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, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  18  * Boston, MA 02111-1307, USA.
  19  *
  20  * Author: David Zeuthen <davidz@redhat.com>
  21  */
  22
  23 #include "config.h"
  24
  25 #include <stdlib.h>
  26 #include <string.h>
  27
  28 #include "gdbusutils.h"
  29 #include "gdbusnamewatching.h"
  30 #include "gdbuserror.h"
  31 #include "gdbusprivate.h"
  32 #include "gdbusconnection.h"
  33 #include "gio-marshal.h"
  34
  35 #include "glibintl.h"
  36
  37 /**
  38  * SECTION:gdbusnamewatching
  39  * @title: Watching Bus Names
  40  * @short_description: Simple API for watching bus names
  41  * @include: gio/gio.h
  42  *
  43  * Convenience API for watching bus names.
  44  *
  45  * <example id="gdbus-watching-names"><title>Simple application watching a name</title><programlisting><xi:include xmlns:xi="http://www.w3.org/2001/XInclude" parse="text" href="../../../../gio/tests/gdbus-example-watch-name.c"><xi:fallback>FIXME: MISSING XINCLUDE CONTENT</xi:fallback></xi:include></programlisting></example>
  46  */
  47
  48 G_LOCK_DEFINE_STATIC (lock);
  49
  50 /* ---------------------------------------------------------------------------------------------------- */
  51
  52 typedef enum
  53 {
  54   PREVIOUS_CALL_NONE = 0,
  55   PREVIOUS_CALL_APPEARED,
  56   PREVIOUS_CALL_VANISHED,
  57 } PreviousCall;
  58
  59 typedef struct
  60 {
  61   volatile gint             ref_count;
  62   guint                     id;
  63   gchar                    *name;
  64   GBusNameWatcherFlags      flags;
  65   gchar                    *name_owner;
  66   GBusNameAppearedCallback  name_appeared_handler;
  67   GBusNameVanishedCallback  name_vanished_handler;
  68   gpointer                  user_data;
  69   GDestroyNotify            user_data_free_func;
  70   GMainContext             *main_context;
  71
  72   GDBusConnection          *connection;
  73   gulong                    disconnected_signal_handler_id;
  74   guint                     name_owner_changed_subscription_id;
  75
  76   PreviousCall              previous_call;
  77
  78   gboolean                  cancelled;
  79   gboolean                  initialized;
  80 } Client;
  81
  82 static guint next_global_id = 1;
  83 static GHashTable *map_id_to_client = NULL;
  84
  85 static Client *
  86 client_ref (Client *client)
  87 {
  88   g_atomic_int_inc (&client->ref_count);
  89   return client;
  90 }
  91
  92 static void
  93 client_unref (Client *client)
  94 {
  95   if (g_atomic_int_dec_and_test (&client->ref_count))
  96     {
  97       if (client->connection != NULL)
  98         {
  99           if (client->name_owner_changed_subscription_id > 0)
 100             g_dbus_connection_signal_unsubscribe (client->connection, client->name_owner_changed_subscription_id);
 101           if (client->disconnected_signal_handler_id > 0)
 102             g_signal_handler_disconnect (client->connection, client->disconnected_signal_handler_id);
 103           g_object_unref (client->connection);
 104         }
 105       g_free (client->name);
 106       g_free (client->name_owner);
 107       if (client->main_context != NULL)
 108         g_main_context_unref (client->main_context);
 109       if (client->user_data_free_func != NULL)
 110         client->user_data_free_func (client->user_data);
 111       g_free (client);
 112     }
 113 }
 114
 115 /* ---------------------------------------------------------------------------------------------------- */
 116
 117 typedef enum
 118 {
 119   CALL_TYPE_NAME_APPEARED,
 120   CALL_TYPE_NAME_VANISHED
 121 } CallType;
 122
 123 typedef struct
 124 {
 125   Client *client;
 126
 127   /* keep this separate because client->connection may
 128    * be set to NULL after scheduling the call
 129    */
 130   GDBusConnection *connection;
 131
 132   /* ditto */
 133   gchar *name_owner;
 134
 135   CallType call_type;
 136 } CallHandlerData;
 137
 138 static void
 139 call_handler_data_free (CallHandlerData *data)
 140 {
 141   if (data->connection != NULL)
 142     g_object_unref (data->connection);
 143   g_free (data->name_owner);
 144   client_unref (data->client);
 145   g_free (data);
 146 }
 147
 148 static void
 149 actually_do_call (Client *client, GDBusConnection *connection, const gchar *name_owner, CallType call_type)
 150 {
 151   switch (call_type)
 152     {
 153     case CALL_TYPE_NAME_APPEARED:
 154       if (client->name_appeared_handler != NULL)
 155         {
 156           client->name_appeared_handler (connection,
 157                                          client->name,
 158                                          name_owner,
 159                                          client->user_data);
 160         }
 161       break;
 162
 163     case CALL_TYPE_NAME_VANISHED:
 164       if (client->name_vanished_handler != NULL)
 165         {
 166           client->name_vanished_handler (connection,
 167                                          client->name,
 168                                          client->user_data);
 169         }
 170       break;
 171
 172     default:
 173       g_assert_not_reached ();
 174       break;
 175     }
 176 }
 177
 178 static gboolean
 179 call_in_idle_cb (gpointer _data)
 180 {
 181   CallHandlerData *data = _data;
 182   actually_do_call (data->client, data->connection, data->name_owner, data->call_type);
 183   return FALSE;
 184 }
 185
 186 static void
 187 schedule_call_in_idle (Client *client, CallType call_type)
 188 {
 189   CallHandlerData *data;
 190   GSource *idle_source;
 191
 192   data = g_new0 (CallHandlerData, 1);
 193   data->client = client_ref (client);
 194   data->connection = client->connection != NULL ? g_object_ref (client->connection) : NULL;
 195   data->name_owner = g_strdup (client->name_owner);
 196   data->call_type = call_type;
 197
 198   idle_source = g_idle_source_new ();
 199   g_source_set_priority (idle_source, G_PRIORITY_HIGH);
 200   g_source_set_callback (idle_source,
 201                          call_in_idle_cb,
 202                          data,
 203                          (GDestroyNotify) call_handler_data_free);
 204   g_source_attach (idle_source, client->main_context);
 205   g_source_unref (idle_source);
 206 }
 207
 208 static void
 209 do_call (Client *client, CallType call_type)
 210 {
 211   /* only schedule in idle if we're not in the right thread */
 212   if (g_main_context_get_thread_default () != client->main_context)
 213     schedule_call_in_idle (client, call_type);
 214   else
 215     actually_do_call (client, client->connection, client->name_owner, call_type);
 216 }
 217
 218 static void
 219 call_appeared_handler (Client *client)
 220 {
 221   if (client->previous_call != PREVIOUS_CALL_APPEARED)
 222     {
 223       client->previous_call = PREVIOUS_CALL_APPEARED;
 224       if (!client->cancelled && client->name_appeared_handler != NULL)
 225         {
 226           do_call (client, CALL_TYPE_NAME_APPEARED);
 227         }
 228     }
 229 }
 230
 231 static void
 232 call_vanished_handler (Client  *client,
 233                        gboolean ignore_cancelled)
 234 {
 235   if (client->previous_call != PREVIOUS_CALL_VANISHED)
 236     {
 237       client->previous_call = PREVIOUS_CALL_VANISHED;
 238       if (((!client->cancelled) || ignore_cancelled) && client->name_vanished_handler != NULL)
 239         {
 240           do_call (client, CALL_TYPE_NAME_VANISHED);
 241         }
 242     }
 243 }
 244
 245 /* ---------------------------------------------------------------------------------------------------- */
 246
 247 static void
 248 on_connection_disconnected (GDBusConnection *connection,
 249                             gboolean         remote_peer_vanished,
 250                             GError          *error,
 251                             gpointer         user_data)
 252 {
 253   Client *client = user_data;
 254
 255   if (client->name_owner_changed_subscription_id > 0)
 256     g_dbus_connection_signal_unsubscribe (client->connection, client->name_owner_changed_subscription_id);
 257   if (client->disconnected_signal_handler_id > 0)
 258     g_signal_handler_disconnect (client->connection, client->disconnected_signal_handler_id);
 259   g_object_unref (client->connection);
 260   client->disconnected_signal_handler_id = 0;
 261   client->name_owner_changed_subscription_id = 0;
 262   client->connection = NULL;
 263
 264   call_vanished_handler (client, FALSE);
 265 }
 266
 267 /* ---------------------------------------------------------------------------------------------------- */
 268
 269 static void
 270 on_name_owner_changed (GDBusConnection *connection,
 271                        const gchar      *sender_name,
 272                        const gchar      *object_path,
 273                        const gchar      *interface_name,
 274                        const gchar      *signal_name,
 275                        GVariant         *parameters,
 276                        gpointer          user_data)
 277 {
 278   Client *client = user_data;
 279   const gchar *name;
 280   const gchar *old_owner;
 281   const gchar *new_owner;
 282
 283   if (!client->initialized)
 284     goto out;
 285
 286   if (g_strcmp0 (object_path, "/org/freedesktop/DBus") != 0 ||
 287       g_strcmp0 (interface_name, "org.freedesktop.DBus") != 0 ||
 288       g_strcmp0 (sender_name, "org.freedesktop.DBus") != 0)
 289     goto out;
 290
 291   g_variant_get (parameters,
 292                  "(&s&s&s)",
 293                  &name,
 294                  &old_owner,
 295                  &new_owner);
 296
 297   /* we only care about a specific name */
 298   if (g_strcmp0 (name, client->name) != 0)
 299     goto out;
 300
 301   if ((old_owner != NULL && strlen (old_owner) > 0) && client->name_owner != NULL)
 302     {
 303       g_free (client->name_owner);
 304       client->name_owner = NULL;
 305       call_vanished_handler (client, FALSE);
 306     }
 307
 308   if (new_owner != NULL && strlen (new_owner) > 0)
 309     {
 310       g_warn_if_fail (client->name_owner == NULL);
 311       g_free (client->name_owner);
 312       client->name_owner = g_strdup (new_owner);
 313       call_appeared_handler (client);
 314     }
 315
 316  out:
 317   ;
 318 }
 319
 320 /* ---------------------------------------------------------------------------------------------------- */
 321
 322 static void
 323 get_name_owner_cb (GObject      *source_object,
 324                    GAsyncResult *res,
 325                    gpointer      user_data)
 326 {
 327   Client *client = user_data;
 328   GVariant *result;
 329   const char *name_owner;
 330
 331   name_owner = NULL;
 332   result = NULL;
 333
 334   result = g_dbus_connection_call_finish (client->connection,
 335                                           res,
 336                                           NULL);
 337   if (result != NULL)
 338     {
 339       g_variant_get (result, "(&s)", &name_owner);
 340     }
 341
 342   if (name_owner != NULL)
 343     {
 344       g_warn_if_fail (client->name_owner == NULL);
 345       client->name_owner = g_strdup (name_owner);
 346       call_appeared_handler (client);
 347     }
 348   else
 349     {
 350       call_vanished_handler (client, FALSE);
 351     }
 352
 353   client->initialized = TRUE;
 354
 355   if (result != NULL)
 356     g_variant_unref (result);
 357   client_unref (client);
 358 }
 359
 360 /* ---------------------------------------------------------------------------------------------------- */
 361
 362 static void
 363 invoke_get_name_owner (Client *client)
 364 {
 365   g_dbus_connection_call (client->connection,
 366                           "org.freedesktop.DBus",  /* bus name */
 367                           "/org/freedesktop/DBus", /* object path */
 368                           "org.freedesktop.DBus",  /* interface name */
 369                           "GetNameOwner",          /* method name */
 370                           g_variant_new ("(s)", client->name),
 371                           G_VARIANT_TYPE ("(s)"),
 372                           G_DBUS_CALL_FLAGS_NONE,
 373                           -1,
 374                           NULL,
 375                           (GAsyncReadyCallback) get_name_owner_cb,
 376                           client_ref (client));
 377 }
 378
 379 /* ---------------------------------------------------------------------------------------------------- */
 380
 381 static void
 382 start_service_by_name_cb (GObject      *source_object,
 383                           GAsyncResult *res,
 384                           gpointer      user_data)
 385 {
 386   Client *client = user_data;
 387   GVariant *result;
 388
 389   result = NULL;
 390
 391   result = g_dbus_connection_call_finish (client->connection,
 392                                           res,
 393                                           NULL);
 394   if (result != NULL)
 395     {
 396       guint32 start_service_result;
 397       g_variant_get (result, "(u)", &start_service_result);
 398
 399       if (start_service_result == 1) /* DBUS_START_REPLY_SUCCESS */
 400         {
 401           invoke_get_name_owner (client);
 402         }
 403       else if (start_service_result == 2) /* DBUS_START_REPLY_ALREADY_RUNNING */
 404         {
 405           invoke_get_name_owner (client);
 406         }
 407       else
 408         {
 409           g_warning ("Unexpected reply %d from StartServiceByName() method", start_service_result);
 410           call_vanished_handler (client, FALSE);
 411           client->initialized = TRUE;
 412         }
 413     }
 414   else
 415     {
 416       /* Errors are not unexpected; the bus will reply e.g.
 417        *
 418        *   org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.Epiphany2
 419        *   was not provided by any .service files
 420        *
 421        * This doesn't mean that the name doesn't have an owner, just
 422        * that it's not provided by a .service file. So proceed to
 423        * invoke GetNameOwner().
 424        */
 425       invoke_get_name_owner (client);
 426     }
 427
 428   if (result != NULL)
 429     g_variant_unref (result);
 430   client_unref (client);
 431 }
 432
 433 /* ---------------------------------------------------------------------------------------------------- */
 434
 435 static void
 436 has_connection (Client *client)
 437 {
 438   /* listen for disconnection */
 439   client->disconnected_signal_handler_id = g_signal_connect (client->connection,
 440                                                              "closed",
 441                                                              G_CALLBACK (on_connection_disconnected),
 442                                                              client);
 443
 444   /* start listening to NameOwnerChanged messages immediately */
 445   client->name_owner_changed_subscription_id = g_dbus_connection_signal_subscribe (client->connection,
 446                                                                                    "org.freedesktop.DBus",  /* name */
 447                                                                                    "org.freedesktop.DBus",  /* if */
 448                                                                                    "NameOwnerChanged",      /* signal */
 449                                                                                    "/org/freedesktop/DBus", /* path */
 450                                                                                    client->name,
 451                                                                                    G_DBUS_SIGNAL_FLAGS_NONE,
 452                                                                                    on_name_owner_changed,
 453                                                                                    client,
 454                                                                                    NULL);
 455
 456   if (client->flags & G_BUS_NAME_WATCHER_FLAGS_AUTO_START)
 457     {
 458       g_dbus_connection_call (client->connection,
 459                               "org.freedesktop.DBus",  /* bus name */
 460                               "/org/freedesktop/DBus", /* object path */
 461                               "org.freedesktop.DBus",  /* interface name */
 462                               "StartServiceByName",    /* method name */
 463                               g_variant_new ("(su)", client->name, 0),
 464                               G_VARIANT_TYPE ("(u)"),
 465                               G_DBUS_CALL_FLAGS_NONE,
 466                               -1,
 467                               NULL,
 468                               (GAsyncReadyCallback) start_service_by_name_cb,
 469                               client_ref (client));
 470     }
 471   else
 472     {
 473       /* check owner */
 474       invoke_get_name_owner (client);
 475     }
 476 }
 477
 478
 479 static void
 480 connection_get_cb (GObject      *source_object,
 481                    GAsyncResult *res,
 482                    gpointer      user_data)
 483 {
 484   Client *client = user_data;
 485
 486   client->connection = g_bus_get_finish (res, NULL);
 487   if (client->connection == NULL)
 488     {
 489       call_vanished_handler (client, FALSE);
 490       goto out;
 491     }
 492
 493   has_connection (client);
 494
 495  out:
 496   client_unref (client);
 497 }
 498
 499 /* ---------------------------------------------------------------------------------------------------- */
 500
 501 /**
 502  * g_bus_watch_name:
 503  * @bus_type: The type of bus to watch a name on.
 504  * @name: The name (well-known or unique) to watch.
 505  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 506  * @name_appeared_handler: Handler to invoke when @name is known to exist or %NULL.
 507  * @name_vanished_handler: Handler to invoke when @name is known to not exist or %NULL.
 508  * @user_data: User data to pass to handlers.
 509  * @user_data_free_func: Function for freeing @user_data or %NULL.
 510  *
 511  * Starts watching @name on the bus specified by @bus_type and calls
 512  * @name_appeared_handler and @name_vanished_handler when the name is
 513  * known to have a owner respectively known to lose its
 514  * owner. Callbacks will be invoked in the <link
 515  * linkend="g-main-context-push-thread-default">thread-default main
 516  * loop</link> of the thread you are calling this function from.
 517  *
 518  * You are guaranteed that one of the handlers will be invoked after
 519  * calling this function. When you are done watching the name, just
 520  * call g_bus_unwatch_name() with the watcher id this function
 521  * returns.
 522  *
 523  * If the name vanishes or appears (for example the application owning
 524  * the name could restart), the handlers are also invoked. If the
 525  * #GDBusConnection that is used for watching the name disconnects, then
 526  * @name_vanished_handler is invoked since it is no longer
 527  * possible to access the name.
 528  *
 529  * Another guarantee is that invocations of @name_appeared_handler
 530  * and @name_vanished_handler are guaranteed to alternate; that
 531  * is, if @name_appeared_handler is invoked then you are
 532  * guaranteed that the next time one of the handlers is invoked, it
 533  * will be @name_vanished_handler. The reverse is also true.
 534  *
 535  * This behavior makes it very simple to write applications that wants
 536  * to take action when a certain name exists, see <xref
 537  * linkend="gdbus-watching-names"/>. Basically, the application
 538  * should create object proxies in @name_appeared_handler and destroy
 539  * them again (if any) in @name_vanished_handler.
 540  *
 541  * Returns: An identifier (never 0) that an be used with
 542  * g_bus_unwatch_name() to stop watching the name.
 543  *
 544  * Since: 2.26
 545  */
 546 guint
 547 g_bus_watch_name (GBusType                  bus_type,
 548                   const gchar              *name,
 549                   GBusNameWatcherFlags      flags,
 550                   GBusNameAppearedCallback  name_appeared_handler,
 551                   GBusNameVanishedCallback  name_vanished_handler,
 552                   gpointer                  user_data,
 553                   GDestroyNotify            user_data_free_func)
 554 {
 555   Client *client;
 556
 557   g_return_val_if_fail (g_dbus_is_name (name), 0);
 558
 559   G_LOCK (lock);
 560
 561   client = g_new0 (Client, 1);
 562   client->ref_count = 1;
 563   client->id = next_global_id++; /* TODO: uh oh, handle overflow */
 564   client->name = g_strdup (name);
 565   client->flags = flags;
 566   client->name_appeared_handler = name_appeared_handler;
 567   client->name_vanished_handler = name_vanished_handler;
 568   client->user_data = user_data;
 569   client->user_data_free_func = user_data_free_func;
 570   client->main_context = g_main_context_get_thread_default ();
 571   if (client->main_context != NULL)
 572     g_main_context_ref (client->main_context);
 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: Handler to invoke when @name is known to exist or %NULL.
 598  * @name_vanished_handler: 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: 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_get_thread_default ();
 635   if (client->main_context != NULL)
 636     g_main_context_ref (client->main_context);
 637
 638   if (map_id_to_client == NULL)
 639     map_id_to_client = g_hash_table_new (g_direct_hash, g_direct_equal);
 640
 641   g_hash_table_insert (map_id_to_client,
 642                        GUINT_TO_POINTER (client->id),
 643                        client);
 644
 645   client->connection = g_object_ref (connection);
 646   G_UNLOCK (lock);
 647
 648   has_connection (client);
 649
 650   return client->id;
 651 }
 652
 653 typedef struct {
 654   GClosure *name_appeared_closure;
 655   GClosure *name_vanished_closure;
 656 } WatchNameData;
 657
 658 static WatchNameData *
 659 watch_name_data_new (GClosure *name_appeared_closure,
 660                      GClosure *name_vanished_closure)
 661 {
 662   WatchNameData *data;
 663
 664   data = g_new0 (WatchNameData, 1);
 665
 666   if (name_appeared_closure != NULL)
 667     {
 668       data->name_appeared_closure = g_closure_ref (name_appeared_closure);
 669       g_closure_sink (name_appeared_closure);
 670       if (G_CLOSURE_NEEDS_MARSHAL (name_appeared_closure))
 671         g_closure_set_marshal (name_appeared_closure, _gio_marshal_VOID__STRING_STRING);
 672     }
 673
 674   if (name_vanished_closure != NULL)
 675     {
 676       data->name_vanished_closure = g_closure_ref (name_vanished_closure);
 677       g_closure_sink (name_vanished_closure);
 678       if (G_CLOSURE_NEEDS_MARSHAL (name_vanished_closure))
 679         g_closure_set_marshal (name_vanished_closure, _gio_marshal_VOID__STRING);
 680     }
 681
 682   return data;
 683 }
 684
 685 static void
 686 watch_with_closures_on_name_appeared (GDBusConnection *connection,
 687                                       const gchar     *name,
 688                                       const gchar     *name_owner,
 689                                       gpointer         user_data)
 690 {
 691   WatchNameData *data = user_data;
 692   GValue params[3] = { { 0, }, { 0, }, { 0, } };
 693
 694   g_value_init (&params[0], G_TYPE_DBUS_CONNECTION);
 695   g_value_set_object (&params[0], connection);
 696
 697   g_value_init (&params[1], G_TYPE_STRING);
 698   g_value_set_string (&params[1], name);
 699
 700   g_value_init (&params[2], G_TYPE_STRING);
 701   g_value_set_string (&params[2], name_owner);
 702
 703   g_closure_invoke (data->name_appeared_closure, NULL, 3, params, NULL);
 704
 705   g_value_unset (params + 0);
 706   g_value_unset (params + 1);
 707   g_value_unset (params + 2);
 708 }
 709
 710 static void
 711 watch_with_closures_on_name_vanished (GDBusConnection *connection,
 712                                       const gchar     *name,
 713                                       gpointer         user_data)
 714 {
 715   WatchNameData *data = user_data;
 716   GValue params[2] = { { 0, }, { 0, } };
 717
 718   g_value_init (&params[0], G_TYPE_DBUS_CONNECTION);
 719   g_value_set_object (&params[0], connection);
 720
 721   g_value_init (&params[1], G_TYPE_STRING);
 722   g_value_set_string (&params[1], name);
 723
 724   g_closure_invoke (data->name_vanished_closure, NULL, 2, params, NULL);
 725
 726   g_value_unset (params + 0);
 727   g_value_unset (params + 1);
 728 }
 729
 730 static void
 731 bus_watch_name_free_func (gpointer user_data)
 732 {
 733   WatchNameData *data = user_data;
 734
 735   if (data->name_appeared_closure != NULL)
 736     g_closure_unref (data->name_appeared_closure);
 737
 738   if (data->name_vanished_closure != NULL)
 739     g_closure_unref (data->name_vanished_closure);
 740
 741   g_free (data);
 742 }
 743
 744 /**
 745  * g_bus_watch_name_with_closures:
 746  * @bus_type: The type of bus to watch a name on.
 747  * @name: The name (well-known or unique) to watch.
 748  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 749  * @name_appeared_closure: (allow-none): #GClosure to invoke when @name is known
 750  * to exist or %NULL.
 751  * @name_vanished_closure: (allow-none): #GClosure to invoke when @name is known
 752  * to not exist or %NULL.
 753  *
 754  * Version of g_bus_watch_name() using closures instead of callbacks for
 755  * easier binding in other languages.
 756  *
 757  * Returns: An identifier (never 0) that an be used with
 758  * g_bus_unwatch_name() to stop watching the name.
 759  *
 760  * Rename to: g_bus_watch_name
 761  *
 762  * Since: 2.26
 763  */
 764 guint
 765 g_bus_watch_name_with_closures (GBusType                 bus_type,
 766                                 const gchar             *name,
 767                                 GBusNameWatcherFlags     flags,
 768                                 GClosure                *name_appeared_closure,
 769                                 GClosure                *name_vanished_closure)
 770 {
 771   return g_bus_watch_name (bus_type,
 772           name,
 773           flags,
 774           name_appeared_closure != NULL ? watch_with_closures_on_name_appeared : NULL,
 775           name_vanished_closure != NULL ? watch_with_closures_on_name_vanished : NULL,
 776           watch_name_data_new (name_appeared_closure, name_vanished_closure),
 777           bus_watch_name_free_func);
 778 }
 779
 780 /**
 781  * g_bus_watch_name_on_connection_with_closures:
 782  * @connection: A #GDBusConnection.
 783  * @name: The name (well-known or unique) to watch.
 784  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 785  * @name_appeared_closure: (allow-none): #GClosure to invoke when @name is known
 786  * to exist or %NULL.
 787  * @name_vanished_closure: (allow-none): #GClosure to invoke when @name is known
 788  * to not exist or %NULL.
 789  *
 790  * Version of g_bus_watch_name_on_connection() using closures instead of callbacks for
 791  * easier binding in other languages.
 792  *
 793  * Returns: An identifier (never 0) that an be used with
 794  * g_bus_unwatch_name() to stop watching the name.
 795  *
 796  * Rename to: g_bus_watch_name_on_connection
 797  *
 798  * Since: 2.26
 799  */
 800 guint g_bus_watch_name_on_connection_with_closures (
 801                                       GDBusConnection          *connection,
 802                                       const gchar              *name,
 803                                       GBusNameWatcherFlags      flags,
 804                                       GClosure                 *name_appeared_closure,
 805                                       GClosure                 *name_vanished_closure)
 806 {
 807   return g_bus_watch_name_on_connection (connection,
 808           name,
 809           flags,
 810           name_appeared_closure != NULL ? watch_with_closures_on_name_appeared : NULL,
 811           name_vanished_closure != NULL ? watch_with_closures_on_name_vanished : NULL,
 812           watch_name_data_new (name_appeared_closure, name_vanished_closure),
 813           bus_watch_name_free_func);
 814 }
 815
 816 /**
 817  * g_bus_unwatch_name:
 818  * @watcher_id: An identifier obtained from g_bus_watch_name()
 819  *
 820  * Stops watching a name.
 821  *
 822  * Since: 2.26
 823  */
 824 void
 825 g_bus_unwatch_name (guint watcher_id)
 826 {
 827   Client *client;
 828
 829   g_return_if_fail (watcher_id > 0);
 830
 831   client = NULL;
 832
 833   G_LOCK (lock);
 834   if (watcher_id == 0 ||
 835       map_id_to_client == NULL ||
 836       (client = g_hash_table_lookup (map_id_to_client, GUINT_TO_POINTER (watcher_id))) == NULL)
 837     {
 838       g_warning ("Invalid id %d passed to g_bus_unwatch_name()", watcher_id);
 839       goto out;
 840     }
 841
 842   client->cancelled = TRUE;
 843   g_warn_if_fail (g_hash_table_remove (map_id_to_client, GUINT_TO_POINTER (watcher_id)));
 844
 845  out:
 846   G_UNLOCK (lock);
 847
 848   /* do callback without holding lock */
 849   if (client != NULL)
 850     {
 851       client_unref (client);
 852     }
 853 }