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