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/* Copyright (C) 2014 The glibmm 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 <glibmm/binding.h>
#include <glib.h>
namespace
{
struct BindingTransformSlots
{
BindingTransformSlots(
const Glib::Binding::BindingTransformSlot& transform_to,
const Glib::Binding::BindingTransformSlot& transform_from)
:
from_source_to_target(transform_to), from_target_to_source(transform_from)
{}
Glib::Binding::BindingTransformSlot from_source_to_target;
Glib::Binding::BindingTransformSlot from_target_to_source;
};
gboolean Binding_transform_callback_common(GBinding* binding,
const GValue* from_value, GValue* to_value,
Glib::Binding::BindingTransformSlot& the_slot)
{
bool result = false;
try
{
Glib::RefPtr<Glib::Binding> cpp_binding = Glib::wrap(binding, true);
result = the_slot(cpp_binding, from_value, to_value);
}
catch (...)
{
Glib::exception_handlers_invoke();
}
return result;
}
gboolean Binding_transform_to_callback(GBinding* binding,
const GValue* from_value, GValue* to_value, gpointer user_data)
{
Glib::Binding::BindingTransformSlot& the_slot =
static_cast<BindingTransformSlots*>(user_data)->from_source_to_target;
return Binding_transform_callback_common(binding, from_value, to_value, the_slot);
}
gboolean Binding_transform_from_callback(GBinding* binding,
const GValue* from_value, GValue* to_value, gpointer user_data)
{
Glib::Binding::BindingTransformSlot& the_slot =
static_cast<BindingTransformSlots*>(user_data)->from_target_to_source;
return Binding_transform_callback_common(binding, from_value, to_value, the_slot);
}
void Binding_transform_callback_destroy(gpointer user_data)
{
delete static_cast<BindingTransformSlots*>(user_data);
}
} // anonymous namespace
namespace Glib
{
//static
Glib::RefPtr<Binding> Binding::bind_property_value(
const PropertyProxy_Base& source_property,
const PropertyProxy_Base& target_property,
BindingFlags flags,
const BindingTransformSlot& transform_to,
const BindingTransformSlot& transform_from)
{
GBinding* binding = 0;
if (transform_to.empty() && transform_from.empty())
{
// No user-supplied transformations.
binding = g_object_bind_property(
source_property.get_object()->gobj(), source_property.get_name(),
target_property.get_object()->gobj(), target_property.get_name(),
(GBindingFlags)flags);
}
else
{
// Create copies of the slots. A pointer to this will be passed
// through the callback's data parameter. It will be deleted
// when Binding_transform_callback_destroy() is called.
BindingTransformSlots* slots_copy = new BindingTransformSlots(transform_to, transform_from);
binding = g_object_bind_property_full(
source_property.get_object()->gobj(), source_property.get_name(),
target_property.get_object()->gobj(), target_property.get_name(),
(GBindingFlags)flags,
transform_to.empty() ? 0 : &Binding_transform_to_callback,
transform_from.empty() ? 0 : &Binding_transform_from_callback,
slots_copy, &Binding_transform_callback_destroy);
}
if (!binding)
return Glib::RefPtr<Binding>();
// Take an extra ref. GBinding uses one ref itself, and drops it if
// either the source object or the target object is finalized.
// The GBinding object must not be destroyed while there are RefPtrs around.
g_object_ref(binding);
return Glib::RefPtr<Binding>(new Binding(binding));
}
void Binding::unbind()
{
// Call g_binding_unbind() only once. It always calls g_object_unref().
if (g_binding_get_source(gobj()))
g_binding_unbind(gobj());
}
// Override unreference() from ObjectBase.
//
// Why is this necessary? Because GBinding is an unusual kind of GObject.
// It calls g_object_unref() itself, if either the source object or the
// target object is finalized, almost like g_binding_unbind().
// But the GBinding object shall be destroyed when and only when the last
// reference from a Glib::RefPtr is dropped.
void Binding::unreference() const
{
GBinding* const binding = const_cast<GBinding*>(gobj());
// If the last Glib::RefPtr is being deleted, and the binding has not been unbound,
// then drop the extra reference that was added by bind_property_value().
if (gobject_->ref_count == 2 && g_binding_get_source(binding))
g_object_unref(binding);
Object::unreference();
}
} // namespace Glib
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