Fix a thread safety issue with QTextLine::glyphRuns

This is a very partial revert of 10ac80708.
Revert back to using engineFromScript, which is reentrant, for cases other
than the "rawfont mode". In that last case, reentrancy is not a big issue
so far as the only client is WebKit, and this is used in the web process,
with no threaded rendering.

Change-Id: I047b04cf0236d52e6d548f34cddd3dcc7c3c5f83
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@nokia.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/gui/text/qtextlayout.cpp b/src/gui/text/qtextlayout.cpp
index bec574bb83..94af3edeeb 100644
--- a/src/gui/text/qtextlayout.cpp
+++ b/src/gui/text/qtextlayout.cpp
@@ -2288,7 +2288,13 @@ QList<QGlyphRun> QTextLine::glyphRuns(int from, int length) const
         iterator.getSelectionBounds(&x, &width);
 
         if (glyphLayout.numGlyphs > 0) {
-            QFontEngine *mainFontEngine = eng->fontEngine(si);
+            QFontEngine *mainFontEngine;
+#ifndef QT_NO_RAWFONT
+            if (eng->useRawFont && eng->rawFont.isValid())
+                mainFontEngine= eng->fontEngine(si);
+            else
+#endif
+                mainFontEngine = font.d->engineForScript(si.analysis.script);
 
             if (mainFontEngine->type() == QFontEngine::Multi) {
                 QFontEngineMulti *multiFontEngine = static_cast<QFontEngineMulti *>(mainFontEngine);