Use the lazily-queried families for all QPA multi font engines.

This is the approach introduced together with the  WebKit "backdoor"
that lets us use QRawFont with QTextLayout. We could use it all
over the place and share more code.

Change-Id: Ie1963679755f37ba9204d67554a163f1d1115604
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@nokia.com>

1 files changed, 32 insertions, 24 deletions

diff --git a/src/gui/text/qfontengine_qpa.cpp b/src/gui/text/qfontengine_qpa.cpp
index 48679824a4..d12e2d651c 100644
--- a/src/gui/text/qfontengine_qpa.cpp
+++ b/src/gui/text/qfontengine_qpa.cpp
@@ -674,6 +674,7 @@ QFontEngineMultiQPA::QFontEngineMultiQPA(QFontEngine *fe, int _script)
     , script(_script)
     , fallbacksQueried(false)
 {
+    fallbackFamilies << QString();
     init(fe);
 }
 
@@ -688,36 +689,43 @@ void QFontEngineMultiQPA::init(QFontEngine *fe)
 
 void QFontEngineMultiQPA::loadEngine(int at)
 {
-    bool canLoadFallbackEngine = true;
-    if (!fallbacksQueried) {
-        // Original FontEngine to restore after the fill.
-        QFontEngine *fe = engines[0];
-        fallbackFamilies = QGuiApplicationPrivate::instance()->platformIntegration()->fontDatabase()->fallbacksForFamily(fe->fontDef.family, QFont::Style(fe->fontDef.style)
-                                                                                                                         , QFont::AnyStyle, QUnicodeTables::Script(script));
-        if (fallbackFamilies.size() > 1) {
-            engines.fill(0, fallbackFamilies.size() + 1);
-            engines[0] = fe;
-        } else {
-            // Turns out we lied about having any fallback at all.
-            canLoadFallbackEngine = false;
-            engines[1] = fe;
-        }
-        fallbacksQueried = true;
-    }
+    ensureFallbackFamiliesQueried();
     Q_ASSERT(at < engines.size());
     Q_ASSERT(engines.at(at) == 0);
     QFontDef request = fontDef;
-    if (canLoadFallbackEngine) {
-        request.styleStrategy |= QFont::NoFontMerging;
-        request.family = fallbackFamilies.at(at-1);
-        engines[at] = QFontDatabase::findFont(script,
-                                              /*fontprivate = */0,
-                                              request, /*multi = */false);
-    }
+    request.styleStrategy |= QFont::NoFontMerging;
+    request.family = fallbackFamilies.at(at-1);
+    engines[at] = QFontDatabase::findFont(script,
+                                          /*fontprivate = */0,
+                                          request, /*multi = */false);
     Q_ASSERT(engines[at]);
     engines[at]->ref.ref();
     engines[at]->fontDef = request;
 }
+void QFontEngineMultiQPA::ensureFallbackFamiliesQueried()
+{
+    if (fallbacksQueried)
+        return;
+    QStringList fallbacks = QGuiApplicationPrivate::instance()->platformIntegration()->fontDatabase()->fallbacksForFamily(engine(0)->fontDef.family, QFont::Style(engine(0)->fontDef.style)
+                                                                                                                     , QFont::AnyStyle, QUnicodeTables::Script(script));
+    setFallbackFamiliesList(fallbacks);
+}
+
+void QFontEngineMultiQPA::setFallbackFamiliesList(const QStringList &fallbacks)
+{
+    // Original FontEngine to restore after the fill.
+    QFontEngine *fe = engines[0];
+    fallbackFamilies = fallbacks;
+    if (!fallbackFamilies.isEmpty()) {
+        engines.fill(0, fallbackFamilies.size() + 1);
+        engines[0] = fe;
+    } else {
+        // Turns out we lied about having any fallback at all.
+        fallbackFamilies << fe->fontDef.family;
+        engines[1] = fe;
+    }
+    fallbacksQueried = true;
+}
 
 /*
   This is used indirectly by QtWebKit when using QTextLayout::setRawFont
@@ -750,7 +758,7 @@ QFontEngine* QFontEngineMultiQPA::createMultiFontEngine(QFontEngine *fe, int scr
         it++;
     }
     if (!engine) {
-        engine = new QFontEngineMultiQPA(fe, script);
+        engine = QGuiApplicationPrivate::instance()->platformIntegration()->fontDatabase()->fontEngineMulti(fe, QUnicodeTables::Script(script));
         QFontCache::instance()->insertEngine(key, engine, /* insertMulti */ !faceIsLocal);
     }
     Q_ASSERT(engine);