From 9ce5d00c801bd9b44317e81a213ad9b6fb3c1ffe Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Thu, 20 Aug 2020 01:32:23 -0400
Subject: Use FcFontSetMatchNext

Instead of calling FcFontSetMatch for the first result
and FcFontSetSort for all the rest, call the new
FcFontSetMatchNext to produce matches as needed.

FcFontSetMatchNext is roughly as fast as FcFontSetMatch.
---
 pango/pangofc-fontmap.c | 77 +++++++++++++++++++++++--------------------------
 1 file changed, 36 insertions(+), 41 deletions(-)

diff --git a/pango/pangofc-fontmap.c b/pango/pangofc-fontmap.c
index 4c2aa094..f0b9ab42 100644
--- a/pango/pangofc-fontmap.c
+++ b/pango/pangofc-fontmap.c
@@ -743,8 +743,10 @@ struct _PangoFcPatterns {
   PangoFcFontMap *fontmap;
 
   FcPattern *pattern;
-  FcPattern *match;
-  FcFontSet *fontset;
+
+  FcBool *skips[2];
+  FcCharSet *cs;
+  GPtrArray *matches;
 };
 
 static PangoFcPatterns *
@@ -765,6 +767,10 @@ pango_fc_patterns_new (FcPattern *pat, PangoFcFontMap *fontmap)
   FcPatternReference (pat);
   pats->pattern = pat;
 
+  pats->matches = g_ptr_array_new_with_free_func ((GDestroyNotify)FcPatternDestroy);
+  pats->skips[0] = pats->skips[1] = NULL;
+  pats->cs = FcCharSetCreate ();
+
   g_hash_table_insert (fontmap->priv->patterns_hash,
 		       pats->pattern, pats);
 
@@ -801,11 +807,12 @@ pango_fc_patterns_unref (PangoFcPatterns *pats)
   if (pats->pattern)
     FcPatternDestroy (pats->pattern);
 
-  if (pats->match)
-    FcPatternDestroy (pats->match);
+  g_ptr_array_free (pats->matches, TRUE);
 
-  if (pats->fontset)
-    FcFontSetDestroy (pats->fontset);
+  g_free (pats->skips[0]);
+  g_free (pats->skips[1]);
+
+  FcCharSetDestroy (pats->cs);
 
   g_slice_free (PangoFcPatterns, pats);
 }
@@ -843,6 +850,9 @@ filter_fontset_by_format (FcFontSet *fontset)
   FcFontSet *result;
   int i;
 
+  if (fontset == NULL)
+    return NULL;
+
   result = FcFontSetCreate ();
 
   for (i = 0; i < fontset->nfont; i++)
@@ -860,50 +870,35 @@ filter_fontset_by_format (FcFontSet *fontset)
 static FcPattern *
 pango_fc_patterns_get_font_pattern (PangoFcPatterns *pats, int i, gboolean *prepare)
 {
-  if (i == 0)
-    {
-      FcResult result;
-      if (!pats->match && !pats->fontset)
-	pats->match = FcFontMatch (pats->fontmap->priv->config, pats->pattern, &result);
+  FcFontSet *sets[2];
+  int nsets;
+  int j;
+  FcConfig *config = pats->fontmap->priv->config;
 
-      if (pats->match && pango_fc_is_supported_font_format (pats->match))
-	{
-	  *prepare = FALSE;
-	  return pats->match;
-	}
+  sets[0] = filter_fontset_by_format (FcConfigGetFonts (config, 0));
+  sets[1] = filter_fontset_by_format (FcConfigGetFonts (config, 1));
+  nsets = sets[1] ? 2 : (sets[0] ? 1 : 0);
+
+  for (j = 0; j < nsets; j++)
+    {
+      if (!pats->skips[j])
+        pats->skips[j] = g_malloc0 (sizeof(FcBool) * sets[j]->nfont);
     }
 
-  if (!pats->fontset)
+  while (i >= pats->matches->len)
     {
       FcResult result;
-      FcFontSet *filtered[2] = { NULL, };
-      int i, n = 0;
-
-      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]);
+      FcPattern *best;
 
+      best = FcFontSetMatchNext (config, sets, nsets, pats->skips, pats->cs, pats->pattern, &result);
 
-      if (pats->match)
-        {
-          FcPatternDestroy (pats->match);
-          pats->match = NULL;
-        }
+      if (best)
+        g_ptr_array_add (pats->matches, best);
     }
 
-  *prepare = TRUE;
-  if (pats->fontset && i < pats->fontset->nfont)
-    return pats->fontset->fonts[i];
-  else
-    return NULL;
+  *prepare = FALSE;
+
+  return g_ptr_array_index (pats->matches, i);
 }
 
 
-- 
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