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  * <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>
  43  */
  44
  45 G_LOCK_DEFINE_STATIC (lock);
  46
  47 /* ---------------------------------------------------------------------------------------------------- */
  48
  49 typedef enum
  50 {
  51   PREVIOUS_CALL_NONE = 0,
  52   PREVIOUS_CALL_APPEARED,
  53   PREVIOUS_CALL_VANISHED,
  54 } PreviousCall;
  55
  56 typedef struct
  57 {
  58   volatile gint             ref_count;
  59   guint                     id;
  60   gchar                    *name;
  61   GBusNameWatcherFlags      flags;
  62   gchar                    *name_owner;
  63   GBusNameAppearedCallback  name_appeared_handler;
  64   GBusNameVanishedCallback  name_vanished_handler;
  65   gpointer                  user_data;
  66   GDestroyNotify            user_data_free_func;
  67   GMainContext             *main_context;
  68
  69   GDBusConnection          *connection;
  70   gulong                    disconnected_signal_handler_id;
  71   guint                     name_owner_changed_subscription_id;
  72
  73   PreviousCall              previous_call;
  74
  75   gboolean                  cancelled;
  76   gboolean                  initialized;
  77 } Client;
  78
  79 static guint next_global_id = 1;
  80 static GHashTable *map_id_to_client = NULL;
  81
  82 static Client *
  83 client_ref (Client *client)
  84 {
  85   g_atomic_int_inc (&client->ref_count);
  86   return client;
  87 }
  88
  89 static void
  90 client_unref (Client *client)
  91 {
  92   if (g_atomic_int_dec_and_test (&client->ref_count))
  93     {
  94       if (client->connection != NULL)
  95         {
  96           if (client->name_owner_changed_subscription_id > 0)
  97             g_dbus_connection_signal_unsubscribe (client->connection, client->name_owner_changed_subscription_id);
  98           if (client->disconnected_signal_handler_id > 0)
  99             g_signal_handler_disconnect (client->connection, client->disconnected_signal_handler_id);
 100           g_object_unref (client->connection);
 101         }
 102       g_free (client->name);
 103       g_free (client->name_owner);
 104       g_main_context_unref (client->main_context);
 105       if (client->user_data_free_func != NULL)
 106         client->user_data_free_func (client->user_data);
 107       g_free (client);
 108     }
 109 }
 110
 111 /* ---------------------------------------------------------------------------------------------------- */
 112
 113 typedef enum
 114 {
 115   CALL_TYPE_NAME_APPEARED,
 116   CALL_TYPE_NAME_VANISHED
 117 } CallType;
 118
 119 typedef struct
 120 {
 121   Client *client;
 122
 123   /* keep this separate because client->connection may
 124    * be set to NULL after scheduling the call
 125    */
 126   GDBusConnection *connection;
 127
 128   /* ditto */
 129   gchar *name_owner;
 130
 131   CallType call_type;
 132 } CallHandlerData;
 133
 134 static void
 135 call_handler_data_free (CallHandlerData *data)
 136 {
 137   if (data->connection != NULL)
 138     g_object_unref (data->connection);
 139   g_free (data->name_owner);
 140   client_unref (data->client);
 141   g_free (data);
 142 }
 143
 144 static void
 145 actually_do_call (Client *client, GDBusConnection *connection, const gchar *name_owner, CallType call_type)
 146 {
 147   switch (call_type)
 148     {
 149     case CALL_TYPE_NAME_APPEARED:
 150       if (client->name_appeared_handler != NULL)
 151         {
 152           client->name_appeared_handler (connection,
 153                                          client->name,
 154                                          name_owner,
 155                                          client->user_data);
 156         }
 157       break;
 158
 159     case CALL_TYPE_NAME_VANISHED:
 160       if (client->name_vanished_handler != NULL)
 161         {
 162           client->name_vanished_handler (connection,
 163                                          client->name,
 164                                          client->user_data);
 165         }
 166       break;
 167
 168     default:
 169       g_assert_not_reached ();
 170       break;
 171     }
 172 }
 173
 174 static gboolean
 175 call_in_idle_cb (gpointer _data)
 176 {
 177   CallHandlerData *data = _data;
 178   actually_do_call (data->client, data->connection, data->name_owner, data->call_type);
 179   return FALSE;
 180 }
 181
 182 static void
 183 schedule_call_in_idle (Client *client, CallType call_type)
 184 {
 185   CallHandlerData *data;
 186   GSource *idle_source;
 187
 188   data = g_new0 (CallHandlerData, 1);
 189   data->client = client_ref (client);
 190   data->connection = client->connection != NULL ? g_object_ref (client->connection) : NULL;
 191   data->name_owner = g_strdup (client->name_owner);
 192   data->call_type = call_type;
 193
 194   idle_source = g_idle_source_new ();
 195   g_source_set_priority (idle_source, G_PRIORITY_HIGH);
 196   g_source_set_callback (idle_source,
 197                          call_in_idle_cb,
 198                          data,
 199                          (GDestroyNotify) call_handler_data_free);
 200   g_source_attach (idle_source, client->main_context);
 201   g_source_unref (idle_source);
 202 }
 203
 204 static void
 205 do_call (Client *client, CallType call_type)
 206 {
 207   GMainContext *current_context;
 208
 209   /* only schedule in idle if we're not in the right thread */
 210   current_context = g_main_context_ref_thread_default ();
 211   if (current_context != client->main_context)
 212     schedule_call_in_idle (client, call_type);
 213   else
 214     actually_do_call (client, client->connection, client->name_owner, call_type);
 215   g_main_context_unref (current_context);
 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: (allow-none): Handler to invoke when @name is known to exist or %NULL.
 507  * @name_vanished_handler: (allow-none): 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: (allow-none): 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_ref_thread_default ();
 571
 572   if (map_id_to_client == NULL)
 573     {
 574       map_id_to_client = g_hash_table_new (g_direct_hash, g_direct_equal);
 575     }
 576   g_hash_table_insert (map_id_to_client,
 577                        GUINT_TO_POINTER (client->id),
 578                        client);
 579
 580   g_bus_get (bus_type,
 581              NULL,
 582              connection_get_cb,
 583              client_ref (client));
 584
 585   G_UNLOCK (lock);
 586
 587   return client->id;
 588 }
 589
 590 /**
 591  * g_bus_watch_name_on_connection:
 592  * @connection: A #GDBusConnection.
 593  * @name: The name (well-known or unique) to watch.
 594  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 595  * @name_appeared_handler: (allow-none): Handler to invoke when @name is known to exist or %NULL.
 596  * @name_vanished_handler: (allow-none): Handler to invoke when @name is known to not exist or %NULL.
 597  * @user_data: User data to pass to handlers.
 598  * @user_data_free_func: (allow-none): Function for freeing @user_data or %NULL.
 599  *
 600  * Like g_bus_watch_name() but takes a #GDBusConnection instead of a
 601  * #GBusType.
 602  *
 603  * Returns: An identifier (never 0) that an be used with
 604  * g_bus_unwatch_name() to stop watching the name.
 605  *
 606  * Since: 2.26
 607  */
 608 guint g_bus_watch_name_on_connection (GDBusConnection          *connection,
 609                                       const gchar              *name,
 610                                       GBusNameWatcherFlags      flags,
 611                                       GBusNameAppearedCallback  name_appeared_handler,
 612                                       GBusNameVanishedCallback  name_vanished_handler,
 613                                       gpointer                  user_data,
 614                                       GDestroyNotify            user_data_free_func)
 615 {
 616   Client *client;
 617
 618   g_return_val_if_fail (G_IS_DBUS_CONNECTION (connection), 0);
 619   g_return_val_if_fail (g_dbus_is_name (name), 0);
 620
 621   G_LOCK (lock);
 622
 623   client = g_new0 (Client, 1);
 624   client->ref_count = 1;
 625   client->id = next_global_id++; /* TODO: uh oh, handle overflow */
 626   client->name = g_strdup (name);
 627   client->flags = flags;
 628   client->name_appeared_handler = name_appeared_handler;
 629   client->name_vanished_handler = name_vanished_handler;
 630   client->user_data = user_data;
 631   client->user_data_free_func = user_data_free_func;
 632   client->main_context = g_main_context_ref_thread_default ();
 633
 634   if (map_id_to_client == NULL)
 635     map_id_to_client = g_hash_table_new (g_direct_hash, g_direct_equal);
 636
 637   g_hash_table_insert (map_id_to_client,
 638                        GUINT_TO_POINTER (client->id),
 639                        client);
 640
 641   client->connection = g_object_ref (connection);
 642   G_UNLOCK (lock);
 643
 644   has_connection (client);
 645
 646   return client->id;
 647 }
 648
 649 typedef struct {
 650   GClosure *name_appeared_closure;
 651   GClosure *name_vanished_closure;
 652 } WatchNameData;
 653
 654 static WatchNameData *
 655 watch_name_data_new (GClosure *name_appeared_closure,
 656                      GClosure *name_vanished_closure)
 657 {
 658   WatchNameData *data;
 659
 660   data = g_new0 (WatchNameData, 1);
 661
 662   if (name_appeared_closure != NULL)
 663     {
 664       data->name_appeared_closure = g_closure_ref (name_appeared_closure);
 665       g_closure_sink (name_appeared_closure);
 666       if (G_CLOSURE_NEEDS_MARSHAL (name_appeared_closure))
 667         g_closure_set_marshal (name_appeared_closure, g_cclosure_marshal_generic);
 668     }
 669
 670   if (name_vanished_closure != NULL)
 671     {
 672       data->name_vanished_closure = g_closure_ref (name_vanished_closure);
 673       g_closure_sink (name_vanished_closure);
 674       if (G_CLOSURE_NEEDS_MARSHAL (name_vanished_closure))
 675         g_closure_set_marshal (name_vanished_closure, g_cclosure_marshal_generic);
 676     }
 677
 678   return data;
 679 }
 680
 681 static void
 682 watch_with_closures_on_name_appeared (GDBusConnection *connection,
 683                                       const gchar     *name,
 684                                       const gchar     *name_owner,
 685                                       gpointer         user_data)
 686 {
 687   WatchNameData *data = user_data;
 688   GValue params[3] = { G_VALUE_INIT, G_VALUE_INIT, G_VALUE_INIT };
 689
 690   g_value_init (&params[0], G_TYPE_DBUS_CONNECTION);
 691   g_value_set_object (&params[0], connection);
 692
 693   g_value_init (&params[1], G_TYPE_STRING);
 694   g_value_set_string (&params[1], name);
 695
 696   g_value_init (&params[2], G_TYPE_STRING);
 697   g_value_set_string (&params[2], name_owner);
 698
 699   g_closure_invoke (data->name_appeared_closure, NULL, 3, params, NULL);
 700
 701   g_value_unset (params + 0);
 702   g_value_unset (params + 1);
 703   g_value_unset (params + 2);
 704 }
 705
 706 static void
 707 watch_with_closures_on_name_vanished (GDBusConnection *connection,
 708                                       const gchar     *name,
 709                                       gpointer         user_data)
 710 {
 711   WatchNameData *data = user_data;
 712   GValue params[2] = { G_VALUE_INIT, G_VALUE_INIT };
 713
 714   g_value_init (&params[0], G_TYPE_DBUS_CONNECTION);
 715   g_value_set_object (&params[0], connection);
 716
 717   g_value_init (&params[1], G_TYPE_STRING);
 718   g_value_set_string (&params[1], name);
 719
 720   g_closure_invoke (data->name_vanished_closure, NULL, 2, params, NULL);
 721
 722   g_value_unset (params + 0);
 723   g_value_unset (params + 1);
 724 }
 725
 726 static void
 727 bus_watch_name_free_func (gpointer user_data)
 728 {
 729   WatchNameData *data = user_data;
 730
 731   if (data->name_appeared_closure != NULL)
 732     g_closure_unref (data->name_appeared_closure);
 733
 734   if (data->name_vanished_closure != NULL)
 735     g_closure_unref (data->name_vanished_closure);
 736
 737   g_free (data);
 738 }
 739
 740 /**
 741  * g_bus_watch_name_with_closures:
 742  * @bus_type: The type of bus to watch a name on.
 743  * @name: The name (well-known or unique) to watch.
 744  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 745  * @name_appeared_closure: (allow-none): #GClosure to invoke when @name is known
 746  * to exist or %NULL.
 747  * @name_vanished_closure: (allow-none): #GClosure to invoke when @name is known
 748  * to not exist or %NULL.
 749  *
 750  * Version of g_bus_watch_name() using closures instead of callbacks for
 751  * easier binding in other languages.
 752  *
 753  * Returns: An identifier (never 0) that an be used with
 754  * g_bus_unwatch_name() to stop watching the name.
 755  *
 756  * Rename to: g_bus_watch_name
 757  *
 758  * Since: 2.26
 759  */
 760 guint
 761 g_bus_watch_name_with_closures (GBusType                 bus_type,
 762                                 const gchar             *name,
 763                                 GBusNameWatcherFlags     flags,
 764                                 GClosure                *name_appeared_closure,
 765                                 GClosure                *name_vanished_closure)
 766 {
 767   return g_bus_watch_name (bus_type,
 768           name,
 769           flags,
 770           name_appeared_closure != NULL ? watch_with_closures_on_name_appeared : NULL,
 771           name_vanished_closure != NULL ? watch_with_closures_on_name_vanished : NULL,
 772           watch_name_data_new (name_appeared_closure, name_vanished_closure),
 773           bus_watch_name_free_func);
 774 }
 775
 776 /**
 777  * g_bus_watch_name_on_connection_with_closures:
 778  * @connection: A #GDBusConnection.
 779  * @name: The name (well-known or unique) to watch.
 780  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 781  * @name_appeared_closure: (allow-none): #GClosure to invoke when @name is known
 782  * to exist or %NULL.
 783  * @name_vanished_closure: (allow-none): #GClosure to invoke when @name is known
 784  * to not exist or %NULL.
 785  *
 786  * Version of g_bus_watch_name_on_connection() using closures instead of callbacks for
 787  * easier binding in other languages.
 788  *
 789  * Returns: An identifier (never 0) that an be used with
 790  * g_bus_unwatch_name() to stop watching the name.
 791  *
 792  * Rename to: g_bus_watch_name_on_connection
 793  *
 794  * Since: 2.26
 795  */
 796 guint g_bus_watch_name_on_connection_with_closures (
 797                                       GDBusConnection          *connection,
 798                                       const gchar              *name,
 799                                       GBusNameWatcherFlags      flags,
 800                                       GClosure                 *name_appeared_closure,
 801                                       GClosure                 *name_vanished_closure)
 802 {
 803   return g_bus_watch_name_on_connection (connection,
 804           name,
 805           flags,
 806           name_appeared_closure != NULL ? watch_with_closures_on_name_appeared : NULL,
 807           name_vanished_closure != NULL ? watch_with_closures_on_name_vanished : NULL,
 808           watch_name_data_new (name_appeared_closure, name_vanished_closure),
 809           bus_watch_name_free_func);
 810 }
 811
 812 /**
 813  * g_bus_unwatch_name:
 814  * @watcher_id: An identifier obtained from g_bus_watch_name()
 815  *
 816  * Stops watching a name.
 817  *
 818  * Since: 2.26
 819  */
 820 void
 821 g_bus_unwatch_name (guint watcher_id)
 822 {
 823   Client *client;
 824
 825   g_return_if_fail (watcher_id > 0);
 826
 827   client = NULL;
 828
 829   G_LOCK (lock);
 830   if (watcher_id == 0 ||
 831       map_id_to_client == NULL ||
 832       (client = g_hash_table_lookup (map_id_to_client, GUINT_TO_POINTER (watcher_id))) == NULL)
 833     {
 834       g_warning ("Invalid id %d passed to g_bus_unwatch_name()", watcher_id);
 835       goto out;
 836     }
 837
 838   client->cancelled = TRUE;
 839   g_warn_if_fail (g_hash_table_remove (map_id_to_client, GUINT_TO_POINTER (watcher_id)));
 840
 841  out:
 842   G_UNLOCK (lock);
 843
 844   /* do callback without holding lock */
 845   if (client != NULL)
 846     {
 847       client_unref (client);
 848     }
 849 }