gio/gpropertyaction.c - third_party/glib - Git at Google

 /*
  * Copyright © 2013 Canonical Limited
  *
  * 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: Ryan Lortie <desrt@desrt.ca>
  */

 #include "config.h"

 #include "gpropertyaction.h"

 #include "gsettings-mapping.h"
 #include "gaction.h"
 #include "glibintl.h"

 /**
  * SECTION:gpropertyaction
  * @title: GPropertyAction
  * @short_description: A GAction reflecting a GObject property
  * @include: gio/gio.h
  *
  * A #GPropertyAction is a way to get a #GAction with a state value
  * reflecting and controlling the value of a #GObject property.
  *
  * The state of the action will correspond to the value of the property.
  * Changing it will change the property (assuming the requested value
  * matches the requirements as specified in the #GParamSpec).
  *
  * Only the most common types are presently supported.  Booleans are
  * mapped to booleans, strings to strings, signed/unsigned integers to
  * int32/uint32 and floats and doubles to doubles.
  *
  * If the property is an enum then the state will be string-typed and
  * conversion will automatically be performed between the enum value and
  * "nick" string as per the #GEnumValue table.
  *
  * Flags types are not currently supported.
  *
  * Properties of object types, boxed types and pointer types are not
  * supported and probably never will be.
  *
  * Properties of #GVariant types are not currently supported.
  *
  * If the property is boolean-valued then the action will have a NULL
  * parameter type, and activating the action (with no parameter) will
  * toggle the value of the property.
  *
  * In all other cases, the parameter type will correspond to the type of
  * the property.
  *
  * The general idea here is to reduce the number of locations where a
  * particular piece of state is kept (and therefore has to be synchronised
  * between). #GPropertyAction does not have a separate state that is kept
  * in sync with the property value -- its state is the property value.
  *
  * For example, it might be useful to create a #GAction corresponding to
  * the "visible-child-name" property of a #GtkStack so that the current
  * page can be switched from a menu.  The active radio indication in the
  * menu is then directly determined from the active page of the
  * #GtkStack.
  *
  * An anti-example would be binding the "active-id" property on a
  * #GtkComboBox.  This is because the state of the combobox itself is
  * probably uninteresting and is actually being used to control
  * something else.
  *
  * Another anti-example would be to bind to the "visible-child-name"
  * property of a #GtkStack if this value is actually stored in
  * #GSettings.  In that case, the real source of the value is
  * #GSettings.  If you want a #GAction to control a setting stored in
  * #GSettings, see g_settings_create_action() instead, and possibly
  * combine its use with g_settings_bind().
  *
  * Since: 2.38
  **/
 struct _GPropertyAction
 {
   GObject     parent_instance;

   gchar              *name;
   gpointer            object;
   GParamSpec         *pspec;
   const GVariantType *state_type;
   gboolean            invert_boolean;
 };

 /**
  * GPropertyAction:
  *
  * This type is opaque.
  *
  * Since: 2.38
  **/

 typedef GObjectClass GPropertyActionClass;

 static void g_property_action_iface_init (GActionInterface *iface);
 G_DEFINE_TYPE_WITH_CODE (GPropertyAction, g_property_action, G_TYPE_OBJECT,
   G_IMPLEMENT_INTERFACE (G_TYPE_ACTION, g_property_action_iface_init))

 enum
 {
   PROP_NONE,
   PROP_NAME,
   PROP_PARAMETER_TYPE,
   PROP_ENABLED,
   PROP_STATE_TYPE,
   PROP_STATE,
   PROP_OBJECT,
   PROP_PROPERTY_NAME,
   PROP_INVERT_BOOLEAN
 };

 static gboolean
 g_property_action_get_invert_boolean (GAction *action)
 {
   GPropertyAction *paction = G_PROPERTY_ACTION (action);

   return paction->invert_boolean;
 }

 static const gchar *
 g_property_action_get_name (GAction *action)
 {
   GPropertyAction *paction = G_PROPERTY_ACTION (action);

   return paction->name;
 }

 static const GVariantType *
 g_property_action_get_parameter_type (GAction *action)
 {
   GPropertyAction *paction = G_PROPERTY_ACTION (action);

   return paction->pspec->value_type == G_TYPE_BOOLEAN ? NULL : paction->state_type;
 }

 static const GVariantType *
 g_property_action_get_state_type (GAction *action)
 {
   GPropertyAction *paction = G_PROPERTY_ACTION (action);

   return paction->state_type;
 }

 static GVariant *
 g_property_action_get_state_hint (GAction *action)
 {
   return NULL;
 }

 static gboolean
 g_property_action_get_enabled (GAction *action)
 {
   return TRUE;
 }

 static void
 g_property_action_set_state (GPropertyAction *paction,
                              GVariant        *variant)
 {
   GValue value = G_VALUE_INIT;

   g_value_init (&value, paction->pspec->value_type);
   g_settings_get_mapping (&value, variant, NULL);

   if (paction->pspec->value_type == G_TYPE_BOOLEAN && paction->invert_boolean)
     g_value_set_boolean (&value, !g_value_get_boolean (&value));

   g_object_set_property (paction->object, paction->pspec->name, &value);
   g_value_unset (&value);
 }

 static void
 g_property_action_change_state (GAction  *action,
                                 GVariant *value)
 {
   GPropertyAction *paction = G_PROPERTY_ACTION (action);

   g_return_if_fail (g_variant_is_of_type (value, paction->state_type));

   g_property_action_set_state (paction, value);
 }

 static GVariant *
 g_property_action_get_state (GAction *action)
 {
   GPropertyAction *paction = G_PROPERTY_ACTION (action);
   GValue value = G_VALUE_INIT;
   GVariant *result;

   g_value_init (&value, paction->pspec->value_type);
   g_object_get_property (paction->object, paction->pspec->name, &value);

   if (paction->pspec->value_type == G_TYPE_BOOLEAN && paction->invert_boolean)
     g_value_set_boolean (&value, !g_value_get_boolean (&value));

   result = g_settings_set_mapping (&value, paction->state_type, NULL);
   g_value_unset (&value);

   return g_variant_ref_sink (result);
 }

 static void
 g_property_action_activate (GAction  *action,
                             GVariant *parameter)
 {
   GPropertyAction *paction = G_PROPERTY_ACTION (action);

   if (paction->pspec->value_type == G_TYPE_BOOLEAN)
     {
       gboolean value;

       g_return_if_fail (paction->pspec->value_type == G_TYPE_BOOLEAN && parameter == NULL);

       g_object_get (paction->object, paction->pspec->name, &value, NULL);
       value = !value;
       g_object_set (paction->object, paction->pspec->name, value, NULL);
     }
   else
     {
       g_return_if_fail (parameter != NULL && g_variant_is_of_type (parameter, paction->state_type));

       g_property_action_set_state (paction, parameter);
     }
 }

 static const GVariantType *
 g_property_action_determine_type (GParamSpec *pspec)
 {
   if (G_TYPE_IS_ENUM (pspec->value_type))
     return G_VARIANT_TYPE_STRING;

   switch (pspec->value_type)
     {
     case G_TYPE_BOOLEAN:
       return G_VARIANT_TYPE_BOOLEAN;

     case G_TYPE_INT:
       return G_VARIANT_TYPE_INT32;

     case G_TYPE_UINT:
       return G_VARIANT_TYPE_UINT32;

     case G_TYPE_DOUBLE:
     case G_TYPE_FLOAT:
       return G_VARIANT_TYPE_DOUBLE;

     case G_TYPE_STRING:
       return G_VARIANT_TYPE_STRING;

     default:
       g_critical ("Unable to use GPropertyAction with property '%s::%s' of type '%s'",
                   g_type_name (pspec->owner_type), pspec->name, g_type_name (pspec->value_type));
       return NULL;
     }
 }

 static void
 g_property_action_notify (GObject    *object,
                           GParamSpec *pspec,
                           gpointer    user_data)
 {
   GPropertyAction *paction = user_data;

   g_assert (object == paction->object);
   g_assert (pspec == paction->pspec);

   g_object_notify (G_OBJECT (paction), "state");
 }

 static void
 g_property_action_set_property_name (GPropertyAction *paction,
                                      const gchar     *property_name)
 {
   GParamSpec *pspec;
   gchar *detailed;

   pspec = g_object_class_find_property (G_OBJECT_GET_CLASS (paction->object), property_name);

   if (pspec == NULL)
     {
       g_critical ("Attempted to use non-existent property '%s::%s' for GPropertyAction",
                   G_OBJECT_TYPE_NAME (paction->object), property_name);
       return;
     }

   if (~pspec->flags & G_PARAM_READABLE || ~pspec->flags & G_PARAM_WRITABLE || pspec->flags & G_PARAM_CONSTRUCT_ONLY)
     {
       g_critical ("Property '%s::%s' used with GPropertyAction must be readable, writable, and not construct-only",
                   G_OBJECT_TYPE_NAME (paction->object), property_name);
       return;
     }

   paction->pspec = pspec;

   detailed = g_strconcat ("notify::", paction->pspec->name, NULL);
   paction->state_type = g_property_action_determine_type (paction->pspec);
   g_signal_connect (paction->object, detailed, G_CALLBACK (g_property_action_notify), paction);
   g_free (detailed);
 }

 static void
 g_property_action_set_property (GObject      *object,
                                 guint         prop_id,
                                 const GValue *value,
                                 GParamSpec   *pspec)
 {
   GPropertyAction *paction = G_PROPERTY_ACTION (object);

   switch (prop_id)
     {
     case PROP_NAME:
       paction->name = g_value_dup_string (value);
       break;

     case PROP_OBJECT:
       paction->object = g_value_dup_object (value);
       break;

     case PROP_PROPERTY_NAME:
       g_property_action_set_property_name (paction, g_value_get_string (value));
       break;

     case PROP_INVERT_BOOLEAN:
       paction->invert_boolean = g_value_get_boolean (value);
       break;

     default:
       g_assert_not_reached ();
     }
 }

 static void
 g_property_action_get_property (GObject    *object,
                                 guint       prop_id,
                                 GValue     *value,
                                 GParamSpec *pspec)
 {
   GAction *action = G_ACTION (object);

   switch (prop_id)
     {
     case PROP_NAME:
       g_value_set_string (value, g_property_action_get_name (action));
       break;

     case PROP_PARAMETER_TYPE:
       g_value_set_boxed (value, g_property_action_get_parameter_type (action));
       break;

     case PROP_ENABLED:
       g_value_set_boolean (value, g_property_action_get_enabled (action));
       break;

     case PROP_STATE_TYPE:
       g_value_set_boxed (value, g_property_action_get_state_type (action));
       break;

     case PROP_STATE:
       g_value_take_variant (value, g_property_action_get_state (action));
       break;

     case PROP_INVERT_BOOLEAN:
       g_value_set_boolean (value, g_property_action_get_invert_boolean (action));
       break;

     default:
       g_assert_not_reached ();
     }
 }

 static void
 g_property_action_finalize (GObject *object)
 {
   GPropertyAction *paction = G_PROPERTY_ACTION (object);

   g_signal_handlers_disconnect_by_func (paction->object, g_property_action_notify, paction);
   g_object_unref (paction->object);
   g_free (paction->name);

   G_OBJECT_CLASS (g_property_action_parent_class)
     ->finalize (object);
 }

 void
 g_property_action_init (GPropertyAction *property)
 {
 }

 void
 g_property_action_iface_init (GActionInterface *iface)
 {
   iface->get_name = g_property_action_get_name;
   iface->get_parameter_type = g_property_action_get_parameter_type;
   iface->get_state_type = g_property_action_get_state_type;
   iface->get_state_hint = g_property_action_get_state_hint;
   iface->get_enabled = g_property_action_get_enabled;
   iface->get_state = g_property_action_get_state;
   iface->change_state = g_property_action_change_state;
   iface->activate = g_property_action_activate;
 }

 void
 g_property_action_class_init (GPropertyActionClass *class)
 {
   GObjectClass *object_class = G_OBJECT_CLASS (class);

   object_class->set_property = g_property_action_set_property;
   object_class->get_property = g_property_action_get_property;
   object_class->finalize = g_property_action_finalize;

   /**
    * GPropertyAction:name:
    *
    * The name of the action.  This is mostly meaningful for identifying
    * the action once it has been added to a #GActionMap.
    *
    * Since: 2.38
    **/
   g_object_class_install_property (object_class, PROP_NAME,
                                    g_param_spec_string ("name",
                                                         P_("Action Name"),
                                                         P_("The name used to invoke the action"),
                                                         NULL,
                                                         G_PARAM_READWRITE |
                                                         G_PARAM_CONSTRUCT_ONLY |
                                                         G_PARAM_STATIC_STRINGS));

   /**
    * GPropertyAction:parameter-type:
    *
    * The type of the parameter that must be given when activating the
    * action.
    *
    * Since: 2.38
    **/
   g_object_class_install_property (object_class, PROP_PARAMETER_TYPE,
                                    g_param_spec_boxed ("parameter-type",
                                                        P_("Parameter Type"),
                                                        P_("The type of GVariant passed to activate()"),
                                                        G_TYPE_VARIANT_TYPE,
                                                        G_PARAM_READABLE |
                                                        G_PARAM_STATIC_STRINGS));

   /**
    * GPropertyAction:enabled:
    *
    * If @action is currently enabled.
    *
    * If the action is disabled then calls to g_action_activate() and
    * g_action_change_state() have no effect.
    *
    * Since: 2.38
    **/
   g_object_class_install_property (object_class, PROP_ENABLED,
                                    g_param_spec_boolean ("enabled",
                                                          P_("Enabled"),
                                                          P_("If the action can be activated"),
                                                          TRUE,
                                                          G_PARAM_READABLE |
                                                          G_PARAM_STATIC_STRINGS));

   /**
    * GPropertyAction:state-type:
    *
    * The #GVariantType of the state that the action has, or %NULL if the
    * action is stateless.
    *
    * Since: 2.38
    **/
   g_object_class_install_property (object_class, PROP_STATE_TYPE,
                                    g_param_spec_boxed ("state-type",
                                                        P_("State Type"),
                                                        P_("The type of the state kept by the action"),
                                                        G_TYPE_VARIANT_TYPE,
                                                        G_PARAM_READABLE |
                                                        G_PARAM_STATIC_STRINGS));

   /**
    * GPropertyAction:state:
    *
    * The state of the action, or %NULL if the action is stateless.
    *
    * Since: 2.38
    **/
   g_object_class_install_property (object_class, PROP_STATE,
                                    g_param_spec_variant ("state",
                                                          P_("State"),
                                                          P_("The state the action is in"),
                                                          G_VARIANT_TYPE_ANY,
                                                          NULL,
                                                          G_PARAM_READABLE |
                                                          G_PARAM_STATIC_STRINGS));

   /**
    * GPropertyAction:object:
    *
    * The object to wrap a property on.
    *
    * The object must be a non-%NULL #GObject with properties.
    *
    * Since: 2.38
    **/
   g_object_class_install_property (object_class, PROP_OBJECT,
                                    g_param_spec_object ("object",
                                                         P_("Object"),
                                                         P_("The object with the property to wrap"),
                                                         G_TYPE_OBJECT,
                                                         G_PARAM_WRITABLE |
                                                         G_PARAM_CONSTRUCT_ONLY |
                                                         G_PARAM_STATIC_STRINGS));

   /**
    * GPropertyAction:property-name:
    *
    * The name of the property to wrap on the object.
    *
    * The property must exist on the passed-in object and it must be
    * readable and writable (and not construct-only).
    *
    * Since: 2.38
    **/
   g_object_class_install_property (object_class, PROP_PROPERTY_NAME,
                                    g_param_spec_string ("property-name",
                                                         P_("Property name"),
                                                         P_("The name of the property to wrap"),
                                                         NULL,
                                                         G_PARAM_WRITABLE |
                                                         G_PARAM_CONSTRUCT_ONLY |
                                                         G_PARAM_STATIC_STRINGS));

   /**
    * GPropertyAction:invert-boolean:
    *
    * If %TRUE, the state of the action will be the negation of the
    * property value, provided the property is boolean.
    *
    * Since: 2.46
    */
   g_object_class_install_property (object_class, PROP_INVERT_BOOLEAN,
                                    g_param_spec_boolean ("invert-boolean",
                                                          P_("Invert boolean"),
                                                          P_("Whether to invert the value of a boolean property"),
                                                          FALSE,
                                                          G_PARAM_READWRITE |
                                                          G_PARAM_CONSTRUCT_ONLY |
                                                          G_PARAM_STATIC_STRINGS));
 }

 /**
  * g_property_action_new:
  * @name: the name of the action to create
  * @object: (type GObject.Object): the object that has the property
  *   to wrap
  * @property_name: the name of the property
  *
  * Creates a #GAction corresponding to the value of property
  * @property_name on @object.
  *
  * The property must be existent and readable and writable (and not
  * construct-only).
  *
  * This function takes a reference on @object and doesn't release it
  * until the action is destroyed.
  *
  * Returns: a new #GPropertyAction
  *
  * Since: 2.38
  **/
 GPropertyAction *
 g_property_action_new (const gchar *name,
                        gpointer     object,
                        const gchar *property_name)
 {
   g_return_val_if_fail (name != NULL, NULL);
   g_return_val_if_fail (G_IS_OBJECT (object), NULL);
   g_return_val_if_fail (property_name != NULL, NULL);

   return g_object_new (G_TYPE_PROPERTY_ACTION,
                        "name", name,
                        "object", object,
                        "property-name", property_name,
                        NULL);
 }
	/*
	* Copyright © 2013 Canonical Limited
	*
	* 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: Ryan Lortie <desrt@desrt.ca>
	*/

	#include "config.h"

	#include "gpropertyaction.h"

	#include "gsettings-mapping.h"
	#include "gaction.h"
	#include "glibintl.h"

	/**
	* SECTION:gpropertyaction
	* @title: GPropertyAction
	* @short_description: A GAction reflecting a GObject property
	* @include: gio/gio.h
	*
	* A #GPropertyAction is a way to get a #GAction with a state value
	* reflecting and controlling the value of a #GObject property.
	*
	* The state of the action will correspond to the value of the property.
	* Changing it will change the property (assuming the requested value
	* matches the requirements as specified in the #GParamSpec).
	*
	* Only the most common types are presently supported. Booleans are
	* mapped to booleans, strings to strings, signed/unsigned integers to
	* int32/uint32 and floats and doubles to doubles.
	*
	* If the property is an enum then the state will be string-typed and
	* conversion will automatically be performed between the enum value and
	* "nick" string as per the #GEnumValue table.
	*
	* Flags types are not currently supported.
	*
	* Properties of object types, boxed types and pointer types are not
	* supported and probably never will be.
	*
	* Properties of #GVariant types are not currently supported.
	*
	* If the property is boolean-valued then the action will have a NULL
	* parameter type, and activating the action (with no parameter) will
	* toggle the value of the property.
	*
	* In all other cases, the parameter type will correspond to the type of
	* the property.
	*
	* The general idea here is to reduce the number of locations where a
	* particular piece of state is kept (and therefore has to be synchronised
	* between). #GPropertyAction does not have a separate state that is kept
	* in sync with the property value -- its state is the property value.
	*
	* For example, it might be useful to create a #GAction corresponding to
	* the "visible-child-name" property of a #GtkStack so that the current
	* page can be switched from a menu. The active radio indication in the
	* menu is then directly determined from the active page of the
	* #GtkStack.
	*
	* An anti-example would be binding the "active-id" property on a
	* #GtkComboBox. This is because the state of the combobox itself is
	* probably uninteresting and is actually being used to control
	* something else.
	*
	* Another anti-example would be to bind to the "visible-child-name"
	* property of a #GtkStack if this value is actually stored in
	* #GSettings. In that case, the real source of the value is
	* #GSettings. If you want a #GAction to control a setting stored in
	* #GSettings, see g_settings_create_action() instead, and possibly
	* combine its use with g_settings_bind().
	*
	* Since: 2.38
	**/
	struct _GPropertyAction
	{
	GObject parent_instance;

	gchar *name;
	gpointer object;
	GParamSpec *pspec;
	const GVariantType *state_type;
	gboolean invert_boolean;
	};

	/**
	* GPropertyAction:
	*
	* This type is opaque.
	*
	* Since: 2.38
	**/

	typedef GObjectClass GPropertyActionClass;

	static void g_property_action_iface_init (GActionInterface *iface);
	G_DEFINE_TYPE_WITH_CODE (GPropertyAction, g_property_action, G_TYPE_OBJECT,
	G_IMPLEMENT_INTERFACE (G_TYPE_ACTION, g_property_action_iface_init))

	enum
	{
	PROP_NONE,
	PROP_NAME,
	PROP_PARAMETER_TYPE,
	PROP_ENABLED,
	PROP_STATE_TYPE,
	PROP_STATE,
	PROP_OBJECT,
	PROP_PROPERTY_NAME,
	PROP_INVERT_BOOLEAN
	};

	static gboolean
	g_property_action_get_invert_boolean (GAction *action)
	{
	GPropertyAction *paction = G_PROPERTY_ACTION (action);

	return paction->invert_boolean;
	}

	static const gchar *
	g_property_action_get_name (GAction *action)
	{
	GPropertyAction *paction = G_PROPERTY_ACTION (action);

	return paction->name;
	}

	static const GVariantType *
	g_property_action_get_parameter_type (GAction *action)
	{
	GPropertyAction *paction = G_PROPERTY_ACTION (action);

	return paction->pspec->value_type == G_TYPE_BOOLEAN ? NULL : paction->state_type;
	}

	static const GVariantType *
	g_property_action_get_state_type (GAction *action)
	{
	GPropertyAction *paction = G_PROPERTY_ACTION (action);

	return paction->state_type;
	}

	static GVariant *
	g_property_action_get_state_hint (GAction *action)
	{
	return NULL;
	}

	static gboolean
	g_property_action_get_enabled (GAction *action)
	{
	return TRUE;
	}

	static void
	g_property_action_set_state (GPropertyAction *paction,
	GVariant *variant)
	{
	GValue value = G_VALUE_INIT;

	g_value_init (&value, paction->pspec->value_type);
	g_settings_get_mapping (&value, variant, NULL);

	if (paction->pspec->value_type == G_TYPE_BOOLEAN && paction->invert_boolean)
	g_value_set_boolean (&value, !g_value_get_boolean (&value));

	g_object_set_property (paction->object, paction->pspec->name, &value);
	g_value_unset (&value);
	}

	static void
	g_property_action_change_state (GAction *action,
	GVariant *value)
	{
	GPropertyAction *paction = G_PROPERTY_ACTION (action);

	g_return_if_fail (g_variant_is_of_type (value, paction->state_type));

	g_property_action_set_state (paction, value);
	}

	static GVariant *
	g_property_action_get_state (GAction *action)
	{
	GPropertyAction *paction = G_PROPERTY_ACTION (action);
	GValue value = G_VALUE_INIT;
	GVariant *result;

	g_value_init (&value, paction->pspec->value_type);
	g_object_get_property (paction->object, paction->pspec->name, &value);

	if (paction->pspec->value_type == G_TYPE_BOOLEAN && paction->invert_boolean)
	g_value_set_boolean (&value, !g_value_get_boolean (&value));

	result = g_settings_set_mapping (&value, paction->state_type, NULL);
	g_value_unset (&value);

	return g_variant_ref_sink (result);
	}

	static void
	g_property_action_activate (GAction *action,
	GVariant *parameter)
	{
	GPropertyAction *paction = G_PROPERTY_ACTION (action);

	if (paction->pspec->value_type == G_TYPE_BOOLEAN)
	{
	gboolean value;

	g_return_if_fail (paction->pspec->value_type == G_TYPE_BOOLEAN && parameter == NULL);

	g_object_get (paction->object, paction->pspec->name, &value, NULL);
	value = !value;
	g_object_set (paction->object, paction->pspec->name, value, NULL);
	}
	else
	{
	g_return_if_fail (parameter != NULL && g_variant_is_of_type (parameter, paction->state_type));

	g_property_action_set_state (paction, parameter);
	}
	}

	static const GVariantType *
	g_property_action_determine_type (GParamSpec *pspec)
	{
	if (G_TYPE_IS_ENUM (pspec->value_type))
	return G_VARIANT_TYPE_STRING;

	switch (pspec->value_type)
	{
	case G_TYPE_BOOLEAN:
	return G_VARIANT_TYPE_BOOLEAN;

	case G_TYPE_INT:
	return G_VARIANT_TYPE_INT32;

	case G_TYPE_UINT:
	return G_VARIANT_TYPE_UINT32;

	case G_TYPE_DOUBLE:
	case G_TYPE_FLOAT:
	return G_VARIANT_TYPE_DOUBLE;

	case G_TYPE_STRING:
	return G_VARIANT_TYPE_STRING;

	default:
	g_critical ("Unable to use GPropertyAction with property '%s::%s' of type '%s'",
	g_type_name (pspec->owner_type), pspec->name, g_type_name (pspec->value_type));
	return NULL;
	}
	}

	static void
	g_property_action_notify (GObject *object,
	GParamSpec *pspec,
	gpointer user_data)
	{
	GPropertyAction *paction = user_data;

	g_assert (object == paction->object);
	g_assert (pspec == paction->pspec);

	g_object_notify (G_OBJECT (paction), "state");
	}

	static void
	g_property_action_set_property_name (GPropertyAction *paction,
	const gchar *property_name)
	{
	GParamSpec *pspec;
	gchar *detailed;

	pspec = g_object_class_find_property (G_OBJECT_GET_CLASS (paction->object), property_name);

	if (pspec == NULL)
	{
	g_critical ("Attempted to use non-existent property '%s::%s' for GPropertyAction",
	G_OBJECT_TYPE_NAME (paction->object), property_name);
	return;
	}

	if (~pspec->flags & G_PARAM_READABLE \|\| ~pspec->flags & G_PARAM_WRITABLE \|\| pspec->flags & G_PARAM_CONSTRUCT_ONLY)
	{
	g_critical ("Property '%s::%s' used with GPropertyAction must be readable, writable, and not construct-only",
	G_OBJECT_TYPE_NAME (paction->object), property_name);
	return;
	}

	paction->pspec = pspec;

	detailed = g_strconcat ("notify::", paction->pspec->name, NULL);
	paction->state_type = g_property_action_determine_type (paction->pspec);
	g_signal_connect (paction->object, detailed, G_CALLBACK (g_property_action_notify), paction);
	g_free (detailed);
	}

	static void
	g_property_action_set_property (GObject *object,
	guint prop_id,
	const GValue *value,
	GParamSpec *pspec)
	{
	GPropertyAction *paction = G_PROPERTY_ACTION (object);

	switch (prop_id)
	{
	case PROP_NAME:
	paction->name = g_value_dup_string (value);
	break;

	case PROP_OBJECT:
	paction->object = g_value_dup_object (value);
	break;

	case PROP_PROPERTY_NAME:
	g_property_action_set_property_name (paction, g_value_get_string (value));
	break;

	case PROP_INVERT_BOOLEAN:
	paction->invert_boolean = g_value_get_boolean (value);
	break;

	default:
	g_assert_not_reached ();
	}
	}

	static void
	g_property_action_get_property (GObject *object,
	guint prop_id,
	GValue *value,
	GParamSpec *pspec)
	{
	GAction *action = G_ACTION (object);

	switch (prop_id)
	{
	case PROP_NAME:
	g_value_set_string (value, g_property_action_get_name (action));
	break;

	case PROP_PARAMETER_TYPE:
	g_value_set_boxed (value, g_property_action_get_parameter_type (action));
	break;

	case PROP_ENABLED:
	g_value_set_boolean (value, g_property_action_get_enabled (action));
	break;

	case PROP_STATE_TYPE:
	g_value_set_boxed (value, g_property_action_get_state_type (action));
	break;

	case PROP_STATE:
	g_value_take_variant (value, g_property_action_get_state (action));
	break;

	case PROP_INVERT_BOOLEAN:
	g_value_set_boolean (value, g_property_action_get_invert_boolean (action));
	break;

	default:
	g_assert_not_reached ();
	}
	}

	static void
	g_property_action_finalize (GObject *object)
	{
	GPropertyAction *paction = G_PROPERTY_ACTION (object);

	g_signal_handlers_disconnect_by_func (paction->object, g_property_action_notify, paction);
	g_object_unref (paction->object);
	g_free (paction->name);

	G_OBJECT_CLASS (g_property_action_parent_class)
	->finalize (object);
	}

	void
	g_property_action_init (GPropertyAction *property)
	{
	}

	void
	g_property_action_iface_init (GActionInterface *iface)
	{
	iface->get_name = g_property_action_get_name;
	iface->get_parameter_type = g_property_action_get_parameter_type;
	iface->get_state_type = g_property_action_get_state_type;
	iface->get_state_hint = g_property_action_get_state_hint;
	iface->get_enabled = g_property_action_get_enabled;
	iface->get_state = g_property_action_get_state;
	iface->change_state = g_property_action_change_state;
	iface->activate = g_property_action_activate;
	}

	void
	g_property_action_class_init (GPropertyActionClass *class)
	{
	GObjectClass *object_class = G_OBJECT_CLASS (class);

	object_class->set_property = g_property_action_set_property;
	object_class->get_property = g_property_action_get_property;
	object_class->finalize = g_property_action_finalize;

	/**
	* GPropertyAction:name:
	*
	* The name of the action. This is mostly meaningful for identifying
	* the action once it has been added to a #GActionMap.
	*
	* Since: 2.38
	**/
	g_object_class_install_property (object_class, PROP_NAME,
	g_param_spec_string ("name",
	P_("Action Name"),
	P_("The name used to invoke the action"),
	NULL,
	G_PARAM_READWRITE \|
	G_PARAM_CONSTRUCT_ONLY \|
	G_PARAM_STATIC_STRINGS));

	/**
	* GPropertyAction:parameter-type:
	*
	* The type of the parameter that must be given when activating the
	* action.
	*
	* Since: 2.38
	**/
	g_object_class_install_property (object_class, PROP_PARAMETER_TYPE,
	g_param_spec_boxed ("parameter-type",
	P_("Parameter Type"),
	P_("The type of GVariant passed to activate()"),
	G_TYPE_VARIANT_TYPE,
	G_PARAM_READABLE \|
	G_PARAM_STATIC_STRINGS));

	/**
	* GPropertyAction:enabled:
	*
	* If @action is currently enabled.
	*
	* If the action is disabled then calls to g_action_activate() and
	* g_action_change_state() have no effect.
	*
	* Since: 2.38
	**/
	g_object_class_install_property (object_class, PROP_ENABLED,
	g_param_spec_boolean ("enabled",
	P_("Enabled"),
	P_("If the action can be activated"),
	TRUE,
	G_PARAM_READABLE \|
	G_PARAM_STATIC_STRINGS));

	/**
	* GPropertyAction:state-type:
	*
	* The #GVariantType of the state that the action has, or %NULL if the
	* action is stateless.
	*
	* Since: 2.38
	**/
	g_object_class_install_property (object_class, PROP_STATE_TYPE,
	g_param_spec_boxed ("state-type",
	P_("State Type"),
	P_("The type of the state kept by the action"),
	G_TYPE_VARIANT_TYPE,
	G_PARAM_READABLE \|
	G_PARAM_STATIC_STRINGS));

	/**
	* GPropertyAction:state:
	*
	* The state of the action, or %NULL if the action is stateless.
	*
	* Since: 2.38
	**/
	g_object_class_install_property (object_class, PROP_STATE,
	g_param_spec_variant ("state",
	P_("State"),
	P_("The state the action is in"),
	G_VARIANT_TYPE_ANY,
	NULL,
	G_PARAM_READABLE \|
	G_PARAM_STATIC_STRINGS));

	/**
	* GPropertyAction:object:
	*
	* The object to wrap a property on.
	*
	* The object must be a non-%NULL #GObject with properties.
	*
	* Since: 2.38
	**/
	g_object_class_install_property (object_class, PROP_OBJECT,
	g_param_spec_object ("object",
	P_("Object"),
	P_("The object with the property to wrap"),
	G_TYPE_OBJECT,
	G_PARAM_WRITABLE \|
	G_PARAM_CONSTRUCT_ONLY \|
	G_PARAM_STATIC_STRINGS));

	/**
	* GPropertyAction:property-name:
	*
	* The name of the property to wrap on the object.
	*
	* The property must exist on the passed-in object and it must be
	* readable and writable (and not construct-only).
	*
	* Since: 2.38
	**/
	g_object_class_install_property (object_class, PROP_PROPERTY_NAME,
	g_param_spec_string ("property-name",
	P_("Property name"),
	P_("The name of the property to wrap"),
	NULL,
	G_PARAM_WRITABLE \|
	G_PARAM_CONSTRUCT_ONLY \|
	G_PARAM_STATIC_STRINGS));

	/**
	* GPropertyAction:invert-boolean:
	*
	* If %TRUE, the state of the action will be the negation of the
	* property value, provided the property is boolean.
	*
	* Since: 2.46
	*/
	g_object_class_install_property (object_class, PROP_INVERT_BOOLEAN,
	g_param_spec_boolean ("invert-boolean",
	P_("Invert boolean"),
	P_("Whether to invert the value of a boolean property"),
	FALSE,
	G_PARAM_READWRITE \|
	G_PARAM_CONSTRUCT_ONLY \|
	G_PARAM_STATIC_STRINGS));
	}

	/**
	* g_property_action_new:
	* @name: the name of the action to create
	* @object: (type GObject.Object): the object that has the property
	* to wrap
	* @property_name: the name of the property
	*
	* Creates a #GAction corresponding to the value of property
	* @property_name on @object.
	*
	* The property must be existent and readable and writable (and not
	* construct-only).
	*
	* This function takes a reference on @object and doesn't release it
	* until the action is destroyed.
	*
	* Returns: a new #GPropertyAction
	*
	* Since: 2.38
	**/
	GPropertyAction *
	g_property_action_new (const gchar *name,
	gpointer object,
	const gchar *property_name)
	{
	g_return_val_if_fail (name != NULL, NULL);
	g_return_val_if_fail (G_IS_OBJECT (object), NULL);
	g_return_val_if_fail (property_name != NULL, NULL);

	return g_object_new (G_TYPE_PROPERTY_ACTION,
	"name", name,
	"object", object,
	"property-name", property_name,
	NULL);
	}