gio/gvolume.c

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright (C) 2006-2007 Red Hat, Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  18  * Boston, MA 02111-1307, USA.
  19  *
  20  * Author: Alexander Larsson <alexl@redhat.com>
  21  *         David Zeuthen <davidz@redhat.com>
  22  */
  23
  24 #include "config.h"
  25 #include "gmount.h"
  26 #include "gvolume.h"
  27 #include "gthemedicon.h"
  28 #include "gasyncresult.h"
  29 #include "gtask.h"
  30 #include "gioerror.h"
  31 #include "glibintl.h"
  32
  33
  34 /**
  35  * SECTION:gvolume
  36  * @short_description: Volume management
  37  * @include: gio/gio.h
  38  *
  39  * The #GVolume interface represents user-visible objects that can be
  40  * mounted. Note, when porting from GnomeVFS, #GVolume is the moral
  41  * equivalent of #GnomeVFSDrive.
  42  *
  43  * Mounting a #GVolume instance is an asynchronous operation. For more
  44  * information about asynchronous operations, see #GAsyncResult and
  45  * #GTask. To mount a #GVolume, first call g_volume_mount() with (at
  46  * least) the #GVolume instance, optionally a #GMountOperation object
  47  * and a #GAsyncReadyCallback.
  48  *
  49  * Typically, one will only want to pass %NULL for the
  50  * #GMountOperation if automounting all volumes when a desktop session
  51  * starts since it's not desirable to put up a lot of dialogs asking
  52  * for credentials.
  53  *
  54  * The callback will be fired when the operation has resolved (either
  55  * with success or failure), and a #GAsyncReady structure will be
  56  * passed to the callback.  That callback should then call
  57  * g_volume_mount_finish() with the #GVolume instance and the
  58  * #GAsyncReady data to see if the operation was completed
  59  * successfully.  If an @error is present when g_volume_mount_finish()
  60  * is called, then it will be filled with any error information.
  61  *
  62  * <para id="volume-identifier">
  63  * It is sometimes necessary to directly access the underlying
  64  * operating system object behind a volume (e.g. for passing a volume
  65  * to an application via the commandline). For this purpose, GIO
  66  * allows to obtain an 'identifier' for the volume. There can be
  67  * different kinds of identifiers, such as Hal UDIs, filesystem labels,
  68  * traditional Unix devices (e.g. <filename>/dev/sda2</filename>),
  69  * uuids. GIO uses predefind strings as names for the different kinds
  70  * of identifiers: #G_VOLUME_IDENTIFIER_KIND_HAL_UDI,
  71  * #G_VOLUME_IDENTIFIER_KIND_LABEL, etc. Use g_volume_get_identifier()
  72  * to obtain an identifier for a volume.
  73  * </para>
  74  *
  75  * Note that #G_VOLUME_IDENTIFIER_KIND_HAL_UDI will only be available
  76  * when the gvfs hal volume monitor is in use. Other volume monitors
  77  * will generally be able to provide the #G_VOLUME_IDENTIFIER_KIND_UNIX_DEVICE
  78  * identifier, which can be used to obtain a hal device by means of
  79  * libhal_manager_find_device_string_match().
  80  */
  81
  82 typedef GVolumeIface GVolumeInterface;
  83 G_DEFINE_INTERFACE(GVolume, g_volume, G_TYPE_OBJECT)
  84
  85 static void
  86 g_volume_default_init (GVolumeInterface *iface)
  87 {
  88   /**
  89    * GVolume::changed:
  90    *
  91    * Emitted when the volume has been changed.
  92    **/
  93   g_signal_new (I_("changed"),
  94                 G_TYPE_VOLUME,
  95                 G_SIGNAL_RUN_LAST,
  96                 G_STRUCT_OFFSET (GVolumeIface, changed),
  97                 NULL, NULL,
  98                 g_cclosure_marshal_VOID__VOID,
  99                 G_TYPE_NONE, 0);
 100
 101   /**
 102    * GVolume::removed:
 103    *
 104    * This signal is emitted when the #GVolume have been removed. If
 105    * the recipient is holding references to the object they should
 106    * release them so the object can be finalized.
 107    **/
 108   g_signal_new (I_("removed"),
 109                 G_TYPE_VOLUME,
 110                 G_SIGNAL_RUN_LAST,
 111                 G_STRUCT_OFFSET (GVolumeIface, removed),
 112                 NULL, NULL,
 113                 g_cclosure_marshal_VOID__VOID,
 114                 G_TYPE_NONE, 0);
 115 }
 116
 117 /**
 118  * g_volume_get_name:
 119  * @volume: a #GVolume.
 120  *
 121  * Gets the name of @volume.
 122  *
 123  * Returns: the name for the given @volume. The returned string should
 124  * be freed with g_free() when no longer needed.
 125  **/
 126 char *
 127 g_volume_get_name (GVolume *volume)
 128 {
 129   GVolumeIface *iface;
 130
 131   g_return_val_if_fail (G_IS_VOLUME (volume), NULL);
 132
 133   iface = G_VOLUME_GET_IFACE (volume);
 134
 135   return (* iface->get_name) (volume);
 136 }
 137
 138 /**
 139  * g_volume_get_icon:
 140  * @volume: a #GVolume.
 141  *
 142  * Gets the icon for @volume.
 143  *
 144  * Returns: (transfer full): a #GIcon.
 145  *     The returned object should be unreffed with g_object_unref()
 146  *     when no longer needed.
 147  **/
 148 GIcon *
 149 g_volume_get_icon (GVolume *volume)
 150 {
 151   GVolumeIface *iface;
 152
 153   g_return_val_if_fail (G_IS_VOLUME (volume), NULL);
 154
 155   iface = G_VOLUME_GET_IFACE (volume);
 156
 157   return (* iface->get_icon) (volume);
 158 }
 159
 160 /**
 161  * g_volume_get_symbolic_icon:
 162  * @volume: a #GVolume.
 163  *
 164  * Gets the symbolic icon for @volume.
 165  *
 166  * Returns: (transfer full): a #GIcon.
 167  *     The returned object should be unreffed with g_object_unref()
 168  *     when no longer needed.
 169  *
 170  * Since: 2.34
 171  **/
 172 GIcon *
 173 g_volume_get_symbolic_icon (GVolume *volume)
 174 {
 175   GVolumeIface *iface;
 176   GIcon *ret;
 177
 178   g_return_val_if_fail (G_IS_VOLUME (volume), NULL);
 179
 180   iface = G_VOLUME_GET_IFACE (volume);
 181
 182   if (iface->get_symbolic_icon != NULL)
 183     ret = iface->get_symbolic_icon (volume);
 184   else
 185     ret = g_themed_icon_new_with_default_fallbacks ("folder-remote-symbolic");
 186
 187   return ret;
 188
 189 }
 190
 191 /**
 192  * g_volume_get_uuid:
 193  * @volume: a #GVolume.
 194  *
 195  * Gets the UUID for the @volume. The reference is typically based on
 196  * the file system UUID for the volume in question and should be
 197  * considered an opaque string. Returns %NULL if there is no UUID
 198  * available.
 199  *
 200  * Returns: the UUID for @volume or %NULL if no UUID can be computed.
 201  *     The returned string should be freed with g_free()
 202  *     when no longer needed.
 203  **/
 204 char *
 205 g_volume_get_uuid (GVolume *volume)
 206 {
 207   GVolumeIface *iface;
 208
 209   g_return_val_if_fail (G_IS_VOLUME (volume), NULL);
 210
 211   iface = G_VOLUME_GET_IFACE (volume);
 212
 213   return (* iface->get_uuid) (volume);
 214 }
 215
 216 /**
 217  * g_volume_get_drive:
 218  * @volume: a #GVolume.
 219  *
 220  * Gets the drive for the @volume.
 221  *
 222  * Returns: (transfer full): a #GDrive or %NULL if @volume is not associated with a drive.
 223  *     The returned object should be unreffed with g_object_unref()
 224  *     when no longer needed.
 225  **/
 226 GDrive *
 227 g_volume_get_drive (GVolume *volume)
 228 {
 229   GVolumeIface *iface;
 230
 231   g_return_val_if_fail (G_IS_VOLUME (volume), NULL);
 232
 233   iface = G_VOLUME_GET_IFACE (volume);
 234
 235   return (* iface->get_drive) (volume);
 236 }
 237
 238 /**
 239  * g_volume_get_mount:
 240  * @volume: a #GVolume.
 241  *
 242  * Gets the mount for the @volume.
 243  *
 244  * Returns: (transfer full): a #GMount or %NULL if @volume isn't mounted.
 245  *     The returned object should be unreffed with g_object_unref()
 246  *     when no longer needed.
 247  **/
 248 GMount *
 249 g_volume_get_mount (GVolume *volume)
 250 {
 251   GVolumeIface *iface;
 252
 253   g_return_val_if_fail (G_IS_VOLUME (volume), NULL);
 254
 255   iface = G_VOLUME_GET_IFACE (volume);
 256
 257   return (* iface->get_mount) (volume);
 258 }
 259
 260
 261 /**
 262  * g_volume_can_mount:
 263  * @volume: a #GVolume.
 264  *
 265  * Checks if a volume can be mounted.
 266  *
 267  * Returns: %TRUE if the @volume can be mounted. %FALSE otherwise.
 268  **/
 269 gboolean
 270 g_volume_can_mount (GVolume *volume)
 271 {
 272   GVolumeIface *iface;
 273
 274   g_return_val_if_fail (G_IS_VOLUME (volume), FALSE);
 275
 276   iface = G_VOLUME_GET_IFACE (volume);
 277
 278   if (iface->can_mount == NULL)
 279     return FALSE;
 280
 281   return (* iface->can_mount) (volume);
 282 }
 283
 284 /**
 285  * g_volume_can_eject:
 286  * @volume: a #GVolume.
 287  *
 288  * Checks if a volume can be ejected.
 289  *
 290  * Returns: %TRUE if the @volume can be ejected. %FALSE otherwise.
 291  **/
 292 gboolean
 293 g_volume_can_eject (GVolume *volume)
 294 {
 295   GVolumeIface *iface;
 296
 297   g_return_val_if_fail (G_IS_VOLUME (volume), FALSE);
 298
 299   iface = G_VOLUME_GET_IFACE (volume);
 300
 301   if (iface->can_eject == NULL)
 302     return FALSE;
 303
 304   return (* iface->can_eject) (volume);
 305 }
 306
 307 /**
 308  * g_volume_should_automount:
 309  * @volume: a #GVolume
 310  *
 311  * Returns whether the volume should be automatically mounted.
 312  *
 313  * Returns: %TRUE if the volume should be automatically mounted.
 314  */
 315 gboolean
 316 g_volume_should_automount (GVolume *volume)
 317 {
 318   GVolumeIface *iface;
 319
 320   g_return_val_if_fail (G_IS_VOLUME (volume), FALSE);
 321
 322   iface = G_VOLUME_GET_IFACE (volume);
 323
 324   if (iface->should_automount == NULL)
 325     return FALSE;
 326
 327   return (* iface->should_automount) (volume);
 328 }
 329
 330
 331 /**
 332  * g_volume_mount:
 333  * @volume: a #GVolume.
 334  * @flags: flags affecting the operation
 335  * @mount_operation: (allow-none): a #GMountOperation or %NULL to avoid user interaction.
 336  * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
 337  * @callback: (allow-none): a #GAsyncReadyCallback, or %NULL.
 338  * @user_data: user data that gets passed to @callback
 339  *
 340  * Mounts a volume. This is an asynchronous operation, and is
 341  * finished by calling g_volume_mount_finish() with the @volume
 342  * and #GAsyncResult returned in the @callback.
 343  *
 344  * Virtual: mount_fn
 345  **/
 346 void
 347 g_volume_mount (GVolume             *volume,
 348                 GMountMountFlags     flags,
 349                 GMountOperation     *mount_operation,
 350                 GCancellable        *cancellable,
 351                 GAsyncReadyCallback  callback,
 352                 gpointer             user_data)
 353 {
 354   GVolumeIface *iface;
 355
 356   g_return_if_fail (G_IS_VOLUME (volume));
 357
 358   iface = G_VOLUME_GET_IFACE (volume);
 359
 360   if (iface->mount_fn == NULL)
 361     {
 362       g_task_report_new_error (volume, callback, user_data,
 363                                g_volume_mount,
 364                                G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 365                                _("volume doesn't implement mount"));
 366       return;
 367     }
 368
 369   (* iface->mount_fn) (volume, flags, mount_operation, cancellable, callback, user_data);
 370 }
 371
 372 /**
 373  * g_volume_mount_finish:
 374  * @volume: a #GVolume
 375  * @result: a #GAsyncResult
 376  * @error: a #GError location to store an error, or %NULL to ignore
 377  *
 378  * Finishes mounting a volume. If any errors occurred during the operation,
 379  * @error will be set to contain the errors and %FALSE will be returned.
 380  *
 381  * If the mount operation succeeded, g_volume_get_mount() on @volume
 382  * is guaranteed to return the mount right after calling this
 383  * function; there's no need to listen for the 'mount-added' signal on
 384  * #GVolumeMonitor.
 385  *
 386  * Returns: %TRUE, %FALSE if operation failed.
 387  **/
 388 gboolean
 389 g_volume_mount_finish (GVolume       *volume,
 390                        GAsyncResult  *result,
 391                        GError       **error)
 392 {
 393   GVolumeIface *iface;
 394
 395   g_return_val_if_fail (G_IS_VOLUME (volume), FALSE);
 396   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), FALSE);
 397
 398   if (g_async_result_legacy_propagate_error (result, error))
 399     return FALSE;
 400   else if (g_async_result_is_tagged (result, g_volume_mount))
 401     return g_task_propagate_boolean (G_TASK (result), error);
 402
 403   iface = G_VOLUME_GET_IFACE (volume);
 404   return (* iface->mount_finish) (volume, result, error);
 405 }
 406
 407 /**
 408  * g_volume_eject:
 409  * @volume: a #GVolume.
 410  * @flags: flags affecting the unmount if required for eject
 411  * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
 412  * @callback: (allow-none): a #GAsyncReadyCallback, or %NULL.
 413  * @user_data: user data that gets passed to @callback
 414  *
 415  * Ejects a volume. This is an asynchronous operation, and is
 416  * finished by calling g_volume_eject_finish() with the @volume
 417  * and #GAsyncResult returned in the @callback.
 418  *
 419  * Deprecated: 2.22: Use g_volume_eject_with_operation() instead.
 420  **/
 421 void
 422 g_volume_eject (GVolume             *volume,
 423                 GMountUnmountFlags   flags,
 424                 GCancellable        *cancellable,
 425                 GAsyncReadyCallback  callback,
 426                 gpointer             user_data)
 427 {
 428   GVolumeIface *iface;
 429
 430   g_return_if_fail (G_IS_VOLUME (volume));
 431
 432   iface = G_VOLUME_GET_IFACE (volume);
 433
 434   if (iface->eject == NULL)
 435     {
 436       g_task_report_new_error (volume, callback, user_data,
 437                                g_volume_eject_with_operation,
 438                                G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 439                                _("volume doesn't implement eject"));
 440       return;
 441     }
 442
 443   (* iface->eject) (volume, flags, cancellable, callback, user_data);
 444 }
 445
 446 /**
 447  * g_volume_eject_finish:
 448  * @volume: pointer to a #GVolume.
 449  * @result: a #GAsyncResult.
 450  * @error: a #GError location to store an error, or %NULL to ignore
 451  *
 452  * Finishes ejecting a volume. If any errors occurred during the operation,
 453  * @error will be set to contain the errors and %FALSE will be returned.
 454  *
 455  * Returns: %TRUE, %FALSE if operation failed.
 456  *
 457  * Deprecated: 2.22: Use g_volume_eject_with_operation_finish() instead.
 458  **/
 459 gboolean
 460 g_volume_eject_finish (GVolume       *volume,
 461                        GAsyncResult  *result,
 462                        GError       **error)
 463 {
 464   GVolumeIface *iface;
 465
 466   g_return_val_if_fail (G_IS_VOLUME (volume), FALSE);
 467   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), FALSE);
 468
 469   if (g_async_result_legacy_propagate_error (result, error))
 470     return FALSE;
 471   if (g_async_result_is_tagged (result, g_volume_eject_with_operation))
 472     return g_task_propagate_boolean (G_TASK (result), error);
 473
 474   iface = G_VOLUME_GET_IFACE (volume);
 475   return (* iface->eject_finish) (volume, result, error);
 476 }
 477
 478 /**
 479  * g_volume_eject_with_operation:
 480  * @volume: a #GVolume.
 481  * @flags: flags affecting the unmount if required for eject
 482  * @mount_operation: (allow-none): a #GMountOperation or %NULL to
 483  *     avoid user interaction.
 484  * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
 485  * @callback: (allow-none): a #GAsyncReadyCallback, or %NULL.
 486  * @user_data: user data passed to @callback.
 487  *
 488  * Ejects a volume. This is an asynchronous operation, and is
 489  * finished by calling g_volume_eject_with_operation_finish() with the @volume
 490  * and #GAsyncResult data returned in the @callback.
 491  *
 492  * Since: 2.22
 493  **/
 494 void
 495 g_volume_eject_with_operation (GVolume              *volume,
 496                                GMountUnmountFlags   flags,
 497                                GMountOperation     *mount_operation,
 498                                GCancellable        *cancellable,
 499                                GAsyncReadyCallback  callback,
 500                                gpointer             user_data)
 501 {
 502   GVolumeIface *iface;
 503
 504   g_return_if_fail (G_IS_VOLUME (volume));
 505
 506   iface = G_VOLUME_GET_IFACE (volume);
 507
 508   if (iface->eject == NULL && iface->eject_with_operation == NULL)
 509     {
 510       g_task_report_new_error (volume, callback, user_data,
 511                                g_volume_eject_with_operation,
 512                                G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 513                                /* Translators: This is an error
 514                                 * message for volume objects that
 515                                 * don't implement any of eject or eject_with_operation. */
 516                                _("volume doesn't implement eject or eject_with_operation"));
 517       return;
 518     }
 519
 520   if (iface->eject_with_operation != NULL)
 521     (* iface->eject_with_operation) (volume, flags, mount_operation, cancellable, callback, user_data);
 522   else
 523     (* iface->eject) (volume, flags, cancellable, callback, user_data);
 524 }
 525
 526 /**
 527  * g_volume_eject_with_operation_finish:
 528  * @volume: a #GVolume.
 529  * @result: a #GAsyncResult.
 530  * @error: a #GError location to store the error occurring, or %NULL to
 531  *     ignore.
 532  *
 533  * Finishes ejecting a volume. If any errors occurred during the operation,
 534  * @error will be set to contain the errors and %FALSE will be returned.
 535  *
 536  * Returns: %TRUE if the volume was successfully ejected. %FALSE otherwise.
 537  *
 538  * Since: 2.22
 539  **/
 540 gboolean
 541 g_volume_eject_with_operation_finish (GVolume        *volume,
 542                                       GAsyncResult  *result,
 543                                       GError       **error)
 544 {
 545   GVolumeIface *iface;
 546
 547   g_return_val_if_fail (G_IS_VOLUME (volume), FALSE);
 548   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), FALSE);
 549
 550   if (g_async_result_legacy_propagate_error (result, error))
 551     return FALSE;
 552   else if (g_async_result_is_tagged (result, g_volume_eject_with_operation))
 553     return g_task_propagate_boolean (G_TASK (result), error);
 554
 555   iface = G_VOLUME_GET_IFACE (volume);
 556   if (iface->eject_with_operation_finish != NULL)
 557     return (* iface->eject_with_operation_finish) (volume, result, error);
 558   else
 559     return (* iface->eject_finish) (volume, result, error);
 560 }
 561
 562 /**
 563  * g_volume_get_identifier:
 564  * @volume: a #GVolume
 565  * @kind: the kind of identifier to return
 566  *
 567  * Gets the identifier of the given kind for @volume.
 568  * See the <link linkend="volume-identifier">introduction</link>
 569  * for more information about volume identifiers.
 570  *
 571  * Returns: a newly allocated string containing the
 572  *   requested identfier, or %NULL if the #GVolume
 573  *   doesn't have this kind of identifier
 574  */
 575 char *
 576 g_volume_get_identifier (GVolume    *volume,
 577                          const char *kind)
 578 {
 579   GVolumeIface *iface;
 580
 581   g_return_val_if_fail (G_IS_VOLUME (volume), NULL);
 582   g_return_val_if_fail (kind != NULL, NULL);
 583
 584   iface = G_VOLUME_GET_IFACE (volume);
 585
 586   if (iface->get_identifier == NULL)
 587     return NULL;
 588
 589   return (* iface->get_identifier) (volume, kind);
 590 }
 591
 592 /**
 593  * g_volume_enumerate_identifiers:
 594  * @volume: a #GVolume
 595  *
 596  * Gets the kinds of <link linkend="volume-identifier">identifiers</link>
 597  * that @volume has. Use g_volume_get_identifier() to obtain
 598  * the identifiers themselves.
 599  *
 600  * Returns: (array zero-terminated=1) (transfer full): a %NULL-terminated array
 601  *   of strings containing kinds of identifiers. Use g_strfreev() to free.
 602  */
 603 char **
 604 g_volume_enumerate_identifiers (GVolume *volume)
 605 {
 606   GVolumeIface *iface;
 607
 608   g_return_val_if_fail (G_IS_VOLUME (volume), NULL);
 609   iface = G_VOLUME_GET_IFACE (volume);
 610
 611   if (iface->enumerate_identifiers == NULL)
 612     return NULL;
 613
 614   return (* iface->enumerate_identifiers) (volume);
 615 }
 616
 617 /**
 618  * g_volume_get_activation_root:
 619  * @volume: a #GVolume
 620  *
 621  * Gets the activation root for a #GVolume if it is known ahead of
 622  * mount time. Returns %NULL otherwise. If not %NULL and if @volume
 623  * is mounted, then the result of g_mount_get_root() on the
 624  * #GMount object obtained from g_volume_get_mount() will always
 625  * either be equal or a prefix of what this function returns. In
 626  * other words, in code
 627  *
 628  * <programlisting>
 629  *   GMount *mount;
 630  *   GFile *mount_root
 631  *   GFile *volume_activation_root;
 632  *
 633  *   mount = g_volume_get_mount (volume); /&ast; mounted, so never NULL &ast;/
 634  *   mount_root = g_mount_get_root (mount);
 635  *   volume_activation_root = g_volume_get_activation_root(volume); /&ast; assume not NULL &ast;/
 636  * </programlisting>
 637  *
 638  * then the expression
 639  *
 640  * <programlisting>
 641  *   (g_file_has_prefix (volume_activation_root, mount_root) ||
 642       g_file_equal (volume_activation_root, mount_root))
 643  * </programlisting>
 644  *
 645  * will always be %TRUE.
 646  *
 647  * Activation roots are typically used in #GVolumeMonitor
 648  * implementations to find the underlying mount to shadow, see
 649  * g_mount_is_shadowed() for more details.
 650  *
 651  * Returns: (transfer full): the activation root of @volume or %NULL. Use
 652  * g_object_unref() to free.
 653  *
 654  * Since: 2.18
 655  **/
 656 GFile *
 657 g_volume_get_activation_root (GVolume *volume)
 658 {
 659   GVolumeIface *iface;
 660
 661   g_return_val_if_fail (G_IS_VOLUME (volume), NULL);
 662   iface = G_VOLUME_GET_IFACE (volume);
 663
 664   if (iface->get_activation_root == NULL)
 665     return NULL;
 666
 667   return (* iface->get_activation_root) (volume);
 668 }
 669
 670 /**
 671  * g_volume_get_sort_key:
 672  * @volume: A #GVolume.
 673  *
 674  * Gets the sort key for @volume, if any.
 675  *
 676  * Returns: Sorting key for @volume or %NULL if no such key is available.
 677  *
 678  * Since: 2.32
 679  */
 680 const gchar *
 681 g_volume_get_sort_key (GVolume  *volume)
 682 {
 683   const gchar *ret = NULL;
 684   GVolumeIface *iface;
 685
 686   g_return_val_if_fail (G_IS_VOLUME (volume), NULL);
 687
 688   iface = G_VOLUME_GET_IFACE (volume);
 689   if (iface->get_sort_key != NULL)
 690     ret = iface->get_sort_key (volume);
 691
 692   return ret;
 693 }