Gio.ApplicationCommandLine¶
class — extends GObject.Object
GApplicationCommandLine represents a command-line invocation of
an application.
It is created by Application and emitted
in the Application.command-line signal and virtual function.
The class contains the list of arguments that the program was invoked with. It is also possible to query if the commandline invocation was local (ie: the current process is running in direct response to the invocation) or remote (ie: some other process forwarded the commandline to this process).
The GApplicationCommandLine object can provide the argc and argv
parameters for use with the GLib.OptionContext command-line parsing API,
with the ApplicationCommandLine.get_arguments function. See
gapplication-example-cmdline3.c
for an example.
The exit status of the originally-invoked process may be set and messages can be printed to stdout or stderr of that process.
For remote invocation, the originally-invoked process exits when
ApplicationCommandLine.done method is called. This method is
also automatically called when the object is disposed.
The main use for GApplicationCommandLine (and the
Application.command-line signal) is 'Emacs server' like use cases:
You can set the EDITOR environment variable to have e.g. git use
your favourite editor to edit commit messages, and if you already
have an instance of the editor running, the editing will happen
in the running instance, instead of opening a new one. An important
aspect of this use case is that the process that gets started by git
does not return until the editing is done.
Normally, the commandline is completely handled in the
Application.command-line handler. The launching instance exits
once the signal handler in the primary instance has returned, and
the return value of the signal handler becomes the exit status
of the launching instance.
static int
command_line (GApplication *application,
GApplicationCommandLine *cmdline)
{
gchar **argv;
gint argc;
gint i;
argv = g_application_command_line_get_arguments (cmdline, &argc);
g_application_command_line_print (cmdline,
"This text is written back\n"
"to stdout of the caller\n");
for (i = 0; i < argc; i++)
g_print ("argument %d: %s\n", i, argv[i]);
g_strfreev (argv);
return 0;
}
The complete example can be found here: gapplication-example-cmdline.c
In more complicated cases, the handling of the commandline can be split between the launcher and the primary instance.
static gboolean
test_local_cmdline (GApplication *application,
gchar ***arguments,
gint *exit_status)
{
gint i, j;
gchar **argv;
argv = *arguments;
if (argv[0] == NULL)
{
*exit_status = 0;
return FALSE;
}
i = 1;
while (argv[i])
{
if (g_str_has_prefix (argv[i], "--local-"))
{
g_print ("handling argument %s locally\n", argv[i]);
g_free (argv[i]);
for (j = i; argv[j]; j++)
argv[j] = argv[j + 1];
}
else
{
g_print ("not handling argument %s locally\n", argv[i]);
i++;
}
}
*exit_status = 0;
return FALSE;
}
static void
test_application_class_init (TestApplicationClass *class)
{
G_APPLICATION_CLASS (class)->local_command_line = test_local_cmdline;
...
}
In this example of split commandline handling, options that start
with --local- are handled locally, all other options are passed
to the Application.command-line handler which runs in the primary
instance.
The complete example can be found here: gapplication-example-cmdline2.c
If handling the commandline requires a lot of work, it may be better to defer it.
static gboolean
my_cmdline_handler (gpointer data)
{
GApplicationCommandLine *cmdline = data;
// do the heavy lifting in an idle
g_application_command_line_set_exit_status (cmdline, 0);
g_object_unref (cmdline); // this releases the application
return G_SOURCE_REMOVE;
}
static int
command_line (GApplication *application,
GApplicationCommandLine *cmdline)
{
// keep the application running until we are done with this commandline
g_application_hold (application);
g_object_set_data_full (G_OBJECT (cmdline),
"application", application,
(GDestroyNotify)g_application_release);
g_object_ref (cmdline);
g_idle_add (my_cmdline_handler, cmdline);
return 0;
}
In this example the commandline is not completely handled before
the Application.command-line handler returns. Instead, we keep
a reference to the GApplicationCommandLine object and handle it
later (in this example, in an idle). Note that it is necessary to
hold the application until you are done with the commandline.
The complete example can be found here: gapplication-example-cmdline3.c
Methods¶
create_file_for_arg¶
Creates a File corresponding to a filename that was given as part
of the invocation of cmdline.
This differs from File.new_for_commandline_arg in that it
resolves relative pathnames using the current working directory of
the invoking process rather than the local process.
Parameters:
arg— an argument fromcmdline
done¶
Signals that command line processing is completed.
For remote invocation, it causes the invoking process to terminate.
For local invocation, it does nothing.
This method should be called in the Application.command-line
handler, after the exit status is set and all messages are printed.
After this call, ApplicationCommandLine.set_exit_status has no effect.
Subsequent calls to this method are no-ops.
This method is automatically called when the ApplicationCommandLine
object is disposed — so you can omit the call in non-garbage collected
languages.
get_arguments¶
Gets the list of arguments that was passed on the command line.
The strings in the array may contain non-UTF-8 data on UNIX (such as filenames or arguments given in the system locale) but are always in UTF-8 on Windows.
If you wish to use the return value with GLib.OptionContext, you must
use GLib.OptionContext.parse_strv.
The return value is None-terminated and should be freed using
GLib.strfreev.
get_cwd¶
Gets the working directory of the command line invocation. The string may contain non-utf8 data.
It is possible that the remote application did not send a working
directory, so this may be None.
The return value should not be modified or freed and is valid for as
long as cmdline exists.
get_environ¶
Gets the contents of the 'environ' variable of the command line
invocation, as would be returned by GLib.get_environ, ie as a
None-terminated list of strings in the form 'NAME=VALUE'.
The strings may contain non-utf8 data.
The remote application usually does not send an environment. Use
ApplicationFlags.SEND_ENVIRONMENT to affect that. Even with this flag
set it is possible that the environment is still not available (due
to invocation messages from other applications).
The return value should not be modified or freed and is valid for as
long as cmdline exists.
See ApplicationCommandLine.getenv if you are only interested
in the value of a single environment variable.
get_exit_status¶
Gets the exit status of cmdline. See
ApplicationCommandLine.set_exit_status for more information.
get_is_remote¶
Determines if cmdline represents a remote invocation.
get_options_dict¶
Gets the options that were passed to g_application_command_line().
If you did not override local_command_line() then these are the same
options that were parsed according to the GOptionEntrys added to the
application with Application.add_main_option_entries and possibly
modified from your GApplication::handle-local-options handler.
If no options were sent then an empty dictionary is returned so that
you don't need to check for None.
The data has been passed via an untrusted external process, so the types of all values must be checked before being used.
get_platform_data¶
Gets the platform data associated with the invocation of cmdline.
This is a GLib.Variant dictionary containing information about the
context in which the invocation occurred. It typically contains
information like the current working directory and the startup
notification ID.
It comes from an untrusted external process and hence the types of all values must be validated before being used.
For local invocation, it will be None.
get_stdin¶
Gets the stdin of the invoking process.
The InputStream can be used to read data passed to the standard
input of the invoking process.
This doesn't work on all platforms. Presently, it is only available
on UNIX when using a D-Bus daemon capable of passing file descriptors.
If stdin is not available then None will be returned. In the
future, support may be expanded to other platforms.
You must only call this function once per commandline invocation.
getenv¶
Gets the value of a particular environment variable of the command
line invocation, as would be returned by GLib.getenv. The strings may
contain non-utf8 data.
The remote application usually does not send an environment. Use
ApplicationFlags.SEND_ENVIRONMENT to affect that. Even with this flag
set it is possible that the environment is still not available (due
to invocation messages from other applications).
The return value should not be modified or freed and is valid for as
long as cmdline exists.
Parameters:
name— the environment variable to get
print_literal¶
Prints a message using the stdout print handler in the invoking process.
Unlike g_application_command_line_print(), message is not a printf()-style
format string. Use this function if message contains text you don't have
control over, that could include printf() escape sequences.
Parameters:
message— the message
printerr_literal¶
Prints a message using the stderr print handler in the invoking process.
Unlike g_application_command_line_printerr(), message is not
a printf()-style format string. Use this function if message contains text
you don't have control over, that could include printf() escape sequences.
Parameters:
message— the message
set_exit_status¶
Sets the exit status that will be used when the invoking process exits.
The return value of the Application::command-line signal is
passed to this function when the handler returns. This is the usual
way of setting the exit status.
In the event that you want the remote invocation to continue running
and want to decide on the exit status in the future, you can use this
call. For the case of a remote invocation, the remote process will
typically exit when the last reference is dropped on cmdline. The
exit status of the remote process will be equal to the last value
that was set with this function.
In the case that the commandline invocation is local, the situation
is slightly more complicated. If the commandline invocation results
in the mainloop running (ie: because the use-count of the application
increased to a non-zero value) then the application is considered to
have been 'successful' in a certain sense, and the exit status is
always zero. If the application use count is zero, though, the exit
status of the local ApplicationCommandLine is used.
This method is a no-op if ApplicationCommandLine.done has
been called.
Parameters:
exit_status— the exit status
Virtual methods¶
do_done¶
Signals that command line processing is completed.
For remote invocation, it causes the invoking process to terminate.
For local invocation, it does nothing.
This method should be called in the Application.command-line
handler, after the exit status is set and all messages are printed.
After this call, ApplicationCommandLine.set_exit_status has no effect.
Subsequent calls to this method are no-ops.
This method is automatically called when the ApplicationCommandLine
object is disposed — so you can omit the call in non-garbage collected
languages.
do_get_stdin¶
Gets the stdin of the invoking process.
The InputStream can be used to read data passed to the standard
input of the invoking process.
This doesn't work on all platforms. Presently, it is only available
on UNIX when using a D-Bus daemon capable of passing file descriptors.
If stdin is not available then None will be returned. In the
future, support may be expanded to other platforms.
You must only call this function once per commandline invocation.
do_print_literal¶
Prints a message using the stdout print handler in the invoking process.
Unlike g_application_command_line_print(), message is not a printf()-style
format string. Use this function if message contains text you don't have
control over, that could include printf() escape sequences.
Parameters:
message— the message
do_printerr_literal¶
Prints a message using the stderr print handler in the invoking process.
Unlike g_application_command_line_printerr(), message is not
a printf()-style format string. Use this function if message contains text
you don't have control over, that could include printf() escape sequences.
Parameters:
message— the message
Properties¶
arguments¶
The commandline that caused this Application.command-line
signal emission.
is_remote¶
Whether this is a remote commandline.
options¶
The options sent along with the commandline.
platform_data¶
Platform-specific data for the commandline.