Allow registering constructor for a set of dynamic types

This feature is needed to register complex types (e.g. Q_GADGETS) at
runtime, using a single constructor method and added type parameter.
Without having the type id available to the Constructor it is impossible
to specialize behavior, thus requiring separate constructors for each
type. Generating these separate constructors at compile time is easy,
but not at runtime.

[ChangeLog][QMetaType] QMetaType can now register constructor for a set
of dynamic types.

Change-Id: I6071271d0e157864594dd07b4bc3a0abbeb15a44
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 24 insertions, 9 deletions

diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h
index 48cbe7f00b..ed7feee775 100644
--- a/src/corelib/kernel/qmetatype.h
+++ b/src/corelib/kernel/qmetatype.h
@@ -493,8 +493,12 @@ public:
     typedef void (*Deleter)(void *);
     typedef void *(*Creator)(const void *);
 
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
     typedef void (*Destructor)(void *);
-    typedef void *(*Constructor)(void *, const void *);
+    typedef void *(*Constructor)(void *, const void *); // TODO Qt6: remove me
+#endif
+    typedef void (*TypedDestructor)(int, void *);
+    typedef void *(*TypedConstructor)(int, void *, const void *);
 
     typedef void (*SaveOperator)(QDataStream &, const void *);
     typedef void (*LoadOperator)(QDataStream &, void *);
@@ -513,6 +517,12 @@ public:
                             int size,
                             QMetaType::TypeFlags flags,
                             const QMetaObject *metaObject);
+    static int registerType(const char *typeName,
+                            TypedDestructor destructor,
+                            TypedConstructor constructor,
+                            int size,
+                            QMetaType::TypeFlags flags,
+                            const QMetaObject *metaObject);
     static bool unregisterType(int type);
     static int registerNormalizedType(const QT_PREPEND_NAMESPACE(QByteArray) &normalizedTypeName, Deleter deleter,
                             Creator creator,
@@ -526,6 +536,11 @@ public:
                             int size,
                             QMetaType::TypeFlags flags,
                             const QMetaObject *metaObject);
+    static int registerNormalizedType(const QT_PREPEND_NAMESPACE(QByteArray) &normalizedTypeName, TypedDestructor destructor,
+                            TypedConstructor constructor,
+                            int size,
+                            QMetaType::TypeFlags flags,
+                            const QMetaObject *metaObject);
     static int registerTypedef(const char *typeName, int aliasId);
     static int registerNormalizedTypedef(const QT_PREPEND_NAMESPACE(QByteArray) &normalizedTypeName, int aliasId);
     static int type(const char *typeName);
@@ -683,8 +698,8 @@ public:
 private:
     static QMetaType typeInfo(const int type);
     inline QMetaType(const ExtensionFlag extensionFlags, const QMetaTypeInterface *info,
-                     Creator creator,
-                     Deleter deleter,
+                     TypedConstructor creator,
+                     TypedDestructor deleter,
                      SaveOperator saveOp,
                      LoadOperator loadOp,
                      Constructor constructor,
@@ -731,8 +746,8 @@ public:
     static void unregisterConverterFunction(int from, int to);
 private:
 
-    Creator m_creator_unused;
-    Deleter m_deleter_unused;
+    TypedConstructor m_typedConstructor;
+    TypedDestructor m_typedDestructor;
     SaveOperator m_saveOp;
     LoadOperator m_loadOp;
     Constructor m_constructor;
@@ -2163,8 +2178,8 @@ QT_BEGIN_NAMESPACE
 #undef Q_DECLARE_METATYPE_TEMPLATE_SMART_POINTER_ITER
 
 inline QMetaType::QMetaType(const ExtensionFlag extensionFlags, const QMetaTypeInterface *info,
-                            Creator creator,
-                            Deleter deleter,
+                            TypedConstructor creator,
+                            TypedDestructor deleter,
                             SaveOperator saveOp,
                             LoadOperator loadOp,
                             Constructor constructor,
@@ -2173,8 +2188,8 @@ inline QMetaType::QMetaType(const ExtensionFlag extensionFlags, const QMetaTypeI
                             uint theTypeFlags,
                             int typeId,
                             const QMetaObject *_metaObject)
-    : m_creator_unused(creator)
-    , m_deleter_unused(deleter)
+    : m_typedConstructor(creator)
+    , m_typedDestructor(deleter)
     , m_saveOp(saveOp)
     , m_loadOp(loadOp)
     , m_constructor(constructor)