gio/gaction.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 #include "gaction.h"
  24 #include "glibintl.h"
  25
  26 #include <string.h>
  27
  28 G_DEFINE_INTERFACE (GAction, g_action, G_TYPE_OBJECT)
  29
  30 /**
  31  * SECTION:gaction
  32  * @title: GAction
  33  * @short_description: An action interface
  34  *
  35  * #GAction represents a single named action.
  36  *
  37  * The main interface to an action is that it can be activated with
  38  * g_action_activate().  This results in the 'activate' signal being
  39  * emitted.  An activation has a #GVariant parameter (which may be
  40  * %NULL).  The correct type for the parameter is determined by a static
  41  * parameter type (which is given at construction time).
  42  *
  43  * An action may optionally have a state, in which case the state may be
  44  * set with g_action_change_state().  This call takes a #GVariant.  The
  45  * correct type for the state is determined by a static state type
  46  * (which is given at construction time).
  47  *
  48  * The state may have a hint associated with it, specifying its valid
  49  * range.
  50  *
  51  * #GAction is merely the interface to the concept of an action, as
  52  * described above.  Various implementations of actions exist, including
  53  * #GSimpleAction and #GtkAction.
  54  *
  55  * In all cases, the implementing class is responsible for storing the
  56  * name of the action, the parameter type, the enabled state, the
  57  * optional state type and the state and emitting the appropriate
  58  * signals when these change.  The implementor responsible for filtering
  59  * calls to g_action_activate() and g_action_change_state() for type
  60  * safety and for the state being enabled.
  61  *
  62  * Probably the only useful thing to do with a #GAction is to put it
  63  * inside of a #GSimpleActionGroup.
  64  **/
  65
  66 /**
  67  * GActionInterface:
  68  * @get_name: the virtual function pointer for g_action_get_name()
  69  * @get_parameter_type: the virtual function pointer for g_action_get_parameter_type()
  70  * @get_state_type: the virtual function pointer for g_action_get_state_type()
  71  * @get_state_hint: the virtual function pointer for g_action_get_state_hint()
  72  * @get_enabled: the virtual function pointer for g_action_get_enabled()
  73  * @get_state: the virtual function pointer for g_action_get_state()
  74  * @change_state: the virtual function pointer for g_action_change_state()
  75  * @activate: the virtual function pointer for g_action_activate().  Note that #GAction does not have an
  76  *            'activate' signal but that implementations of it may have one.
  77  *
  78  * The virtual function table for #GAction.
  79  *
  80  * Since: 2.28
  81  */
  82
  83 void
  84 g_action_default_init (GActionInterface *iface)
  85 {
  86   /**
  87    * GAction:name:
  88    *
  89    * The name of the action.  This is mostly meaningful for identifying
  90    * the action once it has been added to a #GActionGroup.
  91    *
  92    * Since: 2.28
  93    **/
  94   g_object_interface_install_property (iface,
  95                                        g_param_spec_string ("name",
  96                                                             P_("Action Name"),
  97                                                             P_("The name used to invoke the action"),
  98                                                             NULL,
  99                                                             G_PARAM_READABLE |
 100                                                             G_PARAM_STATIC_STRINGS));
 101
 102   /**
 103    * GAction:parameter-type:
 104    *
 105    * The type of the parameter that must be given when activating the
 106    * action.
 107    *
 108    * Since: 2.28
 109    **/
 110   g_object_interface_install_property (iface,
 111                                        g_param_spec_boxed ("parameter-type",
 112                                                            P_("Parameter Type"),
 113                                                            P_("The type of GVariant passed to activate()"),
 114                                                            G_TYPE_VARIANT_TYPE,
 115                                                            G_PARAM_READABLE |
 116                                                            G_PARAM_STATIC_STRINGS));
 117
 118   /**
 119    * GAction:enabled:
 120    *
 121    * If @action is currently enabled.
 122    *
 123    * If the action is disabled then calls to g_action_activate() and
 124    * g_action_change_state() have no effect.
 125    *
 126    * Since: 2.28
 127    **/
 128   g_object_interface_install_property (iface,
 129                                        g_param_spec_boolean ("enabled",
 130                                                              P_("Enabled"),
 131                                                              P_("If the action can be activated"),
 132                                                              TRUE,
 133                                                              G_PARAM_READABLE |
 134                                                              G_PARAM_STATIC_STRINGS));
 135
 136   /**
 137    * GAction:state-type:
 138    *
 139    * The #GVariantType of the state that the action has, or %NULL if the
 140    * action is stateless.
 141    *
 142    * Since: 2.28
 143    **/
 144   g_object_interface_install_property (iface,
 145                                        g_param_spec_boxed ("state-type",
 146                                                            P_("State Type"),
 147                                                            P_("The type of the state kept by the action"),
 148                                                            G_TYPE_VARIANT_TYPE,
 149                                                            G_PARAM_READABLE |
 150                                                            G_PARAM_STATIC_STRINGS));
 151
 152   /**
 153    * GAction:state:
 154    *
 155    * The state of the action, or %NULL if the action is stateless.
 156    *
 157    * Since: 2.28
 158    **/
 159   g_object_interface_install_property (iface,
 160                                        g_param_spec_variant ("state",
 161                                                              P_("State"),
 162                                                              P_("The state the action is in"),
 163                                                              G_VARIANT_TYPE_ANY,
 164                                                              NULL,
 165                                                              G_PARAM_READABLE |
 166                                                              G_PARAM_STATIC_STRINGS));
 167 }
 168
 169 /**
 170  * g_action_change_state:
 171  * @action: a #GAction
 172  * @value: the new state
 173  *
 174  * Request for the state of @action to be changed to @value.
 175  *
 176  * The action must be stateful and @value must be of the correct type.
 177  * See g_action_get_state_type().
 178  *
 179  * This call merely requests a change.  The action may refuse to change
 180  * its state or may change its state to something other than @value.
 181  * See g_action_get_state_hint().
 182  *
 183  * If the @value GVariant is floating, it is consumed.
 184  *
 185  * Since: 2.30
 186  **/
 187 void
 188 g_action_change_state (GAction  *action,
 189                        GVariant *value)
 190 {
 191   const GVariantType *state_type;
 192
 193   g_return_if_fail (G_IS_ACTION (action));
 194   g_return_if_fail (value != NULL);
 195   state_type = g_action_get_state_type (action);
 196   g_return_if_fail (state_type != NULL);
 197   g_return_if_fail (g_variant_is_of_type (value, state_type));
 198
 199   g_variant_ref_sink (value);
 200
 201   G_ACTION_GET_IFACE (action)
 202     ->change_state (action, value);
 203
 204   g_variant_unref (value);
 205 }
 206
 207 /**
 208  * g_action_get_state:
 209  * @action: a #GAction
 210  *
 211  * Queries the current state of @action.
 212  *
 213  * If the action is not stateful then %NULL will be returned.  If the
 214  * action is stateful then the type of the return value is the type
 215  * given by g_action_get_state_type().
 216  *
 217  * The return value (if non-%NULL) should be freed with
 218  * g_variant_unref() when it is no longer required.
 219  *
 220  * Returns: (transfer full): the current state of the action
 221  *
 222  * Since: 2.28
 223  **/
 224 GVariant *
 225 g_action_get_state (GAction *action)
 226 {
 227   g_return_val_if_fail (G_IS_ACTION (action), NULL);
 228
 229   return G_ACTION_GET_IFACE (action)
 230     ->get_state (action);
 231 }
 232
 233 /**
 234  * g_action_get_name:
 235  * @action: a #GAction
 236  *
 237  * Queries the name of @action.
 238  *
 239  * Returns: the name of the action
 240  *
 241  * Since: 2.28
 242  **/
 243 const gchar *
 244 g_action_get_name (GAction *action)
 245 {
 246   g_return_val_if_fail (G_IS_ACTION (action), NULL);
 247
 248   return G_ACTION_GET_IFACE (action)
 249     ->get_name (action);
 250 }
 251
 252 /**
 253  * g_action_get_parameter_type:
 254  * @action: a #GAction
 255  *
 256  * Queries the type of the parameter that must be given when activating
 257  * @action.
 258  *
 259  * When activating the action using g_action_activate(), the #GVariant
 260  * given to that function must be of the type returned by this function.
 261  *
 262  * In the case that this function returns %NULL, you must not give any
 263  * #GVariant, but %NULL instead.
 264  *
 265  * Returns: (allow-none): the parameter type
 266  *
 267  * Since: 2.28
 268  **/
 269 const GVariantType *
 270 g_action_get_parameter_type (GAction *action)
 271 {
 272   g_return_val_if_fail (G_IS_ACTION (action), NULL);
 273
 274   return G_ACTION_GET_IFACE (action)
 275     ->get_parameter_type (action);
 276 }
 277
 278 /**
 279  * g_action_get_state_type:
 280  * @action: a #GAction
 281  *
 282  * Queries the type of the state of @action.
 283  *
 284  * If the action is stateful (e.g. created with
 285  * g_simple_action_new_stateful()) then this function returns the
 286  * #GVariantType of the state.  This is the type of the initial value
 287  * given as the state. All calls to g_action_change_state() must give a
 288  * #GVariant of this type and g_action_get_state() will return a
 289  * #GVariant of the same type.
 290  *
 291  * If the action is not stateful (e.g. created with g_simple_action_new())
 292  * then this function will return %NULL. In that case, g_action_get_state()
 293  * will return %NULL and you must not call g_action_change_state().
 294  *
 295  * Returns: (allow-none): the state type, if the action is stateful
 296  *
 297  * Since: 2.28
 298  **/
 299 const GVariantType *
 300 g_action_get_state_type (GAction *action)
 301 {
 302   g_return_val_if_fail (G_IS_ACTION (action), NULL);
 303
 304   return G_ACTION_GET_IFACE (action)
 305     ->get_state_type (action);
 306 }
 307
 308 /**
 309  * g_action_get_state_hint:
 310  * @action: a #GAction
 311  *
 312  * Requests a hint about the valid range of values for the state of
 313  * @action.
 314  *
 315  * If %NULL is returned it either means that the action is not stateful
 316  * or that there is no hint about the valid range of values for the
 317  * state of the action.
 318  *
 319  * If a #GVariant array is returned then each item in the array is a
 320  * possible value for the state.  If a #GVariant pair (ie: two-tuple) is
 321  * returned then the tuple specifies the inclusive lower and upper bound
 322  * of valid values for the state.
 323  *
 324  * In any case, the information is merely a hint.  It may be possible to
 325  * have a state value outside of the hinted range and setting a value
 326  * within the range may fail.
 327  *
 328  * The return value (if non-%NULL) should be freed with
 329  * g_variant_unref() when it is no longer required.
 330  *
 331  * Returns: (transfer full): the state range hint
 332  *
 333  * Since: 2.28
 334  **/
 335 GVariant *
 336 g_action_get_state_hint (GAction *action)
 337 {
 338   g_return_val_if_fail (G_IS_ACTION (action), NULL);
 339
 340   return G_ACTION_GET_IFACE (action)
 341     ->get_state_hint (action);
 342 }
 343
 344 /**
 345  * g_action_get_enabled:
 346  * @action: a #GAction
 347  *
 348  * Checks if @action is currently enabled.
 349  *
 350  * An action must be enabled in order to be activated or in order to
 351  * have its state changed from outside callers.
 352  *
 353  * Returns: whether the action is enabled
 354  *
 355  * Since: 2.28
 356  **/
 357 gboolean
 358 g_action_get_enabled (GAction *action)
 359 {
 360   g_return_val_if_fail (G_IS_ACTION (action), FALSE);
 361
 362   return G_ACTION_GET_IFACE (action)
 363     ->get_enabled (action);
 364 }
 365
 366 /**
 367  * g_action_activate:
 368  * @action: a #GAction
 369  * @parameter: (allow-none): the parameter to the activation
 370  *
 371  * Activates the action.
 372  *
 373  * @parameter must be the correct type of parameter for the action (ie:
 374  * the parameter type given at construction time).  If the parameter
 375  * type was %NULL then @parameter must also be %NULL.
 376  *
 377  * If the @parameter GVariant is floating, it is consumed.
 378  *
 379  * Since: 2.28
 380  **/
 381 void
 382 g_action_activate (GAction  *action,
 383                    GVariant *parameter)
 384 {
 385   g_return_if_fail (G_IS_ACTION (action));
 386
 387   if (parameter != NULL)
 388     g_variant_ref_sink (parameter);
 389
 390   G_ACTION_GET_IFACE (action)
 391     ->activate (action, parameter);
 392
 393   if (parameter != NULL)
 394     g_variant_unref (parameter);
 395 }
 396
 397 /**
 398  * g_action_name_is_valid:
 399  * @action_name: an potential action name
 400  *
 401  * Checks if @action_name is valid.
 402  *
 403  * @action_name is valid if it consists only of alphanumeric characters,
 404  * plus '-' and '.'.  The empty string is not a valid action name.
 405  *
 406  * It is an error to call this function with a non-utf8 @action_name.
 407  * @action_name must not be %NULL.
 408  *
 409  * Returns: %TRUE if @action_name is valid
 410  *
 411  * Since: 2.38
 412  **/
 413 gboolean
 414 g_action_name_is_valid (const gchar *action_name)
 415 {
 416   gchar c;
 417   gint i;
 418
 419   g_return_val_if_fail (action_name != NULL, FALSE);
 420
 421   for (i = 0; (c = action_name[i]); i++)
 422     if (!g_ascii_isalnum (c) && c != '.' && c != '-')
 423       return FALSE;
 424
 425   return i > 0;
 426 }
 427
 428 /**
 429  * g_action_parse_detailed_name:
 430  * @detailed_name: a detailed action name
 431  * @action_name: (out): the action name
 432  * @target_value: (out): the target value, or %NULL for no target
 433  * @error: a pointer to a %NULL #GError, or %NULL
 434  *
 435  * Parses a detailed action name into its separate name and target
 436  * components.
 437  *
 438  * Detailed action names can have three formats.
 439  *
 440  * The first format is used to represent an action name with no target
 441  * value and consists of just an action name containing no whitespace
 442  * nor the characters ':', '(' or ')'.  For example: "app.action".
 443  *
 444  * The second format is used to represent an action with a target value
 445  * that is a non-empty string consisting only of alphanumerics, plus '-'
 446  * and '.'.  In that case, the action name and target value are
 447  * separated by a double colon ("::").  For example:
 448  * "app.action::target".
 449  *
 450  * The third format is used to represent an action with any type of
 451  * target value, including strings.  The target value follows the action
 452  * name, surrounded in parens.  For example: "app.action(42)".  The
 453  * target value is parsed using g_variant_parse().  If a tuple-typed
 454  * value is desired, it must be specified in the same way, resulting in
 455  * two sets of parens, for example: "app.action((1,2,3))".  A string
 456  * target can be specified this way as well: "app.action('target')".
 457  * For strings, this third format must be used if * target value is
 458  * empty or contains characters other than alphanumerics, '-' and '.'.
 459  *
 460  * Returns: %TRUE if successful, else %FALSE with @error set
 461  *
 462  * Since: 2.38
 463  **/
 464 gboolean
 465 g_action_parse_detailed_name (const gchar  *detailed_name,
 466                               gchar       **action_name,
 467                               GVariant    **target_value,
 468                               GError      **error)
 469 {
 470   const gchar *target;
 471   gsize target_len;
 472   gsize base_len;
 473
 474   /* For historical (compatibility) reasons, this function accepts some
 475    * cases of invalid action names as long as they don't interfere with
 476    * the separation of the action from the target value.
 477    *
 478    * We decide which format we have based on which we see first between
 479    * '::' '(' and '\0'.
 480    */
 481
 482   if (*detailed_name == '\0' || *detailed_name == ' ')
 483     goto bad_fmt;
 484
 485   base_len = strcspn (detailed_name, ": ()");
 486   target = detailed_name + base_len;
 487   target_len = strlen (target);
 488
 489   switch (target[0])
 490     {
 491     case ' ':
 492     case ')':
 493       goto bad_fmt;
 494
 495     case ':':
 496       if (target[1] != ':')
 497         goto bad_fmt;
 498
 499       *target_value = g_variant_ref_sink (g_variant_new_string (target + 2));
 500       break;
 501
 502     case '(':
 503       {
 504         if (target[target_len - 1] != ')')
 505           goto bad_fmt;
 506
 507         *target_value = g_variant_parse (NULL, target + 1, target + target_len - 1, NULL, error);
 508         if (*target_value == NULL)
 509           goto bad_fmt;
 510       }
 511       break;
 512
 513     case '\0':
 514       *target_value = NULL;
 515       break;
 516     }
 517
 518   *action_name = g_strndup (detailed_name, base_len);
 519
 520   return TRUE;
 521
 522 bad_fmt:
 523   if (error)
 524     {
 525       if (*error == NULL)
 526         g_set_error (error, G_VARIANT_PARSE_ERROR, G_VARIANT_PARSE_ERROR_FAILED,
 527                      "Detailed action name '%s' has invalid format", detailed_name);
 528       else
 529         g_prefix_error (error, "Detailed action name '%s' has invalid format: ", detailed_name);
 530     }
 531
 532   return FALSE;
 533 }
 534
 535 /**
 536  * g_action_print_detailed_name:
 537  * @action_name: a valid action name
 538  * @target_value: (allow-none): a #GVariant target value, or %NULL
 539  *
 540  * Formats a detailed action name from @action_name and @target_value.
 541  *
 542  * It is an error to call this function with an invalid action name.
 543  *
 544  * This function is the opposite of
 545  * g_action_parse_detailed_action_name().  It will produce a string that
 546  * can be parsed back to the @action_name and @target_value by that
 547  * function.
 548  *
 549  * See that function for the types of strings that will be printed by
 550  * this function.
 551  *
 552  * Returns: a detailed format string
 553  *
 554  * Since: 2.38
 555  **/
 556 gchar *
 557 g_action_print_detailed_name (const gchar *action_name,
 558                               GVariant    *target_value)
 559 {
 560   g_return_val_if_fail (g_action_name_is_valid (action_name), NULL);
 561
 562   if (target_value == NULL)
 563     return g_strdup (action_name);
 564
 565   if (g_variant_is_of_type (target_value, G_VARIANT_TYPE_STRING))
 566     {
 567       const gchar *str = g_variant_get_string (target_value, NULL);
 568
 569       if (g_action_name_is_valid (str))
 570         return g_strconcat (action_name, "::", str, NULL);
 571     }
 572
 573   {
 574     GString *result = g_string_new (action_name);
 575     g_string_append_c (result, '(');
 576     g_variant_print_string (target_value, result, TRUE);
 577     g_string_append_c (result, ')');
 578
 579     return g_string_free (result, FALSE);
 580   }
 581 }