Fix QTextBoundaryFinder assignment operator

for the case when the boundary finder is assigned to an invalid one.

Change-Id: I5b60984ff3fd99972fcae21895684bd83b012780
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

2 files changed, 40 insertions, 6 deletions

diff --git a/src/corelib/tools/qtextboundaryfinder.cpp b/src/corelib/tools/qtextboundaryfinder.cpp
index 6656569e65..7f120323fe 100644
--- a/src/corelib/tools/qtextboundaryfinder.cpp
+++ b/src/corelib/tools/qtextboundaryfinder.cpp
@@ -202,18 +202,27 @@ QTextBoundaryFinder &QTextBoundaryFinder::operator=(const QTextBoundaryFinder &o
     if (&other == this)
         return *this;
 
+    if (other.d) {
+        uint newCapacity = (length + 1) * sizeof(QCharAttributes);
+        QTextBoundaryFinderPrivate *newD = (QTextBoundaryFinderPrivate *) realloc(freePrivate ? d : 0, newCapacity);
+        Q_CHECK_PTR(newD);
+        freePrivate = true;
+        d = newD;
+    }
+
     t = other.t;
     s = other.s;
     chars = other.chars;
     length = other.length;
     pos = other.pos;
 
-    QTextBoundaryFinderPrivate *newD = (QTextBoundaryFinderPrivate *)
-        realloc(freePrivate ? d : 0, (length + 1) * sizeof(QCharAttributes));
-    Q_CHECK_PTR(newD);
-    freePrivate = true;
-    d = newD;
-    memcpy(d, other.d, (length + 1) * sizeof(QCharAttributes));
+    if (other.d) {
+        memcpy(d, other.d, (length + 1) * sizeof(QCharAttributes));
+    } else {
+        if (freePrivate)
+            free(d);
+        d = 0;
+    }
 
     return *this;
 }
diff --git a/tests/auto/corelib/tools/qtextboundaryfinder/tst_qtextboundaryfinder.cpp b/tests/auto/corelib/tools/qtextboundaryfinder/tst_qtextboundaryfinder.cpp
index 56409447ff..22d3465823 100644
--- a/tests/auto/corelib/tools/qtextboundaryfinder/tst_qtextboundaryfinder.cpp
+++ b/tests/auto/corelib/tools/qtextboundaryfinder/tst_qtextboundaryfinder.cpp
@@ -72,6 +72,7 @@ private slots:
     void lineBoundaries_manual();
 
     void fastConstructor();
+    void assignmentOperator();
     void wordBoundaries_qtbug6498();
     void isAtSoftHyphen_data();
     void isAtSoftHyphen();
@@ -545,6 +546,30 @@ void tst_QTextBoundaryFinder::fastConstructor()
     QCOMPARE(finder.boundaryReasons(), QTextBoundaryFinder::NotAtBoundary);
 }
 
+void tst_QTextBoundaryFinder::assignmentOperator()
+{
+    QString text(QLatin1String("Hello World"));
+
+    QTextBoundaryFinder invalidFinder;
+    QVERIFY(!invalidFinder.isValid());
+    QCOMPARE(invalidFinder.string(), QString());
+
+    QTextBoundaryFinder validFinder(QTextBoundaryFinder::Word, text);
+    QVERIFY(validFinder.isValid());
+    QCOMPARE(validFinder.string(), text);
+
+    QTextBoundaryFinder finder(QTextBoundaryFinder::Line, QLatin1String("dummy"));
+    QVERIFY(finder.isValid());
+
+    finder = invalidFinder;
+    QVERIFY(!finder.isValid());
+    QCOMPARE(finder.string(), QString());
+
+    finder = validFinder;
+    QVERIFY(finder.isValid());
+    QCOMPARE(finder.string(), text);
+}
+
 void tst_QTextBoundaryFinder::wordBoundaries_qtbug6498()
 {
     // text with trailing space