Make the stub implementation of QThread compile again

We cannot inline methods of QThreadPrivate because QThreadData has to
be declared before. The global QThreadData needs to be accessible to
QThreadData::clearCurrentThreadData(), and QAdoptedThread::run() has to
be moved inside the #ifndef QT_NO_THREAD block as run() doesn't exist
in the stub and Q_DECL_OVERRIDE would be wrong.

We also fix the QThreadData::current() method to take and use the same
parameters as in the non-stub case.

Change-Id: Id29ca44b11fa95ed2df7cc39243a07ce7d3c455e
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

src/corelib/thread/qthread.cpp

@@ -140,12 +140,13 @@ QAdoptedThread::~QAdoptedThread()
     // fprintf(stderr, "~QAdoptedThread = %p\n", this);
 }
 
+#ifndef QT_NO_THREAD
 void QAdoptedThread::run()
 {
     // this function should never be called
     qFatal("QAdoptedThread::run(): Internal error, this implementation should never be called.");
 }
-#ifndef QT_NO_THREAD
+
 /*
   QThreadPrivate
 */
@@ -750,7 +751,8 @@ int QThread::loopLevel() const
 #else // QT_NO_THREAD
 
 QThread::QThread(QObject *parent)
-    : QObject(*(new QThreadPrivate), (QObject*)0){
+    : QObject(*(new QThreadPrivate), parent)
+{
     Q_D(QThread);
     d->data->thread = this;
 }
@@ -760,18 +762,27 @@ QThread *QThread::currentThread()
     return QThreadData::current()->thread;
 }
 
-QThreadData* QThreadData::current()
+// No threads: so we can just use static variables
+static QThreadData *data = 0;
+
+QThreadData *QThreadData::current(bool createIfNecessary)
 {
-    static QThreadData *data = 0; // reinterpret_cast<QThreadData *>(pthread_getspecific(current_thread_data_key));
-    if (!data) {
-        QScopedPointer<QThreadData> newdata(new QThreadData);
-        newdata->thread = new QAdoptedThread(newdata.data());
-        data = newdata.take();
+    if (!data && createIfNecessary) {
+        data = new QThreadData;
+        data->thread = new QAdoptedThread(data);
         data->deref();
+        if (!QCoreApplicationPrivate::theMainThread)
+            QCoreApplicationPrivate::theMainThread = data->thread.load();
     }
     return data;
 }
 
+void QThreadData::clearCurrentThreadData()
+{
+    delete data;
+    data = 0;
+}
+
 /*!
     \internal
  */
@@ -783,6 +794,15 @@ QThread::QThread(QThreadPrivate &dd, QObject *parent)
     d->data->thread = this;
 }
 
+QThreadPrivate::QThreadPrivate(QThreadData *d) : data(d ? d : new QThreadData)
+{
+}
+
+QThreadPrivate::~QThreadPrivate()
+{
+    delete data;
+}
+
 #endif // QT_NO_THREAD
 
 /*!
@@ -820,6 +840,8 @@ void QThread::setEventDispatcher(QAbstractEventDispatcher *eventDispatcher)
     }
 }
 
+#ifndef QT_NO_THREAD
+
 /*!
     \reimp
 */
@@ -983,6 +1005,8 @@ QDaemonThread::~QDaemonThread()
 {
 }
 
+#endif // QT_NO_THREAD
+
 QT_END_NAMESPACE
 
 #include "moc_qthread.cpp"

src/corelib/thread/qthread.h

@@ -251,6 +251,9 @@ public:
     static void msleep(unsigned long);
     static void usleep(unsigned long);
 
+    QAbstractEventDispatcher *eventDispatcher() const;
+    void setEventDispatcher(QAbstractEventDispatcher *eventDispatcher);
+
 protected:
     QThread(QThreadPrivate &dd, QObject *parent = nullptr);
 

src/corelib/thread/qthread_p.h

@@ -215,9 +215,10 @@ public:
 class QThreadPrivate : public QObjectPrivate
 {
 public:
-    QThreadPrivate(QThreadData *d = 0) : data(d ? d : new QThreadData) {}
-    ~QThreadPrivate() { delete data; }
+    QThreadPrivate(QThreadData *d = 0);
+    ~QThreadPrivate();
 
+    mutable QMutex mutex;
     QThreadData *data;
 
     static void setCurrentThread(QThread*) {}
@@ -318,7 +319,9 @@ public:
     void init();
 
 private:
+#ifndef QT_NO_THREAD
     void run() override;
+#endif
 };
 
 QT_END_NAMESPACE