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// -*- c++ -*-
/* $Id$ */
/* wrap.cc
*
* Copyright (C) 1998-2002 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.
*/
#include <glibmmconfig.h>
#include <glibmm/object.h>
#include <glibmm/quark.h>
#include <glibmm/wrap.h>
#include <vector>
#include <glib.h>
#include <glib-object.h>
namespace
{
// Although the new g_type_set_qdata() interface is used now, we still need
// a table because we cannot assume that a function pointer fits into void*
// on any platform. Nevertheless, indexing a vector costs almost nothing
// compared to a map lookup.
typedef std::vector<Glib::WrapNewFunction> WrapFuncTable;
static WrapFuncTable* wrap_func_table = nullptr;
} // anonymous namespace
namespace Glib
{
void wrap_register_init()
{
// g_type_init() is deprecated as of 2.36.
// g_type_init();
if(!Glib::quark_)
{
Glib::quark_ = g_quark_from_static_string("glibmm__Glib::quark_");
Glib::quark_cpp_wrapper_deleted_ = g_quark_from_static_string("glibmm__Glib::quark_cpp_wrapper_deleted_");
}
if(!wrap_func_table)
{
// Make the first element a dummy so we can detect unregistered types.
// g_type_get_qdata() returns NULL if no data has been set up.
wrap_func_table = new WrapFuncTable(1);
}
}
void wrap_register_cleanup()
{
if(wrap_func_table)
{
delete wrap_func_table;
wrap_func_table = nullptr;
}
}
// Register the unique wrap_new() function of a new C++ wrapper type.
// The GType argument specifies the parent C type to wrap from.
//
void wrap_register(GType type, WrapNewFunction func)
{
//0 is not a valid GType.
//It would lead to a critical warning in g_type_set_qdata().
//We allow this, failing silently, to make life easier for gstreamermm.
if(type == 0)
return;
const guint idx = wrap_func_table->size();
wrap_func_table->push_back(func);
// Store the table index in the type's static data.
g_type_set_qdata(type, Glib::quark_, GUINT_TO_POINTER(idx));
}
static Glib::ObjectBase* wrap_create_new_wrapper(GObject* object)
{
g_return_val_if_fail(wrap_func_table != nullptr, 0);
const bool gtkmm_wrapper_already_deleted = (bool)g_object_get_qdata((GObject*)object, Glib::quark_cpp_wrapper_deleted_);
if(gtkmm_wrapper_already_deleted)
{
g_warning("Glib::wrap_create_new_wrapper: Attempted to create a 2nd C++ wrapper for a C instance whose C++ wrapper has been deleted.");
return 0;
}
// Traverse upwards through the inheritance hierarchy
// to find the most-specialized wrap_new() for this GType.
//
for(GType type = G_OBJECT_TYPE(object); type != 0; type = g_type_parent(type))
{
// Look up the wrap table index stored in the type's static data.
// If a wrap_new() has been registered for the type then call it.
//
if(const gpointer idx = g_type_get_qdata(type, Glib::quark_))
{
const Glib::WrapNewFunction func = (*wrap_func_table)[GPOINTER_TO_UINT(idx)];
return (*func)(object);
}
}
return 0;
}
static gboolean gtype_wraps_interface(GType implementer_type, GType interface_type)
{
guint n_ifaces = 0;
GType *ifaces = g_type_interfaces (implementer_type, &n_ifaces);
gboolean found = FALSE;
while (n_ifaces-- && !found)
{
found = (ifaces[n_ifaces] == interface_type);
}
g_free (ifaces);
return found;
}
Glib::ObjectBase* wrap_create_new_wrapper_for_interface(GObject* object, GType interface_gtype)
{
g_return_val_if_fail(wrap_func_table != nullptr, 0);
const bool gtkmm_wrapper_already_deleted = (bool)g_object_get_qdata((GObject*)object, Glib::quark_cpp_wrapper_deleted_);
if(gtkmm_wrapper_already_deleted)
{
g_warning("Glib::wrap_create_new_wrapper: Attempted to create a 2nd C++ wrapper for a C instance whose C++ wrapper has been deleted.");
return 0;
}
// Traverse upwards through the inheritance hierarchy
// to find the most-specialized wrap_new() for this GType.
//
for(GType type = G_OBJECT_TYPE(object); type != 0; type = g_type_parent(type))
{
// Look up the wrap table index stored in the type's static data.
// If a wrap_new() has been registered for the type then call it.
// But only if the type implements the interface,
// so that the C++ instance is likely to inherit from the appropriate class too.
//
const gpointer idx = g_type_get_qdata(type, Glib::quark_);
if(idx && gtype_wraps_interface(type, interface_gtype))
{
const Glib::WrapNewFunction func = (*wrap_func_table)[GPOINTER_TO_UINT(idx)];
return (*func)(object);
}
}
return 0;
}
// This is a factory function that converts any type to
// its C++ wrapper instance by looking up a wrap_new() function in a map.
//
ObjectBase* wrap_auto(GObject* object, bool take_copy)
{
if(!object)
return 0;
// Look up current C++ wrapper instance:
ObjectBase* pCppObject = ObjectBase::_get_current_wrapper(object);
if(!pCppObject)
{
// There's not already a wrapper: generate a new C++ instance.
pCppObject = wrap_create_new_wrapper(object);
if(!pCppObject)
{
g_warning("Failed to wrap object of type '%s'. Hint: this error is commonly caused by failing to call a library init() function.", G_OBJECT_TYPE_NAME(object));
return 0;
}
}
// take_copy=true is used where the GTK+ function doesn't do
// an extra ref for us, and always for plain struct members.
if(take_copy)
pCppObject->reference();
return pCppObject;
}
Glib::RefPtr<Object> wrap(GObject* object, bool take_copy /* = false */)
{
return Glib::RefPtr<Object>(dynamic_cast<Object*>(wrap_auto(object, take_copy)));
}
} /* namespace Glib */
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