[pango/speed-up-format-filtering: 1/7] fc: Only do filtering by format once

[Matthias Clasen <matthiasc src gnome org>]

commit eea35d8996b51e332411840e6e9111c9902cf622
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 | 81 +++++++++++++++++++++++++++++++++++--------------
 1 file changed, 58 insertions(+), 23 deletions(-)
---
diff --git a/pango/pangofc-fontmap.c b/pango/pangofc-fontmap.c
index 4c2aa094..b3b6a53e 100644
--- a/pango/pangofc-fontmap.c
+++ b/pango/pangofc-fontmap.c
@@ -157,6 +157,7 @@ struct _PangoFcFontMapPrivate
   guint closed : 1;
 
   FcConfig *config;
+  FcFontSet *fonts;
 };
 
 struct _PangoFcFontFaceData
@@ -837,18 +838,29 @@ pango_fc_is_supported_font_format (FcPattern* pattern)
   return FALSE;
 }
 
+static FcFontSet *pango_fc_font_map_get_config_fonts (PangoFcFontMap *fcfontmap);
+
 static FcFontSet *
-filter_fontset_by_format (FcFontSet *fontset)
+filter_by_format (FcFontSet **sets, int nsets)
 {
   FcFontSet *result;
-  int i;
+  int set;
 
   result = FcFontSetCreate ();
 
-  for (i = 0; i < fontset->nfont; i++)
+  for (set = 0; set < nsets; set++)
     {
-      if (pango_fc_is_supported_font_format (fontset->fonts[i]))
+      FcFontSet *fontset = sets[set];
+      int i;
+
+      if (!fontset)
+        continue;
+
+      for (i = 0; i < fontset->nfont; i++)
         {
+          if (!pango_fc_is_supported_font_format (fontset->fonts[i]))
+            continue;
+
           FcPatternReference (fontset->fonts[i]);
           FcFontSetAdd (result, fontset->fonts[i]);
         }
@@ -863,34 +875,38 @@ 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 *fonts;
 
-      if (pats->match && pango_fc_is_supported_font_format (pats->match))
-       {
-         *prepare = FALSE;
-         return pats->match;
-       }
-    }
+          fonts = pango_fc_font_map_get_config_fonts (pats->fontmap);
 
-  if (!pats->fontset)
-    {
-      FcResult result;
-      FcFontSet *filtered[2] = { NULL, };
-      int i, n = 0;
+          pats->match = FcFontSetMatch (pats->fontmap->priv->config,
+                                        &fonts, 1,
+                                        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 *fonts;
 
-      for (i = 0; i < n; i++)
-        FcFontSetDestroy (filtered[i]);
+      fonts = pango_fc_font_map_get_config_fonts (pats->fontmap);
 
+      pats->fontset = FcFontSetSort (pats->fontmap->priv->config,
+                                     &fonts, 1,
+                                     pats->pattern,
+                                     FcTrue, NULL,
+                                     &result);
 
       if (pats->match)
         {
@@ -1214,6 +1230,8 @@ pango_fc_font_map_fini (PangoFcFontMap *fcfontmap)
   PangoFcFontMapPrivate *priv = fcfontmap->priv;
   int i;
 
+  g_clear_pointer (&priv->fonts, FcFontSetDestroy);
+
   g_queue_free (priv->fontset_cache);
   priv->fontset_cache = NULL;
 
@@ -2065,6 +2083,8 @@ pango_fc_font_map_set_config (PangoFcFontMap *fcfontmap,
 
   fcfontmap->priv->config = fcconfig;
 
+  g_clear_pointer (&fcfontmap->priv->fonts, FcFontSetDestroy);
+
   if (oldconfig != fcconfig)
     pango_fc_font_map_config_changed (fcfontmap);
 
@@ -2093,6 +2113,21 @@ pango_fc_font_map_get_config (PangoFcFontMap *fcfontmap)
   return fcfontmap->priv->config;
 }
 
+static FcFontSet *
+pango_fc_font_map_get_config_fonts (PangoFcFontMap *fcfontmap)
+{
+  if (fcfontmap->priv->fonts == NULL)
+    {
+      FcFontSet *sets[2];
+
+      sets[0] = FcConfigGetFonts (fcfontmap->priv->config, 0);
+      sets[1] = FcConfigGetFonts (fcfontmap->priv->config, 1);
+      fcfontmap->priv->fonts = filter_by_format (sets, 2);
+    }
+
+  return fcfontmap->priv->fonts;
+}
+
 static PangoFcFontFaceData *
 pango_fc_font_map_get_font_face_data (PangoFcFontMap *fcfontmap,
                                      FcPattern      *font_pattern)