qmltc: generate code into namespaces

Generate code into namespaces to avoid clashes between qmltc-generated
and user code. Code generated by qmltc will by default be put in the
URI_OF_MODULE namespace, and will generate subnamespaces
to follow the module hierarchy if URI_OF_MODULE contains dots('.').

Also fix the test to use the new namespaces.

[ChangeLog][Qml][qmltc] The type compiler will generate C++-code into
a namespace by default. The  new default namespace is inferred from
the module's URI, where dots are interpreted as separating subnamespaces
from each other,
e.g., a type in module MyCompany.MyModule.Sub will be generated in the namespace
MyCompany::MyModule::Sub.

Fixes: QTBUG-109274
Change-Id: I3bfe2697b81e90bb63a079dc44c2810fc9925f97
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

10 files changed, 118 insertions, 35 deletions

diff --git a/src/qml/Qt6QmlMacros.cmake b/src/qml/Qt6QmlMacros.cmake
index 2f7659c2a0..c0df7a92f0 100644
--- a/src/qml/Qt6QmlMacros.cmake
+++ b/src/qml/Qt6QmlMacros.cmake
@@ -664,10 +664,15 @@ function(qt6_add_qml_module target)
     endif()
 
     if (arg_ENABLE_TYPE_COMPILER)
+        if (DEFINED arg_TYPE_COMPILER_NAMESPACE AND NOT $<STREQUAL:"${arg_TYPE_COMPILER_NAMESPACE}","">)
+            set(qmltc_namespace ${arg_TYPE_COMPILER_NAMESPACE})
+        else()
+            string(REPLACE "." "::" qmltc_namespace "${arg_URI}")
+        endif()
         _qt_internal_target_enable_qmltc(${target}
             QML_FILES ${arg_QML_FILES}
             IMPORT_PATHS ${arg_IMPORT_PATH}
-            NAMESPACE ${arg_TYPE_COMPILER_NAMESPACE}
+            NAMESPACE ${qmltc_namespace}
         )
     endif()
 
diff --git a/src/qml/doc/snippets/qmltc/tst_qmltc_examples.cpp b/src/qml/doc/snippets/qmltc/tst_qmltc_examples.cpp
index a78da416e2..7bda70f985 100644
--- a/src/qml/doc/snippets/qmltc/tst_qmltc_examples.cpp
+++ b/src/qml/doc/snippets/qmltc/tst_qmltc_examples.cpp
@@ -53,7 +53,7 @@ void tst_qmltc_examples::app()
     QQmlEngine e;
     QQuickWindow window;
 
-    QScopedPointer<myApp> documentRoot(new myApp(&e));
+    QScopedPointer<QmltcExample::myApp> documentRoot(new QmltcExample::myApp(&e));
 
     documentRoot->setParentItem(window.contentItem());
     window.setHeight(documentRoot->height());
diff --git a/src/qml/doc/src/cmake/qt_add_qml_module.qdoc b/src/qml/doc/src/cmake/qt_add_qml_module.qdoc
index 9bef299970..7617d19033 100644
--- a/src/qml/doc/src/cmake/qt_add_qml_module.qdoc
+++ b/src/qml/doc/src/cmake/qt_add_qml_module.qdoc
@@ -655,4 +655,15 @@ with \l{QML Type Compiler}{qmltc}. Files with the source property
 C++ code resides. By default, no namespace is specified for user projects. The
 code generated from Qt's own sources is put under a QT_NAMESPACE namespace.
 
+\c TYPE_COMPILER_NAMESPACE argument allows to override the namespace in which
+\l{QML Type Compiler}{qmltc} generates code.
+By default, the namespace of the generated code follows the module
+hierarchy as depicted in the URI,
+e.g., \c MyModule for a module with URI \c MyModule or
+\c com::example::Module for URI \c com.example.MyModule.
+By specifying the \c TYPE_COMPILER_NAMESPACE option, the generated code
+can be put instead in a custom namespace, where different subnamespaces are to
+be separated by a "::", e.g. "MyNamespace::MySubnamespace" for the namespace MySubnamespace that
+is inside the MyNamespace. Apart from the "::", C++ namespace naming rules
+apply.
 */
diff --git a/tests/auto/qml/qmltc/CMakeLists.txt b/tests/auto/qml/qmltc/CMakeLists.txt
index d71d1ac557..4b86a6c018 100644
--- a/tests/auto/qml/qmltc/CMakeLists.txt
+++ b/tests/auto/qml/qmltc/CMakeLists.txt
@@ -2,6 +2,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 
 add_subdirectory(QmltcTests)
+add_subdirectory(NamespaceTest/Subfolder)
 
 set(test_sources
     nameconflict.h nameconflict.cpp
@@ -16,6 +17,7 @@ set(qmltc_module_libs
     # - Properly see C++ types exposed to QML in the engine (we need C++
     #   automatic type registration that comes from the plugin)
     qmltc_test_moduleplugin
+    qmltc_namespace_test_module
 )
 qt_internal_add_test(tst_qmltc_diskcache
     SOURCES ${test_sources}
diff --git a/tests/auto/qml/qmltc/NamespaceTest/Subfolder/CMakeLists.txt b/tests/auto/qml/qmltc/NamespaceTest/Subfolder/CMakeLists.txt
new file mode 100644
index 0000000000..a93698655c
--- /dev/null
+++ b/tests/auto/qml/qmltc/NamespaceTest/Subfolder/CMakeLists.txt
@@ -0,0 +1,41 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: BSD-3-Clause
+
+set(cpp_sources
+)
+
+set(qml_sources
+    Type.qml
+)
+
+set(js_sources
+)
+
+set(common_libraries
+    Qt::Core
+    Qt::QmlPrivate
+    Qt::QuickPrivate
+    Qt::TestPrivate
+    Qt::Gui # QColor, QMatrix4x4, ...
+)
+
+qt_add_library(qmltc_namespace_test_module STATIC)
+qt_autogen_tools_initial_setup(qmltc_namespace_test_module)
+
+target_link_libraries(qmltc_namespace_test_module PUBLIC ${common_libraries})
+
+qt6_add_qml_module(qmltc_namespace_test_module
+    VERSION 1.0
+    URI NamespaceTest.Subfolder
+    AUTO_RESOURCE_PREFIX
+    SOURCES
+        ${cpp_sources}
+    QML_FILES
+        ${qml_sources}
+        ${js_sources}
+    DEPENDENCIES
+        QtQuick
+    ENABLE_TYPE_COMPILER
+)
+
+qt_autogen_tools_initial_setup(qmltc_namespace_test_moduleplugin)
diff --git a/tests/auto/qml/qmltc/NamespaceTest/Subfolder/Type.qml b/tests/auto/qml/qmltc/NamespaceTest/Subfolder/Type.qml
new file mode 100644
index 0000000000..101e9f69a1
--- /dev/null
+++ b/tests/auto/qml/qmltc/NamespaceTest/Subfolder/Type.qml
@@ -0,0 +1,5 @@
+import QtQuick
+
+Item {
+    property string data
+}
diff --git a/tests/auto/qml/qmltc/QmltcTests/CMakeLists.txt b/tests/auto/qml/qmltc/QmltcTests/CMakeLists.txt
index cfb1469a38..870d21f61d 100644
--- a/tests/auto/qml/qmltc/QmltcTests/CMakeLists.txt
+++ b/tests/auto/qml/qmltc/QmltcTests/CMakeLists.txt
@@ -180,7 +180,6 @@ qt6_add_qml_module(qmltc_test_module
     LIBRARIES
         qmltc_test_module_translation_by_id
     ENABLE_TYPE_COMPILER
-    TYPE_COMPILER_NAMESPACE QmltcTest
 )
 
 qt_autogen_tools_initial_setup(qmltc_test_moduleplugin)
diff --git a/tests/auto/qml/qmltc/tst_qmltc.cpp b/tests/auto/qml/qmltc/tst_qmltc.cpp
index 4e65554e45..1fa4030642 100644
--- a/tests/auto/qml/qmltc/tst_qmltc.cpp
+++ b/tests/auto/qml/qmltc/tst_qmltc.cpp
@@ -82,6 +82,7 @@
 #include "singletons.h"
 #include "mysignals.h"
 #include "namespacedtypes.h"
+#include "type.h"
 
 // Qt:
 #include <QtCore/qstring.h>
@@ -103,7 +104,7 @@
 #    error "QMLTC_TESTS_DISABLE_CACHE is supposed to be defined and be equal to either 0 or 1"
 #endif
 
-#define PREPEND_NAMESPACE(name) ::QmltcTest::name // silent contract that the namespace is QmltcTest
+#define PREPEND_NAMESPACE(name) QmltcTests::name // silent contract that the namespace is QmltcTest
 
 using namespace Qt::StringLiterals;
 
@@ -1647,7 +1648,7 @@ void tst_qmltc::defaultAlias()
     QScopedPointer<QObject> fromEngine(c.create());
     QVERIFY2(fromEngine, qPrintable(c.errorString()));
 
-    auto *child = static_cast<QmltcTest::defaultAlias_QtObject *>(created.child());
+    auto *child = static_cast<PREPEND_NAMESPACE(defaultAlias_QtObject) *>(created.child());
     QVERIFY(fromEngine->property("child").canConvert<QObject *>());
     QObject *childFromEngine = fromEngine->property("child").value<QObject *>();
     QVERIFY(childFromEngine);
@@ -2653,23 +2654,23 @@ void tst_qmltc::appendToQQmlListProperty()
 }
 
 // test classes to access protected member typecount
-class myInlineComponentA : public QmltcTest::inlineComponents_A
+class myInlineComponentA : public PREPEND_NAMESPACE(inlineComponents_A)
 {
     friend class tst_qmltc;
 };
-class myInlineComponentB : public QmltcTest::inlineComponents_B
+class myInlineComponentB : public PREPEND_NAMESPACE(inlineComponents_B)
 {
     friend class tst_qmltc;
 };
-class myInlineComponentMyComponent : public QmltcTest::inlineComponents_MyComponent
+class myInlineComponentMyComponent : public PREPEND_NAMESPACE(inlineComponents_MyComponent)
 {
     friend class tst_qmltc;
 };
-class myInlineComponentAPlus : public QmltcTest::inlineComponents_APlus
+class myInlineComponentAPlus : public PREPEND_NAMESPACE(inlineComponents_APlus)
 {
     friend class tst_qmltc;
 };
-class myInlineComponentAPlusPlus : public QmltcTest::inlineComponents_APlusPlus
+class myInlineComponentAPlusPlus : public PREPEND_NAMESPACE(inlineComponents_APlusPlus)
 {
     friend class tst_qmltc;
 };
@@ -2730,10 +2731,10 @@ void tst_qmltc::inlineComponents()
 
     // test if nonrecursive components behave well
     {
-        auto *myMyComponentFromQmltc = (QmltcTest::inlineComponents_MyComponent_3 *)
-                                               createdByQmltc.myMyComponentComponent();
-        auto *myMyComponentFromQmltc2 = (QmltcTest::inlineComponents_MyComponent_4 *)
-                                                createdByQmltc.myMyComponentComponent2();
+        auto *myMyComponentFromQmltc = (PREPEND_NAMESPACE(
+                inlineComponents_MyComponent_3) *)createdByQmltc.myMyComponentComponent();
+        auto *myMyComponentFromQmltc2 = (PREPEND_NAMESPACE(
+                inlineComponents_MyComponent_4) *)createdByQmltc.myMyComponentComponent2();
         QVERIFY(myMyComponentFromQmltc);
         QVERIFY(myMyComponentFromQmltc2);
         auto *myMyComponentFromComponent =
@@ -2795,10 +2796,12 @@ void tst_qmltc::inlineComponents()
         QCOMPARE(myMyComponentFromQmltc->children().size(), 1);
         QCOMPARE(myMyComponentFromQmltc2->children().size(), 1);
         auto *childFromQmltc =
-                (QmltcTest::inlineComponents_MyComponent_Item *)myMyComponentFromQmltc->children()
+                (PREPEND_NAMESPACE(inlineComponents_MyComponent_Item) *)myMyComponentFromQmltc
+                        ->children()
                         .front();
         auto *childFromQmltc2 =
-                (QmltcTest::inlineComponents_MyComponent_Item *)myMyComponentFromQmltc2->children()
+                (PREPEND_NAMESPACE(inlineComponents_MyComponent_Item) *)myMyComponentFromQmltc2
+                        ->children()
                         .front();
 
         QVERIFY(childFromQmltc);
@@ -2855,15 +2858,18 @@ void tst_qmltc::inlineComponents()
 
     // test if recursive components are behaving well
     {
-        auto *myAFromQmltc = (QmltcTest::inlineComponents_A_1 *)createdByQmltc.myAComponent();
-        auto *innerBFromQmltc = (QmltcTest::inlineComponents_A_B *)myAFromQmltc->b();
+        auto *myAFromQmltc =
+                (PREPEND_NAMESPACE(inlineComponents_A_1) *)createdByQmltc.myAComponent();
+        auto *innerBFromQmltc = (PREPEND_NAMESPACE(inlineComponents_A_B) *)myAFromQmltc->b();
         QVERIFY(innerBFromQmltc);
-        auto *innerAFromQmltc = (QmltcTest::inlineComponents_A_B_A *)innerBFromQmltc->a();
+        auto *innerAFromQmltc = (PREPEND_NAMESPACE(inlineComponents_A_B_A) *)innerBFromQmltc->a();
         QVERIFY(innerAFromQmltc);
         constexpr bool typeNotCompiledAsQQmlComponent =
-                std::is_same_v<decltype(myAFromQmltc->b()), QmltcTest::inlineComponents_B *>;
+                std::is_same_v<decltype(myAFromQmltc->b()),
+                               PREPEND_NAMESPACE(inlineComponents_B) *>;
         constexpr bool typeNotCompiledAsQQmlComponent2 =
-                std::is_same_v<decltype(innerBFromQmltc->a()), QmltcTest::inlineComponents_A *>;
+                std::is_same_v<decltype(innerBFromQmltc->a()),
+                               PREPEND_NAMESPACE(inlineComponents_A) *>;
         QVERIFY(typeNotCompiledAsQQmlComponent);
         QVERIFY(typeNotCompiledAsQQmlComponent2);
 
@@ -2880,10 +2886,11 @@ void tst_qmltc::inlineComponents()
     // test if ids in inlineComponents are not getting mixed up with those from the root component
     {
         auto *conflictingComponentTomFromQmltc =
-                createdByQmltc.tom().value<QmltcTest::inlineComponents_ConflictingComponent_1 *>();
+                createdByQmltc.tom()
+                        .value<PREPEND_NAMESPACE(inlineComponents_ConflictingComponent_1) *>();
         auto *conflictingComponentJerryFromQmltc =
                 createdByQmltc.jerry()
-                        .value<QmltcTest::inlineComponents_ConflictingComponent_2 *>();
+                        .value<PREPEND_NAMESPACE(inlineComponents_ConflictingComponent_2) *>();
 
         auto *conflictingComponentTomFromComponent =
                 createdByComponent->property("tom").value<QObject *>();
@@ -2941,8 +2948,8 @@ void tst_qmltc::inlineComponents()
 
     // check that inline components are resolved in the correct order
     {
-        auto componentFromQmltc =
-                createdByQmltc.inlineComponentOrder().value<QmltcTest::inlineComponents_IC2_1 *>();
+        auto componentFromQmltc = createdByQmltc.inlineComponentOrder()
+                                          .value<PREPEND_NAMESPACE(inlineComponents_IC2_1) *>();
         auto componentFromComponent =
                 createdByComponent->property("inlineComponentOrder").value<QObject *>();
 
@@ -3193,4 +3200,12 @@ void tst_qmltc::cppNamespaces()
     QCOMPARE(createdByQmltc.myObject()->property("value"), 55);
 }
 
+void tst_qmltc::namespacedName()
+{
+    // cmake script should be able to auto-fill the namespace of the generated modules, and to
+    // replace . with ::
+    NamespaceTest::Subfolder::Type *t;
+    Q_UNUSED(t);
+}
+
 QTEST_MAIN(tst_qmltc)
diff --git a/tests/auto/qml/qmltc/tst_qmltc.h b/tests/auto/qml/qmltc/tst_qmltc.h
index a2d656bae7..af084dcc01 100644
--- a/tests/auto/qml/qmltc/tst_qmltc.h
+++ b/tests/auto/qml/qmltc/tst_qmltc.h
@@ -92,4 +92,5 @@ private slots:
     void singletons();
     void constSignalParameters();
     void cppNamespaces();
+    void namespacedName();
 };
diff --git a/tools/qmltc/qmltccodewriter.cpp b/tools/qmltc/qmltccodewriter.cpp
index c4c5c30f83..8010f1066c 100644
--- a/tools/qmltc/qmltccodewriter.cpp
+++ b/tools/qmltc/qmltccodewriter.cpp
@@ -149,24 +149,28 @@ void QmltcCodeWriter::writeGlobalHeader(QmltcOutputWrapper &code, const QString
 
     code.rawAppendToCpp(u""); // blank line
     code.rawAppendToCpp(u"QT_USE_NAMESPACE // avoid issues with QT_NAMESPACE");
-    if (!outNamespace.isEmpty()) {
-        code.rawAppendToHeader(u""); // blank line
-        code.rawAppendToHeader(u"namespace %1 {"_s.arg(outNamespace));
-        code.rawAppendToCpp(u""); // blank line
-        code.rawAppendToCpp(u"namespace %1 {"_s.arg(outNamespace));
+
+    code.rawAppendToHeader(u""); // blank line
+
+    const QStringList namespaces = outNamespace.split(u"::"_s);
+
+    for (const QString &currentNamespace : namespaces) {
+        code.rawAppendToHeader(u"namespace %1 {"_s.arg(currentNamespace));
+        code.rawAppendToCpp(u"namespace %1 {"_s.arg(currentNamespace));
     }
 }
 
 void QmltcCodeWriter::writeGlobalFooter(QmltcOutputWrapper &code, const QString &sourcePath,
                                         const QString &outNamespace)
 {
-    if (!outNamespace.isEmpty()) {
-        code.rawAppendToCpp(u"} // namespace %1"_s.arg(outNamespace));
-        code.rawAppendToCpp(u""); // blank line
-        code.rawAppendToHeader(u"} // namespace %1"_s.arg(outNamespace));
-        code.rawAppendToHeader(u""); // blank line
+    const QStringList namespaces = outNamespace.split(u"::"_s);
+
+    for (auto it = namespaces.crbegin(), end = namespaces.crend(); it != end; it++) {
+        code.rawAppendToCpp(u"} // namespace %1"_s.arg(*it));
+        code.rawAppendToHeader(u"} // namespace %1"_s.arg(*it));
     }
 
+    code.rawAppendToHeader(u""); // blank line
     code.rawAppendToHeader(u"#endif // %1_H"_s.arg(urlToMacro(sourcePath)));
     code.rawAppendToHeader(u""); // blank line
 }