From 932a6a39e35754be571e1274aec4730fd42dba13 Mon Sep 17 00:00:00 2001 From: Martin Pitt <martin.pitt@ubuntu.com> Date: Wed, 18 May 2016 09:22:43 +0200 Subject: lib: Add proper error and cancellable handling to UpClient constructor A GObject's _init() should never fail or block, but this is currently the case as up_client_init() connects to upowerd on D-Bus. Convert this to the GInitable interface and provide a new constructor up_client_new_full() which accepts a GCancellable and GError, so that clients can do proper error handling and reporting. This changes up_client_new() to return NULL when connecting to upowerd fails. This provides a more well-defined behaviour in this case as clients can check for this and our methods stop segfaulting as they have checks like g_return_val_if_fail (UP_IS_CLIENT (client), ...) Previously we returned a valid object, but trying to call any method on it segfaulted due to the NULL D-Bus proxy, so client code had no chance to check whether the UpClient object was really valid. https://bugs.freedesktop.org/show_bug.cgi?id=95350 diff --git a/libupower-glib/up-client.c b/libupower-glib/up-client.c index 5b2218f..adc0b9b 100644 --- a/libupower-glib/up-client.c +++ b/libupower-glib/up-client.c @@ -39,9 +39,10 @@ #include "up-daemon-generated.h" #include "up-device.h" -static void up_client_class_init (UpClientClass *klass); -static void up_client_init (UpClient *client); -static void up_client_finalize (GObject *object); +static void up_client_class_init (UpClientClass *klass); +static void up_client_initable_iface_init (GInitableIface *iface); +static void up_client_init (UpClient *client); +static void up_client_finalize (GObject *object); #define UP_CLIENT_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o), UP_TYPE_CLIENT, UpClientPrivate)) @@ -73,7 +74,8 @@ enum { static guint signals [UP_CLIENT_LAST_SIGNAL] = { 0 }; static gpointer up_client_object = NULL; -G_DEFINE_TYPE (UpClient, up_client, G_TYPE_OBJECT) +G_DEFINE_TYPE_WITH_CODE (UpClient, up_client, G_TYPE_OBJECT, + G_IMPLEMENT_INTERFACE(G_TYPE_INITABLE, up_client_initable_iface_init)) /** * up_client_get_devices: @@ -434,11 +436,10 @@ up_client_class_init (UpClientClass *klass) * up_client_init: * @client: This class instance */ -static void -up_client_init (UpClient *client) +static gboolean +up_client_initable_init (GInitable *initable, GCancellable *cancellable, GError **error) { - GError *error = NULL; - + UpClient *client = UP_CLIENT (initable); client->priv = UP_CLIENT_GET_PRIVATE (client); /* connect to main interface */ @@ -446,13 +447,10 @@ up_client_init (UpClient *client) G_DBUS_PROXY_FLAGS_NONE, "org.freedesktop.UPower", "/org/freedesktop/UPower", - NULL, - &error); - if (client->priv->proxy == NULL) { - g_warning ("Couldn't connect to proxy: %s", error->message); - g_error_free (error); - return; - } + cancellable, + error); + if (client->priv->proxy == NULL) + return FALSE; /* all callbacks */ g_signal_connect (client->priv->proxy, "device-added", @@ -461,6 +459,23 @@ up_client_init (UpClient *client) G_CALLBACK (up_device_removed_cb), client); g_signal_connect (client->priv->proxy, "notify", G_CALLBACK (up_client_notify_cb), client); + + return TRUE; +} + +static void +up_client_initable_iface_init (GInitableIface *iface) +{ + iface->init = up_client_initable_init; +} + +/* + * up_client_init: + * @client: This class instance + */ +static void +up_client_init (UpClient *client) +{ } /* @@ -482,23 +497,52 @@ up_client_finalize (GObject *object) } /** - * up_client_new: + * up_client_new_full: + * @cancellable: (allow-none): A #GCancellable or %NULL. + * @error: Return location for error or %NULL. * - * Creates a new #UpClient object. + * Creates a new #UpClient object. If connecting to upowerd on D-Bus fails, + % this returns %NULL and sets @error. * - * Return value: a new UpClient object. + * Return value: a new UpClient object, or %NULL on failure. * - * Since: 0.9.0 + * Since: 0.99.5 **/ UpClient * -up_client_new (void) +up_client_new_full (GCancellable *cancellable, GError **error) { if (up_client_object != NULL) { g_object_ref (up_client_object); } else { - up_client_object = g_object_new (UP_TYPE_CLIENT, NULL); - g_object_add_weak_pointer (up_client_object, &up_client_object); + up_client_object = g_initable_new (UP_TYPE_CLIENT, cancellable, error, NULL); + if (up_client_object) + g_object_add_weak_pointer (up_client_object, &up_client_object); } return UP_CLIENT (up_client_object); } +/** + * up_client_new: + * + * Creates a new #UpClient object. If connecting to upowerd on D-Bus fails, + * this returns %NULL and prints out a warning with the error message. + * Consider using up_client_new_full() instead which allows you to handle errors + * and cancelling long operations yourself. + * + * Return value: a new UpClient object, or %NULL on failure. + * + * Since: 0.9.0 + **/ +UpClient * +up_client_new (void) +{ + GError *error = NULL; + UpClient *client; + client = up_client_new_full (NULL, &error); + if (client == NULL) { + g_warning ("Couldn't connect to proxy: %s", error->message); + g_error_free (error); + } + return client; +} + diff --git a/libupower-glib/up-client.h b/libupower-glib/up-client.h index 79c2d9e..5b9af3c 100644 --- a/libupower-glib/up-client.h +++ b/libupower-glib/up-client.h @@ -72,6 +72,7 @@ typedef struct /* general */ GType up_client_get_type (void); UpClient *up_client_new (void); +UpClient *up_client_new_full (GCancellable *cancellable, GError **error); /* sync versions */ UpDevice * up_client_get_display_device (UpClient *client); -- cgit v0.10.2