gio/gsimpleaction.c

   1 /*
   2  * Copyright © 2010 Codethink Limited
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License as published
   6  * by the Free Software Foundation; either version 2 of the licence or (at
   7  * your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General
  15  * Public License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  *
  19  * Authors: Ryan Lortie <desrt@desrt.ca>
  20  */
  21
  22 #include "config.h"
  23
  24 #include "gsimpleaction.h"
  25
  26 #include "gaction.h"
  27 #include "glibintl.h"
  28
  29 /**
  30  * SECTION:gsimpleaction
  31  * @title: GSimpleAction
  32  * @short_description: A simple GAction implementation
  33  * @include: gio/gio.h
  34  *
  35  * A #GSimpleAction is the obvious simple implementation of the #GAction
  36  * interface. This is the easiest way to create an action for purposes of
  37  * adding it to a #GSimpleActionGroup.
  38  *
  39  * See also #GtkAction.
  40  */
  41 struct _GSimpleAction
  42 {
  43   GObject       parent_instance;
  44
  45   gchar        *name;
  46   GVariantType *parameter_type;
  47   gboolean      enabled;
  48   GVariant     *state;
  49   gboolean      state_set_already;
  50 };
  51
  52 typedef GObjectClass GSimpleActionClass;
  53
  54 static void g_simple_action_iface_init (GActionInterface *iface);
  55 G_DEFINE_TYPE_WITH_CODE (GSimpleAction, g_simple_action, G_TYPE_OBJECT,
  56   G_IMPLEMENT_INTERFACE (G_TYPE_ACTION, g_simple_action_iface_init))
  57
  58 enum
  59 {
  60   PROP_NONE,
  61   PROP_NAME,
  62   PROP_PARAMETER_TYPE,
  63   PROP_ENABLED,
  64   PROP_STATE_TYPE,
  65   PROP_STATE
  66 };
  67
  68 enum
  69 {
  70   SIGNAL_CHANGE_STATE,
  71   SIGNAL_ACTIVATE,
  72   NR_SIGNALS
  73 };
  74
  75 static guint g_simple_action_signals[NR_SIGNALS];
  76
  77 static const gchar *
  78 g_simple_action_get_name (GAction *action)
  79 {
  80   GSimpleAction *simple = G_SIMPLE_ACTION (action);
  81
  82   return simple->name;
  83 }
  84
  85 static const GVariantType *
  86 g_simple_action_get_parameter_type (GAction *action)
  87 {
  88   GSimpleAction *simple = G_SIMPLE_ACTION (action);
  89
  90   return simple->parameter_type;
  91 }
  92
  93 static const GVariantType *
  94 g_simple_action_get_state_type (GAction *action)
  95 {
  96   GSimpleAction *simple = G_SIMPLE_ACTION (action);
  97
  98   if (simple->state != NULL)
  99     return g_variant_get_type (simple->state);
 100   else
 101     return NULL;
 102 }
 103
 104 static GVariant *
 105 g_simple_action_get_state_hint (GAction *action)
 106 {
 107   return NULL;
 108 }
 109
 110 static gboolean
 111 g_simple_action_get_enabled (GAction *action)
 112 {
 113   GSimpleAction *simple = G_SIMPLE_ACTION (action);
 114
 115   return simple->enabled;
 116 }
 117
 118 static void
 119 g_simple_action_change_state (GAction  *action,
 120                               GVariant *value)
 121 {
 122   GSimpleAction *simple = G_SIMPLE_ACTION (action);
 123
 124   /* If the user connected a signal handler then they are responsible
 125    * for handling state changes.
 126    */
 127   if (g_signal_has_handler_pending (action, g_simple_action_signals[SIGNAL_CHANGE_STATE], 0, TRUE))
 128     g_signal_emit (action, g_simple_action_signals[SIGNAL_CHANGE_STATE], 0, value);
 129
 130   /* If not, then the default behaviour is to just set the state. */
 131   else
 132     g_simple_action_set_state (simple, value);
 133 }
 134
 135 /**
 136  * g_simple_action_set_state:
 137  * @simple: a #GSimpleAction
 138  * @value: the new #GVariant for the state
 139  *
 140  * Sets the state of the action.
 141  *
 142  * This directly updates the 'state' property to the given value.
 143  *
 144  * This should only be called by the implementor of the action.  Users
 145  * of the action should not attempt to directly modify the 'state'
 146  * property.  Instead, they should call g_action_change_state() to
 147  * request the change.
 148  *
 149  * If the @value GVariant is floating, it is consumed.
 150  *
 151  * Since: 2.30
 152  **/
 153 void
 154 g_simple_action_set_state (GSimpleAction *simple,
 155                            GVariant      *value)
 156 {
 157   g_return_if_fail (G_IS_SIMPLE_ACTION (simple));
 158   g_return_if_fail (value != NULL);
 159
 160   {
 161     const GVariantType *state_type;
 162
 163     state_type = simple->state ?
 164                    g_variant_get_type (simple->state) : NULL;
 165     g_return_if_fail (state_type != NULL);
 166     g_return_if_fail (g_variant_is_of_type (value, state_type));
 167   }
 168
 169   g_variant_ref_sink (value);
 170
 171   if (!simple->state || !g_variant_equal (simple->state, value))
 172     {
 173       if (simple->state)
 174         g_variant_unref (simple->state);
 175
 176       simple->state = g_variant_ref (value);
 177
 178       g_object_notify (G_OBJECT (simple), "state");
 179     }
 180
 181   g_variant_unref (value);
 182 }
 183
 184 static GVariant *
 185 g_simple_action_get_state (GAction *action)
 186 {
 187   GSimpleAction *simple = G_SIMPLE_ACTION (action);
 188
 189   return simple->state ? g_variant_ref (simple->state) : NULL;
 190 }
 191
 192 static void
 193 g_simple_action_activate (GAction  *action,
 194                           GVariant *parameter)
 195 {
 196   GSimpleAction *simple = G_SIMPLE_ACTION (action);
 197
 198   g_return_if_fail (simple->parameter_type == NULL ?
 199                       parameter == NULL :
 200                     (parameter != NULL &&
 201                      g_variant_is_of_type (parameter,
 202                                            simple->parameter_type)));
 203
 204   if (parameter != NULL)
 205     g_variant_ref_sink (parameter);
 206
 207   if (simple->enabled)
 208     {
 209       /* If the user connected a signal handler then they are responsible
 210        * for handling activation.
 211        */
 212       if (g_signal_has_handler_pending (action, g_simple_action_signals[SIGNAL_ACTIVATE], 0, TRUE))
 213         g_signal_emit (action, g_simple_action_signals[SIGNAL_ACTIVATE], 0, parameter);
 214
 215       /* If not, do some reasonable defaults for stateful actions. */
 216       else if (simple->state)
 217         {
 218           /* If we have no parameter and this is a boolean action, toggle. */
 219           if (parameter == NULL && g_variant_is_of_type (simple->state, G_VARIANT_TYPE_BOOLEAN))
 220             {
 221               gboolean was_enabled = g_variant_get_boolean (simple->state);
 222               g_simple_action_change_state (action, g_variant_new_boolean (!was_enabled));
 223             }
 224
 225           /* else, if the parameter and state type are the same, do a change-state */
 226           else if (g_variant_is_of_type (simple->state, g_variant_get_type (parameter)))
 227             g_simple_action_change_state (action, parameter);
 228         }
 229     }
 230
 231   if (parameter != NULL)
 232     g_variant_unref (parameter);
 233 }
 234
 235 static void
 236 g_simple_action_set_property (GObject    *object,
 237                               guint       prop_id,
 238                               const GValue     *value,
 239                               GParamSpec *pspec)
 240 {
 241   GSimpleAction *action = G_SIMPLE_ACTION (object);
 242
 243   switch (prop_id)
 244     {
 245     case PROP_NAME:
 246       action->name = g_strdup (g_value_get_string (value));
 247       break;
 248
 249     case PROP_PARAMETER_TYPE:
 250       action->parameter_type = g_value_dup_boxed (value);
 251       break;
 252
 253     case PROP_ENABLED:
 254       action->enabled = g_value_get_boolean (value);
 255       break;
 256
 257     case PROP_STATE:
 258       /* The first time we see this (during construct) we should just
 259        * take the state as it was handed to us.
 260        *
 261        * After that, we should make sure we go through the same checks
 262        * as the C API.
 263        */
 264       if (!action->state_set_already)
 265         {
 266           action->state = g_value_dup_variant (value);
 267           action->state_set_already = TRUE;
 268         }
 269       else
 270         g_simple_action_set_state (action, g_value_get_variant (value));
 271
 272       break;
 273
 274     default:
 275       g_assert_not_reached ();
 276     }
 277 }
 278
 279 static void
 280 g_simple_action_get_property (GObject    *object,
 281                               guint       prop_id,
 282                               GValue     *value,
 283                               GParamSpec *pspec)
 284 {
 285   GAction *action = G_ACTION (object);
 286
 287   switch (prop_id)
 288     {
 289     case PROP_NAME:
 290       g_value_set_string (value, g_simple_action_get_name (action));
 291       break;
 292
 293     case PROP_PARAMETER_TYPE:
 294       g_value_set_boxed (value, g_simple_action_get_parameter_type (action));
 295       break;
 296
 297     case PROP_ENABLED:
 298       g_value_set_boolean (value, g_simple_action_get_enabled (action));
 299       break;
 300
 301     case PROP_STATE_TYPE:
 302       g_value_set_boxed (value, g_simple_action_get_state_type (action));
 303       break;
 304
 305     case PROP_STATE:
 306       g_value_take_variant (value, g_simple_action_get_state (action));
 307       break;
 308
 309     default:
 310       g_assert_not_reached ();
 311     }
 312 }
 313
 314 static void
 315 g_simple_action_finalize (GObject *object)
 316 {
 317   GSimpleAction *simple = G_SIMPLE_ACTION (object);
 318
 319   g_free (simple->name);
 320   if (simple->parameter_type)
 321     g_variant_type_free (simple->parameter_type);
 322   if (simple->state)
 323     g_variant_unref (simple->state);
 324
 325   G_OBJECT_CLASS (g_simple_action_parent_class)
 326     ->finalize (object);
 327 }
 328
 329 void
 330 g_simple_action_init (GSimpleAction *simple)
 331 {
 332   simple->enabled = TRUE;
 333 }
 334
 335 void
 336 g_simple_action_iface_init (GActionInterface *iface)
 337 {
 338   iface->get_name = g_simple_action_get_name;
 339   iface->get_parameter_type = g_simple_action_get_parameter_type;
 340   iface->get_state_type = g_simple_action_get_state_type;
 341   iface->get_state_hint = g_simple_action_get_state_hint;
 342   iface->get_enabled = g_simple_action_get_enabled;
 343   iface->get_state = g_simple_action_get_state;
 344   iface->change_state = g_simple_action_change_state;
 345   iface->activate = g_simple_action_activate;
 346 }
 347
 348 void
 349 g_simple_action_class_init (GSimpleActionClass *class)
 350 {
 351   GObjectClass *object_class = G_OBJECT_CLASS (class);
 352
 353   object_class->set_property = g_simple_action_set_property;
 354   object_class->get_property = g_simple_action_get_property;
 355   object_class->finalize = g_simple_action_finalize;
 356
 357   /**
 358    * GSimpleAction::activate:
 359    * @simple: the #GSimpleAction
 360    * @parameter: (allow-none): the parameter to the activation
 361    *
 362    * Indicates that the action was just activated.
 363    *
 364    * @parameter will always be of the expected type.  In the event that
 365    * an incorrect type was given, no signal will be emitted.
 366    *
 367    * Since GLib 2.40, if no handler is connected to this signal then the
 368    * default behaviour for boolean-stated actions with a %NULL parameter
 369    * type is to toggle them via the #GSimpleAction::change-state signal.
 370    * For stateful actions where the state type is equal to the parameter
 371    * type, the default is to forward them directly to
 372    * #GSimpleAction::change-state.  This should allow almost all users
 373    * of #GSimpleAction to connect only one handler or the other.
 374    *
 375    * Since: 2.28
 376    */
 377   g_simple_action_signals[SIGNAL_ACTIVATE] =
 378     g_signal_new (I_("activate"),
 379                   G_TYPE_SIMPLE_ACTION,
 380                   G_SIGNAL_RUN_LAST | G_SIGNAL_MUST_COLLECT,
 381                   0, NULL, NULL,
 382                   g_cclosure_marshal_VOID__VARIANT,
 383                   G_TYPE_NONE, 1,
 384                   G_TYPE_VARIANT);
 385
 386   /**
 387    * GSimpleAction::change-state:
 388    * @simple: the #GSimpleAction
 389    * @value: (allow-none): the requested value for the state
 390    *
 391    * Indicates that the action just received a request to change its
 392    * state.
 393    *
 394    * @value will always be of the correct state type.  In the event that
 395    * an incorrect type was given, no signal will be emitted.
 396    *
 397    * If no handler is connected to this signal then the default
 398    * behaviour is to call g_simple_action_set_state() to set the state
 399    * to the requested value.  If you connect a signal handler then no
 400    * default action is taken.  If the state should change then you must
 401    * call g_simple_action_set_state() from the handler.
 402    *
 403    * <example>
 404    * <title>Example 'change-state' handler</title>
 405    * <programlisting>
 406    * static void
 407    * change_volume_state (GSimpleAction *action,
 408    *                      GVariant      *value,
 409    *                      gpointer       user_data)
 410    * {
 411    *   gint requested;
 412    *
 413    *   requested = g_variant_get_int32 (value);
 414    *
 415    *   // Volume only goes from 0 to 10
 416    *   if (0 <= requested && requested <= 10)
 417    *     g_simple_action_set_state (action, value);
 418    * }
 419    * </programlisting>
 420    * </example>
 421    *
 422    * The handler need not set the state to the requested value.  It
 423    * could set it to any value at all, or take some other action.
 424    *
 425    * Since: 2.30
 426    */
 427   g_simple_action_signals[SIGNAL_CHANGE_STATE] =
 428     g_signal_new (I_("change-state"),
 429                   G_TYPE_SIMPLE_ACTION,
 430                   G_SIGNAL_RUN_LAST | G_SIGNAL_MUST_COLLECT,
 431                   0, NULL, NULL,
 432                   g_cclosure_marshal_VOID__VARIANT,
 433                   G_TYPE_NONE, 1,
 434                   G_TYPE_VARIANT);
 435
 436   /**
 437    * GSimpleAction:name:
 438    *
 439    * The name of the action.  This is mostly meaningful for identifying
 440    * the action once it has been added to a #GSimpleActionGroup.
 441    *
 442    * Since: 2.28
 443    **/
 444   g_object_class_install_property (object_class, PROP_NAME,
 445                                    g_param_spec_string ("name",
 446                                                         P_("Action Name"),
 447                                                         P_("The name used to invoke the action"),
 448                                                         NULL,
 449                                                         G_PARAM_READWRITE |
 450                                                         G_PARAM_CONSTRUCT_ONLY |
 451                                                         G_PARAM_STATIC_STRINGS));
 452
 453   /**
 454    * GSimpleAction:parameter-type:
 455    *
 456    * The type of the parameter that must be given when activating the
 457    * action.
 458    *
 459    * Since: 2.28
 460    **/
 461   g_object_class_install_property (object_class, PROP_PARAMETER_TYPE,
 462                                    g_param_spec_boxed ("parameter-type",
 463                                                        P_("Parameter Type"),
 464                                                        P_("The type of GVariant passed to activate()"),
 465                                                        G_TYPE_VARIANT_TYPE,
 466                                                        G_PARAM_READWRITE |
 467                                                        G_PARAM_CONSTRUCT_ONLY |
 468                                                        G_PARAM_STATIC_STRINGS));
 469
 470   /**
 471    * GSimpleAction:enabled:
 472    *
 473    * If @action is currently enabled.
 474    *
 475    * If the action is disabled then calls to g_action_activate() and
 476    * g_action_change_state() have no effect.
 477    *
 478    * Since: 2.28
 479    **/
 480   g_object_class_install_property (object_class, PROP_ENABLED,
 481                                    g_param_spec_boolean ("enabled",
 482                                                          P_("Enabled"),
 483                                                          P_("If the action can be activated"),
 484                                                          TRUE,
 485                                                          G_PARAM_READWRITE |
 486                                                          G_PARAM_STATIC_STRINGS));
 487
 488   /**
 489    * GSimpleAction:state-type:
 490    *
 491    * The #GVariantType of the state that the action has, or %NULL if the
 492    * action is stateless.
 493    *
 494    * Since: 2.28
 495    **/
 496   g_object_class_install_property (object_class, PROP_STATE_TYPE,
 497                                    g_param_spec_boxed ("state-type",
 498                                                        P_("State Type"),
 499                                                        P_("The type of the state kept by the action"),
 500                                                        G_TYPE_VARIANT_TYPE,
 501                                                        G_PARAM_READABLE |
 502                                                        G_PARAM_STATIC_STRINGS));
 503
 504   /**
 505    * GSimpleAction:state:
 506    *
 507    * The state of the action, or %NULL if the action is stateless.
 508    *
 509    * Since: 2.28
 510    **/
 511   g_object_class_install_property (object_class, PROP_STATE,
 512                                    g_param_spec_variant ("state",
 513                                                          P_("State"),
 514                                                          P_("The state the action is in"),
 515                                                          G_VARIANT_TYPE_ANY,
 516                                                          NULL,
 517                                                          G_PARAM_READWRITE | G_PARAM_CONSTRUCT |
 518                                                          G_PARAM_STATIC_STRINGS));
 519 }
 520
 521 /**
 522  * g_simple_action_set_enabled:
 523  * @simple: a #GSimpleAction
 524  * @enabled: whether the action is enabled
 525  *
 526  * Sets the action as enabled or not.
 527  *
 528  * An action must be enabled in order to be activated or in order to
 529  * have its state changed from outside callers.
 530  *
 531  * This should only be called by the implementor of the action.  Users
 532  * of the action should not attempt to modify its enabled flag.
 533  *
 534  * Since: 2.28
 535  **/
 536 void
 537 g_simple_action_set_enabled (GSimpleAction *simple,
 538                              gboolean       enabled)
 539 {
 540   g_return_if_fail (G_IS_SIMPLE_ACTION (simple));
 541
 542   enabled = !!enabled;
 543
 544   if (simple->enabled != enabled)
 545     {
 546       simple->enabled = enabled;
 547       g_object_notify (G_OBJECT (simple), "enabled");
 548     }
 549 }
 550 /**
 551  * g_simple_action_new:
 552  * @name: the name of the action
 553  * @parameter_type: (allow-none): the type of parameter to the activate function
 554  *
 555  * Creates a new action.
 556  *
 557  * The created action is stateless.  See g_simple_action_new_stateful().
 558  *
 559  * Returns: a new #GSimpleAction
 560  *
 561  * Since: 2.28
 562  **/
 563 GSimpleAction *
 564 g_simple_action_new (const gchar        *name,
 565                      const GVariantType *parameter_type)
 566 {
 567   return g_object_new (G_TYPE_SIMPLE_ACTION,
 568                        "name", name,
 569                        "parameter-type", parameter_type,
 570                        NULL);
 571 }
 572
 573 /**
 574  * g_simple_action_new_stateful:
 575  * @name: the name of the action
 576  * @parameter_type: (allow-none): the type of the parameter to the activate function
 577  * @state: the initial state of the action
 578  *
 579  * Creates a new stateful action.
 580  *
 581  * @state is the initial state of the action.  All future state values
 582  * must have the same #GVariantType as the initial state.
 583  *
 584  * If the @state GVariant is floating, it is consumed.
 585  *
 586  * Returns: a new #GSimpleAction
 587  *
 588  * Since: 2.28
 589  **/
 590 GSimpleAction *
 591 g_simple_action_new_stateful (const gchar        *name,
 592                               const GVariantType *parameter_type,
 593                               GVariant           *state)
 594 {
 595   return g_object_new (G_TYPE_SIMPLE_ACTION,
 596                        "name", name,
 597                        "parameter-type", parameter_type,
 598                        "state", state,
 599                        NULL);
 600 }