Prevented infinite recursion in QPainterPath::contains().

Limit the amount of recursions in qt_painterpath_isect_curve to prevent
a crash.

Task-number: QTBUG-16422
Reviewed-by: Kim

2 files changed, 9 insertions, 4 deletions

diff --git a/src/gui/painting/qpainterpath.cpp b/src/gui/painting/qpainterpath.cpp
index 7ecf10a..88eef99 100644
--- a/src/gui/painting/qpainterpath.cpp
+++ b/src/gui/painting/qpainterpath.cpp
@@ -1690,7 +1690,7 @@ static void qt_painterpath_isect_line(const QPointF &p1,
 }
 
 static void qt_painterpath_isect_curve(const QBezier &bezier, const QPointF &pt,
-                                       int *winding)
+                                       int *winding, int depth = 0)
 {
     qreal y = pt.y();
     qreal x = pt.x();
@@ -1705,7 +1705,7 @@ static void qt_painterpath_isect_curve(const QBezier &bezier, const QPointF &pt,
         // hit lower limit... This is a rough threshold, but its a
         // tradeoff between speed and precision.
         const qreal lower_bound = qreal(.001);
-        if (bounds.width() < lower_bound && bounds.height() < lower_bound) {
+        if (depth == 32 || (bounds.width() < lower_bound && bounds.height() < lower_bound)) {
             // We make the assumption here that the curve starts to
             // approximate a line after while (i.e. that it doesn't
             // change direction drastically during its slope)
@@ -1718,8 +1718,8 @@ static void qt_painterpath_isect_curve(const QBezier &bezier, const QPointF &pt,
         // split curve and try again...
         QBezier first_half, second_half;
         bezier.split(&first_half, &second_half);
-        qt_painterpath_isect_curve(first_half, pt, winding);
-        qt_painterpath_isect_curve(second_half, pt, winding);
+        qt_painterpath_isect_curve(first_half, pt, winding, depth + 1);
+        qt_painterpath_isect_curve(second_half, pt, winding, depth + 1);
     }
 }
 
diff --git a/tests/auto/qpainterpath/tst_qpainterpath.cpp b/tests/auto/qpainterpath/tst_qpainterpath.cpp
index 00f9b91..4ade9ad 100644
--- a/tests/auto/qpainterpath/tst_qpainterpath.cpp
+++ b/tests/auto/qpainterpath/tst_qpainterpath.cpp
@@ -290,6 +290,11 @@ void tst_QPainterPath::contains_QPointF_data()
     QTest::newRow("horizontal cubic, out left") << path << QPointF(0, 100) << false;
     QTest::newRow("horizontal cubic, out right") << path << QPointF(300, 100) <<false;
     QTest::newRow("horizontal cubic, in mid") << path << QPointF(150, 100) << true;
+
+    path = QPainterPath();
+    path.addEllipse(QRectF(-5000.0, -5000.0, 1500000.0, 1500000.0));
+    QTest::newRow("huge ellipse, qreal=float crash") << path << QPointF(1100000.35, 1098000.2) << true;
+
 }
 
 void tst_QPainterPath::contains_QPointF()