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