Introduces QMetaEnum::fromType

Change-Id: I1976c1844e52ef8d70a1bbe9945f3299428dbf87
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>

src/corelib/kernel/qmetaobject.cpp

@@ -2677,6 +2677,14 @@ QByteArray QMetaEnum::valueToKeys(int value) const
     return keys;
 }
 
+/*!
+    \fn QMetaEnum QMetaEnum::fromType() const
+    \since 5.5
+
+    Returns the QMetaEnum corresponding to the type in the template parameter.
+    The enum needs to be declared with Q_ENUM.
+*/
+
 static QByteArray qualifiedName(const QMetaEnum &e)
 {
     return QByteArray(e.scope()) + "::" + e.name();

src/corelib/kernel/qmetaobject.h

@@ -223,6 +223,15 @@ public:
     inline const QMetaObject *enclosingMetaObject() const { return mobj; }
 
     inline bool isValid() const { return name() != 0; }
+
+    template<typename T> static QMetaEnum fromType() {
+        Q_STATIC_ASSERT_X(QtPrivate::IsQEnumHelper<T>::Value,
+                          "QMetaEnum::fromType only works with enums declared as Q_ENUM or Q_FLAG");
+        const QMetaObject *metaObject = qt_getEnumMetaObject(T());
+        const char *name = qt_getEnumName(T());
+        return metaObject->enumerator(metaObject->indexOfEnumerator(name));
+    }
+
 private:
     const QMetaObject *mobj;
     uint handle;

tests/auto/corelib/kernel/kernel.pro

@@ -9,6 +9,7 @@ SUBDIRS=\
     qmetamethod \
     qmetaproperty \
     qmetatype \
+    qmetaenum \
     qmimedata \
     qobject \
     qpointer \

tests/auto/corelib/kernel/qmetaenum/qmetaenum.pro

@@ -0,0 +1,5 @@
+CONFIG += testcase
+CONFIG += parallel_test
+TARGET = tst_qmetaenum
+QT = core testlib
+SOURCES = tst_qmetaenum.cpp

tests/auto/corelib/kernel/qmetaenum/tst_qmetaenum.cpp

@@ -0,0 +1,69 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Olivier Goffart <ogoffart@woboq.com>
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/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 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+
+#include <QtTest/QtTest>
+
+#include <QtCore/qobject.h>
+#include <QtCore/qmetaobject.h>
+
+class tst_QMetaEnum : public QObject
+{
+    Q_OBJECT
+public:
+    enum SuperEnum { SuperValue1 = 1 , SuperValue2 = 2 };
+    Q_ENUM(SuperEnum)
+
+private slots:
+    void fromType();
+};
+
+void tst_QMetaEnum::fromType()
+{
+    QMetaEnum meta = QMetaEnum::fromType<SuperEnum>();
+    QVERIFY(meta.isValid());
+    QCOMPARE(meta.name(), "SuperEnum");
+    QCOMPARE(meta.enclosingMetaObject(), &staticMetaObject);
+    QCOMPARE(meta.keyCount(), 2);
+}
+
+QTEST_MAIN(tst_QMetaEnum)
+#include "tst_qmetaenum.moc"