Add automatic metatype registration for Q_PROPERTY types.

In Qt 4, the user needs to call qRegisterMetaType if the property
could otherwise be read before the type is registered with the metatype
system. This patch makes that unnecessary and automatic by registering
it when the first read indicates that it is not yet registered instead
or when QMetaProperty::userType is called before it is registered.

The types which are automatically registered exclude the built-in
types, which do not need to be registered, and include metatypes which
are automatically declared, such as pointers to QObject derived types
and containers of existing metatypes.

Change-Id: I0a06d8efdcb64121618e2378366d0142fa0771f5
Reviewed-by: Kent Hansen <kent.hansen@nokia.com>

1 files changed, 88 insertions, 3 deletions

diff --git a/src/tools/moc/generator.cpp b/src/tools/moc/generator.cpp
index 39bd528008..edf2bf8889 100644
--- a/src/tools/moc/generator.cpp
+++ b/src/tools/moc/generator.cpp
@@ -86,8 +86,8 @@ QT_FOR_EACH_STATIC_TYPE(RETURN_METATYPENAME_STRING)
     return 0;
  }
 
-Generator::Generator(ClassDef *classDef, const QList<QByteArray> &metaTypes, FILE *outfile)
-    : out(outfile), cdef(classDef), metaTypes(metaTypes)
+Generator::Generator(ClassDef *classDef, const QList<QByteArray> &metaTypes, const QSet<QByteArray> &knownQObjectClasses, FILE *outfile)
+    : out(outfile), cdef(classDef), metaTypes(metaTypes), knownQObjectClasses(knownQObjectClasses)
 {
     if (cdef->superclassList.size())
         purestSuperClass = cdef->superclassList.first().first;
@@ -140,6 +140,49 @@ static int aggregateParameterCount(const QList<FunctionDef> &list)
     return sum;
 }
 
+bool Generator::registerableMetaType(const QByteArray &propertyType)
+{
+    if (metaTypes.contains(propertyType))
+        return true;
+
+    if (propertyType.endsWith('*')) {
+        QByteArray objectPointerType = propertyType;
+        // The objects container stores class names, such as 'QState', 'QLabel' etc,
+        // not 'QState*', 'QLabel*'. The propertyType does contain the '*', so we need
+        // to chop it to find the class type in the known QObjects list.
+        objectPointerType.chop(1);
+        if (knownQObjectClasses.contains(objectPointerType))
+            return true;
+    }
+
+    static const QVector<QByteArray> smartPointers = QVector<QByteArray>()
+#define STREAM_SMART_POINTER(SMART_POINTER) << #SMART_POINTER
+        QT_FOR_EACH_AUTOMATIC_TEMPLATE_SMART_POINTER(STREAM_SMART_POINTER)
+#undef STREAM_SMART_POINTER
+        ;
+
+    foreach (const QByteArray &smartPointer, smartPointers)
+        if (propertyType.startsWith(smartPointer + "<"))
+            return knownQObjectClasses.contains(propertyType.mid(smartPointer.size() + 1, propertyType.size() - smartPointer.size() - 1 - 1));
+
+    static const QVector<QByteArray> oneArgTemplates = QVector<QByteArray>()
+#define STREAM_1ARG_TEMPLATE(TEMPLATENAME) << #TEMPLATENAME
+      QT_FOR_EACH_AUTOMATIC_TEMPLATE_1ARG(STREAM_1ARG_TEMPLATE)
+#undef STREAM_1ARG_TEMPLATE
+    ;
+    foreach (const QByteArray &oneArgTemplateType, oneArgTemplates)
+        if (propertyType.startsWith(oneArgTemplateType + "<")) {
+            const int argumentSize = propertyType.size() - oneArgTemplateType.size() - 1
+                                     // The closing '>'
+                                     - 1
+                                     // templates inside templates have an extra whitespace char to strip.
+                                     - (propertyType.at(propertyType.size() - 2) == '>' ? 1 : 0 );
+            const QByteArray templateArg = propertyType.mid(oneArgTemplateType.size() + 1, argumentSize);
+            return isBuiltinType(templateArg) || registerableMetaType(templateArg);
+        }
+    return false;
+}
+
 void Generator::generateCode()
 {
     bool isQt = (cdef->classname == "Qt");
@@ -1034,6 +1077,15 @@ void Generator::generateMetacall()
                 "        _id -= %d;\n"
                 "    }", cdef->propertyList.count());
 
+        fprintf(out, " else ");
+        fprintf(out, "if (_c == QMetaObject::RegisterPropertyMetaType) {\n");
+        fprintf(out, "        if (_id < %d)\n", cdef->propertyList.size());
+
+        if (automaticPropertyMetaTypesHelper().isEmpty())
+            fprintf(out, "            *reinterpret_cast<int*>(_a[0]) = -1;\n");
+        else
+            fprintf(out, "            qt_static_metacall(this, _c, _id, _a);\n");
+        fprintf(out, "        _id -= %d;\n    }", cdef->propertyList.size());
 
         fprintf(out, "\n#endif // QT_NO_PROPERTIES");
     }
@@ -1042,6 +1094,18 @@ void Generator::generateMetacall()
     fprintf(out,"return _id;\n}\n");
 }
 
+
+QMultiMap<QByteArray, int> Generator::automaticPropertyMetaTypesHelper()
+{
+    QMultiMap<QByteArray, int> automaticPropertyMetaTypes;
+    for (int i = 0; i < cdef->propertyList.size(); ++i) {
+        const QByteArray propertyType = cdef->propertyList.at(i).type;
+        if (registerableMetaType(propertyType) && !isBuiltinType(propertyType))
+            automaticPropertyMetaTypes.insert(propertyType, i);
+    }
+    return automaticPropertyMetaTypes;
+}
+
 void Generator::generateStaticMetacall()
 {
     fprintf(out, "void %s::qt_static_metacall(QObject *_o, QMetaObject::Call _c, int _id, void **_a)\n{\n",
@@ -1175,12 +1239,33 @@ void Generator::generateStaticMetacall()
         needElse = true;
     }
 
+    QMultiMap<QByteArray, int> automaticPropertyMetaTypes = automaticPropertyMetaTypesHelper();
+
+    if (!automaticPropertyMetaTypes.isEmpty()) {
+        if (needElse)
+            fprintf(out, " else ");
+        else
+            fprintf(out, "    ");
+        fprintf(out, "if (_c == QMetaObject::RegisterPropertyMetaType) {\n");
+        fprintf(out, "        switch (_id) {\n");
+        fprintf(out, "        default: *reinterpret_cast<int*>(_a[0]) = -1; break;\n");
+        foreach (const QByteArray &key, automaticPropertyMetaTypes.uniqueKeys()) {
+            foreach (int propertyID, automaticPropertyMetaTypes.values(key))
+                fprintf(out, "        case %d:\n", propertyID);
+            fprintf(out, "            *reinterpret_cast<int*>(_a[0]) = qRegisterMetaType< %s >(); break;\n", key.constData());
+        }
+        fprintf(out, "        }\n");
+        fprintf(out, "    }\n");
+        isUsed_a = true;
+        needElse = true;
+    }
+
     if (needElse)
         fprintf(out, "\n");
 
     if (methodList.isEmpty()) {
         fprintf(out, "    Q_UNUSED(_o);\n");
-        if (cdef->constructorList.isEmpty()) {
+        if (cdef->constructorList.isEmpty() && automaticPropertyMetaTypes.isEmpty()) {
             fprintf(out, "    Q_UNUSED(_id);\n");
             fprintf(out, "    Q_UNUSED(_c);\n");
         }