FcConfig *config;
+  FcFontSet *config_fonts[2];
+  FcFontSet *filtered_fonts[2];
 };
 
 struct _PangoFcFontFaceData
@@ -837,6 +839,9 @@ 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)
 {
@@ -863,10 +868,21 @@ 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;
+
+          sets = pango_fc_font_map_get_config_fonts (pats->fontmap, &nsets);
 
-      if (pats->match && pango_fc_is_supported_font_format (pats->match))
+         pats->match = FcFontSetMatch (pats->fontmap->priv->config,
+                                        sets, nsets,
+                                        pats->pattern,
+                                        &result);
+        }
+
+      if (pats->match)
        {
          *prepare = FALSE;
          return pats->match;
@@ -876,21 +892,12 @@ pango_fc_patterns_get_font_pattern (PangoFcPatterns *pats, int i, gboolean *prep
   if (!pats->fontset)
     {
       FcResult result;
-      FcFontSet *filtered[2] = { NULL, };
-      int i, n = 0;
+      FcFontSet **sets;
+      int nsets;
 
-      for (i = 0; i < 2; i++)
-        {
-          FcFontSet *fonts = FcConfigGetFonts (pats->fontmap->priv->config, i);
-          if (fonts)
-            filtered[n++] = filter_fontset_by_format (fonts);
-        }
-
-      pats->fontset = FcFontSetSort (pats->fontmap->priv->config, filtered, n, pats->pattern, FcTrue, NULL, 
&result);
-
-      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 +1221,12 @@ pango_fc_font_map_fini (PangoFcFontMap *fcfontmap)
   PangoFcFontMapPrivate *priv = fcfontmap->priv;
   int i;
 
+  for (i = 0; i < 2; i++)
+    {
+      if (priv->filtered_fonts[i])
+        FcFontSetDestroy (priv->filtered_fonts[i]);
+    }
+
   g_queue_free (priv->fontset_cache);
   priv->fontset_cache = NULL;
 
@@ -2055,6 +2068,7 @@ 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 +2079,14 @@ pango_fc_font_map_set_config (PangoFcFontMap *fcfontmap,
 
   fcfontmap->priv->config = fcconfig;
 
+  for (i = 0; i < 2; i++)
+    {
+      if (fcfontmap->priv->filtered_fonts[i])
+        FcFontSetDestroy (fcfontmap->priv->filtered_fonts[i]);
+      fcfontmap->priv->filtered_fonts[i] = NULL;
+      fcfontmap->priv->config_fonts[i] = NULL;
+    }
+
   if (oldconfig != fcconfig)
     pango_fc_font_map_config_changed (fcfontmap);
 
@@ -2093,6 +2115,41 @@ 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)
+{
+  FcFontSet *fonts;
+  int set;
+  int n;
+
+  n = 0;
+  for (set = 0; set < 2; set++)
+    {
+      fonts = FcConfigGetFonts (fcfontmap->priv->config, set);
+      if (fonts != fcfontmap->priv->config_fonts[set])
+        {
+          if (fcfontmap->priv->filtered_fonts[set])
+            {
+              FcFontSetDestroy (fcfontmap->priv->filtered_fonts[set]);
+              fcfontmap->priv->filtered_fonts[set] = NULL;
+              fcfontmap->priv->config_fonts[set] = NULL;
+            }
+          if (fonts)
+            {
+              fcfontmap->priv->filtered_fonts[set] = filter_fontset_by_format (fonts);
+              fcfontmap->priv->config_fonts[set] = fonts;
+            }
+        }
+      if (fcfontmap->priv->filtered_fonts[set])
+        n++;
+    }
+
+  *nsets = n;
+
+  return fcfontmap->priv->filtered_fonts;
+}
+
 static PangoFcFontFaceData *
 pango_fc_font_map_get_font_face_data (PangoFcFontMap *fcfontmap,
                                      FcPattern      *font_pattern)