/*
* Copyright © 2010 Codethink Limited
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*
* 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 .
*
* Authors: Ryan Lortie
*/
#include "config.h"
#include "gactiongroup.h"
#include "gaction.h"
#include "glibintl.h"
#include "gmarshal-internal.h"
/**
* GActionGroup:
*
* `GActionGroup` represents a group of actions.
*
* Actions can be used to expose functionality in a structured way, either
* from one part of a program to another, or to the outside world. Action
* groups are often used together with a [type@Gio.MenuModel] that provides additional
* representation data for displaying the actions to the user, e.g. in a menu.
*
* The main way to interact with the actions in a `GActionGroup` is to
* activate them with [method@Gio.ActionGroup.activate_action]. Activating an
* action may require a [type@GLib.Variant] parameter. The required type of the
* parameter can be inquired with [method@Gio.ActionGroup.get_action_parameter_type].
* Actions may be disabled, see [method@Gio.ActionGroup.get_action_enabled].
* Activating a disabled action has no effect.
*
* Actions may optionally have a state in the form of a [type@GLib.Variant]. The current
* state of an action can be inquired with [method@Gio.ActionGroup.get_action_state].
* Activating a stateful action may change its state, but it is also possible to
* set the state by calling [method@Gio.ActionGroup.change_action_state].
*
* As typical example, consider a text editing application which has an
* option to change the current font to ‘bold’. A good way to represent
* this would be a stateful action, with a boolean state. Activating the
* action would toggle the state.
*
* Each action in the group has a unique name (which is a string). All
* method calls, except [method@Gio.ActionGroup.list_actions] take the name of
* an action as an argument.
*
* The `GActionGroup` API is meant to be the ‘public’ API to the action
* group. The calls here are exactly the interaction that ‘external
* forces’ (eg: UI, incoming D-Bus messages, etc.) are supposed to have
* with actions. ‘Internal’ APIs (ie: ones meant only to be accessed by
* the action group implementation) are found on subclasses. This is
* why you will find – for example – [method@Gio.ActionGroup.get_action_enabled]
* but not an equivalent `set_action_enabled()` method.
*
* Signals are emitted on the action group in response to state changes
* on individual actions.
*
* Implementations of `GActionGroup` should provide implementations for
* the virtual functions [method@Gio.ActionGroup.list_actions] and
* [method@Gio.ActionGroup.query_action]. The other virtual functions should
* not be implemented — their ‘wrappers’ are actually implemented with
* calls to [method@Gio.ActionGroup.query_action].
*/
/**
* GActionGroupInterface:
* @has_action: the virtual function pointer for [method@Gio.ActionGroup.has_action]
* @list_actions: the virtual function pointer for [method@Gio.ActionGroup.list_actions]
* @get_action_parameter_type: the virtual function pointer for [method@Gio.ActionGroup.get_action_parameter_type]
* @get_action_state_type: the virtual function pointer for [method@Gio.ActionGroup.get_action_state_type]
* @get_action_state_hint: the virtual function pointer for [method@Gio.ActionGroup.get_action_state_hint]
* @get_action_enabled: the virtual function pointer for [method@Gio.ActionGroup.get_action_enabled]
* @get_action_state: the virtual function pointer for [method@Gio.ActionGroup.get_action_state]
* @change_action_state: the virtual function pointer for [method@Gio.ActionGroup.change_action_state]
* @activate_action: the virtual function pointer for [method@Gio.ActionGroup.activate_action]
* @action_added: the class closure for the [signal@Gio.ActionGroup::action-added] signal
* @action_removed: the class closure for the [signal@Gio.ActionGroup::action-removed] signal
* @action_enabled_changed: the class closure for the [signal@Gio.ActionGroup::action-enabled-changed] signal
* @action_state_changed: the class closure for the [signal@Gio.ActionGroup::action-enabled-changed] signal
* @query_action: the virtual function pointer for [method@Gio.ActionGroup.query_action]
*
* The virtual function table for [type@Gio.ActionGroup].
*
* Since: 2.28
**/
G_DEFINE_INTERFACE (GActionGroup, g_action_group, G_TYPE_OBJECT)
enum
{
SIGNAL_ACTION_ADDED,
SIGNAL_ACTION_REMOVED,
SIGNAL_ACTION_ENABLED_CHANGED,
SIGNAL_ACTION_STATE_CHANGED,
NR_SIGNALS
};
static guint g_action_group_signals[NR_SIGNALS];
static gboolean
g_action_group_real_has_action (GActionGroup *action_group,
const gchar *action_name)
{
return g_action_group_query_action (action_group, action_name, NULL, NULL, NULL, NULL, NULL);
}
static gboolean
g_action_group_real_get_action_enabled (GActionGroup *action_group,
const gchar *action_name)
{
gboolean enabled;
if (!g_action_group_query_action (action_group, action_name, &enabled, NULL, NULL, NULL, NULL))
return FALSE;
return enabled;
}
static const GVariantType *
g_action_group_real_get_action_parameter_type (GActionGroup *action_group,
const gchar *action_name)
{
const GVariantType *type;
if (!g_action_group_query_action (action_group, action_name, NULL, &type, NULL, NULL, NULL))
return NULL;
return type;
}
static const GVariantType *
g_action_group_real_get_action_state_type (GActionGroup *action_group,
const gchar *action_name)
{
const GVariantType *type;
if (!g_action_group_query_action (action_group, action_name, NULL, NULL, &type, NULL, NULL))
return NULL;
return type;
}
static GVariant *
g_action_group_real_get_action_state_hint (GActionGroup *action_group,
const gchar *action_name)
{
GVariant *hint;
if (!g_action_group_query_action (action_group, action_name, NULL, NULL, NULL, &hint, NULL))
return NULL;
return hint;
}
static GVariant *
g_action_group_real_get_action_state (GActionGroup *action_group,
const gchar *action_name)
{
GVariant *state;
if (!g_action_group_query_action (action_group, action_name, NULL, NULL, NULL, NULL, &state))
return NULL;
return state;
}
static gboolean
g_action_group_real_query_action (GActionGroup *action_group,
const gchar *action_name,
gboolean *enabled,
const GVariantType **parameter_type,
const GVariantType **state_type,
GVariant **state_hint,
GVariant **state)
{
GActionGroupInterface *iface = G_ACTION_GROUP_GET_IFACE (action_group);
/* we expect implementations to override this method, but we also
* allow for implementations that existed before this method was
* introduced to override the individual accessors instead.
*
* detect the case that neither has happened and report it.
*/
if G_UNLIKELY (iface->has_action == g_action_group_real_has_action ||
iface->get_action_enabled == g_action_group_real_get_action_enabled ||
iface->get_action_parameter_type == g_action_group_real_get_action_parameter_type ||
iface->get_action_state_type == g_action_group_real_get_action_state_type ||
iface->get_action_state_hint == g_action_group_real_get_action_state_hint ||
iface->get_action_state == g_action_group_real_get_action_state)
{
g_critical ("Class ‘%s’ implements GActionGroup interface without overriding "
"query_action() method. Bailing out to avoid infinite recursion.",
G_OBJECT_TYPE_NAME (action_group));
return FALSE;
}
if (!(* iface->has_action) (action_group, action_name))
return FALSE;
if (enabled != NULL)
*enabled = (* iface->get_action_enabled) (action_group, action_name);
if (parameter_type != NULL)
*parameter_type = (* iface->get_action_parameter_type) (action_group, action_name);
if (state_type != NULL)
*state_type = (* iface->get_action_state_type) (action_group, action_name);
if (state_hint != NULL)
*state_hint = (* iface->get_action_state_hint) (action_group, action_name);
if (state != NULL)
*state = (* iface->get_action_state) (action_group, action_name);
return TRUE;
}
static void
g_action_group_default_init (GActionGroupInterface *iface)
{
iface->has_action = g_action_group_real_has_action;
iface->get_action_enabled = g_action_group_real_get_action_enabled;
iface->get_action_parameter_type = g_action_group_real_get_action_parameter_type;
iface->get_action_state_type = g_action_group_real_get_action_state_type;
iface->get_action_state_hint = g_action_group_real_get_action_state_hint;
iface->get_action_state = g_action_group_real_get_action_state;
iface->query_action = g_action_group_real_query_action;
/**
* GActionGroup::action-added:
* @action_group: the [type@Gio.ActionGroup] that changed
* @action_name: the name of the action in @action_group
*
* Signals that a new action was just added to the group.
*
* This signal is emitted after the action has been added
* and is now visible.
*
* Since: 2.28
**/
g_action_group_signals[SIGNAL_ACTION_ADDED] =
g_signal_new (I_("action-added"),
G_TYPE_ACTION_GROUP,
G_SIGNAL_RUN_LAST | G_SIGNAL_DETAILED,
G_STRUCT_OFFSET (GActionGroupInterface, action_added),
NULL, NULL,
NULL,
G_TYPE_NONE, 1,
G_TYPE_STRING);
/**
* GActionGroup::action-removed:
* @action_group: the [type@Gio.ActionGroup] that changed
* @action_name: the name of the action in @action_group
*
* Signals that an action is just about to be removed from the group.
*
* This signal is emitted before the action is removed, so the action
* is still visible and can be queried from the signal handler.
*
* Since: 2.28
**/
g_action_group_signals[SIGNAL_ACTION_REMOVED] =
g_signal_new (I_("action-removed"),
G_TYPE_ACTION_GROUP,
G_SIGNAL_RUN_LAST | G_SIGNAL_DETAILED,
G_STRUCT_OFFSET (GActionGroupInterface, action_removed),
NULL, NULL,
NULL,
G_TYPE_NONE, 1,
G_TYPE_STRING);
/**
* GActionGroup::action-enabled-changed:
* @action_group: the [type@Gio.ActionGroup] that changed
* @action_name: the name of the action in @action_group
* @enabled: whether the action is enabled
*
* Signals that the enabled status of the named action has changed.
*
* Since: 2.28
**/
g_action_group_signals[SIGNAL_ACTION_ENABLED_CHANGED] =
g_signal_new (I_("action-enabled-changed"),
G_TYPE_ACTION_GROUP,
G_SIGNAL_RUN_LAST | G_SIGNAL_DETAILED,
G_STRUCT_OFFSET (GActionGroupInterface,
action_enabled_changed),
NULL, NULL,
_g_cclosure_marshal_VOID__STRING_BOOLEAN,
G_TYPE_NONE, 2,
G_TYPE_STRING,
G_TYPE_BOOLEAN);
g_signal_set_va_marshaller (g_action_group_signals[SIGNAL_ACTION_ENABLED_CHANGED],
G_TYPE_FROM_INTERFACE (iface),
_g_cclosure_marshal_VOID__STRING_BOOLEANv);
/**
* GActionGroup::action-state-changed:
* @action_group: the [type@Gio.ActionGroup] that changed
* @action_name: the name of the action in @action_group
* @value: the new value of the state
*
* Signals that the state of the named action has changed.
*
* Since: 2.28
**/
g_action_group_signals[SIGNAL_ACTION_STATE_CHANGED] =
g_signal_new (I_("action-state-changed"),
G_TYPE_ACTION_GROUP,
G_SIGNAL_RUN_LAST |
G_SIGNAL_DETAILED |
G_SIGNAL_MUST_COLLECT,
G_STRUCT_OFFSET (GActionGroupInterface,
action_state_changed),
NULL, NULL,
_g_cclosure_marshal_VOID__STRING_VARIANT,
G_TYPE_NONE, 2,
G_TYPE_STRING,
G_TYPE_VARIANT);
g_signal_set_va_marshaller (g_action_group_signals[SIGNAL_ACTION_STATE_CHANGED],
G_TYPE_FROM_INTERFACE (iface),
_g_cclosure_marshal_VOID__STRING_VARIANTv);
}
/**
* g_action_group_list_actions:
* @action_group: a [type@Gio.ActionGroup]
*
* Lists the actions contained within @action_group.
*
* The caller is responsible for freeing the list with [func@GLib.strfreev] when
* it is no longer required.
*
* Returns: (transfer full) (array zero-terminated=1): a `NULL`-terminated array
* of the names of the actions in the group
*
* Since: 2.28
**/
gchar **
g_action_group_list_actions (GActionGroup *action_group)
{
g_return_val_if_fail (G_IS_ACTION_GROUP (action_group), NULL);
return G_ACTION_GROUP_GET_IFACE (action_group)
->list_actions (action_group);
}
/**
* g_action_group_has_action:
* @action_group: a [type@Gio.ActionGroup]
* @action_name: the name of the action to check for
*
* Checks if the named action exists within @action_group.
*
* Returns: whether the named action exists
*
* Since: 2.28
**/
gboolean
g_action_group_has_action (GActionGroup *action_group,
const gchar *action_name)
{
g_return_val_if_fail (G_IS_ACTION_GROUP (action_group), FALSE);
return G_ACTION_GROUP_GET_IFACE (action_group)
->has_action (action_group, action_name);
}
/**
* g_action_group_get_action_parameter_type:
* @action_group: a [type@Gio.ActionGroup]
* @action_name: the name of the action to query
*
* Queries the type of the parameter that must be given when activating
* the named action within @action_group.
*
* When activating the action using [method@Gio.ActionGroup.activate_action],
* the [type@GLib.Variant] given to that function must be of the type returned
* by this function.
*
* In the case that this function returns `NULL`, you must not give any
* [type@GLib.Variant], but `NULL` instead.
*
* The parameter type of a particular action will never change but it is
* possible for an action to be removed and for a new action to be added
* with the same name but a different parameter type.
*
* Returns: (nullable): the parameter type
*
* Since: 2.28
**/
const GVariantType *
g_action_group_get_action_parameter_type (GActionGroup *action_group,
const gchar *action_name)
{
g_return_val_if_fail (G_IS_ACTION_GROUP (action_group), NULL);
return G_ACTION_GROUP_GET_IFACE (action_group)
->get_action_parameter_type (action_group, action_name);
}
/**
* g_action_group_get_action_state_type:
* @action_group: a [type@Gio.ActionGroup]
* @action_name: the name of the action to query
*
* Queries the type of the state of the named action within
* @action_group.
*
* If the action is stateful then this function returns the
* [type@GLib.VariantType] of the state. All calls to
* [method@Gio.ActionGroup.change_action_state] must give a [type@GLib.Variant] of this
* type and [method@Gio.ActionGroup.get_action_state] will return a [type@GLib.Variant]
* of the same type.
*
* If the action is not stateful then this function will return `NULL`.
* In that case, [method@Gio.ActionGroup.get_action_state] will return `NULL`
* and you must not call [method@Gio.ActionGroup.change_action_state].
*
* The state type of a particular action will never change but it is
* possible for an action to be removed and for a new action to be added
* with the same name but a different state type.
*
* Returns: (nullable): the state type, if the action is stateful
*
* Since: 2.28
**/
const GVariantType *
g_action_group_get_action_state_type (GActionGroup *action_group,
const gchar *action_name)
{
g_return_val_if_fail (G_IS_ACTION_GROUP (action_group), NULL);
return G_ACTION_GROUP_GET_IFACE (action_group)
->get_action_state_type (action_group, action_name);
}
/**
* g_action_group_get_action_state_hint:
* @action_group: a [type@Gio.ActionGroup]
* @action_name: the name of the action to query
*
* Requests a hint about the valid range of values for the state of the
* named action within @action_group.
*
* If `NULL` is returned it either means that the action is not stateful
* or that there is no hint about the valid range of values for the
* state of the action.
*
* If a [type@GLib.Variant] array is returned then each item in the array is a
* possible value for the state. If a [type@GLib.Variant] pair (ie: two-tuple) is
* returned then the tuple specifies the inclusive lower and upper bound
* of valid values for the state.
*
* In any case, the information is merely a hint. It may be possible to
* have a state value outside of the hinted range and setting a value
* within the range may fail.
*
* The return value (if non-`NULL`) should be freed with
* [method@GLib.Variant.unref] when it is no longer required.
*
* Returns: (nullable) (transfer full): the state range hint
*
* Since: 2.28
**/
GVariant *
g_action_group_get_action_state_hint (GActionGroup *action_group,
const gchar *action_name)
{
g_return_val_if_fail (G_IS_ACTION_GROUP (action_group), NULL);
return G_ACTION_GROUP_GET_IFACE (action_group)
->get_action_state_hint (action_group, action_name);
}
/**
* g_action_group_get_action_enabled:
* @action_group: a [type@Gio.ActionGroup]
* @action_name: the name of the action to query
*
* Checks if the named action within @action_group is currently enabled.
*
* An action must be enabled in order to be activated or in order to
* have its state changed from outside callers.
*
* Returns: whether the action is currently enabled
*
* Since: 2.28
**/
gboolean
g_action_group_get_action_enabled (GActionGroup *action_group,
const gchar *action_name)
{
g_return_val_if_fail (G_IS_ACTION_GROUP (action_group), FALSE);
return G_ACTION_GROUP_GET_IFACE (action_group)
->get_action_enabled (action_group, action_name);
}
/**
* g_action_group_get_action_state:
* @action_group: a [type@Gio.ActionGroup]
* @action_name: the name of the action to query
*
* Queries the current state of the named action within @action_group.
*
* If the action is not stateful then `NULL` will be returned. If the
* action is stateful then the type of the return value is the type
* given by [method@Gio.ActionGroup.get_action_state_type].
*
* The return value (if non-`NULL`) should be freed with
* [method@GLib.Variant.unref] when it is no longer required.
*
* Returns: (nullable) (transfer full): the current state of the action
*
* Since: 2.28
**/
GVariant *
g_action_group_get_action_state (GActionGroup *action_group,
const gchar *action_name)
{
g_return_val_if_fail (G_IS_ACTION_GROUP (action_group), NULL);
return G_ACTION_GROUP_GET_IFACE (action_group)
->get_action_state (action_group, action_name);
}
/**
* g_action_group_change_action_state:
* @action_group: a [type@Gio.ActionGroup]
* @action_name: the name of the action to request the change on
* @value: the new state
*
* Request for the state of the named action within @action_group to be
* changed to @value.
*
* The action must be stateful and @value must be of the correct type.
* See [method@Gio.ActionGroup.get_action_state_type].
*
* This call merely requests a change. The action may refuse to change
* its state or may change its state to something other than @value.
* See [method@Gio.ActionGroup.get_action_state_hint].
*
* If the @value GVariant is floating, it is consumed.
*
* Since: 2.28
**/
void
g_action_group_change_action_state (GActionGroup *action_group,
const gchar *action_name,
GVariant *value)
{
g_return_if_fail (G_IS_ACTION_GROUP (action_group));
g_return_if_fail (action_name != NULL);
g_return_if_fail (value != NULL);
G_ACTION_GROUP_GET_IFACE (action_group)
->change_action_state (action_group, action_name, value);
}
/**
* g_action_group_activate_action:
* @action_group: a [type@Gio.ActionGroup]
* @action_name: the name of the action to activate
* @parameter: (nullable): parameters to the activation
*
* Activate the named action within @action_group.
*
* If the action is expecting a parameter, then the correct type of
* parameter must be given as @parameter. If the action is expecting no
* parameters then @parameter must be `NULL`. See
* [method@Gio.ActionGroup.get_action_parameter_type].
*
* If the [type@Gio.ActionGroup] implementation supports asynchronous remote
* activation over D-Bus, this call may return before the relevant
* D-Bus traffic has been sent, or any replies have been received. In
* order to block on such asynchronous activation calls,
* [method@Gio.DBusConnection.flush] should be called prior to the code, which
* depends on the result of the action activation. Without flushing
* the D-Bus connection, there is no guarantee that the action would
* have been activated.
*
* The following code which runs in a remote app instance, shows an
* example of a ‘quit’ action being activated on the primary app
* instance over D-Bus. Here [method@Gio.DBusConnection.flush] is called
* before `exit()`. Without `g_dbus_connection_flush()`, the ‘quit’ action
* may fail to be activated on the primary instance.
*
* ```c
* // call ‘quit’ action on primary instance
* g_action_group_activate_action (G_ACTION_GROUP (app), "quit", NULL);
*
* // make sure the action is activated now
* g_dbus_connection_flush (…);
*
* g_debug ("Application has been terminated. Exiting.");
*
* exit (0);
* ```
*
* Since: 2.28
**/
void
g_action_group_activate_action (GActionGroup *action_group,
const gchar *action_name,
GVariant *parameter)
{
g_return_if_fail (G_IS_ACTION_GROUP (action_group));
g_return_if_fail (action_name != NULL);
G_ACTION_GROUP_GET_IFACE (action_group)
->activate_action (action_group, action_name, parameter);
}
/**
* g_action_group_action_added:
* @action_group: a [type@Gio.ActionGroup]
* @action_name: the name of an action in the group
*
* Emits the [signal@Gio.ActionGroup::action-added] signal on @action_group.
*
* This function should only be called by [type@Gio.ActionGroup] implementations.
*
* Since: 2.28
**/
void
g_action_group_action_added (GActionGroup *action_group,
const gchar *action_name)
{
g_return_if_fail (G_IS_ACTION_GROUP (action_group));
g_return_if_fail (action_name != NULL);
g_signal_emit (action_group,
g_action_group_signals[SIGNAL_ACTION_ADDED],
g_quark_try_string (action_name),
action_name);
}
/**
* g_action_group_action_removed:
* @action_group: a [type@Gio.ActionGroup]
* @action_name: the name of an action in the group
*
* Emits the [signal@Gio.ActionGroup::action-removed] signal on @action_group.
*
* This function should only be called by [type@Gio.ActionGroup] implementations.
*
* Since: 2.28
**/
void
g_action_group_action_removed (GActionGroup *action_group,
const gchar *action_name)
{
g_return_if_fail (G_IS_ACTION_GROUP (action_group));
g_return_if_fail (action_name != NULL);
g_signal_emit (action_group,
g_action_group_signals[SIGNAL_ACTION_REMOVED],
g_quark_try_string (action_name),
action_name);
}
/**
* g_action_group_action_enabled_changed:
* @action_group: a [type@Gio.ActionGroup]
* @action_name: the name of an action in the group
* @enabled: whether the action is now enabled
*
* Emits the [signal@Gio.ActionGroup::action-enabled-changed] signal on @action_group.
*
* This function should only be called by [type@Gio.ActionGroup] implementations.
*
* Since: 2.28
**/
void
g_action_group_action_enabled_changed (GActionGroup *action_group,
const gchar *action_name,
gboolean enabled)
{
g_return_if_fail (G_IS_ACTION_GROUP (action_group));
g_return_if_fail (action_name != NULL);
enabled = !!enabled;
g_signal_emit (action_group,
g_action_group_signals[SIGNAL_ACTION_ENABLED_CHANGED],
g_quark_try_string (action_name),
action_name,
enabled);
}
/**
* g_action_group_action_state_changed:
* @action_group: a [type@Gio.ActionGroup]
* @action_name: the name of an action in the group
* @state: the new state of the named action
*
* Emits the [signal@Gio.ActionGroup::action-state-changed] signal on @action_group.
*
* This function should only be called by [type@Gio.ActionGroup] implementations.
*
* Since: 2.28
**/
void
g_action_group_action_state_changed (GActionGroup *action_group,
const gchar *action_name,
GVariant *state)
{
g_return_if_fail (G_IS_ACTION_GROUP (action_group));
g_return_if_fail (action_name != NULL);
g_signal_emit (action_group,
g_action_group_signals[SIGNAL_ACTION_STATE_CHANGED],
g_quark_try_string (action_name),
action_name,
state);
}
/**
* g_action_group_query_action:
* @action_group: a [type@Gio.ActionGroup]
* @action_name: the name of an action in the group
* @enabled: (out): if the action is presently enabled
* @parameter_type: (out) (transfer none) (optional): the parameter type, or `NULL` if none needed
* @state_type: (out) (transfer none) (optional): the state type, or `NULL` if stateless
* @state_hint: (out) (optional): the state hint, or `NULL` if none
* @state: (out) (optional): the current state, or `NULL` if stateless
*
* Queries all aspects of the named action within an @action_group.
*
* This function acquires the information available from
* [method@Gio.ActionGroup.has_action], [method@Gio.ActionGroup.get_action_enabled],
* [method@Gio.ActionGroup.get_action_parameter_type],
* [method@Gio.ActionGroup.get_action_state_type],
* [method@Gio.ActionGroup.get_action_state_hint] and
* [method@Gio.ActionGroup.get_action_state] with a single function call.
*
* This provides two main benefits.
*
* The first is the improvement in efficiency that comes with not having
* to perform repeated lookups of the action in order to discover
* different things about it. The second is that implementing
* [type@Gio.ActionGroup] can now be done by only overriding this one virtual
* function.
*
* The interface provides a default implementation of this function that
* calls the individual functions, as required, to fetch the
* information. The interface also provides default implementations of
* those functions that call this function. All implementations,
* therefore, must override either this function or all of the others.
*
* If the action exists, `TRUE` is returned and any of the requested
* fields (as indicated by having a non-`NULL` reference passed in) are
* filled. If the action doesn’t exist, `FALSE` is returned and the
* fields may or may not have been modified.
*
* Returns: `TRUE` if the action exists, else `FALSE`
*
* Since: 2.32
**/
gboolean
g_action_group_query_action (GActionGroup *action_group,
const gchar *action_name,
gboolean *enabled,
const GVariantType **parameter_type,
const GVariantType **state_type,
GVariant **state_hint,
GVariant **state)
{
return G_ACTION_GROUP_GET_IFACE (action_group)
->query_action (action_group, action_name, enabled, parameter_type, state_type, state_hint, state);
}