/* GDBus - GLib D-Bus Library * * Copyright (C) 2008-2010 Red Hat, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General * Public License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place, Suite 330, * Boston, MA 02111-1307, USA. * * Author: David Zeuthen */ #include "config.h" #include #include #include "gdbusutils.h" #include "gdbusnamewatching.h" #include "gdbuserror.h" #include "gdbusprivate.h" #include "gdbusconnection.h" #include "glibintl.h" #include "gioalias.h" /** * SECTION:gdbusnamewatching * @title: Watching Bus Names * @short_description: Simple API for watching bus names * @include: gio/gio.h * * Convenience API for watching bus names. * * Simple application watching a nameFIXME: MISSING XINCLUDE CONTENT */ G_LOCK_DEFINE_STATIC (lock); /* ---------------------------------------------------------------------------------------------------- */ typedef enum { PREVIOUS_CALL_NONE = 0, PREVIOUS_CALL_APPEARED, PREVIOUS_CALL_VANISHED, } PreviousCall; typedef struct { volatile gint ref_count; guint id; gchar *name; GBusNameWatcherFlags flags; gchar *name_owner; GBusNameAppearedCallback name_appeared_handler; GBusNameVanishedCallback name_vanished_handler; gpointer user_data; GDestroyNotify user_data_free_func; GMainContext *main_context; GDBusConnection *connection; gulong disconnected_signal_handler_id; guint name_owner_changed_subscription_id; PreviousCall previous_call; gboolean cancelled; gboolean initialized; } Client; static guint next_global_id = 1; static GHashTable *map_id_to_client = NULL; static Client * client_ref (Client *client) { g_atomic_int_inc (&client->ref_count); return client; } static void client_unref (Client *client) { if (g_atomic_int_dec_and_test (&client->ref_count)) { if (client->connection != NULL) { if (client->name_owner_changed_subscription_id > 0) g_dbus_connection_signal_unsubscribe (client->connection, client->name_owner_changed_subscription_id); if (client->disconnected_signal_handler_id > 0) g_signal_handler_disconnect (client->connection, client->disconnected_signal_handler_id); g_object_unref (client->connection); } g_free (client->name); g_free (client->name_owner); if (client->main_context != NULL) g_main_context_unref (client->main_context); if (client->user_data_free_func != NULL) client->user_data_free_func (client->user_data); g_free (client); } } /* ---------------------------------------------------------------------------------------------------- */ typedef enum { CALL_TYPE_NAME_APPEARED, CALL_TYPE_NAME_VANISHED } CallType; typedef struct { Client *client; /* keep this separate because client->connection may * be set to NULL after scheduling the call */ GDBusConnection *connection; /* ditto */ gchar *name_owner; CallType call_type; } CallHandlerData; static void call_handler_data_free (CallHandlerData *data) { if (data->connection != NULL) g_object_unref (data->connection); g_free (data->name_owner); client_unref (data->client); g_free (data); } static void actually_do_call (Client *client, GDBusConnection *connection, const gchar *name_owner, CallType call_type) { switch (call_type) { case CALL_TYPE_NAME_APPEARED: if (client->name_appeared_handler != NULL) { client->name_appeared_handler (connection, client->name, name_owner, client->user_data); } break; case CALL_TYPE_NAME_VANISHED: if (client->name_vanished_handler != NULL) { client->name_vanished_handler (connection, client->name, client->user_data); } break; default: g_assert_not_reached (); break; } } static gboolean call_in_idle_cb (gpointer _data) { CallHandlerData *data = _data; actually_do_call (data->client, data->connection, data->name_owner, data->call_type); return FALSE; } static void schedule_call_in_idle (Client *client, CallType call_type) { CallHandlerData *data; GSource *idle_source; data = g_new0 (CallHandlerData, 1); data->client = client_ref (client); data->connection = client->connection != NULL ? g_object_ref (client->connection) : NULL; data->name_owner = g_strdup (client->name_owner); data->call_type = call_type; idle_source = g_idle_source_new (); g_source_set_priority (idle_source, G_PRIORITY_HIGH); g_source_set_callback (idle_source, call_in_idle_cb, data, (GDestroyNotify) call_handler_data_free); g_source_attach (idle_source, client->main_context); g_source_unref (idle_source); } static void do_call (Client *client, CallType call_type) { /* only schedule in idle if we're not in the right thread */ if (g_main_context_get_thread_default () != client->main_context) schedule_call_in_idle (client, call_type); else actually_do_call (client, client->connection, client->name_owner, call_type); } static void call_appeared_handler (Client *client) { if (client->previous_call != PREVIOUS_CALL_APPEARED) { client->previous_call = PREVIOUS_CALL_APPEARED; if (!client->cancelled && client->name_appeared_handler != NULL) { do_call (client, CALL_TYPE_NAME_APPEARED); } } } static void call_vanished_handler (Client *client, gboolean ignore_cancelled) { if (client->previous_call != PREVIOUS_CALL_VANISHED) { client->previous_call = PREVIOUS_CALL_VANISHED; if (((!client->cancelled) || ignore_cancelled) && client->name_vanished_handler != NULL) { do_call (client, CALL_TYPE_NAME_VANISHED); } } } /* ---------------------------------------------------------------------------------------------------- */ static void on_connection_disconnected (GDBusConnection *connection, gboolean remote_peer_vanished, GError *error, gpointer user_data) { Client *client = user_data; if (client->name_owner_changed_subscription_id > 0) g_dbus_connection_signal_unsubscribe (client->connection, client->name_owner_changed_subscription_id); if (client->disconnected_signal_handler_id > 0) g_signal_handler_disconnect (client->connection, client->disconnected_signal_handler_id); g_object_unref (client->connection); client->disconnected_signal_handler_id = 0; client->name_owner_changed_subscription_id = 0; client->connection = NULL; call_vanished_handler (client, FALSE); } /* ---------------------------------------------------------------------------------------------------- */ static void on_name_owner_changed (GDBusConnection *connection, const gchar *sender_name, const gchar *object_path, const gchar *interface_name, const gchar *signal_name, GVariant *parameters, gpointer user_data) { Client *client = user_data; const gchar *name; const gchar *old_owner; const gchar *new_owner; if (!client->initialized) goto out; if (g_strcmp0 (object_path, "/org/freedesktop/DBus") != 0 || g_strcmp0 (interface_name, "org.freedesktop.DBus") != 0 || g_strcmp0 (sender_name, "org.freedesktop.DBus") != 0) goto out; g_variant_get (parameters, "(&s&s&s)", &name, &old_owner, &new_owner); /* we only care about a specific name */ if (g_strcmp0 (name, client->name) != 0) goto out; if ((old_owner != NULL && strlen (old_owner) > 0) && client->name_owner != NULL) { g_free (client->name_owner); client->name_owner = NULL; call_vanished_handler (client, FALSE); } if (new_owner != NULL && strlen (new_owner) > 0) { g_warn_if_fail (client->name_owner == NULL); g_free (client->name_owner); client->name_owner = g_strdup (new_owner); call_appeared_handler (client); } out: ; } /* ---------------------------------------------------------------------------------------------------- */ static void get_name_owner_cb (GObject *source_object, GAsyncResult *res, gpointer user_data) { Client *client = user_data; GVariant *result; const char *name_owner; name_owner = NULL; result = NULL; result = g_dbus_connection_call_finish (client->connection, res, NULL); if (result != NULL) { g_variant_get (result, "(&s)", &name_owner); } if (name_owner != NULL) { g_warn_if_fail (client->name_owner == NULL); client->name_owner = g_strdup (name_owner); call_appeared_handler (client); } else { call_vanished_handler (client, FALSE); } client->initialized = TRUE; if (result != NULL) g_variant_unref (result); client_unref (client); } /* ---------------------------------------------------------------------------------------------------- */ static void invoke_get_name_owner (Client *client) { g_dbus_connection_call (client->connection, "org.freedesktop.DBus", /* bus name */ "/org/freedesktop/DBus", /* object path */ "org.freedesktop.DBus", /* interface name */ "GetNameOwner", /* method name */ g_variant_new ("(s)", client->name), G_VARIANT_TYPE ("(s)"), G_DBUS_CALL_FLAGS_NONE, -1, NULL, (GAsyncReadyCallback) get_name_owner_cb, client_ref (client)); } /* ---------------------------------------------------------------------------------------------------- */ static void start_service_by_name_cb (GObject *source_object, GAsyncResult *res, gpointer user_data) { Client *client = user_data; GVariant *result; result = NULL; result = g_dbus_connection_call_finish (client->connection, res, NULL); if (result != NULL) { guint32 start_service_result; g_variant_get (result, "(u)", &start_service_result); if (start_service_result == 1) /* DBUS_START_REPLY_SUCCESS */ { invoke_get_name_owner (client); } else if (start_service_result == 2) /* DBUS_START_REPLY_ALREADY_RUNNING */ { invoke_get_name_owner (client); } else { g_warning ("Unexpected reply %d from StartServiceByName() method", start_service_result); call_vanished_handler (client, FALSE); client->initialized = TRUE; } } else { /* Errors are not unexpected; the bus will reply e.g. * * org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.Epiphany2 * was not provided by any .service files * * This doesn't mean that the name doesn't have an owner, just * that it's not provided by a .service file. So proceed to * invoke GetNameOwner(). */ invoke_get_name_owner (client); } if (result != NULL) g_variant_unref (result); client_unref (client); } /* ---------------------------------------------------------------------------------------------------- */ static void has_connection (Client *client) { /* listen for disconnection */ client->disconnected_signal_handler_id = g_signal_connect (client->connection, "closed", G_CALLBACK (on_connection_disconnected), client); /* start listening to NameOwnerChanged messages immediately */ client->name_owner_changed_subscription_id = g_dbus_connection_signal_subscribe (client->connection, "org.freedesktop.DBus", /* name */ "org.freedesktop.DBus", /* if */ "NameOwnerChanged", /* signal */ "/org/freedesktop/DBus", /* path */ client->name, on_name_owner_changed, client, NULL); if (client->flags & G_BUS_NAME_WATCHER_FLAGS_AUTO_START) { g_dbus_connection_call (client->connection, "org.freedesktop.DBus", /* bus name */ "/org/freedesktop/DBus", /* object path */ "org.freedesktop.DBus", /* interface name */ "StartServiceByName", /* method name */ g_variant_new ("(su)", client->name, 0), G_VARIANT_TYPE ("(u)"), G_DBUS_CALL_FLAGS_NONE, -1, NULL, (GAsyncReadyCallback) start_service_by_name_cb, client_ref (client)); } else { /* check owner */ invoke_get_name_owner (client); } } static void connection_get_cb (GObject *source_object, GAsyncResult *res, gpointer user_data) { Client *client = user_data; client->connection = g_bus_get_finish (res, NULL); if (client->connection == NULL) { call_vanished_handler (client, FALSE); goto out; } has_connection (client); out: client_unref (client); } /* ---------------------------------------------------------------------------------------------------- */ /** * g_bus_watch_name: * @bus_type: The type of bus to watch a name on. * @name: The name (well-known or unique) to watch. * @flags: Flags from the #GBusNameWatcherFlags enumeration. * @name_appeared_handler: Handler to invoke when @name is known to exist or %NULL. * @name_vanished_handler: Handler to invoke when @name is known to not exist or %NULL. * @user_data: User data to pass to handlers. * @user_data_free_func: Function for freeing @user_data or %NULL. * * Starts watching @name on the bus specified by @bus_type and calls * @name_appeared_handler and @name_vanished_handler when the name is * known to have a owner respectively known to lose its * owner. Callbacks will be invoked in the thread-default main * loop of the thread you are calling this function from. * * You are guaranteed that one of the handlers will be invoked after * calling this function. When you are done watching the name, just * call g_bus_unwatch_name() with the watcher id this function * returns. * * If the name vanishes or appears (for example the application owning * the name could restart), the handlers are also invoked. If the * #GDBusConnection that is used for watching the name disconnects, then * @name_vanished_handler is invoked since it is no longer * possible to access the name. * * Another guarantee is that invocations of @name_appeared_handler * and @name_vanished_handler are guaranteed to alternate; that * is, if @name_appeared_handler is invoked then you are * guaranteed that the next time one of the handlers is invoked, it * will be @name_vanished_handler. The reverse is also true. * * This behavior makes it very simple to write applications that wants * to take action when a certain name exists, see . Basically, the application * should create object proxies in @name_appeared_handler and destroy * them again (if any) in @name_vanished_handler. * * Returns: An identifier (never 0) that an be used with * g_bus_unwatch_name() to stop watching the name. * * Since: 2.26 */ guint g_bus_watch_name (GBusType bus_type, const gchar *name, GBusNameWatcherFlags flags, GBusNameAppearedCallback name_appeared_handler, GBusNameVanishedCallback name_vanished_handler, gpointer user_data, GDestroyNotify user_data_free_func) { Client *client; g_return_val_if_fail (g_dbus_is_name (name), 0); G_LOCK (lock); client = g_new0 (Client, 1); client->ref_count = 1; client->id = next_global_id++; /* TODO: uh oh, handle overflow */ client->name = g_strdup (name); client->flags = flags; client->name_appeared_handler = name_appeared_handler; client->name_vanished_handler = name_vanished_handler; client->user_data = user_data; client->user_data_free_func = user_data_free_func; client->main_context = g_main_context_get_thread_default (); if (client->main_context != NULL) g_main_context_ref (client->main_context); if (map_id_to_client == NULL) { map_id_to_client = g_hash_table_new (g_direct_hash, g_direct_equal); } g_hash_table_insert (map_id_to_client, GUINT_TO_POINTER (client->id), client); g_bus_get (bus_type, NULL, connection_get_cb, client_ref (client)); G_UNLOCK (lock); return client->id; } /** * g_bus_watch_name_on_connection: * @connection: A #GDBusConnection that is not closed. * @name: The name (well-known or unique) to watch. * @flags: Flags from the #GBusNameWatcherFlags enumeration. * @name_appeared_handler: Handler to invoke when @name is known to exist or %NULL. * @name_vanished_handler: Handler to invoke when @name is known to not exist or %NULL. * @user_data: User data to pass to handlers. * @user_data_free_func: Function for freeing @user_data or %NULL. * * Like g_bus_watch_name() but takes a #GDBusConnection instead of a * #GBusType. * * Returns: An identifier (never 0) that an be used with * g_bus_unwatch_name() to stop watching the name. * * Since: 2.26 */ guint g_bus_watch_name_on_connection (GDBusConnection *connection, const gchar *name, GBusNameWatcherFlags flags, GBusNameAppearedCallback name_appeared_handler, GBusNameVanishedCallback name_vanished_handler, gpointer user_data, GDestroyNotify user_data_free_func) { Client *client; g_return_val_if_fail (G_IS_DBUS_CONNECTION (connection), 0); g_return_val_if_fail (g_dbus_is_name (name), 0); G_LOCK (lock); client = g_new0 (Client, 1); client->ref_count = 1; client->id = next_global_id++; /* TODO: uh oh, handle overflow */ client->name = g_strdup (name); client->flags = flags; client->name_appeared_handler = name_appeared_handler; client->name_vanished_handler = name_vanished_handler; client->user_data = user_data; client->user_data_free_func = user_data_free_func; client->main_context = g_main_context_get_thread_default (); if (client->main_context != NULL) g_main_context_ref (client->main_context); if (map_id_to_client == NULL) { map_id_to_client = g_hash_table_new (g_direct_hash, g_direct_equal); } g_hash_table_insert (map_id_to_client, GUINT_TO_POINTER (client->id), client); client->connection = g_object_ref (connection); G_UNLOCK (lock); has_connection (client); return client->id; } typedef struct { GClosure *name_appeared_closure; GClosure *name_vanished_closure; } WatchNameData; static void watch_with_closures_on_name_appeared (GDBusConnection *connection, const gchar *name, const gchar *name_owner, gpointer user_data) { WatchNameData *data = user_data; GValue params[3] = { { 0, }, { 0, }, { 0, } }; g_value_init (¶ms[0], G_TYPE_DBUS_CONNECTION); g_value_set_object (¶ms[0], connection); g_value_init (¶ms[1], G_TYPE_STRING); g_value_set_string (¶ms[1], name); g_value_init (¶ms[2], G_TYPE_STRING); g_value_set_string (¶ms[2], name_owner); g_closure_invoke (data->name_appeared_closure, NULL, 3, params, NULL); } static void watch_with_closures_on_name_vanished (GDBusConnection *connection, const gchar *name, gpointer user_data) { WatchNameData *data = user_data; GValue params[2] = { { 0, }, { 0, } }; g_value_init (¶ms[0], G_TYPE_DBUS_CONNECTION); g_value_set_object (¶ms[0], connection); g_value_init (¶ms[1], G_TYPE_STRING); g_value_set_string (¶ms[1], name); g_closure_invoke (data->name_vanished_closure, NULL, 2, params, NULL); } static void bus_watch_name_free_func (gpointer user_data) { WatchNameData *data = user_data; if (data->name_appeared_closure != NULL) g_closure_unref (data->name_appeared_closure); if (data->name_vanished_closure != NULL) g_closure_unref (data->name_vanished_closure); g_free (data); } /** * g_bus_watch_name_with_closures: * @bus_type: The type of bus to watch a name on. * @name: The name (well-known or unique) to watch. * @flags: Flags from the #GBusNameWatcherFlags enumeration. * @name_appeared_closure: (allow-none): #GClosure to invoke when @name is known * to exist or %NULL. * @name_vanished_closure: (allow-none): #GClosure to invoke when @name is known * to not exist or %NULL. * * Version of g_bus_watch_name() using closures instead of callbacks for * easier binding in other languages. * * Returns: An identifier (never 0) that an be used with * g_bus_unwatch_name() to stop watching the name. * * Rename to: g_bus_watch_name * * Since: 2.26 */ guint g_bus_watch_name_with_closures (GBusType bus_type, const gchar *name, GBusNameWatcherFlags flags, GClosure *name_appeared_closure, GClosure *name_vanished_closure) { WatchNameData *data; data = g_new0 (WatchNameData, 1); if (name_appeared_closure != NULL) data->name_appeared_closure = g_closure_ref (name_appeared_closure); if (name_vanished_closure != NULL) data->name_vanished_closure = g_closure_ref (name_vanished_closure); return g_bus_watch_name (bus_type, name, flags, name_appeared_closure != NULL ? watch_with_closures_on_name_appeared : NULL, name_vanished_closure != NULL ? watch_with_closures_on_name_vanished : NULL, data, bus_watch_name_free_func); } /** * g_bus_watch_name_on_connection_with_closures: * @connection: A #GDBusConnection that is not closed. * @name: The name (well-known or unique) to watch. * @flags: Flags from the #GBusNameWatcherFlags enumeration. * @name_appeared_closure: (allow-none): #GClosure to invoke when @name is known * to exist or %NULL. * @name_vanished_closure: (allow-none): #GClosure to invoke when @name is known * to not exist or %NULL. * * Version of g_bus_watch_name_on_connection() using closures instead of callbacks for * easier binding in other languages. * * Returns: An identifier (never 0) that an be used with * g_bus_unwatch_name() to stop watching the name. * * Rename to: g_bus_watch_name_on_connection * * Since: 2.26 */ guint g_bus_watch_name_on_connection_with_closures ( GDBusConnection *connection, const gchar *name, GBusNameWatcherFlags flags, GClosure *name_appeared_closure, GClosure *name_vanished_closure) { WatchNameData *data; data = g_new0 (WatchNameData, 1); if (name_appeared_closure != NULL) data->name_appeared_closure = g_closure_ref (name_appeared_closure); if (name_vanished_closure != NULL) data->name_vanished_closure = g_closure_ref (name_vanished_closure); return g_bus_watch_name_on_connection (connection, name, flags, name_appeared_closure != NULL ? watch_with_closures_on_name_appeared : NULL, name_vanished_closure != NULL ? watch_with_closures_on_name_vanished : NULL, data, bus_watch_name_free_func); } /** * g_bus_unwatch_name: * @watcher_id: An identifier obtained from g_bus_watch_name() * * Stops watching a name. * * Since: 2.26 */ void g_bus_unwatch_name (guint watcher_id) { Client *client; g_return_if_fail (watcher_id > 0); client = NULL; G_LOCK (lock); if (watcher_id == 0 || map_id_to_client == NULL || (client = g_hash_table_lookup (map_id_to_client, GUINT_TO_POINTER (watcher_id))) == NULL) { g_warning ("Invalid id %d passed to g_bus_unwatch_name()", watcher_id); goto out; } client->cancelled = TRUE; g_warn_if_fail (g_hash_table_remove (map_id_to_client, GUINT_TO_POINTER (watcher_id))); out: G_UNLOCK (lock); /* do callback without holding lock */ if (client != NULL) { client_unref (client); } } #define __G_DBUS_NAME_WATCHING_C__ #include "gioaliasdef.c"