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 };
  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     g_signal_emit (simple, g_simple_action_signals[SIGNAL_ACTIVATE], 0, parameter);
 207
 208   if (parameter != NULL)
 209     g_variant_unref (parameter);
 210 }
 211
 212 static void
 213 g_simple_action_set_property (GObject    *object,
 214                               guint       prop_id,
 215                               const GValue     *value,
 216                               GParamSpec *pspec)
 217 {
 218   GSimpleAction *action = G_SIMPLE_ACTION (object);
 219
 220   switch (prop_id)
 221     {
 222     case PROP_NAME:
 223       action->name = g_strdup (g_value_get_string (value));
 224       break;
 225
 226     case PROP_PARAMETER_TYPE:
 227       action->parameter_type = g_value_dup_boxed (value);
 228       break;
 229
 230     case PROP_ENABLED:
 231       action->enabled = g_value_get_boolean (value);
 232       break;
 233
 234     case PROP_STATE:
 235       action->state = g_value_dup_variant (value);
 236       break;
 237
 238     default:
 239       g_assert_not_reached ();
 240     }
 241 }
 242
 243 static void
 244 g_simple_action_get_property (GObject    *object,
 245                               guint       prop_id,
 246                               GValue     *value,
 247                               GParamSpec *pspec)
 248 {
 249   GAction *action = G_ACTION (object);
 250
 251   switch (prop_id)
 252     {
 253     case PROP_NAME:
 254       g_value_set_string (value, g_simple_action_get_name (action));
 255       break;
 256
 257     case PROP_PARAMETER_TYPE:
 258       g_value_set_boxed (value, g_simple_action_get_parameter_type (action));
 259       break;
 260
 261     case PROP_ENABLED:
 262       g_value_set_boolean (value, g_simple_action_get_enabled (action));
 263       break;
 264
 265     case PROP_STATE_TYPE:
 266       g_value_set_boxed (value, g_simple_action_get_state_type (action));
 267       break;
 268
 269     case PROP_STATE:
 270       g_value_take_variant (value, g_simple_action_get_state (action));
 271       break;
 272
 273     default:
 274       g_assert_not_reached ();
 275     }
 276 }
 277
 278 static void
 279 g_simple_action_finalize (GObject *object)
 280 {
 281   GSimpleAction *simple = G_SIMPLE_ACTION (object);
 282
 283   g_free (simple->name);
 284   if (simple->parameter_type)
 285     g_variant_type_free (simple->parameter_type);
 286   if (simple->state)
 287     g_variant_unref (simple->state);
 288
 289   G_OBJECT_CLASS (g_simple_action_parent_class)
 290     ->finalize (object);
 291 }
 292
 293 void
 294 g_simple_action_init (GSimpleAction *simple)
 295 {
 296   simple->enabled = TRUE;
 297 }
 298
 299 void
 300 g_simple_action_iface_init (GActionInterface *iface)
 301 {
 302   iface->get_name = g_simple_action_get_name;
 303   iface->get_parameter_type = g_simple_action_get_parameter_type;
 304   iface->get_state_type = g_simple_action_get_state_type;
 305   iface->get_state_hint = g_simple_action_get_state_hint;
 306   iface->get_enabled = g_simple_action_get_enabled;
 307   iface->get_state = g_simple_action_get_state;
 308   iface->change_state = g_simple_action_change_state;
 309   iface->activate = g_simple_action_activate;
 310 }
 311
 312 void
 313 g_simple_action_class_init (GSimpleActionClass *class)
 314 {
 315   GObjectClass *object_class = G_OBJECT_CLASS (class);
 316
 317   object_class->set_property = g_simple_action_set_property;
 318   object_class->get_property = g_simple_action_get_property;
 319   object_class->finalize = g_simple_action_finalize;
 320
 321   /**
 322    * GSimpleAction::activate:
 323    * @simple: the #GSimpleAction
 324    * @parameter: (allow-none): the parameter to the activation
 325    *
 326    * Indicates that the action was just activated.
 327    *
 328    * @parameter will always be of the expected type.  In the event that
 329    * an incorrect type was given, no signal will be emitted.
 330    *
 331    * Since: 2.28
 332    */
 333   g_simple_action_signals[SIGNAL_ACTIVATE] =
 334     g_signal_new (I_("activate"),
 335                   G_TYPE_SIMPLE_ACTION,
 336                   G_SIGNAL_RUN_LAST | G_SIGNAL_MUST_COLLECT,
 337                   0, NULL, NULL,
 338                   g_cclosure_marshal_VOID__VARIANT,
 339                   G_TYPE_NONE, 1,
 340                   G_TYPE_VARIANT);
 341
 342   /**
 343    * GSimpleAction::change-state:
 344    * @simple: the #GSimpleAction
 345    * @value: (allow-none): the requested value for the state
 346    *
 347    * Indicates that the action just received a request to change its
 348    * state.
 349    *
 350    * @value will always be of the correct state type.  In the event that
 351    * an incorrect type was given, no signal will be emitted.
 352    *
 353    * If no handler is connected to this signal then the default
 354    * behaviour is to call g_simple_action_set_state() to set the state
 355    * to the requested value.  If you connect a signal handler then no
 356    * default action is taken.  If the state should change then you must
 357    * call g_simple_action_set_state() from the handler.
 358    *
 359    * <example>
 360    * <title>Example 'change-state' handler</title>
 361    * <programlisting>
 362    * static void
 363    * change_volume_state (GSimpleAction *action,
 364    *                      GVariant      *value,
 365    *                      gpointer       user_data)
 366    * {
 367    *   gint requested;
 368    *
 369    *   requested = g_variant_get_int32 (value);
 370    *
 371    *   // Volume only goes from 0 to 10
 372    *   if (0 <= requested && requested <= 10)
 373    *     g_simple_action_set_state (action, value);
 374    * }
 375    * </programlisting>
 376    * </example>
 377    *
 378    * The handler need not set the state to the requested value.  It
 379    * could set it to any value at all, or take some other action.
 380    *
 381    * Since: 2.30
 382    */
 383   g_simple_action_signals[SIGNAL_CHANGE_STATE] =
 384     g_signal_new (I_("change-state"),
 385                   G_TYPE_SIMPLE_ACTION,
 386                   G_SIGNAL_RUN_LAST | G_SIGNAL_MUST_COLLECT,
 387                   0, NULL, NULL,
 388                   g_cclosure_marshal_VOID__VARIANT,
 389                   G_TYPE_NONE, 1,
 390                   G_TYPE_VARIANT);
 391
 392   /**
 393    * GSimpleAction:name:
 394    *
 395    * The name of the action.  This is mostly meaningful for identifying
 396    * the action once it has been added to a #GSimpleActionGroup.
 397    *
 398    * Since: 2.28
 399    **/
 400   g_object_class_install_property (object_class, PROP_NAME,
 401                                    g_param_spec_string ("name",
 402                                                         P_("Action Name"),
 403                                                         P_("The name used to invoke the action"),
 404                                                         NULL,
 405                                                         G_PARAM_READWRITE |
 406                                                         G_PARAM_CONSTRUCT_ONLY |
 407                                                         G_PARAM_STATIC_STRINGS));
 408
 409   /**
 410    * GSimpleAction:parameter-type:
 411    *
 412    * The type of the parameter that must be given when activating the
 413    * action.
 414    *
 415    * Since: 2.28
 416    **/
 417   g_object_class_install_property (object_class, PROP_PARAMETER_TYPE,
 418                                    g_param_spec_boxed ("parameter-type",
 419                                                        P_("Parameter Type"),
 420                                                        P_("The type of GVariant passed to activate()"),
 421                                                        G_TYPE_VARIANT_TYPE,
 422                                                        G_PARAM_READWRITE |
 423                                                        G_PARAM_CONSTRUCT_ONLY |
 424                                                        G_PARAM_STATIC_STRINGS));
 425
 426   /**
 427    * GSimpleAction:enabled:
 428    *
 429    * If @action is currently enabled.
 430    *
 431    * If the action is disabled then calls to g_action_activate() and
 432    * g_action_change_state() have no effect.
 433    *
 434    * Since: 2.28
 435    **/
 436   g_object_class_install_property (object_class, PROP_ENABLED,
 437                                    g_param_spec_boolean ("enabled",
 438                                                          P_("Enabled"),
 439                                                          P_("If the action can be activated"),
 440                                                          TRUE,
 441                                                          G_PARAM_READWRITE |
 442                                                          G_PARAM_STATIC_STRINGS));
 443
 444   /**
 445    * GSimpleAction:state-type:
 446    *
 447    * The #GVariantType of the state that the action has, or %NULL if the
 448    * action is stateless.
 449    *
 450    * Since: 2.28
 451    **/
 452   g_object_class_install_property (object_class, PROP_STATE_TYPE,
 453                                    g_param_spec_boxed ("state-type",
 454                                                        P_("State Type"),
 455                                                        P_("The type of the state kept by the action"),
 456                                                        G_TYPE_VARIANT_TYPE,
 457                                                        G_PARAM_READABLE |
 458                                                        G_PARAM_STATIC_STRINGS));
 459
 460   /**
 461    * GSimpleAction:state:
 462    *
 463    * The state of the action, or %NULL if the action is stateless.
 464    *
 465    * Since: 2.28
 466    **/
 467   g_object_class_install_property (object_class, PROP_STATE,
 468                                    g_param_spec_variant ("state",
 469                                                          P_("State"),
 470                                                          P_("The state the action is in"),
 471                                                          G_VARIANT_TYPE_ANY,
 472                                                          NULL,
 473                                                          G_PARAM_READWRITE |
 474                                                          G_PARAM_STATIC_STRINGS));
 475 }
 476
 477 /**
 478  * g_simple_action_set_enabled:
 479  * @simple: a #GSimpleAction
 480  * @enabled: whether the action is enabled
 481  *
 482  * Sets the action as enabled or not.
 483  *
 484  * An action must be enabled in order to be activated or in order to
 485  * have its state changed from outside callers.
 486  *
 487  * This should only be called by the implementor of the action.  Users
 488  * of the action should not attempt to modify its enabled flag.
 489  *
 490  * Since: 2.28
 491  **/
 492 void
 493 g_simple_action_set_enabled (GSimpleAction *simple,
 494                              gboolean       enabled)
 495 {
 496   g_return_if_fail (G_IS_SIMPLE_ACTION (simple));
 497
 498   enabled = !!enabled;
 499
 500   if (simple->enabled != enabled)
 501     {
 502       simple->enabled = enabled;
 503       g_object_notify (G_OBJECT (simple), "enabled");
 504     }
 505 }
 506 /**
 507  * g_simple_action_new:
 508  * @name: the name of the action
 509  * @parameter_type: (allow-none): the type of parameter to the activate function
 510  *
 511  * Creates a new action.
 512  *
 513  * The created action is stateless.  See g_simple_action_new_stateful().
 514  *
 515  * Returns: a new #GSimpleAction
 516  *
 517  * Since: 2.28
 518  **/
 519 GSimpleAction *
 520 g_simple_action_new (const gchar        *name,
 521                      const GVariantType *parameter_type)
 522 {
 523   return g_object_new (G_TYPE_SIMPLE_ACTION,
 524                        "name", name,
 525                        "parameter-type", parameter_type,
 526                        NULL);
 527 }
 528
 529 /**
 530  * g_simple_action_new_stateful:
 531  * @name: the name of the action
 532  * @parameter_type: (allow-none): the type of the parameter to the activate function
 533  * @state: the initial state of the action
 534  *
 535  * Creates a new stateful action.
 536  *
 537  * @state is the initial state of the action.  All future state values
 538  * must have the same #GVariantType as the initial state.
 539  *
 540  * If the @state GVariant is floating, it is consumed.
 541  *
 542  * Returns: a new #GSimpleAction
 543  *
 544  * Since: 2.28
 545  **/
 546 GSimpleAction *
 547 g_simple_action_new_stateful (const gchar        *name,
 548                               const GVariantType *parameter_type,
 549                               GVariant           *state)
 550 {
 551   return g_object_new (G_TYPE_SIMPLE_ACTION,
 552                        "name", name,
 553                        "parameter-type", parameter_type,
 554                        "state", state,
 555                        NULL);
 556 }