From 800232e1d3ebfbac28d07014a3c646ea00fcf6ad Mon Sep 17 00:00:00 2001
From: Konstantin Ritt <ritt.ks@gmail.com>
Date: Fri, 7 Mar 2014 01:46:47 +0200
Subject: [PATCH] Fix custom font substitution list support

During the QPA refactoring, the custom font substitution list support
was lost by ignoring the font request's fallbackFamilies member
when the multi font engine gets created/initialized.
If fallbackFamilies is not empty, it should be prepended to the
font database default fallback families list. Also respect the
custom fallback families list in the cache key to avoid picking
a multi font engine with wrong fallbacks list.

Task-number: QTBUG-36628

Change-Id: Ie2b84b3a397bee4816f421cddf76a5375829f13a
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
---
 src/gui/text/qfont_p.h         | 22 ++++++++++++++++------
 src/gui/text/qfontdatabase.cpp |  6 ++++--
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/src/gui/text/qfont_p.h b/src/gui/text/qfont_p.h
index 61655543882..b78d6692b43 100644
--- a/src/gui/text/qfont_p.h
+++ b/src/gui/text/qfont_p.h
@@ -228,22 +228,32 @@ public:
     void clear();
 
     struct Key {
-        Key() : script(0), screen(0) { }
-        Key(const QFontDef &d, int c, int s = 0)
-            : def(d), script(c), screen(s) { }
+        Key() : script(0), multi(0), screen(0) { }
+        Key(const QFontDef &d, uchar c, bool m = 0, uchar s = 0)
+            : def(d), script(c), multi(m), screen(s) { }
 
         QFontDef def;
-        int script;
-        int screen;
+        uchar script;
+        uchar multi: 1;
+        uchar screen: 7;
 
         inline bool operator<(const Key &other) const
         {
             if (script != other.script) return script < other.script;
             if (screen != other.screen) return screen < other.screen;
+            if (multi != other.multi) return multi < other.multi;
+            if (multi && def.fallBackFamilies.size() != other.def.fallBackFamilies.size())
+                return def.fallBackFamilies.size() < other.def.fallBackFamilies.size();
             return def < other.def;
         }
         inline bool operator==(const Key &other) const
-        { return def == other.def && script == other.script && screen == other.screen; }
+        {
+            return script == other.script
+                    && screen == other.screen
+                    && multi == other.multi
+                    && (!multi || def.fallBackFamilies.size() == other.def.fallBackFamilies.size())
+                    && def == other.def;
+        }
     };
 
     // QFontEngineData cache
diff --git a/src/gui/text/qfontdatabase.cpp b/src/gui/text/qfontdatabase.cpp
index 1dfccca57c7..3c2cf4fdcf8 100644
--- a/src/gui/text/qfontdatabase.cpp
+++ b/src/gui/text/qfontdatabase.cpp
@@ -824,9 +824,11 @@ QFontEngine *loadEngine(int script, const QFontDef &request,
             family->askedForFallback = true;
         }
 
-        QStringList fallbacks = privateDb()->fallbackFamilies;
+        QStringList fallbacks = request.fallBackFamilies;
         if (family && !family->fallbackFamilies.isEmpty())
-            fallbacks = family->fallbackFamilies;
+            fallbacks += family->fallbackFamilies;
+        else
+            fallbacks += privateDb()->fallbackFamilies;
 
         QPlatformFontDatabase *pfdb = QGuiApplicationPrivate::platformIntegration()->fontDatabase();
         QFontEngineMulti *pfMultiEngine = pfdb->fontEngineMulti(engine, QChar::Script(script));