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#ifndef _GLIBMM_REFPTR_H
#define _GLIBMM_REFPTR_H
/* 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, see <http://www.gnu.org/licenses/>.
*/
#include <glibmmconfig.h>
#include <glib.h>
#include <memory>
namespace Glib
{
#ifndef DOXYGEN_SHOULD_SKIP_THIS
template <class T_CppObject>
void RefPtrDeleter(T_CppObject* object)
{
if (!object)
return;
object->unreference();
}
#endif // DOXYGEN_SHOULD_SKIP_THIS
// RefPtr is put in a group, because a group (but not a 'using' alias)
// gets its own html file, which can be referred to from outside glibmm,
// for instance from the gtkmm tutorial.
// Without a group, Doxygen generates links to the 'using' alias such as
// .../html/namespaceGlib.html#afa2fecfa732e9ec1107ace03a2911d63
/** @defgroup RefPtr RefPtr
* A reference-counting shared smartpointer
*/
/** RefPtr<> is a reference-counting shared smartpointer.
*
* Some objects in gtkmm are obtained from a shared
* store. Consequently you cannot instantiate them yourself. Instead they
* return a RefPtr which behaves much like an ordinary pointer in that members
* can be reached with the usual <code>object_ptr->member</code> notation.
*
* Reference counting means that a shared reference count is incremented each
* time a RefPtr is copied, and decremented each time a RefPtr is destroyed,
* for instance when it leaves its scope. When the reference count reaches
* zero, the contained object is deleted, meaning you don't need to remember
* to delete the object.
*
* RefPtr is a std::shared_ptr with a special deleter. To cast a RefPtr<SomeType>
* to a RefPtr<SomeOtherType>, use one of the standard library functions that
* apply a cast to the stored pointer, for instance std::dynamic_pointer_cast.
*
* Example:
* @code
* Glib::RefPtr<const Gio::ListModel> monitors = Gdk::Display::get_default()->get_monitors();
* Glib::RefPtr<const Glib::ObjectBase> first_object = monitors->get_object(0);
* Glib::RefPtr<const Gdk::Monitor> first_monitor =
* std::dynamic_pointer_cast<const Gdk::Monitor>(first_object);
* @endcode
*
* See the "Memory Management" section in the "Programming with gtkmm"
* book for further information.
*
* @see Glib::make_refptr_for_instance()
* if you need to implement a create() method for a %Glib::ObjectBase-derived class.
*
* @ingroup RefPtr
*/
template <class T_CppObject>
using RefPtr = std::shared_ptr<T_CppObject>;
/* This would not be useful,
* because application code should not new these objects anyway.
* And it is not useful inside glibmm or gtkmm code because
* the constructors are protected, so can't be called from this utilility
* function.
*
template <class T_CppObject, class... T_Arg>
RefPtr<T_CppObject>
make_refptr(T_Arg... arg)
{
return RefPtr<T_CppObject>(new T_CppObject(arg...));
}
*/
/** Create a RefPtr<> to an instance of any class that has reference() and
* unreference() methods, and whose destructor is noexcept (the default for destructors).
*
* In gtkmm, that is anything derived from Glib::ObjectBase, such as
* Gdk::Pixbuf.
*
* Normal application code should not need to use this. However, this is necessary
* when implementing create() methods for derived Glib::ObjectBase-derived
* (not Gtk::Widget-derived) classes, such as derived Gtk::TreeModels.
*/
template <class T_CppObject>
RefPtr<T_CppObject>
make_refptr_for_instance(T_CppObject* object)
{
return RefPtr<T_CppObject>(object, &RefPtrDeleter<T_CppObject>);
}
} // namespace Glib
#endif /* _GLIBMM_REFPTR_H */
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