gio/gdbusnamewatching.c

   1 /* GDBus - GLib D-Bus Library
   2  *
   3  * Copyright (C) 2008-2010 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, see <http://www.gnu.org/licenses/>.
  17  *
  18  * Author: David Zeuthen <davidz@redhat.com>
  19  */
  20
  21 #include "config.h"
  22
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #include "gdbusutils.h"
  27 #include "gdbusnamewatching.h"
  28 #include "gdbuserror.h"
  29 #include "gdbusprivate.h"
  30 #include "gdbusconnection.h"
  31
  32 #include "glibintl.h"
  33
  34 /**
  35  * SECTION:gdbusnamewatching
  36  * @title: Watching Bus Names
  37  * @short_description: Simple API for watching bus names
  38  * @include: gio/gio.h
  39  *
  40  * Convenience API for watching bus names.
  41  *
  42  * A simple example for watching a name can be found in
  43  * [gdbus-example-watch-name.c](https://git.gnome.org/browse/glib/tree/gio/tests/gdbus-example-watch-name.c)
  44  */
  45
  46 G_LOCK_DEFINE_STATIC (lock);
  47
  48 /* ---------------------------------------------------------------------------------------------------- */
  49
  50 typedef enum
  51 {
  52   PREVIOUS_CALL_NONE = 0,
  53   PREVIOUS_CALL_APPEARED,
  54   PREVIOUS_CALL_VANISHED,
  55 } PreviousCall;
  56
  57 typedef struct
  58 {
  59   volatile gint             ref_count;
  60   guint                     id;
  61   gchar                    *name;
  62   GBusNameWatcherFlags      flags;
  63   gchar                    *name_owner;
  64   GBusNameAppearedCallback  name_appeared_handler;
  65   GBusNameVanishedCallback  name_vanished_handler;
  66   gpointer                  user_data;
  67   GDestroyNotify            user_data_free_func;
  68   GMainContext             *main_context;
  69
  70   GDBusConnection          *connection;
  71   gulong                    disconnected_signal_handler_id;
  72   guint                     name_owner_changed_subscription_id;
  73
  74   PreviousCall              previous_call;
  75
  76   gboolean                  cancelled;
  77   gboolean                  initialized;
  78 } Client;
  79
  80 static guint next_global_id = 1;
  81 static GHashTable *map_id_to_client = NULL;
  82
  83 static Client *
  84 client_ref (Client *client)
  85 {
  86   g_atomic_int_inc (&client->ref_count);
  87   return client;
  88 }
  89
  90 static void
  91 client_unref (Client *client)
  92 {
  93   if (g_atomic_int_dec_and_test (&client->ref_count))
  94     {
  95       if (client->connection != NULL)
  96         {
  97           if (client->name_owner_changed_subscription_id > 0)
  98             g_dbus_connection_signal_unsubscribe (client->connection, client->name_owner_changed_subscription_id);
  99           if (client->disconnected_signal_handler_id > 0)
 100             g_signal_handler_disconnect (client->connection, client->disconnected_signal_handler_id);
 101           g_object_unref (client->connection);
 102         }
 103       g_free (client->name);
 104       g_free (client->name_owner);
 105       g_main_context_unref (client->main_context);
 106       if (client->user_data_free_func != NULL)
 107         client->user_data_free_func (client->user_data);
 108       g_free (client);
 109     }
 110 }
 111
 112 /* ---------------------------------------------------------------------------------------------------- */
 113
 114 typedef enum
 115 {
 116   CALL_TYPE_NAME_APPEARED,
 117   CALL_TYPE_NAME_VANISHED
 118 } CallType;
 119
 120 typedef struct
 121 {
 122   Client *client;
 123
 124   /* keep this separate because client->connection may
 125    * be set to NULL after scheduling the call
 126    */
 127   GDBusConnection *connection;
 128
 129   /* ditto */
 130   gchar *name_owner;
 131
 132   CallType call_type;
 133 } CallHandlerData;
 134
 135 static void
 136 call_handler_data_free (CallHandlerData *data)
 137 {
 138   if (data->connection != NULL)
 139     g_object_unref (data->connection);
 140   g_free (data->name_owner);
 141   client_unref (data->client);
 142   g_free (data);
 143 }
 144
 145 static void
 146 actually_do_call (Client *client, GDBusConnection *connection, const gchar *name_owner, CallType call_type)
 147 {
 148   switch (call_type)
 149     {
 150     case CALL_TYPE_NAME_APPEARED:
 151       if (client->name_appeared_handler != NULL)
 152         {
 153           client->name_appeared_handler (connection,
 154                                          client->name,
 155                                          name_owner,
 156                                          client->user_data);
 157         }
 158       break;
 159
 160     case CALL_TYPE_NAME_VANISHED:
 161       if (client->name_vanished_handler != NULL)
 162         {
 163           client->name_vanished_handler (connection,
 164                                          client->name,
 165                                          client->user_data);
 166         }
 167       break;
 168
 169     default:
 170       g_assert_not_reached ();
 171       break;
 172     }
 173 }
 174
 175 static gboolean
 176 call_in_idle_cb (gpointer _data)
 177 {
 178   CallHandlerData *data = _data;
 179   actually_do_call (data->client, data->connection, data->name_owner, data->call_type);
 180   return FALSE;
 181 }
 182
 183 static void
 184 schedule_call_in_idle (Client *client, CallType call_type)
 185 {
 186   CallHandlerData *data;
 187   GSource *idle_source;
 188
 189   data = g_new0 (CallHandlerData, 1);
 190   data->client = client_ref (client);
 191   data->connection = client->connection != NULL ? g_object_ref (client->connection) : NULL;
 192   data->name_owner = g_strdup (client->name_owner);
 193   data->call_type = call_type;
 194
 195   idle_source = g_idle_source_new ();
 196   g_source_set_priority (idle_source, G_PRIORITY_HIGH);
 197   g_source_set_callback (idle_source,
 198                          call_in_idle_cb,
 199                          data,
 200                          (GDestroyNotify) call_handler_data_free);
 201   g_source_set_name (idle_source, "[gio] call_in_idle_cb");
 202   g_source_attach (idle_source, client->main_context);
 203   g_source_unref (idle_source);
 204 }
 205
 206 static void
 207 do_call (Client *client, CallType call_type)
 208 {
 209   GMainContext *current_context;
 210
 211   /* only schedule in idle if we're not in the right thread */
 212   current_context = g_main_context_ref_thread_default ();
 213   if (current_context != client->main_context)
 214     schedule_call_in_idle (client, call_type);
 215   else
 216     actually_do_call (client, client->connection, client->name_owner, call_type);
 217   g_main_context_unref (current_context);
 218 }
 219
 220 static void
 221 call_appeared_handler (Client *client)
 222 {
 223   if (client->previous_call != PREVIOUS_CALL_APPEARED)
 224     {
 225       client->previous_call = PREVIOUS_CALL_APPEARED;
 226       if (!client->cancelled && client->name_appeared_handler != NULL)
 227         {
 228           do_call (client, CALL_TYPE_NAME_APPEARED);
 229         }
 230     }
 231 }
 232
 233 static void
 234 call_vanished_handler (Client  *client,
 235                        gboolean ignore_cancelled)
 236 {
 237   if (client->previous_call != PREVIOUS_CALL_VANISHED)
 238     {
 239       client->previous_call = PREVIOUS_CALL_VANISHED;
 240       if (((!client->cancelled) || ignore_cancelled) && client->name_vanished_handler != NULL)
 241         {
 242           do_call (client, CALL_TYPE_NAME_VANISHED);
 243         }
 244     }
 245 }
 246
 247 /* ---------------------------------------------------------------------------------------------------- */
 248
 249 static void
 250 on_connection_disconnected (GDBusConnection *connection,
 251                             gboolean         remote_peer_vanished,
 252                             GError          *error,
 253                             gpointer         user_data)
 254 {
 255   Client *client = user_data;
 256
 257   if (client->name_owner_changed_subscription_id > 0)
 258     g_dbus_connection_signal_unsubscribe (client->connection, client->name_owner_changed_subscription_id);
 259   if (client->disconnected_signal_handler_id > 0)
 260     g_signal_handler_disconnect (client->connection, client->disconnected_signal_handler_id);
 261   g_object_unref (client->connection);
 262   client->disconnected_signal_handler_id = 0;
 263   client->name_owner_changed_subscription_id = 0;
 264   client->connection = NULL;
 265
 266   call_vanished_handler (client, FALSE);
 267 }
 268
 269 /* ---------------------------------------------------------------------------------------------------- */
 270
 271 static void
 272 on_name_owner_changed (GDBusConnection *connection,
 273                        const gchar      *sender_name,
 274                        const gchar      *object_path,
 275                        const gchar      *interface_name,
 276                        const gchar      *signal_name,
 277                        GVariant         *parameters,
 278                        gpointer          user_data)
 279 {
 280   Client *client = user_data;
 281   const gchar *name;
 282   const gchar *old_owner;
 283   const gchar *new_owner;
 284
 285   if (!client->initialized)
 286     goto out;
 287
 288   if (g_strcmp0 (object_path, "/org/freedesktop/DBus") != 0 ||
 289       g_strcmp0 (interface_name, "org.freedesktop.DBus") != 0 ||
 290       g_strcmp0 (sender_name, "org.freedesktop.DBus") != 0)
 291     goto out;
 292
 293   g_variant_get (parameters,
 294                  "(&s&s&s)",
 295                  &name,
 296                  &old_owner,
 297                  &new_owner);
 298
 299   /* we only care about a specific name */
 300   if (g_strcmp0 (name, client->name) != 0)
 301     goto out;
 302
 303   if ((old_owner != NULL && strlen (old_owner) > 0) && client->name_owner != NULL)
 304     {
 305       g_free (client->name_owner);
 306       client->name_owner = NULL;
 307       call_vanished_handler (client, FALSE);
 308     }
 309
 310   if (new_owner != NULL && strlen (new_owner) > 0)
 311     {
 312       g_warn_if_fail (client->name_owner == NULL);
 313       g_free (client->name_owner);
 314       client->name_owner = g_strdup (new_owner);
 315       call_appeared_handler (client);
 316     }
 317
 318  out:
 319   ;
 320 }
 321
 322 /* ---------------------------------------------------------------------------------------------------- */
 323
 324 static void
 325 get_name_owner_cb (GObject      *source_object,
 326                    GAsyncResult *res,
 327                    gpointer      user_data)
 328 {
 329   Client *client = user_data;
 330   GVariant *result;
 331   const char *name_owner;
 332
 333   name_owner = NULL;
 334   result = NULL;
 335
 336   result = g_dbus_connection_call_finish (client->connection,
 337                                           res,
 338                                           NULL);
 339   if (result != NULL)
 340     {
 341       g_variant_get (result, "(&s)", &name_owner);
 342     }
 343
 344   if (name_owner != NULL)
 345     {
 346       g_warn_if_fail (client->name_owner == NULL);
 347       client->name_owner = g_strdup (name_owner);
 348       call_appeared_handler (client);
 349     }
 350   else
 351     {
 352       call_vanished_handler (client, FALSE);
 353     }
 354
 355   client->initialized = TRUE;
 356
 357   if (result != NULL)
 358     g_variant_unref (result);
 359   client_unref (client);
 360 }
 361
 362 /* ---------------------------------------------------------------------------------------------------- */
 363
 364 static void
 365 invoke_get_name_owner (Client *client)
 366 {
 367   g_dbus_connection_call (client->connection,
 368                           "org.freedesktop.DBus",  /* bus name */
 369                           "/org/freedesktop/DBus", /* object path */
 370                           "org.freedesktop.DBus",  /* interface name */
 371                           "GetNameOwner",          /* method name */
 372                           g_variant_new ("(s)", client->name),
 373                           G_VARIANT_TYPE ("(s)"),
 374                           G_DBUS_CALL_FLAGS_NONE,
 375                           -1,
 376                           NULL,
 377                           (GAsyncReadyCallback) get_name_owner_cb,
 378                           client_ref (client));
 379 }
 380
 381 /* ---------------------------------------------------------------------------------------------------- */
 382
 383 static void
 384 start_service_by_name_cb (GObject      *source_object,
 385                           GAsyncResult *res,
 386                           gpointer      user_data)
 387 {
 388   Client *client = user_data;
 389   GVariant *result;
 390
 391   result = NULL;
 392
 393   result = g_dbus_connection_call_finish (client->connection,
 394                                           res,
 395                                           NULL);
 396   if (result != NULL)
 397     {
 398       guint32 start_service_result;
 399       g_variant_get (result, "(u)", &start_service_result);
 400
 401       if (start_service_result == 1) /* DBUS_START_REPLY_SUCCESS */
 402         {
 403           invoke_get_name_owner (client);
 404         }
 405       else if (start_service_result == 2) /* DBUS_START_REPLY_ALREADY_RUNNING */
 406         {
 407           invoke_get_name_owner (client);
 408         }
 409       else
 410         {
 411           g_warning ("Unexpected reply %d from StartServiceByName() method", start_service_result);
 412           call_vanished_handler (client, FALSE);
 413           client->initialized = TRUE;
 414         }
 415     }
 416   else
 417     {
 418       /* Errors are not unexpected; the bus will reply e.g.
 419        *
 420        *   org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.Epiphany2
 421        *   was not provided by any .service files
 422        *
 423        * This doesn't mean that the name doesn't have an owner, just
 424        * that it's not provided by a .service file. So proceed to
 425        * invoke GetNameOwner().
 426        */
 427       invoke_get_name_owner (client);
 428     }
 429
 430   if (result != NULL)
 431     g_variant_unref (result);
 432   client_unref (client);
 433 }
 434
 435 /* ---------------------------------------------------------------------------------------------------- */
 436
 437 static void
 438 has_connection (Client *client)
 439 {
 440   /* listen for disconnection */
 441   client->disconnected_signal_handler_id = g_signal_connect (client->connection,
 442                                                              "closed",
 443                                                              G_CALLBACK (on_connection_disconnected),
 444                                                              client);
 445
 446   /* start listening to NameOwnerChanged messages immediately */
 447   client->name_owner_changed_subscription_id = g_dbus_connection_signal_subscribe (client->connection,
 448                                                                                    "org.freedesktop.DBus",  /* name */
 449                                                                                    "org.freedesktop.DBus",  /* if */
 450                                                                                    "NameOwnerChanged",      /* signal */
 451                                                                                    "/org/freedesktop/DBus", /* path */
 452                                                                                    client->name,
 453                                                                                    G_DBUS_SIGNAL_FLAGS_NONE,
 454                                                                                    on_name_owner_changed,
 455                                                                                    client,
 456                                                                                    NULL);
 457
 458   if (client->flags & G_BUS_NAME_WATCHER_FLAGS_AUTO_START)
 459     {
 460       g_dbus_connection_call (client->connection,
 461                               "org.freedesktop.DBus",  /* bus name */
 462                               "/org/freedesktop/DBus", /* object path */
 463                               "org.freedesktop.DBus",  /* interface name */
 464                               "StartServiceByName",    /* method name */
 465                               g_variant_new ("(su)", client->name, 0),
 466                               G_VARIANT_TYPE ("(u)"),
 467                               G_DBUS_CALL_FLAGS_NONE,
 468                               -1,
 469                               NULL,
 470                               (GAsyncReadyCallback) start_service_by_name_cb,
 471                               client_ref (client));
 472     }
 473   else
 474     {
 475       /* check owner */
 476       invoke_get_name_owner (client);
 477     }
 478 }
 479
 480
 481 static void
 482 connection_get_cb (GObject      *source_object,
 483                    GAsyncResult *res,
 484                    gpointer      user_data)
 485 {
 486   Client *client = user_data;
 487
 488   client->connection = g_bus_get_finish (res, NULL);
 489   if (client->connection == NULL)
 490     {
 491       call_vanished_handler (client, FALSE);
 492       goto out;
 493     }
 494
 495   has_connection (client);
 496
 497  out:
 498   client_unref (client);
 499 }
 500
 501 /* ---------------------------------------------------------------------------------------------------- */
 502
 503 /**
 504  * g_bus_watch_name:
 505  * @bus_type: The type of bus to watch a name on.
 506  * @name: The name (well-known or unique) to watch.
 507  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 508  * @name_appeared_handler: (allow-none): Handler to invoke when @name is known to exist or %NULL.
 509  * @name_vanished_handler: (allow-none): Handler to invoke when @name is known to not exist or %NULL.
 510  * @user_data: User data to pass to handlers.
 511  * @user_data_free_func: (allow-none): Function for freeing @user_data or %NULL.
 512  *
 513  * Starts watching @name on the bus specified by @bus_type and calls
 514  * @name_appeared_handler and @name_vanished_handler when the name is
 515  * known to have a owner respectively known to lose its
 516  * owner. Callbacks will be invoked in the
 517  * [thread-default main context][g-main-context-push-thread-default]
 518  * of the thread you are calling this function from.
 519  *
 520  * You are guaranteed that one of the handlers will be invoked after
 521  * calling this function. When you are done watching the name, just
 522  * call g_bus_unwatch_name() with the watcher id this function
 523  * returns.
 524  *
 525  * If the name vanishes or appears (for example the application owning
 526  * the name could restart), the handlers are also invoked. If the
 527  * #GDBusConnection that is used for watching the name disconnects, then
 528  * @name_vanished_handler is invoked since it is no longer
 529  * possible to access the name.
 530  *
 531  * Another guarantee is that invocations of @name_appeared_handler
 532  * and @name_vanished_handler are guaranteed to alternate; that
 533  * is, if @name_appeared_handler is invoked then you are
 534  * guaranteed that the next time one of the handlers is invoked, it
 535  * will be @name_vanished_handler. The reverse is also true.
 536  *
 537  * This behavior makes it very simple to write applications that want
 538  * to take action when a certain [name exists][gdbus-watching-names].
 539  * Basically, the application should create object proxies in
 540  * @name_appeared_handler and destroy them again (if any) in
 541  * @name_vanished_handler.
 542  *
 543  * Returns: An identifier (never 0) that an be used with
 544  * g_bus_unwatch_name() to stop watching the name.
 545  *
 546  * Since: 2.26
 547  */
 548 guint
 549 g_bus_watch_name (GBusType                  bus_type,
 550                   const gchar              *name,
 551                   GBusNameWatcherFlags      flags,
 552                   GBusNameAppearedCallback  name_appeared_handler,
 553                   GBusNameVanishedCallback  name_vanished_handler,
 554                   gpointer                  user_data,
 555                   GDestroyNotify            user_data_free_func)
 556 {
 557   Client *client;
 558
 559   g_return_val_if_fail (g_dbus_is_name (name), 0);
 560
 561   G_LOCK (lock);
 562
 563   client = g_new0 (Client, 1);
 564   client->ref_count = 1;
 565   client->id = next_global_id++; /* TODO: uh oh, handle overflow */
 566   client->name = g_strdup (name);
 567   client->flags = flags;
 568   client->name_appeared_handler = name_appeared_handler;
 569   client->name_vanished_handler = name_vanished_handler;
 570   client->user_data = user_data;
 571   client->user_data_free_func = user_data_free_func;
 572   client->main_context = g_main_context_ref_thread_default ();
 573
 574   if (map_id_to_client == NULL)
 575     {
 576       map_id_to_client = g_hash_table_new (g_direct_hash, g_direct_equal);
 577     }
 578   g_hash_table_insert (map_id_to_client,
 579                        GUINT_TO_POINTER (client->id),
 580                        client);
 581
 582   g_bus_get (bus_type,
 583              NULL,
 584              connection_get_cb,
 585              client_ref (client));
 586
 587   G_UNLOCK (lock);
 588
 589   return client->id;
 590 }
 591
 592 /**
 593  * g_bus_watch_name_on_connection:
 594  * @connection: A #GDBusConnection.
 595  * @name: The name (well-known or unique) to watch.
 596  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 597  * @name_appeared_handler: (allow-none): Handler to invoke when @name is known to exist or %NULL.
 598  * @name_vanished_handler: (allow-none): Handler to invoke when @name is known to not exist or %NULL.
 599  * @user_data: User data to pass to handlers.
 600  * @user_data_free_func: (allow-none): Function for freeing @user_data or %NULL.
 601  *
 602  * Like g_bus_watch_name() but takes a #GDBusConnection instead of a
 603  * #GBusType.
 604  *
 605  * Returns: An identifier (never 0) that an be used with
 606  * g_bus_unwatch_name() to stop watching the name.
 607  *
 608  * Since: 2.26
 609  */
 610 guint g_bus_watch_name_on_connection (GDBusConnection          *connection,
 611                                       const gchar              *name,
 612                                       GBusNameWatcherFlags      flags,
 613                                       GBusNameAppearedCallback  name_appeared_handler,
 614                                       GBusNameVanishedCallback  name_vanished_handler,
 615                                       gpointer                  user_data,
 616                                       GDestroyNotify            user_data_free_func)
 617 {
 618   Client *client;
 619
 620   g_return_val_if_fail (G_IS_DBUS_CONNECTION (connection), 0);
 621   g_return_val_if_fail (g_dbus_is_name (name), 0);
 622
 623   G_LOCK (lock);
 624
 625   client = g_new0 (Client, 1);
 626   client->ref_count = 1;
 627   client->id = next_global_id++; /* TODO: uh oh, handle overflow */
 628   client->name = g_strdup (name);
 629   client->flags = flags;
 630   client->name_appeared_handler = name_appeared_handler;
 631   client->name_vanished_handler = name_vanished_handler;
 632   client->user_data = user_data;
 633   client->user_data_free_func = user_data_free_func;
 634   client->main_context = g_main_context_ref_thread_default ();
 635
 636   if (map_id_to_client == NULL)
 637     map_id_to_client = g_hash_table_new (g_direct_hash, g_direct_equal);
 638
 639   g_hash_table_insert (map_id_to_client,
 640                        GUINT_TO_POINTER (client->id),
 641                        client);
 642
 643   client->connection = g_object_ref (connection);
 644   G_UNLOCK (lock);
 645
 646   has_connection (client);
 647
 648   return client->id;
 649 }
 650
 651 typedef struct {
 652   GClosure *name_appeared_closure;
 653   GClosure *name_vanished_closure;
 654 } WatchNameData;
 655
 656 static WatchNameData *
 657 watch_name_data_new (GClosure *name_appeared_closure,
 658                      GClosure *name_vanished_closure)
 659 {
 660   WatchNameData *data;
 661
 662   data = g_new0 (WatchNameData, 1);
 663
 664   if (name_appeared_closure != NULL)
 665     {
 666       data->name_appeared_closure = g_closure_ref (name_appeared_closure);
 667       g_closure_sink (name_appeared_closure);
 668       if (G_CLOSURE_NEEDS_MARSHAL (name_appeared_closure))
 669         g_closure_set_marshal (name_appeared_closure, g_cclosure_marshal_generic);
 670     }
 671
 672   if (name_vanished_closure != NULL)
 673     {
 674       data->name_vanished_closure = g_closure_ref (name_vanished_closure);
 675       g_closure_sink (name_vanished_closure);
 676       if (G_CLOSURE_NEEDS_MARSHAL (name_vanished_closure))
 677         g_closure_set_marshal (name_vanished_closure, g_cclosure_marshal_generic);
 678     }
 679
 680   return data;
 681 }
 682
 683 static void
 684 watch_with_closures_on_name_appeared (GDBusConnection *connection,
 685                                       const gchar     *name,
 686                                       const gchar     *name_owner,
 687                                       gpointer         user_data)
 688 {
 689   WatchNameData *data = user_data;
 690   GValue params[3] = { G_VALUE_INIT, G_VALUE_INIT, G_VALUE_INIT };
 691
 692   g_value_init (&params[0], G_TYPE_DBUS_CONNECTION);
 693   g_value_set_object (&params[0], connection);
 694
 695   g_value_init (&params[1], G_TYPE_STRING);
 696   g_value_set_string (&params[1], name);
 697
 698   g_value_init (&params[2], G_TYPE_STRING);
 699   g_value_set_string (&params[2], name_owner);
 700
 701   g_closure_invoke (data->name_appeared_closure, NULL, 3, params, NULL);
 702
 703   g_value_unset (params + 0);
 704   g_value_unset (params + 1);
 705   g_value_unset (params + 2);
 706 }
 707
 708 static void
 709 watch_with_closures_on_name_vanished (GDBusConnection *connection,
 710                                       const gchar     *name,
 711                                       gpointer         user_data)
 712 {
 713   WatchNameData *data = user_data;
 714   GValue params[2] = { G_VALUE_INIT, G_VALUE_INIT };
 715
 716   g_value_init (&params[0], G_TYPE_DBUS_CONNECTION);
 717   g_value_set_object (&params[0], connection);
 718
 719   g_value_init (&params[1], G_TYPE_STRING);
 720   g_value_set_string (&params[1], name);
 721
 722   g_closure_invoke (data->name_vanished_closure, NULL, 2, params, NULL);
 723
 724   g_value_unset (params + 0);
 725   g_value_unset (params + 1);
 726 }
 727
 728 static void
 729 bus_watch_name_free_func (gpointer user_data)
 730 {
 731   WatchNameData *data = user_data;
 732
 733   if (data->name_appeared_closure != NULL)
 734     g_closure_unref (data->name_appeared_closure);
 735
 736   if (data->name_vanished_closure != NULL)
 737     g_closure_unref (data->name_vanished_closure);
 738
 739   g_free (data);
 740 }
 741
 742 /**
 743  * g_bus_watch_name_with_closures:
 744  * @bus_type: The type of bus to watch a name on.
 745  * @name: The name (well-known or unique) to watch.
 746  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 747  * @name_appeared_closure: (allow-none): #GClosure to invoke when @name is known
 748  * to exist or %NULL.
 749  * @name_vanished_closure: (allow-none): #GClosure to invoke when @name is known
 750  * to not exist or %NULL.
 751  *
 752  * Version of g_bus_watch_name() using closures instead of callbacks for
 753  * easier binding in other languages.
 754  *
 755  * Returns: An identifier (never 0) that an be used with
 756  * g_bus_unwatch_name() to stop watching the name.
 757  *
 758  * Rename to: g_bus_watch_name
 759  *
 760  * Since: 2.26
 761  */
 762 guint
 763 g_bus_watch_name_with_closures (GBusType                 bus_type,
 764                                 const gchar             *name,
 765                                 GBusNameWatcherFlags     flags,
 766                                 GClosure                *name_appeared_closure,
 767                                 GClosure                *name_vanished_closure)
 768 {
 769   return g_bus_watch_name (bus_type,
 770           name,
 771           flags,
 772           name_appeared_closure != NULL ? watch_with_closures_on_name_appeared : NULL,
 773           name_vanished_closure != NULL ? watch_with_closures_on_name_vanished : NULL,
 774           watch_name_data_new (name_appeared_closure, name_vanished_closure),
 775           bus_watch_name_free_func);
 776 }
 777
 778 /**
 779  * g_bus_watch_name_on_connection_with_closures:
 780  * @connection: A #GDBusConnection.
 781  * @name: The name (well-known or unique) to watch.
 782  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 783  * @name_appeared_closure: (allow-none): #GClosure to invoke when @name is known
 784  * to exist or %NULL.
 785  * @name_vanished_closure: (allow-none): #GClosure to invoke when @name is known
 786  * to not exist or %NULL.
 787  *
 788  * Version of g_bus_watch_name_on_connection() using closures instead of callbacks for
 789  * easier binding in other languages.
 790  *
 791  * Returns: An identifier (never 0) that an be used with
 792  * g_bus_unwatch_name() to stop watching the name.
 793  *
 794  * Rename to: g_bus_watch_name_on_connection
 795  *
 796  * Since: 2.26
 797  */
 798 guint g_bus_watch_name_on_connection_with_closures (
 799                                       GDBusConnection          *connection,
 800                                       const gchar              *name,
 801                                       GBusNameWatcherFlags      flags,
 802                                       GClosure                 *name_appeared_closure,
 803                                       GClosure                 *name_vanished_closure)
 804 {
 805   return g_bus_watch_name_on_connection (connection,
 806           name,
 807           flags,
 808           name_appeared_closure != NULL ? watch_with_closures_on_name_appeared : NULL,
 809           name_vanished_closure != NULL ? watch_with_closures_on_name_vanished : NULL,
 810           watch_name_data_new (name_appeared_closure, name_vanished_closure),
 811           bus_watch_name_free_func);
 812 }
 813
 814 /**
 815  * g_bus_unwatch_name:
 816  * @watcher_id: An identifier obtained from g_bus_watch_name()
 817  *
 818  * Stops watching a name.
 819  *
 820  * Since: 2.26
 821  */
 822 void
 823 g_bus_unwatch_name (guint watcher_id)
 824 {
 825   Client *client;
 826
 827   g_return_if_fail (watcher_id > 0);
 828
 829   client = NULL;
 830
 831   G_LOCK (lock);
 832   if (watcher_id == 0 ||
 833       map_id_to_client == NULL ||
 834       (client = g_hash_table_lookup (map_id_to_client, GUINT_TO_POINTER (watcher_id))) == NULL)
 835     {
 836       g_warning ("Invalid id %d passed to g_bus_unwatch_name()", watcher_id);
 837       goto out;
 838     }
 839
 840   client->cancelled = TRUE;
 841   g_warn_if_fail (g_hash_table_remove (map_id_to_client, GUINT_TO_POINTER (watcher_id)));
 842
 843  out:
 844   G_UNLOCK (lock);
 845
 846   /* do callback without holding lock */
 847   if (client != NULL)
 848     {
 849       client_unref (client);
 850     }
 851 }