Allow QFinalStatePrivate to be subclassed.

- put it in a separate private header
- add a protected QFinalState constructor that takes a
  QFinalStatePrivate
- when passing through, also export QStatePrivate, so the linker can
  find the symbol

Change-Id: I8563da16739731d9d6142be438a8769fc29de148
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

src/corelib/statemachine/qfinalstate.cpp

@@ -31,12 +31,10 @@
 **
 ****************************************************************************/
 
-#include "qfinalstate.h"
+#include "qfinalstate_p.h"
 
 #ifndef QT_NO_STATEMACHINE
 
-#include "qabstractstate_p.h"
-
 QT_BEGIN_NAMESPACE
 
 /*!
@@ -76,19 +74,16 @@ QT_BEGIN_NAMESPACE
   \sa QState::finished()
 */
 
-class QFinalStatePrivate : public QAbstractStatePrivate
-{
-    Q_DECLARE_PUBLIC(QFinalState)
-
-public:
-    QFinalStatePrivate();
-};
-
 QFinalStatePrivate::QFinalStatePrivate()
     : QAbstractStatePrivate(FinalState)
 {
 }
 
+QFinalStatePrivate::~QFinalStatePrivate()
+{
+    // to prevent vtables being generated in every file that includes the private header
+}
+
 /*!
   Constructs a new QFinalState object with the given \a parent state.
 */
@@ -97,6 +92,15 @@ QFinalState::QFinalState(QState *parent)
 {
 }
 
+/*!
+  \internal
+ */
+QFinalState::QFinalState(QFinalStatePrivate &dd, QState *parent)
+    : QAbstractState(dd, parent)
+{
+}
+
+
 /*!
   Destroys this final state.
 */

src/corelib/statemachine/qfinalstate.h

@@ -38,7 +38,6 @@
 
 QT_BEGIN_NAMESPACE
 
-
 #ifndef QT_NO_STATEMACHINE
 
 class QFinalStatePrivate;
@@ -55,6 +54,9 @@ protected:
 
     bool event(QEvent *e) Q_DECL_OVERRIDE;
 
+protected:
+    explicit QFinalState(QFinalStatePrivate &dd, QState *parent);
+
 private:
     Q_DISABLE_COPY(QFinalState)
     Q_DECLARE_PRIVATE(QFinalState)

src/corelib/statemachine/qfinalstate_p.h

@@ -0,0 +1,68 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QFINALSTATE_P_H
+#define QFINALSTATE_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include "qfinalstate.h"
+#include "private/qabstractstate_p.h"
+
+#ifndef QT_NO_STATEMACHINE
+
+QT_BEGIN_NAMESPACE
+
+class Q_CORE_EXPORT QFinalStatePrivate : public QAbstractStatePrivate
+{
+    Q_DECLARE_PUBLIC(QFinalState)
+
+public:
+    QFinalStatePrivate();
+    ~QFinalStatePrivate();
+};
+
+QT_END_NAMESPACE
+
+#endif // QT_NO_STATEMACHINE
+
+#endif // QFINALSTATE_P_H

src/corelib/statemachine/qstate.cpp

@@ -31,11 +31,10 @@
 **
 ****************************************************************************/
 
-#include "qstate.h"
+#include "qstate_p.h"
 
 #ifndef QT_NO_STATEMACHINE
 
-#include "qstate_p.h"
 #include "qhistorystate.h"
 #include "qhistorystate_p.h"
 #include "qabstracttransition.h"

src/corelib/statemachine/qstate_p.h

@@ -45,6 +45,7 @@
 // We mean it.
 //
 
+#include "qstate.h"
 #include "private/qabstractstate_p.h"
 
 #include <QtCore/qlist.h>
@@ -52,6 +53,8 @@
 #include <QtCore/qpointer.h>
 #include <QtCore/qvariant.h>
 
+#ifndef QT_NO_STATEMACHINE
+
 QT_BEGIN_NAMESPACE
 
 #ifndef QT_NO_PROPERTIES
@@ -83,7 +86,7 @@ class QAbstractTransition;
 class QHistoryState;
 
 class QState;
-class Q_AUTOTEST_EXPORT QStatePrivate : public QAbstractStatePrivate
+class Q_CORE_EXPORT QStatePrivate : public QAbstractStatePrivate
 {
     Q_DECLARE_PUBLIC(QState)
 public:
@@ -115,4 +118,6 @@ public:
 
 QT_END_NAMESPACE
 
+#endif // QT_NO_STATEMACHINE
+
 #endif

src/corelib/statemachine/statemachine.pri

@@ -6,6 +6,7 @@ HEADERS += $$PWD/qstatemachine.h \
 	   $$PWD/qstate.h \
 	   $$PWD/qstate_p.h \
 	   $$PWD/qfinalstate.h \
+	   $$PWD/qfinalstate_p.h \
 	   $$PWD/qhistorystate.h \
 	   $$PWD/qhistorystate_p.h \
 	   $$PWD/qabstracttransition.h \