gio/gmenuexporter.c

   1 /*
   2  * Copyright © 2011 Canonical Ltd.
   3  *
   4  *  This library is free software; you can redistribute it and/or modify
   5  *  it under the terms of the GNU Lesser General Public License as
   6  *  published by the Free Software Foundation; either version 2 of the
   7  *  licence, or (at your option) any later version.
   8  *
   9  *  This library is distributed in the hope that it will be useful, but
  10  *  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 Public
  15  *  License along with this library; if not, write to the Free Software
  16  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  17  *  USA.
  18  *
  19  * Author: Ryan Lortie <desrt@desrt.ca>
  20  */
  21
  22 #include "gmenuexporter.h"
  23
  24 #include "gdbusmethodinvocation.h"
  25 #include "gdbusintrospection.h"
  26 #include "gdbusnamewatching.h"
  27 #include "gdbuserror.h"
  28
  29 /**
  30  * SECTION:gmenuexporter
  31  * @title: GMenuModel exporter
  32  * @short_description: Export GMenuModels on D-Bus
  33  * @see_also: #GMenuModel, #GDBusMenuModel
  34  *
  35  * These functions support exporting a #GMenuModel on D-Bus.
  36  * The D-Bus interface that is used is a private implementation
  37  * detail.
  38  *
  39  * To access an exported #GMenuModel remotely, use
  40  * g_dbus_menu_model_get() to obtain a #GDBusMenuModel.
  41  */
  42
  43 /* {{{1 D-Bus Interface description */
  44
  45 /* The org.gtk.Menus interface
  46  * ===========================
  47  *
  48  * The interface is primarily concerned with three things:
  49  *
  50  * - communicating menus to the client
  51  * - establishing links between menus and other menus
  52  * - notifying clients of changes
  53  *
  54  * As a basic principle, it is recognised that the menu structure
  55  * of an application is often large. It is also recognised that some
  56  * menus are liable to frequently change without the user ever having
  57  * opened the menu. For both of these reasons, the individual menus are
  58  * arranged into subscription groups. Each subscription group is specified
  59  * by an unsigned integer. The assignment of integers need not be consecutive.
  60  *
  61  * Within a subscription group there are multiple menus. Each menu is
  62  * identified with an unsigned integer, unique to its subscription group.
  63  *
  64  * By convention, the primary menu is numbered 0 without subscription group 0.
  65  *
  66  * Actionable menu items (ie: those that produce some effect in the
  67  * application when they are activated) have a related action, specified by
  68  * a string. This string specifies the name of the action, according to the
  69  * org.gtk.Actions interface, at the same object path as the menu.
  70  *
  71  * Methods
  72  * -------
  73  *
  74  * Start :: (au) → (a(uuaa{sv}))
  75  *
  76  *   The Start method is used to indicate that a client is interested in
  77  *   tracking and displaying the content of the menus of a particular list
  78  *   of subscription groups.
  79  *
  80  *   Most typically, the client will request subscription group 0 to start.
  81  *
  82  *   The call has two effects. First, it replies with all menus defined
  83  *   within the requested subscription groups. The format of the reply is
  84  *   an array of tuples, where the items in each tuple are:
  85  *   - the subscription group of the menu
  86  *   - the number of the menu within that group
  87  *   - an array of menu items
  88  *
  89  *   Each menu item is a dictionary of attributes (a{sv}).
  90  *
  91  *   Secondly, this call has a side effect: it atomically requests that
  92  *   the Changed signal start to be emitted for the requested subscription
  93  *   group. Each group has a subscription count and only signals changes
  94  *   on itself when this count is greater than zero.
  95  *
  96  *   If a group is specified multiple times then the result is that the
  97  *   contents of that group is only returned once, but the subscription
  98  *   count is increased multiple times.
  99  *
 100  *   If a client disconnects from the bus while holding subscriptions then
 101  *   its subscriptions will be cancelled. This prevents "leaking" subscriptions
 102  *   in the case of crashes and is also useful for applications that want
 103  *   to exit without manually cleaning up.
 104  *
 105  * End :: (au)
 106  *
 107  *   The End method reverses the previous effects of a call to Start.
 108  *
 109  *   When clients are no longer interested in the contents of a subscription
 110  *   group, they should call the End method.
 111  *
 112  *   The parameter lists the subscription groups. A subscription group
 113  *   needs to be cancelled the same number of times as it was requested.
 114  *   For this reason, it might make sense to specify the same subscription
 115  *   group multiple times (if multiple Start calls were made for this group).
 116  *
 117  * Signals
 118  * -------
 119  *
 120  * Changed :: (a(uuuuaa{sv}))
 121  *
 122  *   The changed signal indicates changes to a particular menu.
 123  *
 124  *   The changes come as an array of tuples where the items in each tuple are:
 125  *   - the subscription group of the menu
 126  *   - the number of the menu within that group
 127  *   - the position in the menu at which to make the change
 128  *   - the number of items to delete from that position
 129  *   - a list of new items to insert at that position
 130  *
 131  *   Each new menu item is a dictionary of attributes (a{sv}).
 132  *
 133  * Attributes
 134  * ----------
 135  *
 136  * label (string): the label to display
 137  * action (string): the name of the action
 138  * target (variant): the parameter to pass when activating the action
 139  * :section ((uu)): the menu to use to populate that section, specified
 140  *     as a pair of subscription group and menu within that group
 141  * :submenu ((uu)): the menu to use as a submenu, specified
 142  *     as a pair of subscription group and menu within that group
 143  */
 144
 145 static GDBusInterfaceInfo *
 146 org_gtk_Menus_get_interface (void)
 147 {
 148   static GDBusInterfaceInfo *interface_info;
 149
 150   if (interface_info == NULL)
 151     {
 152       GError *error = NULL;
 153       GDBusNodeInfo *info;
 154
 155       info = g_dbus_node_info_new_for_xml ("<node>"
 156                                            "  <interface name='org.gtk.Menus'>"
 157                                            "    <method name='Start'>"
 158                                            "      <arg type='au' name='groups' direction='in'/>"
 159                                            "      <arg type='a(uuaa{sv})' name='content' direction='out'/>"
 160                                            "    </method>"
 161                                            "    <method name='End'>"
 162                                            "      <arg type='au' name='groups' direction='in'/>"
 163                                            "    </method>"
 164                                            "    <signal name='Changed'>"
 165                                            "      arg type='a(uuuuaa{sv})' name='changes'/>"
 166                                            "    </signal>"
 167                                            "  </interface>"
 168                                            "</node>", &error);
 169       if (info == NULL)
 170         g_error ("%s\n", error->message);
 171       interface_info = g_dbus_node_info_lookup_interface (info, "org.gtk.Menus");
 172       g_assert (interface_info != NULL);
 173       g_dbus_interface_info_ref (interface_info);
 174       g_dbus_node_info_unref (info);
 175     }
 176
 177   return interface_info;
 178 }
 179
 180 /* {{{1 Forward declarations */
 181 typedef struct _GMenuExporterMenu                           GMenuExporterMenu;
 182 typedef struct _GMenuExporterLink                           GMenuExporterLink;
 183 typedef struct _GMenuExporterGroup                          GMenuExporterGroup;
 184 typedef struct _GMenuExporterRemote                         GMenuExporterRemote;
 185 typedef struct _GMenuExporterWatch                          GMenuExporterWatch;
 186 typedef struct _GMenuExporter                               GMenuExporter;
 187
 188 static gboolean                 g_menu_exporter_group_is_subscribed    (GMenuExporterGroup *group);
 189 static guint                    g_menu_exporter_group_get_id           (GMenuExporterGroup *group);
 190 static GMenuExporter *          g_menu_exporter_group_get_exporter     (GMenuExporterGroup *group);
 191 static GMenuExporterMenu *      g_menu_exporter_group_add_menu         (GMenuExporterGroup *group,
 192                                                                         GMenuModel         *model);
 193 static void                     g_menu_exporter_group_remove_menu      (GMenuExporterGroup *group,
 194                                                                         guint               id);
 195
 196 static GMenuExporterGroup *     g_menu_exporter_create_group           (GMenuExporter      *exporter);
 197 static GMenuExporterGroup *     g_menu_exporter_lookup_group           (GMenuExporter      *exporter,
 198                                                                         guint               group_id);
 199 static void                     g_menu_exporter_report                 (GMenuExporter      *exporter,
 200                                                                         GVariant           *report);
 201 static void                     g_menu_exporter_remove_group           (GMenuExporter      *exporter,
 202                                                                         guint               id);
 203
 204 /* {{{1 GMenuExporterLink, GMenuExporterMenu */
 205
 206 struct _GMenuExporterMenu
 207 {
 208   GMenuExporterGroup *group;
 209   guint               id;
 210
 211   GMenuModel *model;
 212   gulong      handler_id;
 213   GSequence  *item_links;
 214 };
 215
 216 struct _GMenuExporterLink
 217 {
 218   gchar             *name;
 219   GMenuExporterMenu *menu;
 220   GMenuExporterLink *next;
 221 };
 222
 223 static void
 224 g_menu_exporter_menu_free (GMenuExporterMenu *menu)
 225 {
 226   g_menu_exporter_group_remove_menu (menu->group, menu->id);
 227
 228   if (menu->handler_id != 0)
 229     g_signal_handler_disconnect (menu->model, menu->handler_id);
 230
 231   if (menu->item_links != NULL)
 232     g_sequence_free (menu->item_links);
 233
 234   g_object_unref (menu->model);
 235
 236   g_slice_free (GMenuExporterMenu, menu);
 237 }
 238
 239 static void
 240 g_menu_exporter_link_free (gpointer data)
 241 {
 242   GMenuExporterLink *link = data;
 243
 244   while (link != NULL)
 245     {
 246       GMenuExporterLink *tmp = link;
 247       link = tmp->next;
 248
 249       g_menu_exporter_menu_free (tmp->menu);
 250       g_free (tmp->name);
 251
 252       g_slice_free (GMenuExporterLink, tmp);
 253     }
 254 }
 255
 256 static GMenuExporterLink *
 257 g_menu_exporter_menu_create_links (GMenuExporterMenu *menu,
 258                                    gint               position)
 259 {
 260   GMenuExporterLink *list = NULL;
 261   GMenuLinkIter *iter;
 262   const char *name;
 263   GMenuModel *model;
 264
 265   iter = g_menu_model_iterate_item_links (menu->model, position);
 266
 267   while (g_menu_link_iter_get_next (iter, &name, &model))
 268     {
 269       GMenuExporterGroup *group;
 270       GMenuExporterLink *tmp;
 271
 272       /* keep sections in the same group, but create new groups
 273        * otherwise
 274        */
 275       if (!g_str_equal (name, "section"))
 276         group = g_menu_exporter_create_group (g_menu_exporter_group_get_exporter (menu->group));
 277       else
 278         group = menu->group;
 279
 280       tmp = g_slice_new (GMenuExporterLink);
 281       tmp->name = g_strconcat (":", name, NULL);
 282       tmp->menu = g_menu_exporter_group_add_menu (group, model);
 283       tmp->next = list;
 284       list = tmp;
 285
 286       g_object_unref (model);
 287     }
 288
 289   g_object_unref (iter);
 290
 291   return list;
 292 }
 293
 294 static GVariant *
 295 g_menu_exporter_menu_describe_item (GMenuExporterMenu *menu,
 296                                     gint               position)
 297 {
 298   GMenuAttributeIter *attr_iter;
 299   GVariantBuilder builder;
 300   GSequenceIter *iter;
 301   GMenuExporterLink *link;
 302   const char *name;
 303   GVariant *value;
 304
 305   g_variant_builder_init (&builder, G_VARIANT_TYPE_VARDICT);
 306
 307   attr_iter = g_menu_model_iterate_item_attributes (menu->model, position);
 308   while (g_menu_attribute_iter_get_next (attr_iter, &name, &value))
 309     {
 310       g_variant_builder_add (&builder, "{sv}", name, value);
 311       g_variant_unref (value);
 312     }
 313   g_object_unref (attr_iter);
 314
 315   iter = g_sequence_get_iter_at_pos (menu->item_links, position);
 316   for (link = g_sequence_get (iter); link; link = link->next)
 317     g_variant_builder_add (&builder, "{sv}", link->name,
 318                            g_variant_new ("(uu)", g_menu_exporter_group_get_id (link->menu->group), link->menu->id));
 319
 320   return g_variant_builder_end (&builder);
 321 }
 322
 323 static GVariant *
 324 g_menu_exporter_menu_list (GMenuExporterMenu *menu)
 325 {
 326   GVariantBuilder builder;
 327   gint i, n;
 328
 329   g_variant_builder_init (&builder, G_VARIANT_TYPE ("aa{sv}"));
 330
 331   n = g_sequence_get_length (menu->item_links);
 332   for (i = 0; i < n; i++)
 333     g_variant_builder_add_value (&builder, g_menu_exporter_menu_describe_item (menu, i));
 334
 335   return g_variant_builder_end (&builder);
 336 }
 337
 338 static void
 339 g_menu_exporter_menu_items_changed (GMenuModel *model,
 340                                     gint        position,
 341                                     gint        removed,
 342                                     gint        added,
 343                                     gpointer    user_data)
 344 {
 345   GMenuExporterMenu *menu = user_data;
 346   GSequenceIter *point;
 347   gint i;
 348
 349   g_assert (menu->model == model);
 350   g_assert (menu->item_links != NULL);
 351   g_assert (position + removed <= g_sequence_get_length (menu->item_links));
 352
 353   point = g_sequence_get_iter_at_pos (menu->item_links, position + removed);
 354   g_sequence_remove_range (g_sequence_get_iter_at_pos (menu->item_links, position), point);
 355
 356   for (i = position; i < position + added; i++)
 357     g_sequence_insert_before (point, g_menu_exporter_menu_create_links (menu, i));
 358
 359   if (g_menu_exporter_group_is_subscribed (menu->group))
 360     {
 361       GVariantBuilder builder;
 362
 363       g_variant_builder_init (&builder, G_VARIANT_TYPE ("(uuuuaa{sv})"));
 364       g_variant_builder_add (&builder, "u", g_menu_exporter_group_get_id (menu->group));
 365       g_variant_builder_add (&builder, "u", menu->id);
 366       g_variant_builder_add (&builder, "u", position);
 367       g_variant_builder_add (&builder, "u", removed);
 368
 369       g_variant_builder_open (&builder, G_VARIANT_TYPE ("aa{sv}"));
 370       for (i = position; i < position + added; i++)
 371         g_variant_builder_add_value (&builder, g_menu_exporter_menu_describe_item (menu, i));
 372       g_variant_builder_close (&builder);
 373
 374       g_menu_exporter_report (g_menu_exporter_group_get_exporter (menu->group), g_variant_builder_end (&builder));
 375     }
 376 }
 377
 378 static void
 379 g_menu_exporter_menu_prepare (GMenuExporterMenu *menu)
 380 {
 381   gint n_items;
 382
 383   g_assert (menu->item_links == NULL);
 384
 385   if (g_menu_model_is_mutable (menu->model))
 386     menu->handler_id = g_signal_connect (menu->model, "items-changed",
 387                                          G_CALLBACK (g_menu_exporter_menu_items_changed), menu);
 388
 389   menu->item_links = g_sequence_new (g_menu_exporter_link_free);
 390
 391   n_items = g_menu_model_get_n_items (menu->model);
 392   if (n_items)
 393     g_menu_exporter_menu_items_changed (menu->model, 0, 0, n_items, menu);
 394 }
 395
 396 static GMenuExporterMenu *
 397 g_menu_exporter_menu_new (GMenuExporterGroup *group,
 398                           guint               id,
 399                           GMenuModel         *model)
 400 {
 401   GMenuExporterMenu *menu;
 402
 403   menu = g_slice_new0 (GMenuExporterMenu);
 404   menu->group = group;
 405   menu->id = id;
 406   menu->model = g_object_ref (model);
 407
 408   return menu;
 409 }
 410
 411 /* {{{1 GMenuExporterGroup */
 412
 413 struct _GMenuExporterGroup
 414 {
 415   GMenuExporter *exporter;
 416   guint          id;
 417
 418   GHashTable *menus;
 419   guint       next_menu_id;
 420   gboolean    prepared;
 421
 422   gint subscribed;
 423 };
 424
 425 static void
 426 g_menu_exporter_group_check_if_useless (GMenuExporterGroup *group)
 427 {
 428   if (g_hash_table_size (group->menus) == 0 && group->subscribed == 0)
 429     {
 430       g_menu_exporter_remove_group (group->exporter, group->id);
 431
 432       g_hash_table_unref (group->menus);
 433
 434       g_slice_free (GMenuExporterGroup, group);
 435     }
 436 }
 437
 438 static void
 439 g_menu_exporter_group_subscribe (GMenuExporterGroup *group,
 440                                  GVariantBuilder    *builder)
 441 {
 442   GHashTableIter iter;
 443   gpointer key, val;
 444
 445   if (!group->prepared)
 446     {
 447       GMenuExporterMenu *menu;
 448
 449       /* set this first, so that any menus created during the
 450        * preparation of the first menu also end up in the prepared
 451        * state.
 452        * */
 453       group->prepared = TRUE;
 454
 455       menu = g_hash_table_lookup (group->menus, 0);
 456       g_menu_exporter_menu_prepare (menu);
 457     }
 458
 459   group->subscribed++;
 460
 461   g_hash_table_iter_init (&iter, group->menus);
 462   while (g_hash_table_iter_next (&iter, &key, &val))
 463     {
 464       guint id = GPOINTER_TO_INT (key);
 465       GMenuExporterMenu *menu = val;
 466
 467       if (g_sequence_get_length (menu->item_links))
 468         {
 469           g_variant_builder_open (builder, G_VARIANT_TYPE ("(uuaa{sv})"));
 470           g_variant_builder_add (builder, "u", group->id);
 471           g_variant_builder_add (builder, "u", id);
 472           g_variant_builder_add_value (builder, g_menu_exporter_menu_list (menu));
 473           g_variant_builder_close (builder);
 474         }
 475     }
 476 }
 477
 478 static void
 479 g_menu_exporter_group_unsubscribe (GMenuExporterGroup *group,
 480                                    gint                count)
 481 {
 482   g_assert (group->subscribed >= count);
 483
 484   group->subscribed -= count;
 485
 486   g_menu_exporter_group_check_if_useless (group);
 487 }
 488
 489 static GMenuExporter *
 490 g_menu_exporter_group_get_exporter (GMenuExporterGroup *group)
 491 {
 492   return group->exporter;
 493 }
 494
 495 static gboolean
 496 g_menu_exporter_group_is_subscribed (GMenuExporterGroup *group)
 497 {
 498   return group->subscribed > 0;
 499 }
 500
 501 static guint
 502 g_menu_exporter_group_get_id (GMenuExporterGroup *group)
 503 {
 504   return group->id;
 505 }
 506
 507 static void
 508 g_menu_exporter_group_remove_menu (GMenuExporterGroup *group,
 509                                    guint               id)
 510 {
 511   g_hash_table_remove (group->menus, GINT_TO_POINTER (id));
 512
 513   g_menu_exporter_group_check_if_useless (group);
 514 }
 515
 516 static GMenuExporterMenu *
 517 g_menu_exporter_group_add_menu (GMenuExporterGroup *group,
 518                                 GMenuModel         *model)
 519 {
 520   GMenuExporterMenu *menu;
 521   guint id;
 522
 523   id = group->next_menu_id++;
 524   menu = g_menu_exporter_menu_new (group, id, model);
 525   g_hash_table_insert (group->menus, GINT_TO_POINTER (id), menu);
 526
 527   if (group->prepared)
 528     g_menu_exporter_menu_prepare (menu);
 529
 530   return menu;
 531 }
 532
 533 static GMenuExporterGroup *
 534 g_menu_exporter_group_new (GMenuExporter *exporter,
 535                            guint          id)
 536 {
 537   GMenuExporterGroup *group;
 538
 539   group = g_slice_new0 (GMenuExporterGroup);
 540   group->menus = g_hash_table_new (NULL, NULL);
 541   group->exporter = exporter;
 542   group->id = id;
 543
 544   return group;
 545 }
 546
 547 /* {{{1 GMenuExporterRemote */
 548
 549 struct _GMenuExporterRemote
 550 {
 551   GMenuExporter *exporter;
 552   GHashTable    *watches;
 553   guint          watch_id;
 554 };
 555
 556 static void
 557 g_menu_exporter_remote_subscribe (GMenuExporterRemote *remote,
 558                                   guint                group_id,
 559                                   GVariantBuilder     *builder)
 560 {
 561   GMenuExporterGroup *group;
 562   guint count;
 563
 564   count = (gsize) g_hash_table_lookup (remote->watches, GINT_TO_POINTER (group_id));
 565   g_hash_table_insert (remote->watches, GINT_TO_POINTER (group_id), GINT_TO_POINTER (count + 1));
 566
 567   group = g_menu_exporter_lookup_group (remote->exporter, group_id);
 568   g_menu_exporter_group_subscribe (group, builder);
 569 }
 570
 571 static void
 572 g_menu_exporter_remote_unsubscribe (GMenuExporterRemote *remote,
 573                                     guint                group_id)
 574 {
 575   GMenuExporterGroup *group;
 576   guint count;
 577
 578   count = (gsize) g_hash_table_lookup (remote->watches, GINT_TO_POINTER (group_id));
 579
 580   if (count == 0)
 581     return;
 582
 583   if (count != 1)
 584     g_hash_table_insert (remote->watches, GINT_TO_POINTER (group_id), GINT_TO_POINTER (count - 1));
 585   else
 586     g_hash_table_remove (remote->watches, GINT_TO_POINTER (group_id));
 587
 588   group = g_menu_exporter_lookup_group (remote->exporter, group_id);
 589   g_menu_exporter_group_unsubscribe (group, 1);
 590 }
 591
 592 static gboolean
 593 g_menu_exporter_remote_has_subscriptions (GMenuExporterRemote *remote)
 594 {
 595   return g_hash_table_size (remote->watches) != 0;
 596 }
 597
 598 static void
 599 g_menu_exporter_remote_free (gpointer data)
 600 {
 601   GMenuExporterRemote *remote = data;
 602   GHashTableIter iter;
 603   gpointer key, val;
 604
 605   g_hash_table_iter_init (&iter, remote->watches);
 606   while (g_hash_table_iter_next (&iter, &key, &val))
 607     {
 608       GMenuExporterGroup *group;
 609
 610       group = g_menu_exporter_lookup_group (remote->exporter, GPOINTER_TO_INT (key));
 611       g_menu_exporter_group_unsubscribe (group, GPOINTER_TO_INT (val));
 612     }
 613
 614   g_bus_unwatch_name (remote->watch_id);
 615   g_hash_table_unref (remote->watches);
 616
 617   g_slice_free (GMenuExporterRemote, remote);
 618 }
 619
 620 static GMenuExporterRemote *
 621 g_menu_exporter_remote_new (GMenuExporter *exporter,
 622                             guint          watch_id)
 623 {
 624   GMenuExporterRemote *remote;
 625
 626   remote = g_slice_new0 (GMenuExporterRemote);
 627   remote->exporter = exporter;
 628   remote->watches = g_hash_table_new (NULL, NULL);
 629   remote->watch_id = watch_id;
 630
 631   return remote;
 632 }
 633
 634 /* {{{1 GMenuExporter */
 635
 636 struct _GMenuExporter
 637 {
 638   GDBusConnection *connection;
 639   gchar *object_path;
 640   guint registration_id;
 641   GHashTable *groups;
 642   guint next_group_id;
 643
 644   GMenuExporterMenu *root;
 645   GHashTable *remotes;
 646 };
 647
 648 static void
 649 g_menu_exporter_name_vanished (GDBusConnection *connection,
 650                                const gchar     *name,
 651                                gpointer         user_data)
 652 {
 653   GMenuExporter *exporter = user_data;
 654
 655   g_assert (exporter->connection == connection);
 656
 657   g_hash_table_remove (exporter->remotes, name);
 658 }
 659
 660 static GVariant *
 661 g_menu_exporter_subscribe (GMenuExporter *exporter,
 662                            const gchar   *sender,
 663                            GVariant      *group_ids)
 664 {
 665   GMenuExporterRemote *remote;
 666   GVariantBuilder builder;
 667   GVariantIter iter;
 668   guint32 id;
 669
 670   remote = g_hash_table_lookup (exporter->remotes, sender);
 671
 672   if (remote == NULL)
 673     {
 674       guint watch_id;
 675
 676       watch_id = g_bus_watch_name_on_connection (exporter->connection, sender, G_BUS_NAME_WATCHER_FLAGS_NONE,
 677                                                  NULL, g_menu_exporter_name_vanished, exporter, NULL);
 678       remote = g_menu_exporter_remote_new (exporter, watch_id);
 679       g_hash_table_insert (exporter->remotes, g_strdup (sender), remote);
 680     }
 681
 682   g_variant_builder_init (&builder, G_VARIANT_TYPE ("(a(uuaa{sv}))"));
 683
 684   g_variant_builder_open (&builder, G_VARIANT_TYPE ("a(uuaa{sv})"));
 685
 686   g_variant_iter_init (&iter, group_ids);
 687   while (g_variant_iter_next (&iter, "u", &id))
 688     g_menu_exporter_remote_subscribe (remote, id, &builder);
 689
 690   g_variant_builder_close (&builder);
 691
 692   return g_variant_builder_end (&builder);
 693 }
 694
 695 static void
 696 g_menu_exporter_unsubscribe (GMenuExporter *exporter,
 697                              const gchar   *sender,
 698                              GVariant      *group_ids)
 699 {
 700   GMenuExporterRemote *remote;
 701   GVariantIter iter;
 702   guint32 id;
 703
 704   remote = g_hash_table_lookup (exporter->remotes, sender);
 705
 706   if (remote == NULL)
 707     return;
 708
 709   g_variant_iter_init (&iter, group_ids);
 710   while (g_variant_iter_next (&iter, "u", &id))
 711     g_menu_exporter_remote_unsubscribe (remote, id);
 712
 713   if (!g_menu_exporter_remote_has_subscriptions (remote))
 714     g_hash_table_remove (exporter->remotes, sender);
 715 }
 716
 717 static void
 718 g_menu_exporter_report (GMenuExporter *exporter,
 719                         GVariant      *report)
 720 {
 721   GVariantBuilder builder;
 722
 723   g_variant_builder_init (&builder, G_VARIANT_TYPE_TUPLE);
 724   g_variant_builder_open (&builder, G_VARIANT_TYPE_ARRAY);
 725   g_variant_builder_add_value (&builder, report);
 726   g_variant_builder_close (&builder);
 727
 728   g_dbus_connection_emit_signal (exporter->connection,
 729                                  NULL,
 730                                  exporter->object_path,
 731                                  "org.gtk.Menus", "Changed",
 732                                  g_variant_builder_end (&builder),
 733                                  NULL);
 734 }
 735
 736 static void
 737 g_menu_exporter_remove_group (GMenuExporter *exporter,
 738                               guint          id)
 739 {
 740   g_hash_table_remove (exporter->groups, GINT_TO_POINTER (id));
 741 }
 742
 743 static GMenuExporterGroup *
 744 g_menu_exporter_lookup_group (GMenuExporter *exporter,
 745                               guint          group_id)
 746 {
 747   GMenuExporterGroup *group;
 748
 749   group = g_hash_table_lookup (exporter->groups, GINT_TO_POINTER (group_id));
 750
 751   if (group == NULL)
 752     {
 753       group = g_menu_exporter_group_new (exporter, group_id);
 754       g_hash_table_insert (exporter->groups, GINT_TO_POINTER (group_id), group);
 755     }
 756
 757   return group;
 758 }
 759
 760 static GMenuExporterGroup *
 761 g_menu_exporter_create_group (GMenuExporter *exporter)
 762 {
 763   GMenuExporterGroup *group;
 764   guint id;
 765
 766   id = exporter->next_group_id++;
 767   group = g_menu_exporter_group_new (exporter, id);
 768   g_hash_table_insert (exporter->groups, GINT_TO_POINTER (id), group);
 769
 770   return group;
 771 }
 772
 773 static void
 774 g_menu_exporter_free (gpointer user_data)
 775 {
 776   GMenuExporter *exporter = user_data;
 777
 778   g_menu_exporter_menu_free (exporter->root);
 779   g_hash_table_unref (exporter->remotes);
 780   g_hash_table_unref (exporter->groups);
 781   g_object_unref (exporter->connection);
 782   g_free (exporter->object_path);
 783
 784   g_slice_free (GMenuExporter, exporter);
 785 }
 786
 787 static void
 788 g_menu_exporter_method_call (GDBusConnection       *connection,
 789                              const gchar           *sender,
 790                              const gchar           *object_path,
 791                              const gchar           *interface_name,
 792                              const gchar           *method_name,
 793                              GVariant              *parameters,
 794                              GDBusMethodInvocation *invocation,
 795                              gpointer               user_data)
 796 {
 797   GMenuExporter *exporter = user_data;
 798   GVariant *group_ids;
 799
 800   group_ids = g_variant_get_child_value (parameters, 0);
 801
 802   if (g_str_equal (method_name, "Start"))
 803     g_dbus_method_invocation_return_value (invocation, g_menu_exporter_subscribe (exporter, sender, group_ids));
 804
 805   else if (g_str_equal (method_name, "End"))
 806     {
 807       g_menu_exporter_unsubscribe (exporter, sender, group_ids);
 808       g_dbus_method_invocation_return_value (invocation, NULL);
 809     }
 810
 811   else
 812     g_assert_not_reached ();
 813
 814   g_variant_unref (group_ids);
 815 }
 816
 817 /* {{{1 Public API */
 818
 819 /**
 820  * g_dbus_connection_export_menu_model:
 821  * @connection: a #GDBusConnection
 822  * @object_path: a D-Bus object path
 823  * @menu: a #GMenuModel
 824  * @error: return location for an error, or %NULL
 825  *
 826  * Exports @menu on @connection at @object_path.
 827  *
 828  * The implemented D-Bus API should be considered private.
 829  * It is subject to change in the future.
 830  *
 831  * An object path can only have one action group exported on it. If this
 832  * constraint is violated, the export will fail and 0 will be
 833  * returned (with @error set accordingly).
 834  *
 835  * You can unexport the menu model using
 836  * g_dbus_connection_unexport_menu_model() with the return value of
 837  * this function.
 838  *
 839  * Returns: the ID of the export (never zero), or 0 in case of failure
 840  *
 841  * Since: 2.32
 842  */
 843 guint
 844 g_dbus_connection_export_menu_model (GDBusConnection  *connection,
 845                                      const gchar      *object_path,
 846                                      GMenuModel       *menu,
 847                                      GError          **error)
 848 {
 849   const GDBusInterfaceVTable vtable = {
 850     g_menu_exporter_method_call,
 851   };
 852   GMenuExporter *exporter;
 853   guint id;
 854
 855   exporter = g_slice_new0 (GMenuExporter);
 856
 857   id = g_dbus_connection_register_object (connection, object_path, org_gtk_Menus_get_interface (),
 858                                           &vtable, exporter, g_menu_exporter_free, error);
 859
 860   if (id == 0)
 861     {
 862       g_slice_free (GMenuExporter, exporter);
 863       return 0;
 864     }
 865
 866   exporter->connection = g_object_ref (connection);
 867   exporter->object_path = g_strdup (object_path);
 868   exporter->groups = g_hash_table_new (NULL, NULL);
 869   exporter->remotes = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, g_menu_exporter_remote_free);
 870   exporter->root = g_menu_exporter_group_add_menu (g_menu_exporter_create_group (exporter), menu);
 871
 872   return id;
 873 }
 874
 875 /**
 876  * g_dbus_connection_unexport_menu_model:
 877  * @connection: a #GDBusConnection
 878  * @export_id: the ID from g_dbus_connection_export_menu_model()
 879  *
 880  * Reverses the effect of a previous call to
 881  * g_dbus_connection_export_menu_model().
 882  *
 883  * It is an error to call this function with an ID that wasn't returned
 884  * from g_dbus_connection_export_menu_model() or to call it with the
 885  * same ID more than once.
 886  *
 887  * Since: 2.32
 888  */
 889 void
 890 g_dbus_connection_unexport_menu_model (GDBusConnection *connection,
 891                                        guint            export_id)
 892 {
 893   g_dbus_connection_unregister_object (connection, export_id);
 894 }
 895
 896 /* {{{1 Epilogue */
 897 /* vim:set foldmethod=marker: */