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
  34 #include "glibintl.h"
  35
  36 /**
  37  * SECTION:gdbusnamewatching
  38  * @title: Watching Bus Names
  39  * @short_description: Simple API for watching bus names
  40  * @include: gio/gio.h
  41  *
  42  * Convenience API for watching bus names.
  43  *
  44  * <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>
  45  */
  46
  47 G_LOCK_DEFINE_STATIC (lock);
  48
  49 /* ---------------------------------------------------------------------------------------------------- */
  50
  51 typedef enum
  52 {
  53   PREVIOUS_CALL_NONE = 0,
  54   PREVIOUS_CALL_APPEARED,
  55   PREVIOUS_CALL_VANISHED,
  56 } PreviousCall;
  57
  58 typedef struct
  59 {
  60   volatile gint             ref_count;
  61   guint                     id;
  62   gchar                    *name;
  63   GBusNameWatcherFlags      flags;
  64   gchar                    *name_owner;
  65   GBusNameAppearedCallback  name_appeared_handler;
  66   GBusNameVanishedCallback  name_vanished_handler;
  67   gpointer                  user_data;
  68   GDestroyNotify            user_data_free_func;
  69   GMainContext             *main_context;
  70
  71   GDBusConnection          *connection;
  72   gulong                    disconnected_signal_handler_id;
  73   guint                     name_owner_changed_subscription_id;
  74
  75   PreviousCall              previous_call;
  76
  77   gboolean                  cancelled;
  78   gboolean                  initialized;
  79 } Client;
  80
  81 static guint next_global_id = 1;
  82 static GHashTable *map_id_to_client = NULL;
  83
  84 static Client *
  85 client_ref (Client *client)
  86 {
  87   g_atomic_int_inc (&client->ref_count);
  88   return client;
  89 }
  90
  91 static void
  92 client_unref (Client *client)
  93 {
  94   if (g_atomic_int_dec_and_test (&client->ref_count))
  95     {
  96       if (client->connection != NULL)
  97         {
  98           if (client->name_owner_changed_subscription_id > 0)
  99             g_dbus_connection_signal_unsubscribe (client->connection, client->name_owner_changed_subscription_id);
 100           if (client->disconnected_signal_handler_id > 0)
 101             g_signal_handler_disconnect (client->connection, client->disconnected_signal_handler_id);
 102           g_object_unref (client->connection);
 103         }
 104       g_free (client->name);
 105       g_free (client->name_owner);
 106       if (client->main_context != NULL)
 107         g_main_context_unref (client->main_context);
 108       if (client->user_data_free_func != NULL)
 109         client->user_data_free_func (client->user_data);
 110       g_free (client);
 111     }
 112 }
 113
 114 /* ---------------------------------------------------------------------------------------------------- */
 115
 116 typedef enum
 117 {
 118   CALL_TYPE_NAME_APPEARED,
 119   CALL_TYPE_NAME_VANISHED
 120 } CallType;
 121
 122 typedef struct
 123 {
 124   Client *client;
 125
 126   /* keep this separate because client->connection may
 127    * be set to NULL after scheduling the call
 128    */
 129   GDBusConnection *connection;
 130
 131   /* ditto */
 132   gchar *name_owner;
 133
 134   CallType call_type;
 135 } CallHandlerData;
 136
 137 static void
 138 call_handler_data_free (CallHandlerData *data)
 139 {
 140   if (data->connection != NULL)
 141     g_object_unref (data->connection);
 142   g_free (data->name_owner);
 143   client_unref (data->client);
 144   g_free (data);
 145 }
 146
 147 static void
 148 actually_do_call (Client *client, GDBusConnection *connection, const gchar *name_owner, CallType call_type)
 149 {
 150   switch (call_type)
 151     {
 152     case CALL_TYPE_NAME_APPEARED:
 153       if (client->name_appeared_handler != NULL)
 154         {
 155           client->name_appeared_handler (connection,
 156                                          client->name,
 157                                          name_owner,
 158                                          client->user_data);
 159         }
 160       break;
 161
 162     case CALL_TYPE_NAME_VANISHED:
 163       if (client->name_vanished_handler != NULL)
 164         {
 165           client->name_vanished_handler (connection,
 166                                          client->name,
 167                                          client->user_data);
 168         }
 169       break;
 170
 171     default:
 172       g_assert_not_reached ();
 173       break;
 174     }
 175 }
 176
 177 static gboolean
 178 call_in_idle_cb (gpointer _data)
 179 {
 180   CallHandlerData *data = _data;
 181   actually_do_call (data->client, data->connection, data->name_owner, data->call_type);
 182   return FALSE;
 183 }
 184
 185 static void
 186 schedule_call_in_idle (Client *client, CallType call_type)
 187 {
 188   CallHandlerData *data;
 189   GSource *idle_source;
 190
 191   data = g_new0 (CallHandlerData, 1);
 192   data->client = client_ref (client);
 193   data->connection = client->connection != NULL ? g_object_ref (client->connection) : NULL;
 194   data->name_owner = g_strdup (client->name_owner);
 195   data->call_type = call_type;
 196
 197   idle_source = g_idle_source_new ();
 198   g_source_set_priority (idle_source, G_PRIORITY_HIGH);
 199   g_source_set_callback (idle_source,
 200                          call_in_idle_cb,
 201                          data,
 202                          (GDestroyNotify) call_handler_data_free);
 203   g_source_attach (idle_source, client->main_context);
 204   g_source_unref (idle_source);
 205 }
 206
 207 static void
 208 do_call (Client *client, CallType call_type)
 209 {
 210   /* only schedule in idle if we're not in the right thread */
 211   if (g_main_context_get_thread_default () != 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 }
 216
 217 static void
 218 call_appeared_handler (Client *client)
 219 {
 220   if (client->previous_call != PREVIOUS_CALL_APPEARED)
 221     {
 222       client->previous_call = PREVIOUS_CALL_APPEARED;
 223       if (!client->cancelled && client->name_appeared_handler != NULL)
 224         {
 225           do_call (client, CALL_TYPE_NAME_APPEARED);
 226         }
 227     }
 228 }
 229
 230 static void
 231 call_vanished_handler (Client  *client,
 232                        gboolean ignore_cancelled)
 233 {
 234   if (client->previous_call != PREVIOUS_CALL_VANISHED)
 235     {
 236       client->previous_call = PREVIOUS_CALL_VANISHED;
 237       if (((!client->cancelled) || ignore_cancelled) && client->name_vanished_handler != NULL)
 238         {
 239           do_call (client, CALL_TYPE_NAME_VANISHED);
 240         }
 241     }
 242 }
 243
 244 /* ---------------------------------------------------------------------------------------------------- */
 245
 246 static void
 247 on_connection_disconnected (GDBusConnection *connection,
 248                             gboolean         remote_peer_vanished,
 249                             GError          *error,
 250                             gpointer         user_data)
 251 {
 252   Client *client = user_data;
 253
 254   if (client->name_owner_changed_subscription_id > 0)
 255     g_dbus_connection_signal_unsubscribe (client->connection, client->name_owner_changed_subscription_id);
 256   if (client->disconnected_signal_handler_id > 0)
 257     g_signal_handler_disconnect (client->connection, client->disconnected_signal_handler_id);
 258   g_object_unref (client->connection);
 259   client->disconnected_signal_handler_id = 0;
 260   client->name_owner_changed_subscription_id = 0;
 261   client->connection = NULL;
 262
 263   call_vanished_handler (client, FALSE);
 264 }
 265
 266 /* ---------------------------------------------------------------------------------------------------- */
 267
 268 static void
 269 on_name_owner_changed (GDBusConnection *connection,
 270                        const gchar      *sender_name,
 271                        const gchar      *object_path,
 272                        const gchar      *interface_name,
 273                        const gchar      *signal_name,
 274                        GVariant         *parameters,
 275                        gpointer          user_data)
 276 {
 277   Client *client = user_data;
 278   const gchar *name;
 279   const gchar *old_owner;
 280   const gchar *new_owner;
 281
 282   if (!client->initialized)
 283     goto out;
 284
 285   if (g_strcmp0 (object_path, "/org/freedesktop/DBus") != 0 ||
 286       g_strcmp0 (interface_name, "org.freedesktop.DBus") != 0 ||
 287       g_strcmp0 (sender_name, "org.freedesktop.DBus") != 0)
 288     goto out;
 289
 290   g_variant_get (parameters,
 291                  "(&s&s&s)",
 292                  &name,
 293                  &old_owner,
 294                  &new_owner);
 295
 296   /* we only care about a specific name */
 297   if (g_strcmp0 (name, client->name) != 0)
 298     goto out;
 299
 300   if ((old_owner != NULL && strlen (old_owner) > 0) && client->name_owner != NULL)
 301     {
 302       g_free (client->name_owner);
 303       client->name_owner = NULL;
 304       call_vanished_handler (client, FALSE);
 305     }
 306
 307   if (new_owner != NULL && strlen (new_owner) > 0)
 308     {
 309       g_warn_if_fail (client->name_owner == NULL);
 310       g_free (client->name_owner);
 311       client->name_owner = g_strdup (new_owner);
 312       call_appeared_handler (client);
 313     }
 314
 315  out:
 316   ;
 317 }
 318
 319 /* ---------------------------------------------------------------------------------------------------- */
 320
 321 static void
 322 get_name_owner_cb (GObject      *source_object,
 323                    GAsyncResult *res,
 324                    gpointer      user_data)
 325 {
 326   Client *client = user_data;
 327   GVariant *result;
 328   const char *name_owner;
 329
 330   name_owner = NULL;
 331   result = NULL;
 332
 333   result = g_dbus_connection_call_finish (client->connection,
 334                                           res,
 335                                           NULL);
 336   if (result != NULL)
 337     {
 338       g_variant_get (result, "(&s)", &name_owner);
 339     }
 340
 341   if (name_owner != NULL)
 342     {
 343       g_warn_if_fail (client->name_owner == NULL);
 344       client->name_owner = g_strdup (name_owner);
 345       call_appeared_handler (client);
 346     }
 347   else
 348     {
 349       call_vanished_handler (client, FALSE);
 350     }
 351
 352   client->initialized = TRUE;
 353
 354   if (result != NULL)
 355     g_variant_unref (result);
 356   client_unref (client);
 357 }
 358
 359 /* ---------------------------------------------------------------------------------------------------- */
 360
 361 static void
 362 invoke_get_name_owner (Client *client)
 363 {
 364   g_dbus_connection_call (client->connection,
 365                           "org.freedesktop.DBus",  /* bus name */
 366                           "/org/freedesktop/DBus", /* object path */
 367                           "org.freedesktop.DBus",  /* interface name */
 368                           "GetNameOwner",          /* method name */
 369                           g_variant_new ("(s)", client->name),
 370                           G_VARIANT_TYPE ("(s)"),
 371                           G_DBUS_CALL_FLAGS_NONE,
 372                           -1,
 373                           NULL,
 374                           (GAsyncReadyCallback) get_name_owner_cb,
 375                           client_ref (client));
 376 }
 377
 378 /* ---------------------------------------------------------------------------------------------------- */
 379
 380 static void
 381 start_service_by_name_cb (GObject      *source_object,
 382                           GAsyncResult *res,
 383                           gpointer      user_data)
 384 {
 385   Client *client = user_data;
 386   GVariant *result;
 387
 388   result = NULL;
 389
 390   result = g_dbus_connection_call_finish (client->connection,
 391                                           res,
 392                                           NULL);
 393   if (result != NULL)
 394     {
 395       guint32 start_service_result;
 396       g_variant_get (result, "(u)", &start_service_result);
 397
 398       if (start_service_result == 1) /* DBUS_START_REPLY_SUCCESS */
 399         {
 400           invoke_get_name_owner (client);
 401         }
 402       else if (start_service_result == 2) /* DBUS_START_REPLY_ALREADY_RUNNING */
 403         {
 404           invoke_get_name_owner (client);
 405         }
 406       else
 407         {
 408           g_warning ("Unexpected reply %d from StartServiceByName() method", start_service_result);
 409           call_vanished_handler (client, FALSE);
 410           client->initialized = TRUE;
 411         }
 412     }
 413   else
 414     {
 415       /* Errors are not unexpected; the bus will reply e.g.
 416        *
 417        *   org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.Epiphany2
 418        *   was not provided by any .service files
 419        *
 420        * This doesn't mean that the name doesn't have an owner, just
 421        * that it's not provided by a .service file. So proceed to
 422        * invoke GetNameOwner().
 423        */
 424       invoke_get_name_owner (client);
 425     }
 426
 427   if (result != NULL)
 428     g_variant_unref (result);
 429   client_unref (client);
 430 }
 431
 432 /* ---------------------------------------------------------------------------------------------------- */
 433
 434 static void
 435 has_connection (Client *client)
 436 {
 437   /* listen for disconnection */
 438   client->disconnected_signal_handler_id = g_signal_connect (client->connection,
 439                                                              "closed",
 440                                                              G_CALLBACK (on_connection_disconnected),
 441                                                              client);
 442
 443   /* start listening to NameOwnerChanged messages immediately */
 444   client->name_owner_changed_subscription_id = g_dbus_connection_signal_subscribe (client->connection,
 445                                                                                    "org.freedesktop.DBus",  /* name */
 446                                                                                    "org.freedesktop.DBus",  /* if */
 447                                                                                    "NameOwnerChanged",      /* signal */
 448                                                                                    "/org/freedesktop/DBus", /* path */
 449                                                                                    client->name,
 450                                                                                    G_DBUS_SIGNAL_FLAGS_NONE,
 451                                                                                    on_name_owner_changed,
 452                                                                                    client,
 453                                                                                    NULL);
 454
 455   if (client->flags & G_BUS_NAME_WATCHER_FLAGS_AUTO_START)
 456     {
 457       g_dbus_connection_call (client->connection,
 458                               "org.freedesktop.DBus",  /* bus name */
 459                               "/org/freedesktop/DBus", /* object path */
 460                               "org.freedesktop.DBus",  /* interface name */
 461                               "StartServiceByName",    /* method name */
 462                               g_variant_new ("(su)", client->name, 0),
 463                               G_VARIANT_TYPE ("(u)"),
 464                               G_DBUS_CALL_FLAGS_NONE,
 465                               -1,
 466                               NULL,
 467                               (GAsyncReadyCallback) start_service_by_name_cb,
 468                               client_ref (client));
 469     }
 470   else
 471     {
 472       /* check owner */
 473       invoke_get_name_owner (client);
 474     }
 475 }
 476
 477
 478 static void
 479 connection_get_cb (GObject      *source_object,
 480                    GAsyncResult *res,
 481                    gpointer      user_data)
 482 {
 483   Client *client = user_data;
 484
 485   client->connection = g_bus_get_finish (res, NULL);
 486   if (client->connection == NULL)
 487     {
 488       call_vanished_handler (client, FALSE);
 489       goto out;
 490     }
 491
 492   has_connection (client);
 493
 494  out:
 495   client_unref (client);
 496 }
 497
 498 /* ---------------------------------------------------------------------------------------------------- */
 499
 500 /**
 501  * g_bus_watch_name:
 502  * @bus_type: The type of bus to watch a name on.
 503  * @name: The name (well-known or unique) to watch.
 504  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 505  * @name_appeared_handler: Handler to invoke when @name is known to exist or %NULL.
 506  * @name_vanished_handler: Handler to invoke when @name is known to not exist or %NULL.
 507  * @user_data: User data to pass to handlers.
 508  * @user_data_free_func: Function for freeing @user_data or %NULL.
 509  *
 510  * Starts watching @name on the bus specified by @bus_type and calls
 511  * @name_appeared_handler and @name_vanished_handler when the name is
 512  * known to have a owner respectively known to lose its
 513  * owner. Callbacks will be invoked in the <link
 514  * linkend="g-main-context-push-thread-default">thread-default main
 515  * loop</link> of the thread you are calling this function from.
 516  *
 517  * You are guaranteed that one of the handlers will be invoked after
 518  * calling this function. When you are done watching the name, just
 519  * call g_bus_unwatch_name() with the watcher id this function
 520  * returns.
 521  *
 522  * If the name vanishes or appears (for example the application owning
 523  * the name could restart), the handlers are also invoked. If the
 524  * #GDBusConnection that is used for watching the name disconnects, then
 525  * @name_vanished_handler is invoked since it is no longer
 526  * possible to access the name.
 527  *
 528  * Another guarantee is that invocations of @name_appeared_handler
 529  * and @name_vanished_handler are guaranteed to alternate; that
 530  * is, if @name_appeared_handler is invoked then you are
 531  * guaranteed that the next time one of the handlers is invoked, it
 532  * will be @name_vanished_handler. The reverse is also true.
 533  *
 534  * This behavior makes it very simple to write applications that wants
 535  * to take action when a certain name exists, see <xref
 536  * linkend="gdbus-watching-names"/>. Basically, the application
 537  * should create object proxies in @name_appeared_handler and destroy
 538  * them again (if any) in @name_vanished_handler.
 539  *
 540  * Returns: An identifier (never 0) that an be used with
 541  * g_bus_unwatch_name() to stop watching the name.
 542  *
 543  * Since: 2.26
 544  */
 545 guint
 546 g_bus_watch_name (GBusType                  bus_type,
 547                   const gchar              *name,
 548                   GBusNameWatcherFlags      flags,
 549                   GBusNameAppearedCallback  name_appeared_handler,
 550                   GBusNameVanishedCallback  name_vanished_handler,
 551                   gpointer                  user_data,
 552                   GDestroyNotify            user_data_free_func)
 553 {
 554   Client *client;
 555
 556   g_return_val_if_fail (g_dbus_is_name (name), 0);
 557
 558   G_LOCK (lock);
 559
 560   client = g_new0 (Client, 1);
 561   client->ref_count = 1;
 562   client->id = next_global_id++; /* TODO: uh oh, handle overflow */
 563   client->name = g_strdup (name);
 564   client->flags = flags;
 565   client->name_appeared_handler = name_appeared_handler;
 566   client->name_vanished_handler = name_vanished_handler;
 567   client->user_data = user_data;
 568   client->user_data_free_func = user_data_free_func;
 569   client->main_context = g_main_context_get_thread_default ();
 570   if (client->main_context != NULL)
 571     g_main_context_ref (client->main_context);
 572
 573   if (map_id_to_client == NULL)
 574     {
 575       map_id_to_client = g_hash_table_new (g_direct_hash, g_direct_equal);
 576     }
 577   g_hash_table_insert (map_id_to_client,
 578                        GUINT_TO_POINTER (client->id),
 579                        client);
 580
 581   g_bus_get (bus_type,
 582              NULL,
 583              connection_get_cb,
 584              client_ref (client));
 585
 586   G_UNLOCK (lock);
 587
 588   return client->id;
 589 }
 590
 591 /**
 592  * g_bus_watch_name_on_connection:
 593  * @connection: A #GDBusConnection.
 594  * @name: The name (well-known or unique) to watch.
 595  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 596  * @name_appeared_handler: Handler to invoke when @name is known to exist or %NULL.
 597  * @name_vanished_handler: Handler to invoke when @name is known to not exist or %NULL.
 598  * @user_data: User data to pass to handlers.
 599  * @user_data_free_func: Function for freeing @user_data or %NULL.
 600  *
 601  * Like g_bus_watch_name() but takes a #GDBusConnection instead of a
 602  * #GBusType.
 603  *
 604  * Returns: An identifier (never 0) that an be used with
 605  * g_bus_unwatch_name() to stop watching the name.
 606  *
 607  * Since: 2.26
 608  */
 609 guint g_bus_watch_name_on_connection (GDBusConnection          *connection,
 610                                       const gchar              *name,
 611                                       GBusNameWatcherFlags      flags,
 612                                       GBusNameAppearedCallback  name_appeared_handler,
 613                                       GBusNameVanishedCallback  name_vanished_handler,
 614                                       gpointer                  user_data,
 615                                       GDestroyNotify            user_data_free_func)
 616 {
 617   Client *client;
 618
 619   g_return_val_if_fail (G_IS_DBUS_CONNECTION (connection), 0);
 620   g_return_val_if_fail (g_dbus_is_name (name), 0);
 621
 622   G_LOCK (lock);
 623
 624   client = g_new0 (Client, 1);
 625   client->ref_count = 1;
 626   client->id = next_global_id++; /* TODO: uh oh, handle overflow */
 627   client->name = g_strdup (name);
 628   client->flags = flags;
 629   client->name_appeared_handler = name_appeared_handler;
 630   client->name_vanished_handler = name_vanished_handler;
 631   client->user_data = user_data;
 632   client->user_data_free_func = user_data_free_func;
 633   client->main_context = g_main_context_get_thread_default ();
 634   if (client->main_context != NULL)
 635     g_main_context_ref (client->main_context);
 636
 637   if (map_id_to_client == NULL)
 638     map_id_to_client = g_hash_table_new (g_direct_hash, g_direct_equal);
 639
 640   g_hash_table_insert (map_id_to_client,
 641                        GUINT_TO_POINTER (client->id),
 642                        client);
 643
 644   client->connection = g_object_ref (connection);
 645   G_UNLOCK (lock);
 646
 647   has_connection (client);
 648
 649   return client->id;
 650 }
 651
 652 typedef struct {
 653   GClosure *name_appeared_closure;
 654   GClosure *name_vanished_closure;
 655 } WatchNameData;
 656
 657 static WatchNameData *
 658 watch_name_data_new (GClosure *name_appeared_closure,
 659                      GClosure *name_vanished_closure)
 660 {
 661   WatchNameData *data;
 662
 663   data = g_new0 (WatchNameData, 1);
 664
 665   if (name_appeared_closure != NULL)
 666     {
 667       data->name_appeared_closure = g_closure_ref (name_appeared_closure);
 668       g_closure_sink (name_appeared_closure);
 669       if (G_CLOSURE_NEEDS_MARSHAL (name_appeared_closure))
 670         g_closure_set_marshal (name_appeared_closure, g_cclosure_marshal_generic);
 671     }
 672
 673   if (name_vanished_closure != NULL)
 674     {
 675       data->name_vanished_closure = g_closure_ref (name_vanished_closure);
 676       g_closure_sink (name_vanished_closure);
 677       if (G_CLOSURE_NEEDS_MARSHAL (name_vanished_closure))
 678         g_closure_set_marshal (name_vanished_closure, g_cclosure_marshal_generic);
 679     }
 680
 681   return data;
 682 }
 683
 684 static void
 685 watch_with_closures_on_name_appeared (GDBusConnection *connection,
 686                                       const gchar     *name,
 687                                       const gchar     *name_owner,
 688                                       gpointer         user_data)
 689 {
 690   WatchNameData *data = user_data;
 691   GValue params[3] = { { 0, }, { 0, }, { 0, } };
 692
 693   g_value_init (&params[0], G_TYPE_DBUS_CONNECTION);
 694   g_value_set_object (&params[0], connection);
 695
 696   g_value_init (&params[1], G_TYPE_STRING);
 697   g_value_set_string (&params[1], name);
 698
 699   g_value_init (&params[2], G_TYPE_STRING);
 700   g_value_set_string (&params[2], name_owner);
 701
 702   g_closure_invoke (data->name_appeared_closure, NULL, 3, params, NULL);
 703
 704   g_value_unset (params + 0);
 705   g_value_unset (params + 1);
 706   g_value_unset (params + 2);
 707 }
 708
 709 static void
 710 watch_with_closures_on_name_vanished (GDBusConnection *connection,
 711                                       const gchar     *name,
 712                                       gpointer         user_data)
 713 {
 714   WatchNameData *data = user_data;
 715   GValue params[2] = { { 0, }, { 0, } };
 716
 717   g_value_init (&params[0], G_TYPE_DBUS_CONNECTION);
 718   g_value_set_object (&params[0], connection);
 719
 720   g_value_init (&params[1], G_TYPE_STRING);
 721   g_value_set_string (&params[1], name);
 722
 723   g_closure_invoke (data->name_vanished_closure, NULL, 2, params, NULL);
 724
 725   g_value_unset (params + 0);
 726   g_value_unset (params + 1);
 727 }
 728
 729 static void
 730 bus_watch_name_free_func (gpointer user_data)
 731 {
 732   WatchNameData *data = user_data;
 733
 734   if (data->name_appeared_closure != NULL)
 735     g_closure_unref (data->name_appeared_closure);
 736
 737   if (data->name_vanished_closure != NULL)
 738     g_closure_unref (data->name_vanished_closure);
 739
 740   g_free (data);
 741 }
 742
 743 /**
 744  * g_bus_watch_name_with_closures:
 745  * @bus_type: The type of bus to watch a name on.
 746  * @name: The name (well-known or unique) to watch.
 747  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 748  * @name_appeared_closure: (allow-none): #GClosure to invoke when @name is known
 749  * to exist or %NULL.
 750  * @name_vanished_closure: (allow-none): #GClosure to invoke when @name is known
 751  * to not exist or %NULL.
 752  *
 753  * Version of g_bus_watch_name() using closures instead of callbacks for
 754  * easier binding in other languages.
 755  *
 756  * Returns: An identifier (never 0) that an be used with
 757  * g_bus_unwatch_name() to stop watching the name.
 758  *
 759  * Rename to: g_bus_watch_name
 760  *
 761  * Since: 2.26
 762  */
 763 guint
 764 g_bus_watch_name_with_closures (GBusType                 bus_type,
 765                                 const gchar             *name,
 766                                 GBusNameWatcherFlags     flags,
 767                                 GClosure                *name_appeared_closure,
 768                                 GClosure                *name_vanished_closure)
 769 {
 770   return g_bus_watch_name (bus_type,
 771           name,
 772           flags,
 773           name_appeared_closure != NULL ? watch_with_closures_on_name_appeared : NULL,
 774           name_vanished_closure != NULL ? watch_with_closures_on_name_vanished : NULL,
 775           watch_name_data_new (name_appeared_closure, name_vanished_closure),
 776           bus_watch_name_free_func);
 777 }
 778
 779 /**
 780  * g_bus_watch_name_on_connection_with_closures:
 781  * @connection: A #GDBusConnection.
 782  * @name: The name (well-known or unique) to watch.
 783  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 784  * @name_appeared_closure: (allow-none): #GClosure to invoke when @name is known
 785  * to exist or %NULL.
 786  * @name_vanished_closure: (allow-none): #GClosure to invoke when @name is known
 787  * to not exist or %NULL.
 788  *
 789  * Version of g_bus_watch_name_on_connection() using closures instead of callbacks for
 790  * easier binding in other languages.
 791  *
 792  * Returns: An identifier (never 0) that an be used with
 793  * g_bus_unwatch_name() to stop watching the name.
 794  *
 795  * Rename to: g_bus_watch_name_on_connection
 796  *
 797  * Since: 2.26
 798  */
 799 guint g_bus_watch_name_on_connection_with_closures (
 800                                       GDBusConnection          *connection,
 801                                       const gchar              *name,
 802                                       GBusNameWatcherFlags      flags,
 803                                       GClosure                 *name_appeared_closure,
 804                                       GClosure                 *name_vanished_closure)
 805 {
 806   return g_bus_watch_name_on_connection (connection,
 807           name,
 808           flags,
 809           name_appeared_closure != NULL ? watch_with_closures_on_name_appeared : NULL,
 810           name_vanished_closure != NULL ? watch_with_closures_on_name_vanished : NULL,
 811           watch_name_data_new (name_appeared_closure, name_vanished_closure),
 812           bus_watch_name_free_func);
 813 }
 814
 815 /**
 816  * g_bus_unwatch_name:
 817  * @watcher_id: An identifier obtained from g_bus_watch_name()
 818  *
 819  * Stops watching a name.
 820  *
 821  * Since: 2.26
 822  */
 823 void
 824 g_bus_unwatch_name (guint watcher_id)
 825 {
 826   Client *client;
 827
 828   g_return_if_fail (watcher_id > 0);
 829
 830   client = NULL;
 831
 832   G_LOCK (lock);
 833   if (watcher_id == 0 ||
 834       map_id_to_client == NULL ||
 835       (client = g_hash_table_lookup (map_id_to_client, GUINT_TO_POINTER (watcher_id))) == NULL)
 836     {
 837       g_warning ("Invalid id %d passed to g_bus_unwatch_name()", watcher_id);
 838       goto out;
 839     }
 840
 841   client->cancelled = TRUE;
 842   g_warn_if_fail (g_hash_table_remove (map_id_to_client, GUINT_TO_POINTER (watcher_id)));
 843
 844  out:
 845   G_UNLOCK (lock);
 846
 847   /* do callback without holding lock */
 848   if (client != NULL)
 849     {
 850       client_unref (client);
 851     }
 852 }