QtProtobuf: add QML support

Enable QML flag for qtgrpcgen/qtprotobufgen plugins.
Generated output is updated: QProtobufMessage classes are Q_GADGETs,
such classes can be registered in QML code via QML_VALUE_TYPE macros only.
Also QProtobufMessages are not inherited from QObject class, it means
there is no full qmetaobject system support (no signals!).

Task-number: QTBUG-104513
Change-Id: I18c8f93782884efb8d923843df716ff8284ed8fb
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>

src/tools/qtprotobufgen/Qt6ProtobufToolsMacros.cmake

@@ -8,6 +8,7 @@ macro(_qt_internal_get_protoc_common_options option_args single_args multi_args)
     set(${option_args}
         COPY_COMMENTS
         GENERATE_PACKAGE_SUBFOLDERS
+        QML
     )
     set(${single_args}
         EXTRA_NAMESPACE

src/tools/qtprotobufgen/messagedeclarationprinter.cpp

@@ -141,6 +141,10 @@ void MessageDeclarationPrinter::printClassDeclarationBegin()
     } else {
         m_printer->Print(m_typeMap, CommonTemplates::ClassMessageBeginDeclarationTemplate());
     }
+
+    if (Options::instance().hasQml()) {
+        m_printer->Print(m_typeMap, CommonTemplates::ClassMessageQmlBeginDeclarationTemplate());
+    }
 }
 
 void MessageDeclarationPrinter::printMetaTypesDeclaration()

src/tools/qtprotobufgen/qprotobufgenerator.cpp

@@ -77,7 +77,7 @@ void QProtobufGenerator::GenerateSources(const FileDescriptor *file,
     sourcePrinter->Print({{"include", "QtProtobuf/qprotobufserializer.h"}},
                          CommonTemplates::ExternalIncludeTemplate());
     if (Options::instance().hasQml()) {
-        sourcePrinter->Print({{"include", "QQmlEngine"}},
+        sourcePrinter->Print({{"include", "QtQml/QQmlEngine"}},
                              CommonTemplates::ExternalIncludeTemplate());
     }
 

src/tools/qtprotoccommon/commontemplates.cpp

@@ -61,8 +61,8 @@ const char *CommonTemplates::DefaultSystemIncludesTemplate()
 
 const char *CommonTemplates::QmlProtobufIncludesTemplate()
 {
-    return "#include <QtQml/QQmlListProperty>\n"
-           "#include <QtProtobufQuick/qtprotobufqmllistpropertyconstructor.h>\n\n";
+    return "#include <QtQml/qqmlregistration.h>\n"
+           "#include <QtQml/qqmllist.h>\n\n";
 }
 
 const char *CommonTemplates::DisclaimerTemplate()
@@ -159,6 +159,12 @@ const char *CommonTemplates::ClassMessageForwardDeclarationTemplate()
 {
     return "class $classname$;\n";
 }
+
+const char *CommonTemplates::ClassMessageQmlBeginDeclarationTemplate()
+{
+    return "    QML_VALUE_TYPE($classname_low_case$)\n";
+}
+
 const char *CommonTemplates::ClassMessageBeginDeclarationTemplate()
 {
     return "\nclass $export_macro$ $classname$ : public QProtobufMessage\n"

src/tools/qtprotoccommon/commontemplates.h

@@ -42,6 +42,7 @@ public:
     static const char *ClassMessageForwardDeclarationTemplate();
     static const char *ClassMessageBeginDeclarationTemplate();
     static const char *ClassMessageBeginDeclarationTemplateEmptyMacros();
+    static const char *ClassMessageQmlBeginDeclarationTemplate();
     static const char *EmptyConstructorTemplate();
     static const char *UseNamespace();
 

src/tools/qtprotoccommon/generatorcommon.cpp

@@ -214,6 +214,7 @@ TypeMap common::produceMessageTypeMap(const Descriptor *type, const Descriptor *
 
     const std::string initializer = "nullptr";
     return { { "classname", name },
+             { "classname_low_case", utils::deCapitalizeAsciiName(type->name()) },
              { "type", name },
              { "full_type", fullName },
              { "scope_type", scopeName },
@@ -266,6 +267,7 @@ TypeMap common::produceEnumTypeMap(const EnumDescriptor *type, const Descriptor
 
     std::string initializer = scopeName + "::" + type->value(0)->name();
     return { { "classname", enumGadget },
+             { "classname_low_case", utils::deCapitalizeAsciiName(enumGadget) },
              { "type", name },
              { "full_type", fullName },
              { "scope_type", scopeName },
@@ -350,6 +352,7 @@ MethodMap common::produceMethodMap(const MethodDescriptor *method, const std::st
     inputTypeName = utils::replace(inputTypeName, ".", "::");
     outputTypeName = utils::replace(outputTypeName, ".", "::");
     return { { "classname", scope },          { "return_type", outputTypeName },
+             { "classname_low_case", utils::deCapitalizeAsciiName(scope) },
              { "method_name", methodName },   { "method_name_upper", methodNameUpper },
              { "param_type", inputTypeName }, { "param_name", "arg" },
              { "return_name", "ret" } };
@@ -367,6 +370,7 @@ TypeMap common::produceServiceTypeMap(const ServiceDescriptor *service, const De
                                                           getFullNamespace(scope, "::"));
 
     return { { "classname", name },
+             { "classname_low_case", utils::deCapitalizeAsciiName(name) },
              { "full_type", fullName },
              { "scope_type", scopeName },
              { "scope_namespaces", scopeNamespaces },
@@ -386,6 +390,7 @@ TypeMap common::produceClientTypeMap(const ServiceDescriptor *service, const Des
                                                           getFullNamespace(scope, "::"));
 
     return { { "classname", name },
+             { "classname_low_case", utils::deCapitalizeAsciiName(name) },
              { "full_type", fullName },
              { "scope_type", scopeName },
              { "scope_namespaces", scopeNamespaces },

src/tools/qtprotoccommon/options.cpp

@@ -51,9 +51,8 @@ void Options::setFromString(const std::string &options)
     for (const auto &option : utils::split(options, ";")) {
         QT_PROTOBUF_DEBUG("option: " << option);
         if (option == QmlPluginOption) {
-            // TODO: Disable QML until the porting is complete.
-            // QT_PROTOBUF_DEBUG("set m_hasQml: true");
-            // instance.m_hasQml = true;
+            QT_PROTOBUF_DEBUG("set m_hasQml: true");
+            instance.m_hasQml = true;
         } else if (option == CommentsGenerationOption) {
             QT_PROTOBUF_DEBUG("set m_generateComments: true");
             instance.m_generateComments = true;