text: // -*- c++ -*-
  /* $Id$ */
  
  /* Copyright 2002 The gtkmm Development Team
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library 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
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free
   * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  #ifndef _GLIBMM_VALUE_CUSTOM_H
  #define _GLIBMM_VALUE_CUSTOM_H
  
  #ifndef DOXYGEN_SHOULD_SKIP_THIS
  #ifndef _GLIBMM_VALUE_H_INCLUDE_VALUE_CUSTOM_H
  #error "glibmm/value_custom.h cannot be included directly"
  #endif
  #endif
  
  #include <glibmmconfig.h>
  #include <new>
  #include <typeinfo>
  
  namespace Glib
  {
  
  #ifndef DOXYGEN_SHOULD_SKIP_THIS
  
  extern "C"
  {
    typedef void (* ValueInitFunc) (GValue*);
    typedef void (* ValueFreeFunc) (GValue*);
    typedef void (* ValueCopyFunc) (const GValue*, GValue*);
  }
  
  /* When using Glib::Value<T> with custom types, each T will be registered
   * as subtype of G_TYPE_BOXED, via this function.  The type_name argument
   * should be the C++ RTTI name.
   */
  GType custom_boxed_type_register(const char*   type_name,
                                   ValueInitFunc init_func,
                                   ValueFreeFunc free_func,
                                   ValueCopyFunc copy_func);
  
  /* When using Glib::Value<T*> or Glib::Value<const T*> with custom types,
   * each T* or const T* will be registered as a subtype of G_TYPE_POINTER,
   * via this function.  The type_name argument should be the C++ RTTI name.
   */
  GType custom_pointer_type_register(const char* type_name);
  
  #endif /* DOXYGEN_SHOULD_SKIP_THIS */
  
  
  /**
   * @ingroup glibmmValue
   */
  template <class T, class PtrT>
  class Value_Pointer : public ValueBase_Object
  {
  public:
    typedef PtrT  CppType;
    typedef void* CType;
  
    static inline GType value_type() G_GNUC_CONST;
  
    inline void set(CppType data);
    inline CppType get() const;
  
  private:
    inline
    static GType value_type_(Glib::Object*);
    static GType value_type_(void*);
  
    inline void set_(CppType data, Glib::Object*);
    inline void set_(CppType data, void*);
  
    inline CppType get_(Glib::Object*) const;
    inline CppType get_(void*) const;
  };
  
  
  /** Generic value implementation for custom types.
   * @ingroup glibmmValue
   * Any type to be used with this template must implement:
   * - default constructor
   * - copy constructor
   * - assignment operator
   * - destructor
   *
   * Compiler-generated implementations are OK, provided they do the
   * right thing for the type.  In other words, any type that works with
   * <tt>std::vector</tt> will work with Glib::Value<>.
   *
   * @note None of the operations listed above are allowed to throw.  If you
   * cannot ensure that no exceptions will be thrown, consider using either
   * a normal pointer or a smart pointer to hold your objects indirectly.
   */
  template <class T>
  class Value : public ValueBase_Boxed
  {
  public:
    typedef T  CppType;
    typedef T* CType;
  
    static GType value_type() G_GNUC_CONST;
  
    inline void set(const CppType& data);
    inline CppType get() const;
  
  private:
    static GType custom_type_;
  
    static void value_init_func(GValue* value);
    static void value_free_func(GValue* value);
    static void value_copy_func(const GValue* src_value, GValue* dest_value);
  };
  
  
  /** Specialization for pointers to instances of any type.
   * @ingroup glibmmValue
   * No attempt is made to manage the memory associated with the
   * pointer, you must take care of that yourself.
   */
  template <class T>
  class Value<T*> : public Value_Pointer<T,T*>
  {};
  
  /** Specialization for pointers to const instances of any type.
   * @ingroup glibmmValue
   * No attempt is made to manage the memory associated with the
   * pointer, you must take care of that yourself.
   */
  template <class T>
  class Value<const T*> : public Value_Pointer<T,const T*>
  {};
  
  
  #ifndef DOXYGEN_SHOULD_SKIP_THIS
  
  /**** Glib::Value_Pointer<T, PtrT> *****************************************/
  
  /** Implementation for Glib::Object pointers **/
  
  // static
  template <class T, class PtrT> inline
  GType Value_Pointer<T,PtrT>::value_type_(Glib::Object*)
  {
    return T::get_base_type();
  }
  
  template <class T, class PtrT> inline
  void Value_Pointer<T,PtrT>::set_(PtrT data, Glib::Object*)
  {
    set_object(const_cast<T*>(data));
  }
  
  //More spec-compliant compilers (such as Tru64) need this to be near Glib::Object instead.
  #ifdef GLIBMM_CAN_USE_DYNAMIC_CAST_IN_UNUSED_TEMPLATE_WITHOUT_DEFINITION
  template <class T, class PtrT> inline
  PtrT Value_Pointer<T,PtrT>::get_(Glib::Object*) const
  {
    return dynamic_cast<T*>(get_object());
  }
  #endif //GLIBMM_CAN_USE_DYNAMIC_CAST_IN_UNUSED_TEMPLATE_WITHOUT_DEFINITION
  
  /** Implementation for custom pointers **/
  
  // static
  template <class T, class PtrT>
  GType Value_Pointer<T,PtrT>::value_type_(void*)
  {
    static GType custom_type = 0;
  
    if(!custom_type)
      custom_type = Glib::custom_pointer_type_register(typeid(PtrT).name());
  
    return custom_type;
  }
  
  template <class T, class PtrT> inline
  void Value_Pointer<T,PtrT>::set_(PtrT data, void*)
  {
    gobject_.data[0].v_pointer = const_cast<T*>(data);
  }
  
  template <class T, class PtrT> inline
  PtrT Value_Pointer<T,PtrT>::get_(void*) const
  {
    return static_cast<T*>(gobject_.data[0].v_pointer);
  }
  
  /** Public forwarding interface **/
  
  // static
  template <class T, class PtrT> inline
  GType Value_Pointer<T,PtrT>::value_type()
  {
    // Dispatch to the specific value_type_() overload.
    return Value_Pointer<T,PtrT>::value_type_(static_cast<T*>(0));
  }
  
  template <class T, class PtrT> inline
  void Value_Pointer<T,PtrT>::set(PtrT data)
  {
    // Dispatch to the specific set_() overload.
    this->set_(data, static_cast<T*>(0));
  }
  
  template <class T, class PtrT> inline
  PtrT Value_Pointer<T,PtrT>::get() const
  {
    // Dispatch to the specific get_() overload.
    return this->get_(static_cast<T*>(0));
  }
  
  
  /**** Glib::Value<T> *******************************************************/
  
  // Static data, specific to each template instantiation.
  template <class T>
  GType Value<T>::custom_type_ = 0;
  
  template <class T> inline
  void Value<T>::set(const typename Value<T>::CppType& data)
  {
    // Assume the value is already default-initialized.  See value_init_func().
    *static_cast<T*>(gobject_.data[0].v_pointer) = data;
  }
  
  template <class T> inline
  typename Value<T>::CppType Value<T>::get() const
  {
    // Assume the pointer is not NULL.  See value_init_func().
    return *static_cast<T*>(gobject_.data[0].v_pointer);
  }
  
  // static
  template <class T>
  GType Value<T>::value_type()
  {
    if(!custom_type_)
    {
      custom_type_ = Glib::custom_boxed_type_register(
          typeid(CppType).name(),
          &Value<T>::value_init_func,
          &Value<T>::value_free_func,
          &Value<T>::value_copy_func);
    }
    return custom_type_;
  }
  
  // static
  template <class T>
  void Value<T>::value_init_func(GValue* value)
  {
    // Never store a NULL pointer (unless we're out of memory).
    value->data[0].v_pointer = new(std::nothrow) T();
  }
  
  // static
  template <class T>
  void Value<T>::value_free_func(GValue* value)
  {
    delete static_cast<T*>(value->data[0].v_pointer);
  }
  
  // static
  template <class T>
  void Value<T>::value_copy_func(const GValue* src_value, GValue* dest_value)
  {
    // Assume the source is not NULL.  See value_init_func().
    const T& source = *static_cast<T*>(src_value->data[0].v_pointer);
    dest_value->data[0].v_pointer = new(std::nothrow) T(source);
  }
  
  #endif /* DOXYGEN_SHOULD_SKIP_THIS */
  
  } // namespace Glib
  
  #endif //_GLIBMM_VALUE_CUSTOM_H
  