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gdbus-tool: Add a command to wait for a well-known name on the bus

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This is effectively the mc-wait-for-name tool from
telepathy-mission-control; moving it in to gdbus-tool will make it more
widely useful without making people depend on telepathy-mission-control
for no other reason. The code here is reimplemented from scratch to use
GDBus.

It blocks until the specified well-known name is owned by some process
on the bus (which can be the session, system, or any other bus). By
passing --activate, the same (or a different) name can be auto-started
on the bus first.

A timeout can be specified to ensure the process doesn’t block forever.

https://bugzilla.gnome.org/show_bug.cgi?id=745971
This commit is contained in:
Philip Withnall 2015-03-10 15:01:13 +00:00 committed by Philip Withnall
parent ff7f32f643
commit 7890573f6e
2 changed files with 303 additions and 1 deletions
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55
docs/reference/gio/gdbus.xml
View File

@ -91,6 +91,20 @@
<arg choice="plain">ARG1</arg>
<arg choice="plain" rep="repeat">ARG2</arg>
</cmdsynopsis>
<cmdsynopsis>
<command>gdbus</command>
<arg choice="plain">wait</arg>
<group>
<arg choice="plain">--system</arg>
<arg choice="plain">--session</arg>
<arg choice="plain">--address <replaceable>address</replaceable></arg>
</group>
<arg choice="plain">--activate <replaceable>bus_name</replaceable></arg>
<group>
<arg choice="plain">--timeout <replaceable>seconds</replaceable></arg>
</group>
<arg choice="plain"><replaceable>bus_name</replaceable></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>gdbus</command>
<arg choice="plain">help</arg>
@ -147,6 +161,15 @@
not need explicit quotes.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>wait</option></term>
<listitem><para>
Waits until <replaceable>bus_name</replaceable> is owned by some
process on the bus. If the <option>--activate</option> is specified,
that bus name will be auto-started first. It may be the same as the
bus name being waited for, or different.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>help</option></term>
<listitem><para>
@ -337,6 +360,38 @@ $ gdbus emit --session --object-path /foo --signal org.bar.Foo "['foo', 'bar', '
$ gdbus emit --session --object-path /bar --signal org.bar.Bar someString --dest :1.42
</programlisting>
<para>
Waiting for a well-known name to be owned on the bus; this will
<emphasis>not</emphasis> auto-start the service:
</para>
<programlisting>
$ gdbus wait --session org.bar.SomeName
</programlisting>
<para>
Auto-starting then waiting for a well-known name to be owned on the bus:
</para>
<programlisting>
$ gdbus wait --session --activate org.bar.SomeName
</programlisting>
<para>
Auto-starting a different service, then waiting for a well-known name to be
owned on the bus. This is useful in situations where
<replaceable>SomeName</replaceable> is not directly activatable:
</para>
<programlisting>
$ gdbus wait --session --activate org.bar.PrerequisiteName org.bar.SomeName
</programlisting>
<para>
Waiting for a well-known name and giving up after 30 seconds. By default,
the timeout is disabled; or set <option>--timeout</option> to 0 to disable it:
</para>
<programlisting>
$ gdbus wait --session --timeout 30 org.bar.SomeName
</programlisting>
</refsect1>
<refsect1>

249
gio/gdbus-tool.c
View File

@ -98,6 +98,7 @@ usage (gint *argc, gchar **argv[], gboolean use_stdout)
" monitor Monitor a remote object\n"
" call Invoke a method on a remote object\n"
" emit Emit a signal\n"
" wait Wait for a bus name to appear\n"
"\n"
"Use “%s COMMAND --help” to get help on each command.\n"),
program_name);
@ -1949,6 +1950,242 @@ handle_monitor (gint *argc,
/* ---------------------------------------------------------------------------------------------------- */
static gboolean opt_wait_activate_set = FALSE;
static gchar *opt_wait_activate_name = NULL;
static gint64 opt_wait_timeout = 0; /* no timeout */
typedef enum {
WAIT_STATE_RUNNING, /* waiting to see the service */
WAIT_STATE_SUCCESS, /* seen it successfully */
WAIT_STATE_TIMEOUT, /* timed out before seeing it */
} WaitState;
static gboolean
opt_wait_activate_cb (const gchar *option_name,
const gchar *value,
gpointer data,
GError **error)
{
/* @value may be NULL */
opt_wait_activate_set = TRUE;
opt_wait_activate_name = g_strdup (value);
return TRUE;
}
static const GOptionEntry wait_entries[] =
{
{ "activate", 'a', G_OPTION_FLAG_OPTIONAL_ARG, G_OPTION_ARG_CALLBACK,
opt_wait_activate_cb,
N_("Service to activate before waiting for the other one (well-known name)"),
"[NAME]" },
{ "timeout", 't', 0, G_OPTION_ARG_INT64, &opt_wait_timeout,
N_("Timeout to wait for before exiting with an error (seconds); 0 for "
"no timeout (default)"), "SECS" },
{ NULL }
};
static void
wait_name_appeared_cb (GDBusConnection *connection,
const gchar *name,
const gchar *name_owner,
gpointer user_data)
{
WaitState *wait_state = user_data;
*wait_state = WAIT_STATE_SUCCESS;
}
static gboolean
wait_timeout_cb (gpointer user_data)
{
WaitState *wait_state = user_data;
*wait_state = WAIT_STATE_TIMEOUT;
/* Removed in handle_wait(). */
return G_SOURCE_CONTINUE;
}
static gboolean
handle_wait (gint *argc,
gchar **argv[],
gboolean request_completion,
const gchar *completion_cur,
const gchar *completion_prev)
{
gint ret;
GOptionContext *o;
gchar *s;
GError *error;
GDBusConnection *c;
guint watch_id, timer_id = 0, activate_watch_id;
const gchar *activate_service, *wait_service;
WaitState wait_state = WAIT_STATE_RUNNING;
ret = FALSE;
c = NULL;
modify_argv0_for_command (argc, argv, "wait");
o = g_option_context_new (NULL);
g_option_context_set_help_enabled (o, FALSE);
g_option_context_set_summary (o, _("Wait for a bus name to appear."));
g_option_context_add_main_entries (o, wait_entries, GETTEXT_PACKAGE);
g_option_context_add_group (o, connection_get_group ());
if (!g_option_context_parse (o, argc, argv, NULL))
{
if (!request_completion)
{
s = g_option_context_get_help (o, FALSE, NULL);
g_printerr ("%s", s);
g_free (s);
goto out;
}
}
error = NULL;
c = connection_get_dbus_connection (&error);
if (c == NULL)
{
if (request_completion)
{
if (g_strcmp0 (completion_prev, "--address") == 0)
{
g_print ("unix:\n"
"tcp:\n"
"nonce-tcp:\n");
}
else
{
g_print ("--system \n--session \n--address \n");
}
}
else
{
g_printerr (_("Error connecting: %s\n"), error->message);
g_error_free (error);
}
goto out;
}
/* All done with completion now */
if (request_completion)
goto out;
/*
* Try and disentangle the command line arguments, with the aim of supporting:
* gdbus wait --session --activate ActivateName WaitName
* gdbus wait --session --activate ActivateAndWaitName
* gdbus wait --activate --session ActivateAndWaitName
* gdbus wait --session WaitName
*/
if (*argc == 2 && opt_wait_activate_set && opt_wait_activate_name != NULL)
{
activate_service = opt_wait_activate_name;
wait_service = (*argv)[1];
}
else if (*argc == 2 &&
opt_wait_activate_set && opt_wait_activate_name == NULL)
{
activate_service = (*argv)[1];
wait_service = (*argv)[1];
}
else if (*argc == 2 && !opt_wait_activate_set)
{
activate_service = NULL; /* disabled */
wait_service = (*argv)[1];
}
else if (*argc == 1 &&
opt_wait_activate_set && opt_wait_activate_name != NULL)
{
activate_service = opt_wait_activate_name;
wait_service = opt_wait_activate_name;
}
else if (*argc == 1 &&
opt_wait_activate_set && opt_wait_activate_name == NULL)
{
g_printerr (_("Error: A service to activate for must be specified.\n"));
goto out;
}
else if (*argc == 1 && !opt_wait_activate_set)
{
g_printerr (_("Error: A service to wait for must be specified.\n"));
goto out;
}
else /* if (*argc > 2) */
{
g_printerr (_("Error: Too many arguments.\n"));
goto out;
}
if (activate_service != NULL &&
(!g_dbus_is_name (activate_service) ||
g_dbus_is_unique_name (activate_service)))
{
g_printerr (_("Error: %s is not a valid well-known bus name.\n"),
activate_service);
goto out;
}
if (!g_dbus_is_name (wait_service) || g_dbus_is_unique_name (wait_service))
{
g_printerr (_("Error: %s is not a valid well-known bus name.\n"),
wait_service);
goto out;
}
/* All done with completion now */
if (request_completion)
goto out;
/* Start the prerequisite service if needed. */
if (activate_service != NULL)
{
activate_watch_id = g_bus_watch_name_on_connection (c, activate_service,
G_BUS_NAME_WATCHER_FLAGS_AUTO_START,
NULL, NULL,
NULL, NULL);
}
else
{
activate_watch_id = 0;
}
/* Wait for the expected name to appear. */
watch_id = g_bus_watch_name_on_connection (c,
wait_service,
G_BUS_NAME_WATCHER_FLAGS_NONE,
wait_name_appeared_cb,
NULL, &wait_state, NULL);
/* Safety timeout. */
if (opt_wait_timeout > 0)
timer_id = g_timeout_add (opt_wait_timeout, wait_timeout_cb, &wait_state);
while (wait_state == WAIT_STATE_RUNNING)
g_main_context_iteration (NULL, TRUE);
g_bus_unwatch_name (watch_id);
if (timer_id != 0)
g_source_remove (timer_id);
if (activate_watch_id != 0)
g_bus_unwatch_name (activate_watch_id);
ret = (wait_state == WAIT_STATE_SUCCESS);
out:
g_clear_object (&c);
g_option_context_free (o);
g_free (opt_wait_activate_name);
opt_wait_activate_name = NULL;
return ret;
}
/* ---------------------------------------------------------------------------------------------------- */
static gchar *
pick_word_at (const gchar *s,
gint cursor,
@ -2081,6 +2318,16 @@ main (gint argc, gchar *argv[])
ret = 0;
goto out;
}
else if (g_strcmp0 (command, "wait") == 0)
{
if (handle_wait (&argc,
&argv,
request_completion,
completion_cur,
completion_prev))
ret = 0;
goto out;
}
else if (g_strcmp0 (command, "complete") == 0 && argc == 4 && !request_completion)
{
const gchar *completion_line;
@ -2150,7 +2397,7 @@ main (gint argc, gchar *argv[])
{
if (request_completion)
{
g_print ("help \nemit \ncall \nintrospect \nmonitor \n");
g_print ("help \nemit \ncall \nintrospect \nmonitor \nwait \n");
ret = 0;
goto out;
}