gio/gdbusnamewatching.c

   1 /* GDBus - GLib D-Bus Library
   2  *
   3  * Copyright (C) 2008-2010 Red Hat, Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17  *
  18  * Author: David Zeuthen <davidz@redhat.com>
  19  */
  20
  21 #include "config.h"
  22
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #include "gdbusutils.h"
  27 #include "gdbusnamewatching.h"
  28 #include "gdbuserror.h"
  29 #include "gdbusprivate.h"
  30 #include "gdbusconnection.h"
  31
  32 #include "glibintl.h"
  33
  34 /**
  35  * SECTION:gdbusnamewatching
  36  * @title: Watching Bus Names
  37  * @short_description: Simple API for watching bus names
  38  * @include: gio/gio.h
  39  *
  40  * Convenience API for watching bus names.
  41  *
  42  * A simple example for watching a name can be found in
  43  * [gdbus-example-watch-name.c](https://git.gnome.org/browse/glib/tree/gio/tests/gdbus-example-watch-name.c)
  44  */
  45
  46 G_LOCK_DEFINE_STATIC (lock);
  47
  48 /* ---------------------------------------------------------------------------------------------------- */
  49
  50 typedef enum
  51 {
  52   PREVIOUS_CALL_NONE = 0,
  53   PREVIOUS_CALL_APPEARED,
  54   PREVIOUS_CALL_VANISHED,
  55 } PreviousCall;
  56
  57 typedef struct
  58 {
  59   volatile gint             ref_count;
  60   guint                     id;
  61   gchar                    *name;
  62   GBusNameWatcherFlags      flags;
  63   gchar                    *name_owner;
  64   GBusNameAppearedCallback  name_appeared_handler;
  65   GBusNameVanishedCallback  name_vanished_handler;
  66   gpointer                  user_data;
  67   GDestroyNotify            user_data_free_func;
  68   GMainContext             *main_context;
  69
  70   GDBusConnection          *connection;
  71   gulong                    disconnected_signal_handler_id;
  72   guint                     name_owner_changed_subscription_id;
  73
  74   PreviousCall              previous_call;
  75
  76   gboolean                  cancelled;
  77   gboolean                  initialized;
  78 } Client;
  79
  80 static guint next_global_id = 1;
  81 static GHashTable *map_id_to_client = NULL;
  82
  83 static Client *
  84 client_ref (Client *client)
  85 {
  86   g_atomic_int_inc (&client->ref_count);
  87   return client;
  88 }
  89
  90 static void
  91 client_unref (Client *client)
  92 {
  93   if (g_atomic_int_dec_and_test (&client->ref_count))
  94     {
  95       if (client->connection != NULL)
  96         {
  97           if (client->name_owner_changed_subscription_id > 0)
  98             g_dbus_connection_signal_unsubscribe (client->connection, client->name_owner_changed_subscription_id);
  99           if (client->disconnected_signal_handler_id > 0)
 100             g_signal_handler_disconnect (client->connection, client->disconnected_signal_handler_id);
 101           g_object_unref (client->connection);
 102         }
 103       g_free (client->name);
 104       g_free (client->name_owner);
 105       g_main_context_unref (client->main_context);
 106       if (client->user_data_free_func != NULL)
 107         client->user_data_free_func (client->user_data);
 108       g_free (client);
 109     }
 110 }
 111
 112 /* ---------------------------------------------------------------------------------------------------- */
 113
 114 typedef enum
 115 {
 116   CALL_TYPE_NAME_APPEARED,
 117   CALL_TYPE_NAME_VANISHED
 118 } CallType;
 119
 120 typedef struct
 121 {
 122   Client *client;
 123
 124   /* keep this separate because client->connection may
 125    * be set to NULL after scheduling the call
 126    */
 127   GDBusConnection *connection;
 128
 129   /* ditto */
 130   gchar *name_owner;
 131
 132   CallType call_type;
 133 } CallHandlerData;
 134
 135 static void
 136 call_handler_data_free (CallHandlerData *data)
 137 {
 138   if (data->connection != NULL)
 139     g_object_unref (data->connection);
 140   g_free (data->name_owner);
 141   client_unref (data->client);
 142   g_free (data);
 143 }
 144
 145 static void
 146 actually_do_call (Client *client, GDBusConnection *connection, const gchar *name_owner, CallType call_type)
 147 {
 148   switch (call_type)
 149     {
 150     case CALL_TYPE_NAME_APPEARED:
 151       if (client->name_appeared_handler != NULL)
 152         {
 153           client->name_appeared_handler (connection,
 154                                          client->name,
 155                                          name_owner,
 156                                          client->user_data);
 157         }
 158       break;
 159
 160     case CALL_TYPE_NAME_VANISHED:
 161       if (client->name_vanished_handler != NULL)
 162         {
 163           client->name_vanished_handler (connection,
 164                                          client->name,
 165                                          client->user_data);
 166         }
 167       break;
 168
 169     default:
 170       g_assert_not_reached ();
 171       break;
 172     }
 173 }
 174
 175 static gboolean
 176 call_in_idle_cb (gpointer _data)
 177 {
 178   CallHandlerData *data = _data;
 179   actually_do_call (data->client, data->connection, data->name_owner, data->call_type);
 180   return FALSE;
 181 }
 182
 183 static void
 184 schedule_call_in_idle (Client *client, CallType call_type)
 185 {
 186   CallHandlerData *data;
 187   GSource *idle_source;
 188
 189   data = g_new0 (CallHandlerData, 1);
 190   data->client = client_ref (client);
 191   data->connection = client->connection != NULL ? g_object_ref (client->connection) : NULL;
 192   data->name_owner = g_strdup (client->name_owner);
 193   data->call_type = call_type;
 194
 195   idle_source = g_idle_source_new ();
 196   g_source_set_priority (idle_source, G_PRIORITY_HIGH);
 197   g_source_set_callback (idle_source,
 198                          call_in_idle_cb,
 199                          data,
 200                          (GDestroyNotify) call_handler_data_free);
 201   g_source_attach (idle_source, client->main_context);
 202   g_source_unref (idle_source);
 203 }
 204
 205 static void
 206 do_call (Client *client, CallType call_type)
 207 {
 208   GMainContext *current_context;
 209
 210   /* only schedule in idle if we're not in the right thread */
 211   current_context = g_main_context_ref_thread_default ();
 212   if (current_context != 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   g_main_context_unref (current_context);
 217 }
 218
 219 static void
 220 call_appeared_handler (Client *client)
 221 {
 222   if (client->previous_call != PREVIOUS_CALL_APPEARED)
 223     {
 224       client->previous_call = PREVIOUS_CALL_APPEARED;
 225       if (!client->cancelled && client->name_appeared_handler != NULL)
 226         {
 227           do_call (client, CALL_TYPE_NAME_APPEARED);
 228         }
 229     }
 230 }
 231
 232 static void
 233 call_vanished_handler (Client  *client,
 234                        gboolean ignore_cancelled)
 235 {
 236   if (client->previous_call != PREVIOUS_CALL_VANISHED)
 237     {
 238       client->previous_call = PREVIOUS_CALL_VANISHED;
 239       if (((!client->cancelled) || ignore_cancelled) && client->name_vanished_handler != NULL)
 240         {
 241           do_call (client, CALL_TYPE_NAME_VANISHED);
 242         }
 243     }
 244 }
 245
 246 /* ---------------------------------------------------------------------------------------------------- */
 247
 248 static void
 249 on_connection_disconnected (GDBusConnection *connection,
 250                             gboolean         remote_peer_vanished,
 251                             GError          *error,
 252                             gpointer         user_data)
 253 {
 254   Client *client = user_data;
 255
 256   if (client->name_owner_changed_subscription_id > 0)
 257     g_dbus_connection_signal_unsubscribe (client->connection, client->name_owner_changed_subscription_id);
 258   if (client->disconnected_signal_handler_id > 0)
 259     g_signal_handler_disconnect (client->connection, client->disconnected_signal_handler_id);
 260   g_object_unref (client->connection);
 261   client->disconnected_signal_handler_id = 0;
 262   client->name_owner_changed_subscription_id = 0;
 263   client->connection = NULL;
 264
 265   call_vanished_handler (client, FALSE);
 266 }
 267
 268 /* ---------------------------------------------------------------------------------------------------- */
 269
 270 static void
 271 on_name_owner_changed (GDBusConnection *connection,
 272                        const gchar      *sender_name,
 273                        const gchar      *object_path,
 274                        const gchar      *interface_name,
 275                        const gchar      *signal_name,
 276                        GVariant         *parameters,
 277                        gpointer          user_data)
 278 {
 279   Client *client = user_data;
 280   const gchar *name;
 281   const gchar *old_owner;
 282   const gchar *new_owner;
 283
 284   if (!client->initialized)
 285     goto out;
 286
 287   if (g_strcmp0 (object_path, "/org/freedesktop/DBus") != 0 ||
 288       g_strcmp0 (interface_name, "org.freedesktop.DBus") != 0 ||
 289       g_strcmp0 (sender_name, "org.freedesktop.DBus") != 0)
 290     goto out;
 291
 292   g_variant_get (parameters,
 293                  "(&s&s&s)",
 294                  &name,
 295                  &old_owner,
 296                  &new_owner);
 297
 298   /* we only care about a specific name */
 299   if (g_strcmp0 (name, client->name) != 0)
 300     goto out;
 301
 302   if ((old_owner != NULL && strlen (old_owner) > 0) && client->name_owner != NULL)
 303     {
 304       g_free (client->name_owner);
 305       client->name_owner = NULL;
 306       call_vanished_handler (client, FALSE);
 307     }
 308
 309   if (new_owner != NULL && strlen (new_owner) > 0)
 310     {
 311       g_warn_if_fail (client->name_owner == NULL);
 312       g_free (client->name_owner);
 313       client->name_owner = g_strdup (new_owner);
 314       call_appeared_handler (client);
 315     }
 316
 317  out:
 318   ;
 319 }
 320
 321 /* ---------------------------------------------------------------------------------------------------- */
 322
 323 static void
 324 get_name_owner_cb (GObject      *source_object,
 325                    GAsyncResult *res,
 326                    gpointer      user_data)
 327 {
 328   Client *client = user_data;
 329   GVariant *result;
 330   const char *name_owner;
 331
 332   name_owner = NULL;
 333   result = NULL;
 334
 335   result = g_dbus_connection_call_finish (client->connection,
 336                                           res,
 337                                           NULL);
 338   if (result != NULL)
 339     {
 340       g_variant_get (result, "(&s)", &name_owner);
 341     }
 342
 343   if (name_owner != NULL)
 344     {
 345       g_warn_if_fail (client->name_owner == NULL);
 346       client->name_owner = g_strdup (name_owner);
 347       call_appeared_handler (client);
 348     }
 349   else
 350     {
 351       call_vanished_handler (client, FALSE);
 352     }
 353
 354   client->initialized = TRUE;
 355
 356   if (result != NULL)
 357     g_variant_unref (result);
 358   client_unref (client);
 359 }
 360
 361 /* ---------------------------------------------------------------------------------------------------- */
 362
 363 static void
 364 invoke_get_name_owner (Client *client)
 365 {
 366   g_dbus_connection_call (client->connection,
 367                           "org.freedesktop.DBus",  /* bus name */
 368                           "/org/freedesktop/DBus", /* object path */
 369                           "org.freedesktop.DBus",  /* interface name */
 370                           "GetNameOwner",          /* method name */
 371                           g_variant_new ("(s)", client->name),
 372                           G_VARIANT_TYPE ("(s)"),
 373                           G_DBUS_CALL_FLAGS_NONE,
 374                           -1,
 375                           NULL,
 376                           (GAsyncReadyCallback) get_name_owner_cb,
 377                           client_ref (client));
 378 }
 379
 380 /* ---------------------------------------------------------------------------------------------------- */
 381
 382 static void
 383 start_service_by_name_cb (GObject      *source_object,
 384                           GAsyncResult *res,
 385                           gpointer      user_data)
 386 {
 387   Client *client = user_data;
 388   GVariant *result;
 389
 390   result = NULL;
 391
 392   result = g_dbus_connection_call_finish (client->connection,
 393                                           res,
 394                                           NULL);
 395   if (result != NULL)
 396     {
 397       guint32 start_service_result;
 398       g_variant_get (result, "(u)", &start_service_result);
 399
 400       if (start_service_result == 1) /* DBUS_START_REPLY_SUCCESS */
 401         {
 402           invoke_get_name_owner (client);
 403         }
 404       else if (start_service_result == 2) /* DBUS_START_REPLY_ALREADY_RUNNING */
 405         {
 406           invoke_get_name_owner (client);
 407         }
 408       else
 409         {
 410           g_warning ("Unexpected reply %d from StartServiceByName() method", start_service_result);
 411           call_vanished_handler (client, FALSE);
 412           client->initialized = TRUE;
 413         }
 414     }
 415   else
 416     {
 417       /* Errors are not unexpected; the bus will reply e.g.
 418        *
 419        *   org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.Epiphany2
 420        *   was not provided by any .service files
 421        *
 422        * This doesn't mean that the name doesn't have an owner, just
 423        * that it's not provided by a .service file. So proceed to
 424        * invoke GetNameOwner().
 425        */
 426       invoke_get_name_owner (client);
 427     }
 428
 429   if (result != NULL)
 430     g_variant_unref (result);
 431   client_unref (client);
 432 }
 433
 434 /* ---------------------------------------------------------------------------------------------------- */
 435
 436 static void
 437 has_connection (Client *client)
 438 {
 439   /* listen for disconnection */
 440   client->disconnected_signal_handler_id = g_signal_connect (client->connection,
 441                                                              "closed",
 442                                                              G_CALLBACK (on_connection_disconnected),
 443                                                              client);
 444
 445   /* start listening to NameOwnerChanged messages immediately */
 446   client->name_owner_changed_subscription_id = g_dbus_connection_signal_subscribe (client->connection,
 447                                                                                    "org.freedesktop.DBus",  /* name */
 448                                                                                    "org.freedesktop.DBus",  /* if */
 449                                                                                    "NameOwnerChanged",      /* signal */
 450                                                                                    "/org/freedesktop/DBus", /* path */
 451                                                                                    client->name,
 452                                                                                    G_DBUS_SIGNAL_FLAGS_NONE,
 453                                                                                    on_name_owner_changed,
 454                                                                                    client,
 455                                                                                    NULL);
 456
 457   if (client->flags & G_BUS_NAME_WATCHER_FLAGS_AUTO_START)
 458     {
 459       g_dbus_connection_call (client->connection,
 460                               "org.freedesktop.DBus",  /* bus name */
 461                               "/org/freedesktop/DBus", /* object path */
 462                               "org.freedesktop.DBus",  /* interface name */
 463                               "StartServiceByName",    /* method name */
 464                               g_variant_new ("(su)", client->name, 0),
 465                               G_VARIANT_TYPE ("(u)"),
 466                               G_DBUS_CALL_FLAGS_NONE,
 467                               -1,
 468                               NULL,
 469                               (GAsyncReadyCallback) start_service_by_name_cb,
 470                               client_ref (client));
 471     }
 472   else
 473     {
 474       /* check owner */
 475       invoke_get_name_owner (client);
 476     }
 477 }
 478
 479
 480 static void
 481 connection_get_cb (GObject      *source_object,
 482                    GAsyncResult *res,
 483                    gpointer      user_data)
 484 {
 485   Client *client = user_data;
 486
 487   client->connection = g_bus_get_finish (res, NULL);
 488   if (client->connection == NULL)
 489     {
 490       call_vanished_handler (client, FALSE);
 491       goto out;
 492     }
 493
 494   has_connection (client);
 495
 496  out:
 497   client_unref (client);
 498 }
 499
 500 /* ---------------------------------------------------------------------------------------------------- */
 501
 502 /**
 503  * g_bus_watch_name:
 504  * @bus_type: The type of bus to watch a name on.
 505  * @name: The name (well-known or unique) to watch.
 506  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 507  * @name_appeared_handler: (allow-none): Handler to invoke when @name is known to exist or %NULL.
 508  * @name_vanished_handler: (allow-none): Handler to invoke when @name is known to not exist or %NULL.
 509  * @user_data: User data to pass to handlers.
 510  * @user_data_free_func: (allow-none): Function for freeing @user_data or %NULL.
 511  *
 512  * Starts watching @name on the bus specified by @bus_type and calls
 513  * @name_appeared_handler and @name_vanished_handler when the name is
 514  * known to have a owner respectively known to lose its
 515  * owner. Callbacks will be invoked in the
 516  * [thread-default main context][g-main-context-push-thread-default]
 517  * of the thread you are calling this function from.
 518  *
 519  * You are guaranteed that one of the handlers will be invoked after
 520  * calling this function. When you are done watching the name, just
 521  * call g_bus_unwatch_name() with the watcher id this function
 522  * returns.
 523  *
 524  * If the name vanishes or appears (for example the application owning
 525  * the name could restart), the handlers are also invoked. If the
 526  * #GDBusConnection that is used for watching the name disconnects, then
 527  * @name_vanished_handler is invoked since it is no longer
 528  * possible to access the name.
 529  *
 530  * Another guarantee is that invocations of @name_appeared_handler
 531  * and @name_vanished_handler are guaranteed to alternate; that
 532  * is, if @name_appeared_handler is invoked then you are
 533  * guaranteed that the next time one of the handlers is invoked, it
 534  * will be @name_vanished_handler. The reverse is also true.
 535  *
 536  * This behavior makes it very simple to write applications that want
 537  * to take action when a certain [name exists][gdbus-watching-names].
 538  * Basically, the application should create object proxies in
 539  * @name_appeared_handler and destroy them again (if any) in
 540  * @name_vanished_handler.
 541  *
 542  * Returns: An identifier (never 0) that an be used with
 543  * g_bus_unwatch_name() to stop watching the name.
 544  *
 545  * Since: 2.26
 546  */
 547 guint
 548 g_bus_watch_name (GBusType                  bus_type,
 549                   const gchar              *name,
 550                   GBusNameWatcherFlags      flags,
 551                   GBusNameAppearedCallback  name_appeared_handler,
 552                   GBusNameVanishedCallback  name_vanished_handler,
 553                   gpointer                  user_data,
 554                   GDestroyNotify            user_data_free_func)
 555 {
 556   Client *client;
 557
 558   g_return_val_if_fail (g_dbus_is_name (name), 0);
 559
 560   G_LOCK (lock);
 561
 562   client = g_new0 (Client, 1);
 563   client->ref_count = 1;
 564   client->id = next_global_id++; /* TODO: uh oh, handle overflow */
 565   client->name = g_strdup (name);
 566   client->flags = flags;
 567   client->name_appeared_handler = name_appeared_handler;
 568   client->name_vanished_handler = name_vanished_handler;
 569   client->user_data = user_data;
 570   client->user_data_free_func = user_data_free_func;
 571   client->main_context = g_main_context_ref_thread_default ();
 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: (allow-none): Handler to invoke when @name is known to exist or %NULL.
 597  * @name_vanished_handler: (allow-none): 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: (allow-none): 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_ref_thread_default ();
 634
 635   if (map_id_to_client == NULL)
 636     map_id_to_client = g_hash_table_new (g_direct_hash, g_direct_equal);
 637
 638   g_hash_table_insert (map_id_to_client,
 639                        GUINT_TO_POINTER (client->id),
 640                        client);
 641
 642   client->connection = g_object_ref (connection);
 643   G_UNLOCK (lock);
 644
 645   has_connection (client);
 646
 647   return client->id;
 648 }
 649
 650 typedef struct {
 651   GClosure *name_appeared_closure;
 652   GClosure *name_vanished_closure;
 653 } WatchNameData;
 654
 655 static WatchNameData *
 656 watch_name_data_new (GClosure *name_appeared_closure,
 657                      GClosure *name_vanished_closure)
 658 {
 659   WatchNameData *data;
 660
 661   data = g_new0 (WatchNameData, 1);
 662
 663   if (name_appeared_closure != NULL)
 664     {
 665       data->name_appeared_closure = g_closure_ref (name_appeared_closure);
 666       g_closure_sink (name_appeared_closure);
 667       if (G_CLOSURE_NEEDS_MARSHAL (name_appeared_closure))
 668         g_closure_set_marshal (name_appeared_closure, g_cclosure_marshal_generic);
 669     }
 670
 671   if (name_vanished_closure != NULL)
 672     {
 673       data->name_vanished_closure = g_closure_ref (name_vanished_closure);
 674       g_closure_sink (name_vanished_closure);
 675       if (G_CLOSURE_NEEDS_MARSHAL (name_vanished_closure))
 676         g_closure_set_marshal (name_vanished_closure, g_cclosure_marshal_generic);
 677     }
 678
 679   return data;
 680 }
 681
 682 static void
 683 watch_with_closures_on_name_appeared (GDBusConnection *connection,
 684                                       const gchar     *name,
 685                                       const gchar     *name_owner,
 686                                       gpointer         user_data)
 687 {
 688   WatchNameData *data = user_data;
 689   GValue params[3] = { G_VALUE_INIT, G_VALUE_INIT, G_VALUE_INIT };
 690
 691   g_value_init (&params[0], G_TYPE_DBUS_CONNECTION);
 692   g_value_set_object (&params[0], connection);
 693
 694   g_value_init (&params[1], G_TYPE_STRING);
 695   g_value_set_string (&params[1], name);
 696
 697   g_value_init (&params[2], G_TYPE_STRING);
 698   g_value_set_string (&params[2], name_owner);
 699
 700   g_closure_invoke (data->name_appeared_closure, NULL, 3, params, NULL);
 701
 702   g_value_unset (params + 0);
 703   g_value_unset (params + 1);
 704   g_value_unset (params + 2);
 705 }
 706
 707 static void
 708 watch_with_closures_on_name_vanished (GDBusConnection *connection,
 709                                       const gchar     *name,
 710                                       gpointer         user_data)
 711 {
 712   WatchNameData *data = user_data;
 713   GValue params[2] = { G_VALUE_INIT, G_VALUE_INIT };
 714
 715   g_value_init (&params[0], G_TYPE_DBUS_CONNECTION);
 716   g_value_set_object (&params[0], connection);
 717
 718   g_value_init (&params[1], G_TYPE_STRING);
 719   g_value_set_string (&params[1], name);
 720
 721   g_closure_invoke (data->name_vanished_closure, NULL, 2, params, NULL);
 722
 723   g_value_unset (params + 0);
 724   g_value_unset (params + 1);
 725 }
 726
 727 static void
 728 bus_watch_name_free_func (gpointer user_data)
 729 {
 730   WatchNameData *data = user_data;
 731
 732   if (data->name_appeared_closure != NULL)
 733     g_closure_unref (data->name_appeared_closure);
 734
 735   if (data->name_vanished_closure != NULL)
 736     g_closure_unref (data->name_vanished_closure);
 737
 738   g_free (data);
 739 }
 740
 741 /**
 742  * g_bus_watch_name_with_closures:
 743  * @bus_type: The type of bus to watch a name on.
 744  * @name: The name (well-known or unique) to watch.
 745  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 746  * @name_appeared_closure: (allow-none): #GClosure to invoke when @name is known
 747  * to exist or %NULL.
 748  * @name_vanished_closure: (allow-none): #GClosure to invoke when @name is known
 749  * to not exist or %NULL.
 750  *
 751  * Version of g_bus_watch_name() using closures instead of callbacks for
 752  * easier binding in other languages.
 753  *
 754  * Returns: An identifier (never 0) that an be used with
 755  * g_bus_unwatch_name() to stop watching the name.
 756  *
 757  * Rename to: g_bus_watch_name
 758  *
 759  * Since: 2.26
 760  */
 761 guint
 762 g_bus_watch_name_with_closures (GBusType                 bus_type,
 763                                 const gchar             *name,
 764                                 GBusNameWatcherFlags     flags,
 765                                 GClosure                *name_appeared_closure,
 766                                 GClosure                *name_vanished_closure)
 767 {
 768   return g_bus_watch_name (bus_type,
 769           name,
 770           flags,
 771           name_appeared_closure != NULL ? watch_with_closures_on_name_appeared : NULL,
 772           name_vanished_closure != NULL ? watch_with_closures_on_name_vanished : NULL,
 773           watch_name_data_new (name_appeared_closure, name_vanished_closure),
 774           bus_watch_name_free_func);
 775 }
 776
 777 /**
 778  * g_bus_watch_name_on_connection_with_closures:
 779  * @connection: A #GDBusConnection.
 780  * @name: The name (well-known or unique) to watch.
 781  * @flags: Flags from the #GBusNameWatcherFlags enumeration.
 782  * @name_appeared_closure: (allow-none): #GClosure to invoke when @name is known
 783  * to exist or %NULL.
 784  * @name_vanished_closure: (allow-none): #GClosure to invoke when @name is known
 785  * to not exist or %NULL.
 786  *
 787  * Version of g_bus_watch_name_on_connection() using closures instead of callbacks for
 788  * easier binding in other languages.
 789  *
 790  * Returns: An identifier (never 0) that an be used with
 791  * g_bus_unwatch_name() to stop watching the name.
 792  *
 793  * Rename to: g_bus_watch_name_on_connection
 794  *
 795  * Since: 2.26
 796  */
 797 guint g_bus_watch_name_on_connection_with_closures (
 798                                       GDBusConnection          *connection,
 799                                       const gchar              *name,
 800                                       GBusNameWatcherFlags      flags,
 801                                       GClosure                 *name_appeared_closure,
 802                                       GClosure                 *name_vanished_closure)
 803 {
 804   return g_bus_watch_name_on_connection (connection,
 805           name,
 806           flags,
 807           name_appeared_closure != NULL ? watch_with_closures_on_name_appeared : NULL,
 808           name_vanished_closure != NULL ? watch_with_closures_on_name_vanished : NULL,
 809           watch_name_data_new (name_appeared_closure, name_vanished_closure),
 810           bus_watch_name_free_func);
 811 }
 812
 813 /**
 814  * g_bus_unwatch_name:
 815  * @watcher_id: An identifier obtained from g_bus_watch_name()
 816  *
 817  * Stops watching a name.
 818  *
 819  * Since: 2.26
 820  */
 821 void
 822 g_bus_unwatch_name (guint watcher_id)
 823 {
 824   Client *client;
 825
 826   g_return_if_fail (watcher_id > 0);
 827
 828   client = NULL;
 829
 830   G_LOCK (lock);
 831   if (watcher_id == 0 ||
 832       map_id_to_client == NULL ||
 833       (client = g_hash_table_lookup (map_id_to_client, GUINT_TO_POINTER (watcher_id))) == NULL)
 834     {
 835       g_warning ("Invalid id %d passed to g_bus_unwatch_name()", watcher_id);
 836       goto out;
 837     }
 838
 839   client->cancelled = TRUE;
 840   g_warn_if_fail (g_hash_table_remove (map_id_to_client, GUINT_TO_POINTER (watcher_id)));
 841
 842  out:
 843   G_UNLOCK (lock);
 844
 845   /* do callback without holding lock */
 846   if (client != NULL)
 847     {
 848       client_unref (client);
 849     }
 850 }