QThread::exec(): Fix possibility to enter several time the event loop

If one call exit() before calling exec(), this should prevent the
event loop from starting once, but later calls to exec() should work.

This is a regression against Qt 4.6 introduced when fixing QTBUG-1184

Task-number: QTBUG-15378
Reviewed-by: Joao
Reviewed-by: Brad

2 files changed, 43 insertions, 1 deletions

diff --git a/src/corelib/thread/qthread.cpp b/src/corelib/thread/qthread.cpp
index 69b70cb..6fb182b 100644
--- a/src/corelib/thread/qthread.cpp
+++ b/src/corelib/thread/qthread.cpp
@@ -482,8 +482,10 @@ int QThread::exec()
     Q_D(QThread);
     QMutexLocker locker(&d->mutex);
     d->data->quitNow = false;
-    if (d->exited)
+    if (d->exited) {
+        d->exited = false;
         return d->returnCode;
+    }
     locker.unlock();
 
     QEventLoop eventLoop;
diff --git a/tests/auto/qthread/tst_qthread.cpp b/tests/auto/qthread/tst_qthread.cpp
index 843749a..85b8f04 100644
--- a/tests/auto/qthread/tst_qthread.cpp
+++ b/tests/auto/qthread/tst_qthread.cpp
@@ -106,6 +106,7 @@ private slots:
     void adoptMultipleThreads();
 
     void QTBUG13810_exitAndStart();
+    void QTBUG15378_exitAndExec();
 
     void stressTest();
 };
@@ -976,5 +977,44 @@ void tst_QThread::QTBUG13810_exitAndStart()
 }
 
 
+void tst_QThread::QTBUG15378_exitAndExec()
+{
+    class Thread : public QThread {
+    public:
+        QSemaphore sem1;
+        QSemaphore sem2;
+        volatile int value;
+        void run() {
+            sem1.acquire();
+            value = exec();  //First entrence
+            sem2.release();
+            value = exec(); // Second loop
+        }
+    };
+    Thread thread;
+    thread.value = 0;
+    thread.start();
+    thread.exit(556);
+    thread.sem1.release(); //should exit the first loop
+    thread.sem2.acquire();
+    QCOMPARE(int(thread.value), 556);
+
+    //test that the thread is running by executing queued connected signal there
+    Syncronizer sync1;
+    sync1.moveToThread(&thread);
+    Syncronizer sync2;
+    sync2.moveToThread(&thread);
+    connect(&sync2, SIGNAL(propChanged(int)), &sync1, SLOT(setProp(int)), Qt::QueuedConnection);
+    connect(&sync1, SIGNAL(propChanged(int)), &thread, SLOT(quit()), Qt::QueuedConnection);
+    QMetaObject::invokeMethod(&sync2, "setProp", Qt::QueuedConnection , Q_ARG(int, 89));
+    QTest::qWait(50);
+    while(!thread.wait(10))
+        QTest::qWait(10);
+    QCOMPARE(sync2.m_prop, 89);
+    QCOMPARE(sync1.m_prop, 89);
+}
+
+
+
 QTEST_MAIN(tst_QThread)
 #include "tst_qthread.moc"