moc: Add support for C++17 nested namespaces (N4230)

[ChangeLog][moc] Added Support for C++17 nested namespaces

Change-Id: Ib83fc5bf48f66546fa97b49710582fbf9c984503
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

src/tools/moc/moc.cpp

@@ -549,12 +549,20 @@ void Moc::parse()
             case NAMESPACE: {
                 int rewind = index;
                 if (test(IDENTIFIER)) {
+                    QByteArray nsName = lexem();
+                    QByteArrayList nested;
+                    while (test(SCOPE)) {
+                        next(IDENTIFIER);
+                        nested.append(nsName);
+                        nsName = lexem();
+                    }
                     if (test(EQ)) {
                         // namespace Foo = Bar::Baz;
                         until(SEMIC);
                     } else if (!test(SEMIC)) {
                         NamespaceDef def;
-                        def.classname = lexem();
+                        def.classname = nsName;
+
                         next(LBRACE);
                         def.begin = index - 1;
                         until(RBRACE);
@@ -568,11 +576,23 @@ void Moc::parse()
                                     def.qualified.prepend(namespaceList.at(i).classname + "::");
                                 }
                             }
+                            for (const QByteArray &ns : nested) {
+                                NamespaceDef parentNs;
+                                parentNs.classname = ns;
+                                parentNs.qualified = def.qualified;
+                                def.qualified += ns + "::";
+                                parentNs.begin = def.begin;
+                                parentNs.end = def.end;
+                                namespaceList += parentNs;
+                            }
                         }
+
                         while (parseNamespace && inNamespace(&def) && hasNext()) {
                             switch (next()) {
                             case NAMESPACE:
                                 if (test(IDENTIFIER)) {
+                                    while (test(SCOPE))
+                                        next(IDENTIFIER);
                                     if (test(EQ)) {
                                         // namespace Foo = Bar::Baz;
                                         until(SEMIC);

tests/auto/tools/moc/cxx17-namespaces.h

@@ -0,0 +1,64 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Olivier Goffart.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** 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 https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef CXX17_NAMESPACES_H
+#define CXX11_NAMESPACES_H
+#include <QtCore/QObject>
+
+#if defined(__cpp_nested_namespace_definitions) || defined(Q_MOC_RUN)
+namespace CXX17Namespace::A::B {
+namespace C::D {
+namespace E::F::G { } // don't confuse moc
+#else
+namespace CXX17Namespace { namespace A { namespace B {
+namespace C { namespace D {
+#endif
+
+Q_NAMESPACE
+
+class ClassInNamespace
+{
+    Q_GADGET
+public:
+    enum GadEn { Value = 3 };
+    Q_ENUM(GadEn)
+};
+
+enum NamEn { Value = 4 };
+Q_ENUM_NS(NamEn);
+
+
+#if defined(__cpp_nested_namespace_definitions) || defined(Q_MOC_RUN)
+}
+}
+#else
+} } }
+} }
+#endif
+
+#endif

tests/auto/tools/moc/moc.pro

@@ -29,7 +29,7 @@ HEADERS += using-namespaces.h no-keywords.h task87883.h c-comments.h backslash-n
            non-gadget-parent-class.h grand-parent-gadget-class.h \
            related-metaobjects-in-gadget.h \
            related-metaobjects-name-conflict.h \
-           namespace.h
+           namespace.h cxx17-namespaces.h
 
 
 if(*-g++*|*-icc*|*-clang*|*-llvm):!irix-*:!win32-*: HEADERS += os9-newlines.h win-newlines.h

tests/auto/tools/moc/tst_moc.cpp

@@ -70,6 +70,7 @@
 #include "non-gadget-parent-class.h"
 #include "grand-parent-gadget-class.h"
 #include "namespace.h"
+#include "cxx17-namespaces.h"
 
 #ifdef Q_MOC_RUN
 // check that moc can parse these constructs, they are being used in Windows winsock2.h header
@@ -700,6 +701,7 @@ private slots:
     void optionsFileError_data();
     void optionsFileError();
     void testQNamespace();
+    void cxx17Namespaces();
 
 signals:
     void sigWithUnsignedArg(unsigned foo);
@@ -3803,6 +3805,25 @@ void tst_Moc::testQNamespace()
     QCOMPARE(FooNamespace::FooNestedNamespace::FooMoreNestedNamespace::staticMetaObject.enumeratorCount(), 1);
 }
 
+void tst_Moc::cxx17Namespaces()
+{
+    QCOMPARE(CXX17Namespace::A::B::C::D::staticMetaObject.className(),
+             "CXX17Namespace::A::B::C::D");
+    QCOMPARE(CXX17Namespace::A::B::C::D::staticMetaObject.enumeratorCount(), 1);
+    QCOMPARE(CXX17Namespace::A::B::C::D::staticMetaObject.enumerator(0).name(), "NamEn");
+    QCOMPARE(QMetaEnum::fromType<CXX17Namespace::A::B::C::D::NamEn>().name(), "NamEn");
+    QCOMPARE(QMetaEnum::fromType<CXX17Namespace::A::B::C::D::NamEn>().keyCount(), 1);
+    QCOMPARE(QMetaEnum::fromType<CXX17Namespace::A::B::C::D::NamEn>().value(0), 4);
+
+    QCOMPARE(CXX17Namespace::A::B::C::D::ClassInNamespace::staticMetaObject.className(),
+             "CXX17Namespace::A::B::C::D::ClassInNamespace");
+    QCOMPARE(CXX17Namespace::A::B::C::D::ClassInNamespace::staticMetaObject.enumeratorCount(), 1);
+    QCOMPARE(CXX17Namespace::A::B::C::D::ClassInNamespace::staticMetaObject.enumerator(0).name(), "GadEn");
+    QCOMPARE(QMetaEnum::fromType<CXX17Namespace::A::B::C::D::ClassInNamespace::GadEn>().name(), "GadEn");
+    QCOMPARE(QMetaEnum::fromType<CXX17Namespace::A::B::C::D::ClassInNamespace::GadEn>().keyCount(), 1);
+    QCOMPARE(QMetaEnum::fromType<CXX17Namespace::A::B::C::D::ClassInNamespace::GadEn>().value(0), 3);
+}
+
 QTEST_MAIN(tst_Moc)
 
 // the generated code must compile with QT_NO_KEYWORDS