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     g_signal_emit (simple, g_simple_action_signals[SIGNAL_ACTIVATE], 0, parameter);
 209
 210   if (parameter != NULL)
 211     g_variant_unref (parameter);
 212 }
 213
 214 static void
 215 g_simple_action_set_property (GObject    *object,
 216                               guint       prop_id,
 217                               const GValue     *value,
 218                               GParamSpec *pspec)
 219 {
 220   GSimpleAction *action = G_SIMPLE_ACTION (object);
 221
 222   switch (prop_id)
 223     {
 224     case PROP_NAME:
 225       action->name = g_strdup (g_value_get_string (value));
 226       break;
 227
 228     case PROP_PARAMETER_TYPE:
 229       action->parameter_type = g_value_dup_boxed (value);
 230       break;
 231
 232     case PROP_ENABLED:
 233       action->enabled = g_value_get_boolean (value);
 234       break;
 235
 236     case PROP_STATE:
 237       /* The first time we see this (during construct) we should just
 238        * take the state as it was handed to us.
 239        *
 240        * After that, we should make sure we go through the same checks
 241        * as the C API.
 242        */
 243       if (!action->state_set_already)
 244         {
 245           action->state = g_value_dup_variant (value);
 246           action->state_set_already = TRUE;
 247         }
 248       else
 249         g_simple_action_set_state (action, g_value_get_variant (value));
 250
 251       break;
 252
 253     default:
 254       g_assert_not_reached ();
 255     }
 256 }
 257
 258 static void
 259 g_simple_action_get_property (GObject    *object,
 260                               guint       prop_id,
 261                               GValue     *value,
 262                               GParamSpec *pspec)
 263 {
 264   GAction *action = G_ACTION (object);
 265
 266   switch (prop_id)
 267     {
 268     case PROP_NAME:
 269       g_value_set_string (value, g_simple_action_get_name (action));
 270       break;
 271
 272     case PROP_PARAMETER_TYPE:
 273       g_value_set_boxed (value, g_simple_action_get_parameter_type (action));
 274       break;
 275
 276     case PROP_ENABLED:
 277       g_value_set_boolean (value, g_simple_action_get_enabled (action));
 278       break;
 279
 280     case PROP_STATE_TYPE:
 281       g_value_set_boxed (value, g_simple_action_get_state_type (action));
 282       break;
 283
 284     case PROP_STATE:
 285       g_value_take_variant (value, g_simple_action_get_state (action));
 286       break;
 287
 288     default:
 289       g_assert_not_reached ();
 290     }
 291 }
 292
 293 static void
 294 g_simple_action_finalize (GObject *object)
 295 {
 296   GSimpleAction *simple = G_SIMPLE_ACTION (object);
 297
 298   g_free (simple->name);
 299   if (simple->parameter_type)
 300     g_variant_type_free (simple->parameter_type);
 301   if (simple->state)
 302     g_variant_unref (simple->state);
 303
 304   G_OBJECT_CLASS (g_simple_action_parent_class)
 305     ->finalize (object);
 306 }
 307
 308 void
 309 g_simple_action_init (GSimpleAction *simple)
 310 {
 311   simple->enabled = TRUE;
 312 }
 313
 314 void
 315 g_simple_action_iface_init (GActionInterface *iface)
 316 {
 317   iface->get_name = g_simple_action_get_name;
 318   iface->get_parameter_type = g_simple_action_get_parameter_type;
 319   iface->get_state_type = g_simple_action_get_state_type;
 320   iface->get_state_hint = g_simple_action_get_state_hint;
 321   iface->get_enabled = g_simple_action_get_enabled;
 322   iface->get_state = g_simple_action_get_state;
 323   iface->change_state = g_simple_action_change_state;
 324   iface->activate = g_simple_action_activate;
 325 }
 326
 327 void
 328 g_simple_action_class_init (GSimpleActionClass *class)
 329 {
 330   GObjectClass *object_class = G_OBJECT_CLASS (class);
 331
 332   object_class->set_property = g_simple_action_set_property;
 333   object_class->get_property = g_simple_action_get_property;
 334   object_class->finalize = g_simple_action_finalize;
 335
 336   /**
 337    * GSimpleAction::activate:
 338    * @simple: the #GSimpleAction
 339    * @parameter: (allow-none): the parameter to the activation
 340    *
 341    * Indicates that the action was just activated.
 342    *
 343    * @parameter will always be of the expected type.  In the event that
 344    * an incorrect type was given, no signal will be emitted.
 345    *
 346    * Since: 2.28
 347    */
 348   g_simple_action_signals[SIGNAL_ACTIVATE] =
 349     g_signal_new (I_("activate"),
 350                   G_TYPE_SIMPLE_ACTION,
 351                   G_SIGNAL_RUN_LAST | G_SIGNAL_MUST_COLLECT,
 352                   0, NULL, NULL,
 353                   g_cclosure_marshal_VOID__VARIANT,
 354                   G_TYPE_NONE, 1,
 355                   G_TYPE_VARIANT);
 356
 357   /**
 358    * GSimpleAction::change-state:
 359    * @simple: the #GSimpleAction
 360    * @value: (allow-none): the requested value for the state
 361    *
 362    * Indicates that the action just received a request to change its
 363    * state.
 364    *
 365    * @value will always be of the correct state type.  In the event that
 366    * an incorrect type was given, no signal will be emitted.
 367    *
 368    * If no handler is connected to this signal then the default
 369    * behaviour is to call g_simple_action_set_state() to set the state
 370    * to the requested value.  If you connect a signal handler then no
 371    * default action is taken.  If the state should change then you must
 372    * call g_simple_action_set_state() from the handler.
 373    *
 374    * <example>
 375    * <title>Example 'change-state' handler</title>
 376    * <programlisting>
 377    * static void
 378    * change_volume_state (GSimpleAction *action,
 379    *                      GVariant      *value,
 380    *                      gpointer       user_data)
 381    * {
 382    *   gint requested;
 383    *
 384    *   requested = g_variant_get_int32 (value);
 385    *
 386    *   // Volume only goes from 0 to 10
 387    *   if (0 <= requested && requested <= 10)
 388    *     g_simple_action_set_state (action, value);
 389    * }
 390    * </programlisting>
 391    * </example>
 392    *
 393    * The handler need not set the state to the requested value.  It
 394    * could set it to any value at all, or take some other action.
 395    *
 396    * Since: 2.30
 397    */
 398   g_simple_action_signals[SIGNAL_CHANGE_STATE] =
 399     g_signal_new (I_("change-state"),
 400                   G_TYPE_SIMPLE_ACTION,
 401                   G_SIGNAL_RUN_LAST | G_SIGNAL_MUST_COLLECT,
 402                   0, NULL, NULL,
 403                   g_cclosure_marshal_VOID__VARIANT,
 404                   G_TYPE_NONE, 1,
 405                   G_TYPE_VARIANT);
 406
 407   /**
 408    * GSimpleAction:name:
 409    *
 410    * The name of the action.  This is mostly meaningful for identifying
 411    * the action once it has been added to a #GSimpleActionGroup.
 412    *
 413    * Since: 2.28
 414    **/
 415   g_object_class_install_property (object_class, PROP_NAME,
 416                                    g_param_spec_string ("name",
 417                                                         P_("Action Name"),
 418                                                         P_("The name used to invoke the action"),
 419                                                         NULL,
 420                                                         G_PARAM_READWRITE |
 421                                                         G_PARAM_CONSTRUCT_ONLY |
 422                                                         G_PARAM_STATIC_STRINGS));
 423
 424   /**
 425    * GSimpleAction:parameter-type:
 426    *
 427    * The type of the parameter that must be given when activating the
 428    * action.
 429    *
 430    * Since: 2.28
 431    **/
 432   g_object_class_install_property (object_class, PROP_PARAMETER_TYPE,
 433                                    g_param_spec_boxed ("parameter-type",
 434                                                        P_("Parameter Type"),
 435                                                        P_("The type of GVariant passed to activate()"),
 436                                                        G_TYPE_VARIANT_TYPE,
 437                                                        G_PARAM_READWRITE |
 438                                                        G_PARAM_CONSTRUCT_ONLY |
 439                                                        G_PARAM_STATIC_STRINGS));
 440
 441   /**
 442    * GSimpleAction:enabled:
 443    *
 444    * If @action is currently enabled.
 445    *
 446    * If the action is disabled then calls to g_action_activate() and
 447    * g_action_change_state() have no effect.
 448    *
 449    * Since: 2.28
 450    **/
 451   g_object_class_install_property (object_class, PROP_ENABLED,
 452                                    g_param_spec_boolean ("enabled",
 453                                                          P_("Enabled"),
 454                                                          P_("If the action can be activated"),
 455                                                          TRUE,
 456                                                          G_PARAM_READWRITE |
 457                                                          G_PARAM_STATIC_STRINGS));
 458
 459   /**
 460    * GSimpleAction:state-type:
 461    *
 462    * The #GVariantType of the state that the action has, or %NULL if the
 463    * action is stateless.
 464    *
 465    * Since: 2.28
 466    **/
 467   g_object_class_install_property (object_class, PROP_STATE_TYPE,
 468                                    g_param_spec_boxed ("state-type",
 469                                                        P_("State Type"),
 470                                                        P_("The type of the state kept by the action"),
 471                                                        G_TYPE_VARIANT_TYPE,
 472                                                        G_PARAM_READABLE |
 473                                                        G_PARAM_STATIC_STRINGS));
 474
 475   /**
 476    * GSimpleAction:state:
 477    *
 478    * The state of the action, or %NULL if the action is stateless.
 479    *
 480    * Since: 2.28
 481    **/
 482   g_object_class_install_property (object_class, PROP_STATE,
 483                                    g_param_spec_variant ("state",
 484                                                          P_("State"),
 485                                                          P_("The state the action is in"),
 486                                                          G_VARIANT_TYPE_ANY,
 487                                                          NULL,
 488                                                          G_PARAM_READWRITE | G_PARAM_CONSTRUCT |
 489                                                          G_PARAM_STATIC_STRINGS));
 490 }
 491
 492 /**
 493  * g_simple_action_set_enabled:
 494  * @simple: a #GSimpleAction
 495  * @enabled: whether the action is enabled
 496  *
 497  * Sets the action as enabled or not.
 498  *
 499  * An action must be enabled in order to be activated or in order to
 500  * have its state changed from outside callers.
 501  *
 502  * This should only be called by the implementor of the action.  Users
 503  * of the action should not attempt to modify its enabled flag.
 504  *
 505  * Since: 2.28
 506  **/
 507 void
 508 g_simple_action_set_enabled (GSimpleAction *simple,
 509                              gboolean       enabled)
 510 {
 511   g_return_if_fail (G_IS_SIMPLE_ACTION (simple));
 512
 513   enabled = !!enabled;
 514
 515   if (simple->enabled != enabled)
 516     {
 517       simple->enabled = enabled;
 518       g_object_notify (G_OBJECT (simple), "enabled");
 519     }
 520 }
 521 /**
 522  * g_simple_action_new:
 523  * @name: the name of the action
 524  * @parameter_type: (allow-none): the type of parameter to the activate function
 525  *
 526  * Creates a new action.
 527  *
 528  * The created action is stateless.  See g_simple_action_new_stateful().
 529  *
 530  * Returns: a new #GSimpleAction
 531  *
 532  * Since: 2.28
 533  **/
 534 GSimpleAction *
 535 g_simple_action_new (const gchar        *name,
 536                      const GVariantType *parameter_type)
 537 {
 538   return g_object_new (G_TYPE_SIMPLE_ACTION,
 539                        "name", name,
 540                        "parameter-type", parameter_type,
 541                        NULL);
 542 }
 543
 544 /**
 545  * g_simple_action_new_stateful:
 546  * @name: the name of the action
 547  * @parameter_type: (allow-none): the type of the parameter to the activate function
 548  * @state: the initial state of the action
 549  *
 550  * Creates a new stateful action.
 551  *
 552  * @state is the initial state of the action.  All future state values
 553  * must have the same #GVariantType as the initial state.
 554  *
 555  * If the @state GVariant is floating, it is consumed.
 556  *
 557  * Returns: a new #GSimpleAction
 558  *
 559  * Since: 2.28
 560  **/
 561 GSimpleAction *
 562 g_simple_action_new_stateful (const gchar        *name,
 563                               const GVariantType *parameter_type,
 564                               GVariant           *state)
 565 {
 566   return g_object_new (G_TYPE_SIMPLE_ACTION,
 567                        "name", name,
 568                        "parameter-type", parameter_type,
 569                        "state", state,
 570                        NULL);
 571 }