Class ApplicationCommandLine

java.lang.Object
org.javagi.base.ProxyInstance
org.gnome.gobject.TypeInstance
org.gnome.gobject.GObject
org.gnome.gio.ApplicationCommandLine
All Implemented Interfaces:
Proxy
@Generated("org.javagi.JavaGI") public class ApplicationCommandLine extends GObject

GApplicationCommandLine represents a command-line invocation of an application.

It is created by Application and emitted in the Gio.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 getArguments() 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 done() method is called. This method is also automatically called when the object is disposed.

The main use for GApplicationCommandLine (and the Gio.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 Gio.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 Gio.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 Gio.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

  • Constructor Details

    • ApplicationCommandLine

      public ApplicationCommandLine(MemorySegment address)
      Create a ApplicationCommandLine instance for the provided memory address.
      Parameters:
      address - the memory address of the native object

    • ApplicationCommandLine

      public ApplicationCommandLine()
      Create a new ApplicationCommandLine.

  • Method Details

    • getType

      public static @Nullable Type getType()
      Get the GType of the ApplicationCommandLine class.
      Returns:
      the GType

    • getMemoryLayout

      public static MemoryLayout getMemoryLayout()
      The memory layout of the native struct.
      Returns:
      the memory layout

    • asParent

      protected ApplicationCommandLine asParent()
      Return this instance as if it were its parent type. Comparable to the Java super keyword, but ensures the parent typeclass is also used in native code.
      Overrides:
      asParent in class GObject
      Returns:
      the instance as if it were its parent type

    • createFileForArg

      public File createFileForArg(String arg)

      Creates a GFile corresponding to a filename that was given as part of the invocation of cmdline.

      This differs from g_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 from this ApplicationCommandLine
      Returns:
      a new GFile
      Since:
      2.36

    • done

      public void 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 Gio.Application::command-line handler, after the exit status is set and all messages are printed.

      After this call, g_application_command_line_set_exit_status() has no effect. Subsequent calls to this method are no-ops.

      This method is automatically called when the GApplicationCommandLine object is disposed — so you can omit the call in non-garbage collected languages.

      Since:
      2.80

    • getArguments

      public String[] getArguments()

      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 GOptionContext, you must use g_option_context_parse_strv().

      The return value is null-terminated and should be freed using g_strfreev().

      Returns:
      the string array containing the arguments (the argv)
      Since:
      2.28

    • getCwd

      public @Nullable String getCwd()

      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 null.

      The return value should not be modified or freed and is valid for as long as this ApplicationCommandLine exists.

      Returns:
      the current directory, or null
      Since:
      2.28

    • getEnviron

      public @Nullable String @Nullable [] getEnviron()

      Gets the contents of the 'environ' variable of the command line invocation, as would be returned by g_get_environ(), ie as a null-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 this ApplicationCommandLine exists.

      See g_application_command_line_getenv() if you are only interested in the value of a single environment variable.

      Returns:
      the environment strings, or null if they were not sent
      Since:
      2.28

    • getExitStatus

      public int getExitStatus()
      Gets the exit status of cmdline. See g_application_command_line_set_exit_status() for more information.
      Returns:
      the exit status
      Since:
      2.28

    • getIsRemote

      public boolean getIsRemote()
      Determines if this ApplicationCommandLine represents a remote invocation.
      Returns:
      true if the invocation was remote
      Since:
      2.28

    • getOptionsDict

      public VariantDict getOptionsDict()

      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 g_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 null.

      The data has been passed via an untrusted external process, so the types of all values must be checked before being used.

      Returns:
      a GVariantDict with the options
      Since:
      2.40

    • getPlatformData

      public @Nullable Variant getPlatformData()

      Gets the platform data associated with the invocation of cmdline.

      This is a GVariant 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 null.

      Returns:
      the platform data, or null
      Since:
      2.28

    • getStdin

      public @Nullable InputStream getStdin()

      Gets the stdin of the invoking process.

      The GInputStream 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 null will be returned. In the future, support may be expanded to other platforms.

      You must only call this function once per commandline invocation.

      Returns:
      a GInputStream for stdin
      Since:
      2.34

    • getenv

      public @Nullable String getenv(String name)

      Gets the value of a particular environment variable of the command line invocation, as would be returned by g_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 this ApplicationCommandLine exists.

      Parameters:
      name - the environment variable to get
      Returns:
      the value of the variable, or null if unset or unsent
      Since:
      2.28

    • print

      public void print(String format, Object... varargs)

      Formats a message and prints it using the stdout print handler in the invoking process.

      If this ApplicationCommandLine is a local invocation then this is exactly equivalent to g_print(). If this ApplicationCommandLine is remote then this is equivalent to calling g_print() in the invoking process.

      Parameters:
      format - a printf-style format string
      varargs - arguments, as per format
      Since:
      2.28

    • printLiteral

      public void printLiteral(String message)

      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
      Since:
      2.80

    • printerr

      public void printerr(String format, Object... varargs)

      Formats a message and prints it using the stderr print handler in the invoking process.

      If this ApplicationCommandLine is a local invocation then this is exactly equivalent to g_printerr(). If this ApplicationCommandLine is remote then this is equivalent to calling g_printerr() in the invoking process.

      Parameters:
      format - a printf-style format string
      varargs - arguments, as per format
      Since:
      2.28

    • printerrLiteral

      public void printerrLiteral(String message)

      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
      Since:
      2.80

    • setExitStatus

      public void setExitStatus(int exitStatus)

      Sets the exit status that will be used when the invoking process exits.

      The return value of the GApplication::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 GApplicationCommandLine is used.

      This method is a no-op if g_application_command_line_done() has been called.

      Parameters:
      exitStatus - the exit status
      Since:
      2.28

    • builder

      public static ApplicationCommandLine.Builder<? extends ApplicationCommandLine.Builder> builder()
      A ApplicationCommandLine.Builder object constructs a ApplicationCommandLine with the specified properties. Use the various set...() methods to set properties, and finish construction with ApplicationCommandLine.Builder.build().
      Returns:
      the builder object