+/*
+ * Copyright © 2013 Canonical Limited
+ *
+ * This program 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 of the licence 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., 59 Temple Place, Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ * 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
+ *
+ * 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
+ * <em>is</em> 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;
+};
+
+/**
+ * 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
+};
+
+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);
+ 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);
+ 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;
+
+ 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;
+
+ 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));
+}
+
+/**
+ * g_property_action_new:
+ * @name: the name of the action to create
+ * @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);
+}