Release font engine refcount when done using it in QTextEngine

5f2b6dd2a50275bc05ae5d7e9dd8902d6d49d9df increased refcounts for
font engines in QTextEngine cache, we need to decrease them when
the QTextEngine is deallocated.

Task-number: QTBUG-21222
Reviewed-by: Eskil

3 files changed, 12 insertions, 5 deletions

diff --git a/src/gui/text/qtextengine.cpp b/src/gui/text/qtextengine.cpp
index cff3641..ee2eef6 100644
--- a/src/gui/text/qtextengine.cpp
+++ b/src/gui/text/qtextengine.cpp
@@ -1334,6 +1334,7 @@ QTextEngine::~QTextEngine()
     if (!stackEngine)
         delete layoutData;
     delete specialData;
+    resetFontEngineCache();
 }
 
 const HB_CharAttributes *QTextEngine::attributes() const
@@ -1394,6 +1395,13 @@ static inline void releaseCachedFontEngine(QFontEngine *fontEngine)
     }
 }
 
+void QTextEngine::resetFontEngineCache()
+{
+    releaseCachedFontEngine(feCache.prevFontEngine);
+    releaseCachedFontEngine(feCache.prevScaledFontEngine);
+    feCache.reset();
+}
+
 void QTextEngine::invalidate()
 {
     freeMemory();
@@ -1402,9 +1410,7 @@ void QTextEngine::invalidate()
     if (specialData)
         specialData->resolvedFormatIndices.clear();
 
-    releaseCachedFontEngine(feCache.prevFontEngine);
-    releaseCachedFontEngine(feCache.prevScaledFontEngine);
-    feCache.reset();
+    resetFontEngineCache();
 }
 
 void QTextEngine::clearLineData()
diff --git a/src/gui/text/qtextengine_p.h b/src/gui/text/qtextengine_p.h
index c920c7b..2b6db67 100644
--- a/src/gui/text/qtextengine_p.h
+++ b/src/gui/text/qtextengine_p.h
@@ -614,6 +614,7 @@ public:
     QFixed leadingSpaceWidth(const QScriptLine &line);
 
     int positionInLigature(const QScriptItem *si, int end, QFixed x, QFixed edge, int glyph_pos, bool cursorOnCharacter);
+    void resetFontEngineCache();
 
 private:
     void setBoundary(int strPos) const;
diff --git a/src/gui/text/qtextlayout.cpp b/src/gui/text/qtextlayout.cpp
index d180f0e..f2d3de1 100644
--- a/src/gui/text/qtextlayout.cpp
+++ b/src/gui/text/qtextlayout.cpp
@@ -386,7 +386,7 @@ QTextLayout::~QTextLayout()
 void QTextLayout::setFont(const QFont &font)
 {
     d->fnt = font;
-    d->feCache.reset();
+    d->resetFontEngineCache();
 }
 
 /*!
@@ -519,7 +519,7 @@ void QTextLayout::setAdditionalFormats(const QList<FormatRange> &formatList)
     }
     if (d->block.docHandle())
         d->block.docHandle()->documentChange(d->block.position(), d->block.length());
-    d->feCache.reset();
+    d->resetFontEngineCache();
 }
 
 /*!