Add qOverload to select overloaded functions

[ChangeLog][QtCore][Global] qOverload added to select
overloaded functions.

Change-Id: I7c9b1b054e6631eca0b5594db59e1202ef552c33
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

1 files changed, 122 insertions, 0 deletions

diff --git a/tests/auto/corelib/global/qglobal/tst_qglobal.cpp b/tests/auto/corelib/global/qglobal/tst_qglobal.cpp
index d1a6e66203..152906287c 100644
--- a/tests/auto/corelib/global/qglobal/tst_qglobal.cpp
+++ b/tests/auto/corelib/global/qglobal/tst_qglobal.cpp
@@ -55,6 +55,7 @@ private slots:
     void qprintable();
     void qprintable_data();
     void buildAbiEndianness();
+    void testqOverload();
 };
 
 void tst_QGlobal::qIsNull()
@@ -652,5 +653,126 @@ void tst_QGlobal::buildAbiEndianness()
     QVERIFY(QSysInfo::buildAbi().contains(endian));
 }
 
+struct Overloaded
+{
+    void foo() {}
+    void foo(QByteArray) {}
+    void foo(QByteArray, const QString &) {}
+
+    void constFoo() const {}
+    void constFoo(QByteArray) const {}
+    void constFoo(QByteArray, const QString &) const {}
+
+    void mixedFoo() {}
+    void mixedFoo(QByteArray) const {}
+};
+
+void freeOverloaded() {}
+void freeOverloaded(QByteArray) {}
+void freeOverloaded(QByteArray, const QString &) {}
+
+void freeOverloadedGet(QByteArray) {}
+QByteArray freeOverloadedGet() { return QByteArray(); }
+
+
+void tst_QGlobal::testqOverload()
+{
+#ifdef Q_COMPILER_VARIADIC_TEMPLATES
+
+    // void returning free overloaded functions
+    QVERIFY(QOverload<>::of(&freeOverloaded) ==
+             static_cast<void (*)()>(&freeOverloaded));
+
+    QVERIFY(QOverload<QByteArray>::of(&freeOverloaded) ==
+             static_cast<void (*)(QByteArray)>(&freeOverloaded));
+
+    QVERIFY((QOverload<QByteArray, const QString &>::of(&freeOverloaded)) ==
+             static_cast<void (*)(QByteArray, const QString &)>(&freeOverloaded));
+
+    // value returning free overloaded functions
+    QVERIFY(QOverload<>::of(&freeOverloadedGet) ==
+             static_cast<QByteArray (*)()>(&freeOverloadedGet));
+
+    QVERIFY(QOverload<QByteArray>::of(&freeOverloadedGet) ==
+             static_cast<void (*)(QByteArray)>(&freeOverloadedGet));
+
+    // void returning overloaded member functions
+    QVERIFY(QOverload<>::of(&Overloaded::foo) ==
+             static_cast<void (Overloaded::*)()>(&Overloaded::foo));
+
+    QVERIFY(QOverload<QByteArray>::of(&Overloaded::foo) ==
+             static_cast<void (Overloaded::*)(QByteArray)>(&Overloaded::foo));
+
+    QVERIFY((QOverload<QByteArray, const QString &>::of(&Overloaded::foo)) ==
+             static_cast<void (Overloaded::*)(QByteArray, const QString &)>(&Overloaded::foo));
+
+    // void returning overloaded const member functions
+    QVERIFY(QOverload<>::of(&Overloaded::constFoo) ==
+             static_cast<void (Overloaded::*)() const>(&Overloaded::constFoo));
+
+    QVERIFY(QOverload<QByteArray>::of(&Overloaded::constFoo) ==
+             static_cast<void (Overloaded::*)(QByteArray) const>(&Overloaded::constFoo));
+
+    QVERIFY((QOverload<QByteArray, const QString &>::of(&Overloaded::constFoo)) ==
+             static_cast<void (Overloaded::*)(QByteArray, const QString &) const>(&Overloaded::constFoo));
+
+    // void returning overloaded const AND non-const member functions
+    QVERIFY(QNonConstOverload<>::of(&Overloaded::mixedFoo) ==
+             static_cast<void (Overloaded::*)()>(&Overloaded::mixedFoo));
+
+    QVERIFY(QConstOverload<QByteArray>::of(&Overloaded::mixedFoo) ==
+             static_cast<void (Overloaded::*)(QByteArray) const>(&Overloaded::mixedFoo));
+
+#if defined(__cpp_variable_templates) && __cpp_variable_templates >= 201304 // C++14
+
+    // void returning free overloaded functions
+    QVERIFY(qOverload<>(&freeOverloaded) ==
+             static_cast<void (*)()>(&freeOverloaded));
+
+    QVERIFY(qOverload<QByteArray>(&freeOverloaded) ==
+             static_cast<void (*)(QByteArray)>(&freeOverloaded));
+
+    QVERIFY((qOverload<QByteArray, const QString &>(&freeOverloaded)),
+             static_cast<void (*)(QByteArray, const QString &)>(&freeOverloaded));
+
+    // value returning free overloaded functions
+    QVERIFY(qOverload<>(&freeOverloadedGet) ==
+             static_cast<QByteArray (*)()>(&freeOverloadedGet));
+
+    QVERIFY(qOverload<QByteArray>(&freeOverloadedGet) ==
+             static_cast<void (*)(QByteArray)>(&freeOverloadedGet));
+
+    // void returning overloaded member functions
+    QVERIFY(qOverload<>(&Overloaded::foo) ==
+             static_cast<void (Overloaded::*)()>(&Overloaded::foo));
+
+    QVERIFY(qOverload<QByteArray>(&Overloaded::foo) ==
+             static_cast<void (Overloaded::*)(QByteArray)>(&Overloaded::foo));
+
+    QVERIFY((qOverload<QByteArray, const QString &>(&Overloaded::foo)) ==
+             static_cast<void (Overloaded::*)(QByteArray, const QString &)>(&Overloaded::foo));
+
+    // void returning overloaded const member functions
+    QVERIFY(qOverload<>(&Overloaded::constFoo) ==
+             static_cast<void (Overloaded::*)() const>(&Overloaded::constFoo));
+
+    QVERIFY(qOverload<QByteArray>(&Overloaded::constFoo) ==
+             static_cast<void (Overloaded::*)(QByteArray) const>(&Overloaded::constFoo));
+
+    QVERIFY((qOverload<QByteArray, const QString &>(&Overloaded::constFoo)) ==
+             static_cast<void (Overloaded::*)(QByteArray, const QString &) const>(&Overloaded::constFoo));
+
+    // void returning overloaded const AND non-const member functions
+    QVERIFY(qNonConstOverload<>(&Overloaded::mixedFoo) ==
+             static_cast<void (Overloaded::*)()>(&Overloaded::mixedFoo));
+
+    QVERIFY(qConstOverload<QByteArray>(&Overloaded::mixedFoo) ==
+             static_cast<void (Overloaded::*)(QByteArray) const>(&Overloaded::mixedFoo));
+#endif
+
+#endif
+}
+
+
 QTEST_APPLESS_MAIN(tst_QGlobal)
 #include "tst_qglobal.moc"