Learning_GTK4_tree/gtk/gtksignallistitemfactory.c

284 lines
11 KiB
C

/*
* Copyright © 2019 Benjamin Otte
*
* 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/>.
*
* Authors: Benjamin Otte <otte@gnome.org>
*/
#include "config.h"
#include "gtksignallistitemfactory.h"
#include "gtklistitemfactoryprivate.h"
#include "gtklistitem.h"
#include "gtkprivate.h"
/**
* GtkSignalListItemFactory:
*
* `GtkSignalListItemFactory` is a `GtkListItemFactory` that emits signals
* to manage listitems.
*
* Signals are emitted for every listitem in the same order:
*
* 1. [signal@Gtk.SignalListItemFactory::setup] is emitted to set up permanent
* things on the listitem. This usually means constructing the widgets used in
* the row and adding them to the listitem.
*
* 2. [signal@Gtk.SignalListItemFactory::bind] is emitted to bind the item passed
* via [property@Gtk.ListItem:item] to the widgets that have been created in
* step 1 or to add item-specific widgets. Signals are connected to listen to
* changes - both to changes in the item to update the widgets or to changes
* in the widgets to update the item. After this signal has been called, the
* listitem may be shown in a list widget.
*
* 3. [signal@Gtk.SignalListItemFactory::unbind] is emitted to undo everything
* done in step 2. Usually this means disconnecting signal handlers. Once this
* signal has been called, the listitem will no longer be used in a list
* widget.
*
* 4. [signal@Gtk.SignalListItemFactory::bind] and
* [signal@Gtk.SignalListItemFactory::unbind] may be emitted multiple times
* again to bind the listitem for use with new items. By reusing listitems,
* potentially costly setup can be avoided. However, it means code needs to
* make sure to properly clean up the listitem in step 3 so that no information
* from the previous use leaks into the next use.
*
* 5. [signal@Gtk.SignalListItemFactory::teardown] is emitted to allow undoing
* the effects of [signal@Gtk.SignalListItemFactory::setup]. After this signal
* was emitted on a listitem, the listitem will be destroyed and not be used again.
*
* Note that during the signal emissions, changing properties on the
* listitems passed will not trigger notify signals as the listitem's
* notifications are frozen. See g_object_freeze_notify() for details.
*
* For tracking changes in other properties in the listitem, the
* ::notify signal is recommended. The signal can be connected in the
* [signal@Gtk.SignalListItemFactory::setup] signal and removed again during
* [signal@Gtk.SignalListItemFactory::teardown].
*/
struct _GtkSignalListItemFactory
{
GtkListItemFactory parent_instance;
};
struct _GtkSignalListItemFactoryClass
{
GtkListItemFactoryClass parent_class;
void (* setup) (GtkSignalListItemFactory *self,
GObject *list_item);
void (* teardown) (GtkSignalListItemFactory *self,
GObject *list_item);
void (* bind) (GtkSignalListItemFactory *self,
GObject *list_item);
void (* unbind) (GtkSignalListItemFactory *self,
GObject *list_item);
};
enum {
SETUP,
BIND,
UNBIND,
TEARDOWN,
LAST_SIGNAL
};
G_DEFINE_TYPE (GtkSignalListItemFactory, gtk_signal_list_item_factory, GTK_TYPE_LIST_ITEM_FACTORY)
static guint signals[LAST_SIGNAL] = { 0 };
static void
gtk_signal_list_item_factory_setup (GtkListItemFactory *factory,
GObject *item,
gboolean bind,
GFunc func,
gpointer data)
{
g_signal_emit (factory, signals[SETUP], 0, item);
GTK_LIST_ITEM_FACTORY_CLASS (gtk_signal_list_item_factory_parent_class)->setup (factory, item, bind, func, data);
if (bind)
g_signal_emit (factory, signals[BIND], 0, item);
}
static void
gtk_signal_list_item_factory_update (GtkListItemFactory *factory,
GObject *item,
gboolean unbind,
gboolean bind,
GFunc func,
gpointer data)
{
if (unbind)
g_signal_emit (factory, signals[UNBIND], 0, item);
GTK_LIST_ITEM_FACTORY_CLASS (gtk_signal_list_item_factory_parent_class)->update (factory, item, unbind, bind, func, data);
if (bind)
g_signal_emit (factory, signals[BIND], 0, item);
}
static void
gtk_signal_list_item_factory_teardown (GtkListItemFactory *factory,
GObject *item,
gboolean unbind,
GFunc func,
gpointer data)
{
if (unbind)
g_signal_emit (factory, signals[UNBIND], 0, item);
GTK_LIST_ITEM_FACTORY_CLASS (gtk_signal_list_item_factory_parent_class)->teardown (factory, item, unbind, func, data);
g_signal_emit (factory, signals[TEARDOWN], 0, item);
}
static void
gtk_signal_list_item_factory_class_init (GtkSignalListItemFactoryClass *klass)
{
GtkListItemFactoryClass *factory_class = GTK_LIST_ITEM_FACTORY_CLASS (klass);
factory_class->setup = gtk_signal_list_item_factory_setup;
factory_class->teardown = gtk_signal_list_item_factory_teardown;
factory_class->update = gtk_signal_list_item_factory_update;
/**
* GtkSignalListItemFactory::setup:
* @self: The `GtkSignalListItemFactory`
* @object: The `GObject` to set up
*
* Emitted when a new listitem has been created and needs to be setup for use.
*
* It is the first signal emitted for every listitem.
*
* The [signal@Gtk.SignalListItemFactory::teardown] signal is the opposite
* of this signal and can be used to undo everything done in this signal.
*/
signals[SETUP] =
g_signal_new (I_("setup"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (GtkSignalListItemFactoryClass, setup),
NULL, NULL,
g_cclosure_marshal_VOID__OBJECT,
G_TYPE_NONE, 1,
G_TYPE_OBJECT);
g_signal_set_va_marshaller (signals[SETUP],
G_TYPE_FROM_CLASS (klass),
g_cclosure_marshal_VOID__OBJECTv);
/**
* GtkSignalListItemFactory::bind:
* @self: The `GtkSignalListItemFactory`
* @object: The `GObject` to bind
*
* Emitted when an object has been bound, for example when a
* new [property@Gtk.ListItem:item] has been set on a
* listitem and should be bound for use.
*
* After this signal was emitted, the object might be shown in
* a [class@Gtk.ListView] or other widget.
*
* The [signal@Gtk.SignalListItemFactory::unbind] signal is the
* opposite of this signal and can be used to undo everything done
* in this signal.
*/
signals[BIND] =
g_signal_new (I_("bind"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (GtkSignalListItemFactoryClass, bind),
NULL, NULL,
g_cclosure_marshal_VOID__OBJECT,
G_TYPE_NONE, 1,
G_TYPE_OBJECT);
g_signal_set_va_marshaller (signals[BIND],
G_TYPE_FROM_CLASS (klass),
g_cclosure_marshal_VOID__OBJECTv);
/**
* GtkSignalListItemFactory::unbind:
* @self: The `GtkSignalListItemFactory`
* @object: The `GObject` to unbind
*
* Emitted when an object has been unbound from its item, for example when
* a listitem was removed from use in a list widget
* and its [property@Gtk.ListItem:item] is about to be unset.
*
* This signal is the opposite of the [signal@Gtk.SignalListItemFactory::bind]
* signal and should be used to undo everything done in that signal.
*/
signals[UNBIND] =
g_signal_new (I_("unbind"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (GtkSignalListItemFactoryClass, unbind),
NULL, NULL,
g_cclosure_marshal_VOID__OBJECT,
G_TYPE_NONE, 1,
G_TYPE_OBJECT);
g_signal_set_va_marshaller (signals[UNBIND],
G_TYPE_FROM_CLASS (klass),
g_cclosure_marshal_VOID__OBJECTv);
/**
* GtkSignalListItemFactory::teardown:
* @self: The `GtkSignalListItemFactory`
* @object: The `GObject` to tear down
*
* Emitted when an object is about to be destroyed.
*
* It is the last signal ever emitted for this @object.
*
* This signal is the opposite of the [signal@Gtk.SignalListItemFactory::setup]
* signal and should be used to undo everything done in that signal.
*/
signals[TEARDOWN] =
g_signal_new (I_("teardown"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (GtkSignalListItemFactoryClass, teardown),
NULL, NULL,
g_cclosure_marshal_VOID__OBJECT,
G_TYPE_NONE, 1,
G_TYPE_OBJECT);
g_signal_set_va_marshaller (signals[TEARDOWN],
G_TYPE_FROM_CLASS (klass),
g_cclosure_marshal_VOID__OBJECTv);
}
static void
gtk_signal_list_item_factory_init (GtkSignalListItemFactory *self)
{
}
/**
* gtk_signal_list_item_factory_new:
*
* Creates a new `GtkSignalListItemFactory`.
*
* You need to connect signal handlers before you use it.
*
* Returns: a new `GtkSignalListItemFactory`
**/
GtkListItemFactory *
gtk_signal_list_item_factory_new (void)
{
return g_object_new (GTK_TYPE_SIGNAL_LIST_ITEM_FACTORY, NULL);
}