WIP: first solution for lost references issue

* The solution consists of attaching a bridge object
  to QObjects. If the host object is destroyed, the
  bridge object will notify the script client
* The bridge object attachment is optimized so it
  only happens if required (but still too often ...)
* The child object of QChildEvent gets a special
  handling since this object is almost dead in case
  of remove. This special handling consists of
  a special, stripped class which is used to
  only represent QObject in that particular case.

scripts/mkqtdecl/mkqtdecl.conf

@@ -192,6 +192,7 @@ drop_method "QObject", /QObject::findChild/ # template member
 drop_method "QObject", /QObject::findChildren/ # template member
 drop_method "QObject", /QObject::setUserData/ # QObjectUserData not available
 drop_method "QObject", /QObject::userData/ # QObjectUserData not available
+drop_method "QChildEvent", /QChildEvent::child/ # provided through a special implementation
 drop_method "QFile", /QFile::setDecodingFunction/ # uses callbacks
 drop_method "QFile", /QFile::setEncodingFunction/ # uses callbacks
 drop_method "QFile", /QFile::open.*IO_FILE/ # uses internal struct
@@ -272,6 +273,64 @@ CODE
   gsi::method_ext("findChild", &find_child_impl, "@brief Specialisation for findChild (uses QObject as T).") 
 DECL
 
+# alternative implementation for QChildEvent::child
+# Reason: this method does not supply a true QObject pointer. Instead it will 
+# deliver a pointer to an object that is almost destroyed. Normal RTTI will 
+# not work on this. Neighter can it be attached an gsi::ObjectBase object.
+add_native_impl("QChildEvent", <<'CODE', <<'DECL')
+
+  namespace gsi 
+  {
+    gsi::Class<QObject> &qtdecl_QObject ();
+  }
+
+  namespace
+  {
+    struct DummyQObject { };
+
+    class RawQObjectClass
+      : public gsi::Class<QObject>
+    {
+    public:
+      RawQObjectClass ()
+        : gsi::Class<QObject> (gsi::qtdecl_QObject (), "QObject_Raw", gsi::Methods (), "@hide")
+      {
+      }
+
+      //  Final class - because of missing RTTI, subclassing won't work.
+      virtual const gsi::ClassBase *subclass_decl (const void *) const { return this; }
+      virtual bool can_upcast (const void *) const { return false; }
+
+      //  Does not bind to a particular type
+      virtual bool is_of_type (const std::type_info & /*ti*/) const { return false; }
+      virtual const std::type_info &type () const { return typeid (DummyQObject); }
+    };
+  }
+
+  static void _init_f_child (qt_gsi::GenericMethod *decl)
+  {
+    //  Make the QChildEvent::child method return a special class which is final 
+    //  and does not try to return a gsi::ObjectBase object.
+    static RawQObjectClass s_cls;
+    decl->set_return<QObject * > ();
+    decl->ret_type ().set_cls (&s_cls);
+  }
+
+  static void _call_f_child (const qt_gsi::GenericMethod * /*decl*/, void *cls, gsi::SerialArgs & /*args*/, gsi::SerialArgs &ret) 
+  {
+    ret.write<QObject * > ((QObject *)((QChildEvent *)cls)->child ());
+  }
+
+CODE
+  gsi::Methods(new qt_gsi::GenericMethod ("child", 
+      "@brief Method QObject *QChildEvent::child()\n"
+      "NOTE: the object returned by this method is not memory managed. It may be destroyed internally without notice. \n"
+      "The returned object shall not be stored or used outside the childEvent handler. "
+      "If used outside this handler, the reference might get lost and the application may crash.\n"
+      "Furthermore, the object returned will only represent a QObject, not any derived type.\n",
+      true, &_init_f_child, &_call_f_child))
+DECL
+
 # alternative implementation for QFont::Light, QFont::Bold, QFont::Normal, QFont::DemiBold, QFont::Black
 add_native_impl("QFont", <<'CODE', <<'DECL')
   static unsigned int font_const_light () { return (unsigned int) QFont::Light; }

scripts/mkqtdecl_common/produce.rb

@@ -2211,7 +2211,11 @@ def produce_class(conf, decl_obj, ofile)
     ofile.puts("}")
     ofile.puts("")
 
-    decl_type = "gsi::Class<#{cls}>"
+    if is_qobject
+      decl_type = "qt_gsi::QtNativeClass<#{cls}>"
+    else
+      decl_type = "gsi::Class<#{cls}>"
+    end
 
     if base_cls
       ofile.puts("gsi::Class<#{base_cls}> &qtdecl_#{base_clsn} ();")

src/gsi/gsiClass.h

@@ -729,29 +729,29 @@ class Class
   typedef typename tl::type_traits<X>::has_default_constructor has_default_ctor;
   typedef typename tl::type_traits<X>::has_public_destructor has_public_dtor;
 
-  Class (const std::string &name, const Methods &mm, const std::string &doc = std::string ())
-    : ClassBase (doc, mm)
+  Class (const std::string &name, const Methods &mm, const std::string &doc = std::string (), bool do_register = true)
+    : ClassBase (doc, mm, do_register)
   {
     set_name (name);
   }
 
   template <class B>
-  Class (const Class<B> &base, const std::string &name, const Methods &mm, const std::string &doc = std::string ())
-    : ClassBase (doc, mm), m_subclass_tester (new SubClassTester<X, B, typename is_polymorphic<B>::value> ())
+  Class (const Class<B> &base, const std::string &name, const Methods &mm, const std::string &doc = std::string (), bool do_register = true)
+    : ClassBase (doc, mm, do_register), m_subclass_tester (new SubClassTester<X, B, typename is_polymorphic<B>::value> ())
   {
     set_name (name);
     set_base (&base);
   }
 
-  Class (const std::string &name, const std::string &doc = std::string ())
-    : ClassBase (doc, Methods ())
+  Class (const std::string &name, const std::string &doc = std::string (), bool do_register = true)
+    : ClassBase (doc, Methods (), do_register)
   {
     set_name (name);
   }
 
   template <class B>
-  Class (const Class<B> &base, const std::string &name, const std::string &doc = std::string ())
-    : ClassBase (doc, Methods ()), m_subclass_tester (new SubClassTester<X, B, typename is_polymorphic<B>::value> ())
+  Class (const Class<B> &base, const std::string &name, const std::string &doc = std::string (), bool do_register = true)
+    : ClassBase (doc, Methods (), do_register), m_subclass_tester (new SubClassTester<X, B, typename is_polymorphic<B>::value> ())
   {
     set_name (name);
     set_base (&base);
@@ -785,7 +785,7 @@ class Class
     return tl::is_derived<gsi::ObjectBase, X> ();
   }
 
-  gsi::ObjectBase *gsi_object (void *p) const
+  gsi::ObjectBase *gsi_object (void *p, bool /*required*/) const
   {
     return tl::try_static_cast<gsi::ObjectBase, X> ((X *) p);
   }

src/gsi/gsiClassBase.cc

@@ -39,13 +39,15 @@ namespace gsi
 
 ClassBase::class_collection *ClassBase::mp_class_collection = 0;
 
-ClassBase::ClassBase (const std::string &doc, const Methods &mm)
+ClassBase::ClassBase (const std::string &doc, const Methods &mm, bool do_register)
   : mp_base (0), mp_parent (0), m_doc (doc), m_methods (mm)
 { 
-  if (! mp_class_collection) {
-    mp_class_collection = new class_collection ();
+  if (do_register) {
+    if (! mp_class_collection) {
+      mp_class_collection = new class_collection ();
+    }
+    mp_class_collection->push_back (this);
   }
-  mp_class_collection->push_back (this);
 }
 
 ClassBase::~ClassBase ()

src/gsi/gsiClassBase.h

@@ -85,7 +85,7 @@ class GSI_PUBLIC ClassBase
    *
    *  The constructor supplies information about the connector class (can be 0), a documentation string and the method declarations.
    */
-  ClassBase (const std::string &doc, const Methods &mm);
+  ClassBase (const std::string &doc, const Methods &mm, bool do_register = true);
 
   /**
    *  @brief Destructor
@@ -437,8 +437,13 @@ class GSI_PUBLIC ClassBase
   /**
    *  @brief Gets the basic gsi::ObjectBase object from a generic pointer
    *  This method will return 0, if the object is not managed.
+   *  If required is false, a return value of 0 is permitted, indicating that
+   *  no dynamic allocation of a gsi::ObjectBase has happened yet. This is useful
+   *  in case of the Qt-GSI bridge which means a special Qt object needs to be
+   *  created in order to provide the gsi::ObjectBase interface. If required is
+   *  false, this initialization does not need to happen.
    */
-  virtual gsi::ObjectBase *gsi_object (void * /*p*/) const
+  virtual gsi::ObjectBase *gsi_object (void * /*p*/, bool /*required*/ = true) const
   {
     tl_assert (false);
     return 0;

src/gsi/gsiDeclInternal.cc

@@ -226,7 +226,7 @@ Class<MethodBase> decl_Method ("Method",
   gsi::iterator ("each_argument", &MethodBase::begin_arguments, &MethodBase::end_arguments,
     "@brief Iterate over all arguments of this method\n"
   ) +
-  gsi::method ("ret_type", &MethodBase::ret_type,
+  gsi::method ("ret_type", (const gsi::ArgType &(MethodBase::*)() const) &MethodBase::ret_type,
     "@brief The return type of this method\n"
   ) +
   gsi::method ("is_protected?", &MethodBase::is_protected,

src/gsi/gsiMethods.h

@@ -193,6 +193,14 @@ class GSI_PUBLIC MethodBase
     return m_doc;
   }
 
+  /**
+   *  @brief Sets the documentation text
+   */
+  void set_doc (const std::string &d)
+  {
+    m_doc = d;
+  }
+
   /**
    *  @brief Returns the nth (index) argument
    */
@@ -202,6 +210,15 @@ class GSI_PUBLIC MethodBase
     return m_arg_types [index];
   }
 
+  /**
+   *  @brief Returns the nth (index) argument (non_const version)
+   */
+  ArgType &arg (size_t index)
+  {
+    tl_assert (m_arg_types.size () > index);
+    return m_arg_types [index];
+  }
+
   /**
    *  @brief Iterates the arguments (begin)
    */
@@ -226,6 +243,14 @@ class GSI_PUBLIC MethodBase
     return m_ret_type;
   }
 
+  /**
+   *  @brief Gets the return type (non-const version)
+   */
+  ArgType &ret_type ()
+  {
+    return m_ret_type;
+  }
+
   /**
    *  @brief Gets a value indicating whether this method is a const method
    */

src/gsi/gsiObject.cc

@@ -92,7 +92,10 @@ void
 Proxy::detach ()
 {
   if (m_cls_decl && m_cls_decl->is_managed ()) {
-    m_cls_decl->gsi_object (m_obj)->status_changed_event ().remove (this, &Proxy::object_status_changed);
+    gsi::ObjectBase *gsi_object = m_cls_decl->gsi_object (m_obj, false);
+    if (gsi_object) {
+      gsi_object->status_changed_event ().remove (this, &Proxy::object_status_changed);
+    }
   }
 
   m_obj = 0;
@@ -157,7 +160,10 @@ Proxy::set (void *obj, bool owned, bool const_ref, bool can_destroy)
     if (m_obj) {
 
       if (cls->is_managed ()) {
-        cls->gsi_object (m_obj)->status_changed_event ().remove (this, &Proxy::object_status_changed);
+        gsi::ObjectBase *gsi_object = cls->gsi_object (m_obj, false);
+        if (gsi_object) {
+          gsi_object->status_changed_event ().remove (this, &Proxy::object_status_changed);
+        }
       }
 
       //  Destroy the object if we are owner. We don't destroy the object if it was locked
@@ -211,14 +217,7 @@ void
 Proxy::object_status_changed (gsi::ObjectBase::StatusEventType type)
 {
   if (type == gsi::ObjectBase::ObjectDestroyed) {
-
-    //  external reset - the object no longer will be available so we unlink from it
-    m_obj = 0;
-    m_destroyed = true;
-    m_const_ref = false;
-    m_owned = false;
-    m_can_destroy = false;
-
+    detach ();
   } else if (type == gsi::ObjectBase::ObjectKeep) {
     m_owned = false;
   } else if (type == gsi::ObjectBase::ObjectRelease) {

src/gsiqt/gsiDeclQAbstractButton.cc

@@ -1,3 +1,25 @@
+
+/*
+
+  KLayout Layout Viewer
+  Copyright (C) 2006-2017 Matthias Koefferlein
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+*/
+
 /**
 *  @file gsiDeclQAbstractButton.cc 
 *

src/gsiqt/gsiDeclQAbstractFormBuilder.cc

@@ -1,3 +1,25 @@
+
+/*
+
+  KLayout Layout Viewer
+  Copyright (C) 2006-2017 Matthias Koefferlein
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+*/
+
 /**
 *  @file gsiDeclQAbstractFormBuilder.cc 
 *

src/gsiqt/gsiDeclQAbstractGraphicsShapeItem.cc

@@ -1,3 +1,25 @@
+
+/*
+
+  KLayout Layout Viewer
+  Copyright (C) 2006-2017 Matthias Koefferlein
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+*/
+
 /**
 *  @file gsiDeclQAbstractGraphicsShapeItem.cc 
 *

src/gsiqt/gsiDeclQAbstractItemDelegate.cc

@@ -1,3 +1,25 @@
+
+/*
+
+  KLayout Layout Viewer
+  Copyright (C) 2006-2017 Matthias Koefferlein
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+*/
+
 /**
 *  @file gsiDeclQAbstractItemDelegate.cc 
 *