gio/gaction.c

   1 /*
   2  * Copyright © 2010 Codethink Limited
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at 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 #include "gaction.h"
  22 #include "glibintl.h"
  23
  24 #include <string.h>
  25
  26 G_DEFINE_INTERFACE (GAction, g_action, G_TYPE_OBJECT)
  27
  28 /**
  29  * SECTION:gaction
  30  * @title: GAction
  31  * @short_description: An action interface
  32  * @include: gio/gio.h
  33  *
  34  * #GAction represents a single named action.
  35  *
  36  * The main interface to an action is that it can be activated with
  37  * g_action_activate().  This results in the 'activate' signal being
  38  * emitted.  An activation has a #GVariant parameter (which may be
  39  * %NULL).  The correct type for the parameter is determined by a static
  40  * parameter type (which is given at construction time).
  41  *
  42  * An action may optionally have a state, in which case the state may be
  43  * set with g_action_change_state().  This call takes a #GVariant.  The
  44  * correct type for the state is determined by a static state type
  45  * (which is given at construction time).
  46  *
  47  * The state may have a hint associated with it, specifying its valid
  48  * range.
  49  *
  50  * #GAction is merely the interface to the concept of an action, as
  51  * described above.  Various implementations of actions exist, including
  52  * #GSimpleAction.
  53  *
  54  * In all cases, the implementing class is responsible for storing the
  55  * name of the action, the parameter type, the enabled state, the
  56  * optional state type and the state and emitting the appropriate
  57  * signals when these change.  The implementor is responsible for filtering
  58  * calls to g_action_activate() and g_action_change_state() for type
  59  * safety and for the state being enabled.
  60  *
  61  * Probably the only useful thing to do with a #GAction is to put it
  62  * inside of a #GSimpleActionGroup.
  63  **/
  64
  65 /**
  66  * GAction:
  67  *
  68  * #GAction is an opaque data structure and can only be accessed
  69  * using the following functions.
  70  **/
  71
  72 /**
  73  * GActionInterface:
  74  * @get_name: the virtual function pointer for g_action_get_name()
  75  * @get_parameter_type: the virtual function pointer for g_action_get_parameter_type()
  76  * @get_state_type: the virtual function pointer for g_action_get_state_type()
  77  * @get_state_hint: the virtual function pointer for g_action_get_state_hint()
  78  * @get_enabled: the virtual function pointer for g_action_get_enabled()
  79  * @get_state: the virtual function pointer for g_action_get_state()
  80  * @change_state: the virtual function pointer for g_action_change_state()
  81  * @activate: the virtual function pointer for g_action_activate().  Note that #GAction does not have an
  82  *            'activate' signal but that implementations of it may have one.
  83  *
  84  * The virtual function table for #GAction.
  85  *
  86  * Since: 2.28
  87  */
  88
  89 void
  90 g_action_default_init (GActionInterface *iface)
  91 {
  92   /**
  93    * GAction:name:
  94    *
  95    * The name of the action.  This is mostly meaningful for identifying
  96    * the action once it has been added to a #GActionGroup. It is immutable.
  97    *
  98    * Since: 2.28
  99    **/
 100   g_object_interface_install_property (iface,
 101                                        g_param_spec_string ("name",
 102                                                             P_("Action Name"),
 103                                                             P_("The name used to invoke the action"),
 104                                                             NULL,
 105                                                             G_PARAM_READABLE |
 106                                                             G_PARAM_STATIC_STRINGS));
 107
 108   /**
 109    * GAction:parameter-type:
 110    *
 111    * The type of the parameter that must be given when activating the
 112    * action. This is immutable, and may be %NULL if no parameter is needed when
 113    * activating the action.
 114    *
 115    * Since: 2.28
 116    **/
 117   g_object_interface_install_property (iface,
 118                                        g_param_spec_boxed ("parameter-type",
 119                                                            P_("Parameter Type"),
 120                                                            P_("The type of GVariant passed to activate()"),
 121                                                            G_TYPE_VARIANT_TYPE,
 122                                                            G_PARAM_READABLE |
 123                                                            G_PARAM_STATIC_STRINGS));
 124
 125   /**
 126    * GAction:enabled:
 127    *
 128    * If @action is currently enabled.
 129    *
 130    * If the action is disabled then calls to g_action_activate() and
 131    * g_action_change_state() have no effect.
 132    *
 133    * Since: 2.28
 134    **/
 135   g_object_interface_install_property (iface,
 136                                        g_param_spec_boolean ("enabled",
 137                                                              P_("Enabled"),
 138                                                              P_("If the action can be activated"),
 139                                                              TRUE,
 140                                                              G_PARAM_READABLE |
 141                                                              G_PARAM_STATIC_STRINGS));
 142
 143   /**
 144    * GAction:state-type:
 145    *
 146    * The #GVariantType of the state that the action has, or %NULL if the
 147    * action is stateless. This is immutable.
 148    *
 149    * Since: 2.28
 150    **/
 151   g_object_interface_install_property (iface,
 152                                        g_param_spec_boxed ("state-type",
 153                                                            P_("State Type"),
 154                                                            P_("The type of the state kept by the action"),
 155                                                            G_TYPE_VARIANT_TYPE,
 156                                                            G_PARAM_READABLE |
 157                                                            G_PARAM_STATIC_STRINGS));
 158
 159   /**
 160    * GAction:state:
 161    *
 162    * The state of the action, or %NULL if the action is stateless.
 163    *
 164    * Since: 2.28
 165    **/
 166   g_object_interface_install_property (iface,
 167                                        g_param_spec_variant ("state",
 168                                                              P_("State"),
 169                                                              P_("The state the action is in"),
 170                                                              G_VARIANT_TYPE_ANY,
 171                                                              NULL,
 172                                                              G_PARAM_READABLE |
 173                                                              G_PARAM_STATIC_STRINGS));
 174 }
 175
 176 /**
 177  * g_action_change_state:
 178  * @action: a #GAction
 179  * @value: the new state
 180  *
 181  * Request for the state of @action to be changed to @value.
 182  *
 183  * The action must be stateful and @value must be of the correct type.
 184  * See g_action_get_state_type().
 185  *
 186  * This call merely requests a change.  The action may refuse to change
 187  * its state or may change its state to something other than @value.
 188  * See g_action_get_state_hint().
 189  *
 190  * If the @value GVariant is floating, it is consumed.
 191  *
 192  * Since: 2.30
 193  **/
 194 void
 195 g_action_change_state (GAction  *action,
 196                        GVariant *value)
 197 {
 198   const GVariantType *state_type;
 199
 200   g_return_if_fail (G_IS_ACTION (action));
 201   g_return_if_fail (value != NULL);
 202   state_type = g_action_get_state_type (action);
 203   g_return_if_fail (state_type != NULL);
 204   g_return_if_fail (g_variant_is_of_type (value, state_type));
 205
 206   g_variant_ref_sink (value);
 207
 208   G_ACTION_GET_IFACE (action)
 209     ->change_state (action, value);
 210
 211   g_variant_unref (value);
 212 }
 213
 214 /**
 215  * g_action_get_state:
 216  * @action: a #GAction
 217  *
 218  * Queries the current state of @action.
 219  *
 220  * If the action is not stateful then %NULL will be returned.  If the
 221  * action is stateful then the type of the return value is the type
 222  * given by g_action_get_state_type().
 223  *
 224  * The return value (if non-%NULL) should be freed with
 225  * g_variant_unref() when it is no longer required.
 226  *
 227  * Returns: (transfer full): the current state of the action
 228  *
 229  * Since: 2.28
 230  **/
 231 GVariant *
 232 g_action_get_state (GAction *action)
 233 {
 234   g_return_val_if_fail (G_IS_ACTION (action), NULL);
 235
 236   return G_ACTION_GET_IFACE (action)
 237     ->get_state (action);
 238 }
 239
 240 /**
 241  * g_action_get_name:
 242  * @action: a #GAction
 243  *
 244  * Queries the name of @action.
 245  *
 246  * Returns: the name of the action
 247  *
 248  * Since: 2.28
 249  **/
 250 const gchar *
 251 g_action_get_name (GAction *action)
 252 {
 253   g_return_val_if_fail (G_IS_ACTION (action), NULL);
 254
 255   return G_ACTION_GET_IFACE (action)
 256     ->get_name (action);
 257 }
 258
 259 /**
 260  * g_action_get_parameter_type:
 261  * @action: a #GAction
 262  *
 263  * Queries the type of the parameter that must be given when activating
 264  * @action.
 265  *
 266  * When activating the action using g_action_activate(), the #GVariant
 267  * given to that function must be of the type returned by this function.
 268  *
 269  * In the case that this function returns %NULL, you must not give any
 270  * #GVariant, but %NULL instead.
 271  *
 272  * Returns: (nullable): the parameter type
 273  *
 274  * Since: 2.28
 275  **/
 276 const GVariantType *
 277 g_action_get_parameter_type (GAction *action)
 278 {
 279   g_return_val_if_fail (G_IS_ACTION (action), NULL);
 280
 281   return G_ACTION_GET_IFACE (action)
 282     ->get_parameter_type (action);
 283 }
 284
 285 /**
 286  * g_action_get_state_type:
 287  * @action: a #GAction
 288  *
 289  * Queries the type of the state of @action.
 290  *
 291  * If the action is stateful (e.g. created with
 292  * g_simple_action_new_stateful()) then this function returns the
 293  * #GVariantType of the state.  This is the type of the initial value
 294  * given as the state. All calls to g_action_change_state() must give a
 295  * #GVariant of this type and g_action_get_state() will return a
 296  * #GVariant of the same type.
 297  *
 298  * If the action is not stateful (e.g. created with g_simple_action_new())
 299  * then this function will return %NULL. In that case, g_action_get_state()
 300  * will return %NULL and you must not call g_action_change_state().
 301  *
 302  * Returns: (nullable): the state type, if the action is stateful
 303  *
 304  * Since: 2.28
 305  **/
 306 const GVariantType *
 307 g_action_get_state_type (GAction *action)
 308 {
 309   g_return_val_if_fail (G_IS_ACTION (action), NULL);
 310
 311   return G_ACTION_GET_IFACE (action)
 312     ->get_state_type (action);
 313 }
 314
 315 /**
 316  * g_action_get_state_hint:
 317  * @action: a #GAction
 318  *
 319  * Requests a hint about the valid range of values for the state of
 320  * @action.
 321  *
 322  * If %NULL is returned it either means that the action is not stateful
 323  * or that there is no hint about the valid range of values for the
 324  * state of the action.
 325  *
 326  * If a #GVariant array is returned then each item in the array is a
 327  * possible value for the state.  If a #GVariant pair (ie: two-tuple) is
 328  * returned then the tuple specifies the inclusive lower and upper bound
 329  * of valid values for the state.
 330  *
 331  * In any case, the information is merely a hint.  It may be possible to
 332  * have a state value outside of the hinted range and setting a value
 333  * within the range may fail.
 334  *
 335  * The return value (if non-%NULL) should be freed with
 336  * g_variant_unref() when it is no longer required.
 337  *
 338  * Returns: (nullable) (transfer full): the state range hint
 339  *
 340  * Since: 2.28
 341  **/
 342 GVariant *
 343 g_action_get_state_hint (GAction *action)
 344 {
 345   g_return_val_if_fail (G_IS_ACTION (action), NULL);
 346
 347   return G_ACTION_GET_IFACE (action)
 348     ->get_state_hint (action);
 349 }
 350
 351 /**
 352  * g_action_get_enabled:
 353  * @action: a #GAction
 354  *
 355  * Checks if @action is currently enabled.
 356  *
 357  * An action must be enabled in order to be activated or in order to
 358  * have its state changed from outside callers.
 359  *
 360  * Returns: whether the action is enabled
 361  *
 362  * Since: 2.28
 363  **/
 364 gboolean
 365 g_action_get_enabled (GAction *action)
 366 {
 367   g_return_val_if_fail (G_IS_ACTION (action), FALSE);
 368
 369   return G_ACTION_GET_IFACE (action)
 370     ->get_enabled (action);
 371 }
 372
 373 /**
 374  * g_action_activate:
 375  * @action: a #GAction
 376  * @parameter: (nullable): the parameter to the activation
 377  *
 378  * Activates the action.
 379  *
 380  * @parameter must be the correct type of parameter for the action (ie:
 381  * the parameter type given at construction time).  If the parameter
 382  * type was %NULL then @parameter must also be %NULL.
 383  *
 384  * If the @parameter GVariant is floating, it is consumed.
 385  *
 386  * Since: 2.28
 387  **/
 388 void
 389 g_action_activate (GAction  *action,
 390                    GVariant *parameter)
 391 {
 392   g_return_if_fail (G_IS_ACTION (action));
 393
 394   if (parameter != NULL)
 395     g_variant_ref_sink (parameter);
 396
 397   G_ACTION_GET_IFACE (action)
 398     ->activate (action, parameter);
 399
 400   if (parameter != NULL)
 401     g_variant_unref (parameter);
 402 }
 403
 404 /**
 405  * g_action_name_is_valid:
 406  * @action_name: an potential action name
 407  *
 408  * Checks if @action_name is valid.
 409  *
 410  * @action_name is valid if it consists only of alphanumeric characters,
 411  * plus '-' and '.'.  The empty string is not a valid action name.
 412  *
 413  * It is an error to call this function with a non-utf8 @action_name.
 414  * @action_name must not be %NULL.
 415  *
 416  * Returns: %TRUE if @action_name is valid
 417  *
 418  * Since: 2.38
 419  **/
 420 gboolean
 421 g_action_name_is_valid (const gchar *action_name)
 422 {
 423   gchar c;
 424   gint i;
 425
 426   g_return_val_if_fail (action_name != NULL, FALSE);
 427
 428   for (i = 0; (c = action_name[i]); i++)
 429     if (!g_ascii_isalnum (c) && c != '.' && c != '-')
 430       return FALSE;
 431
 432   return i > 0;
 433 }
 434
 435 /**
 436  * g_action_parse_detailed_name:
 437  * @detailed_name: a detailed action name
 438  * @action_name: (out): the action name
 439  * @target_value: (out): the target value, or %NULL for no target
 440  * @error: a pointer to a %NULL #GError, or %NULL
 441  *
 442  * Parses a detailed action name into its separate name and target
 443  * components.
 444  *
 445  * Detailed action names can have three formats.
 446  *
 447  * The first format is used to represent an action name with no target
 448  * value and consists of just an action name containing no whitespace
 449  * nor the characters ':', '(' or ')'.  For example: "app.action".
 450  *
 451  * The second format is used to represent an action with a target value
 452  * that is a non-empty string consisting only of alphanumerics, plus '-'
 453  * and '.'.  In that case, the action name and target value are
 454  * separated by a double colon ("::").  For example:
 455  * "app.action::target".
 456  *
 457  * The third format is used to represent an action with any type of
 458  * target value, including strings.  The target value follows the action
 459  * name, surrounded in parens.  For example: "app.action(42)".  The
 460  * target value is parsed using g_variant_parse().  If a tuple-typed
 461  * value is desired, it must be specified in the same way, resulting in
 462  * two sets of parens, for example: "app.action((1,2,3))".  A string
 463  * target can be specified this way as well: "app.action('target')".
 464  * For strings, this third format must be used if * target value is
 465  * empty or contains characters other than alphanumerics, '-' and '.'.
 466  *
 467  * Returns: %TRUE if successful, else %FALSE with @error set
 468  *
 469  * Since: 2.38
 470  **/
 471 gboolean
 472 g_action_parse_detailed_name (const gchar  *detailed_name,
 473                               gchar       **action_name,
 474                               GVariant    **target_value,
 475                               GError      **error)
 476 {
 477   const gchar *target;
 478   gsize target_len;
 479   gsize base_len;
 480
 481   /* For historical (compatibility) reasons, this function accepts some
 482    * cases of invalid action names as long as they don't interfere with
 483    * the separation of the action from the target value.
 484    *
 485    * We decide which format we have based on which we see first between
 486    * '::' '(' and '\0'.
 487    */
 488
 489   if (*detailed_name == '\0' || *detailed_name == ' ')
 490     goto bad_fmt;
 491
 492   base_len = strcspn (detailed_name, ": ()");
 493   target = detailed_name + base_len;
 494   target_len = strlen (target);
 495
 496   switch (target[0])
 497     {
 498     case ' ':
 499     case ')':
 500       goto bad_fmt;
 501
 502     case ':':
 503       if (target[1] != ':')
 504         goto bad_fmt;
 505
 506       *target_value = g_variant_ref_sink (g_variant_new_string (target + 2));
 507       break;
 508
 509     case '(':
 510       {
 511         if (target[target_len - 1] != ')')
 512           goto bad_fmt;
 513
 514         *target_value = g_variant_parse (NULL, target + 1, target + target_len - 1, NULL, error);
 515         if (*target_value == NULL)
 516           goto bad_fmt;
 517       }
 518       break;
 519
 520     case '\0':
 521       *target_value = NULL;
 522       break;
 523     }
 524
 525   *action_name = g_strndup (detailed_name, base_len);
 526
 527   return TRUE;
 528
 529 bad_fmt:
 530   if (error)
 531     {
 532       if (*error == NULL)
 533         g_set_error (error, G_VARIANT_PARSE_ERROR, G_VARIANT_PARSE_ERROR_FAILED,
 534                      "Detailed action name '%s' has invalid format", detailed_name);
 535       else
 536         g_prefix_error (error, "Detailed action name '%s' has invalid format: ", detailed_name);
 537     }
 538
 539   return FALSE;
 540 }
 541
 542 /**
 543  * g_action_print_detailed_name:
 544  * @action_name: a valid action name
 545  * @target_value: (nullable): a #GVariant target value, or %NULL
 546  *
 547  * Formats a detailed action name from @action_name and @target_value.
 548  *
 549  * It is an error to call this function with an invalid action name.
 550  *
 551  * This function is the opposite of g_action_parse_detailed_name().
 552  * It will produce a string that can be parsed back to the @action_name
 553  * and @target_value by that function.
 554  *
 555  * See that function for the types of strings that will be printed by
 556  * this function.
 557  *
 558  * Returns: a detailed format string
 559  *
 560  * Since: 2.38
 561  **/
 562 gchar *
 563 g_action_print_detailed_name (const gchar *action_name,
 564                               GVariant    *target_value)
 565 {
 566   g_return_val_if_fail (g_action_name_is_valid (action_name), NULL);
 567
 568   if (target_value == NULL)
 569     return g_strdup (action_name);
 570
 571   if (g_variant_is_of_type (target_value, G_VARIANT_TYPE_STRING))
 572     {
 573       const gchar *str = g_variant_get_string (target_value, NULL);
 574
 575       if (g_action_name_is_valid (str))
 576         return g_strconcat (action_name, "::", str, NULL);
 577     }
 578
 579   {
 580     GString *result = g_string_new (action_name);
 581     g_string_append_c (result, '(');
 582     g_variant_print_string (target_value, result, TRUE);
 583     g_string_append_c (result, ')');
 584
 585     return g_string_free (result, FALSE);
 586   }
 587 }