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Gnome::Gio::Application

Gnome::Gio::Application

Description

Gnome::Gio::Application is the core class for application support.

A Gnome::Gio::Application is the foundation of an application. It wraps some low-level platform-specific services and is intended to act as the foundation for higher-level application classes such as GtkApplication or MxApplication. In general, you should not use this class outside of a higher level framework.

Gnome::Gio::Application provides convenient life-cycle management by maintaining a "use count" for the primary application instance. The use count can be changed using .hold() and .release(). If it drops to zero, the application exits. Higher-level classes such as GtkApplication employ the use count to ensure that the application stays alive as long as it has any opened windows.

Another feature that Gnome::Gio::Application (optionally) provides is process uniqueness. Applications can make use of this functionality by providing a unique application ID. If given, only one application with this ID can be running at a time per session. The session concept is platform-dependent, but corresponds roughly to a graphical desktop login. When your application is launched again, its arguments are passed through platform communication to the already running program. The already running instance of the program is called the "primary instance"; for non-unique applications this is always the current instance. On Linux, the D-Bus session bus is used for communication.

The use of Gnome::Gio::Application differs from some other commonly-used uniqueness libraries (such as libunique) in important ways. The application is not expected to manually register itself and check if it is the primary instance. Instead, the main() function of a Gnome::Gio::Application should do very little more than instantiating the application instance, possibly connecting signal handlers, then calling .run(). All checks for uniqueness are done internally. If the application is the primary instance then the startup signal is emitted and the mainloop runs. If the application is not the primary instance then a signal is sent to the primary instance and .run() promptly returns. See the code examples below.

If used, the expected form of an application identifier is the same as that of a [D-Bus well-known bus name](https://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus). Examples include: com.example.MyApp`, org.example.internal_apps.Calculator`, org._7_zip.Archiver`. For details on valid application identifiers, see .Application.id-is-valid() in package Gnome::Gio.

On Linux, the application identifier is claimed as a well-known bus name on the user's session bus. This means that the uniqueness of your application is scoped to the current session. It also means that your application may provide additional services (through registration of other object paths) at that bus name. The registration of these object paths should be done with the shared GDBus session bus. Note that due to the internal architecture of GDBus, method calls can be dispatched at any time (even if a main loop is not running). For this reason, you must ensure that any object paths that you wish to register are registered before Gnome::Gio::Application attempts to acquire the bus name of your application (which happens in .register()). Unfortunately, this means that you cannot use is-remote defined in Gnome::Gio::Application to decide if you want to register object paths.

Gnome::Gio::Application also implements the Gnome::Gio::Application and Gnome::Gio::Application interfaces and lets you easily export actions by adding them with .add-action() in class Gnome::Gio::R-ActionMap. When invoking an action by calling .activate-action() in class Gnome::Gio::R-ActionGroup on the application, it is always invoked in the primary instance. The actions are also exported on the session bus, and GIO provides the Gnome::Gio::Application wrapper to conveniently access them remotely. GIO provides a Gnome::Gio::Application wrapper for remote access to exported Gnome::Gio::Applications.

Note: Due to the fact that actions are exported on the session bus, using maybe parameters is not supported, since D-Bus does not support maybe types.

There is a number of different entry points into a Gnome::Gio::Application:

  • via 'Activate' (i.e. just starting the application)

  • via 'Open' (i.e. opening some files)

  • by handling a command-line

  • via activating an action

The [signal $Gio.Application::startup] signal lets you handle the application initialization for all of these in a single place.

Regardless of which of these entry points is used to start the application, Gnome::Gio::Application passes some ‘platform data’ from the launching instance to the primary instance, in the form of a Variant dictionary mapping strings to variants. To use platform data, override the [vfunc $Gio.Application.before_emit] or [vfunc $Gio.Application.after_emit] virtual functions in your Gnome::Gio::Application subclass. When dealing with Gnome::Gio::Application objects, the platform data is directly available via .get-cwd() in class Gnome::Gio::ApplicationCommandLine, .get-environ() in class Gnome::Gio::ApplicationCommandLine and .get-platform-data() in class Gnome::Gio::ApplicationCommandLine.

As the name indicates, the platform data may vary depending on the operating system, but it always includes the current directory (key cwd), and optionally the environment (ie the set of environment variables and their values) of the calling process (key environ). The environment is only added to the platform data if the G_APPLICATION_SEND_ENVIRONMENT flag is set. Gnome::Gio::Application subclasses can add their own platform data by overriding the [vfunc $Gio.Application.add_platform_data] virtual function. For instance, GtkApplication adds startup notification data in this way.

To parse commandline arguments you may handle the [signal $Gio.Application::command-line] signal or override the [vfunc $Gio.Application.local_command_line] virtual funcion, to parse them in either the primary instance or the local instance, respectively.

For an example of opening files with a Gnome::Gio::Application, see [gapplication-example-open.c](https://gitlab.gnome.org/GNOME/glib/-/blob/HEAD/gio/tests/gapplication-example-open.c).

For an example of using actions with Gnome::Gio::Application, see [gapplication-example-actions.c](https://gitlab.gnome.org/GNOME/glib/-/blob/HEAD/gio/tests/gapplication-example-actions.c).

For an example of using extra D-Bus hooks with Gnome::Gio::Application, see [gapplication-example-dbushooks.c](https://gitlab.gnome.org/GNOME/glib/-/blob/HEAD/gio/tests/gapplication-example-dbushooks.c).

Uml Diagram

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Class initialization

new

:native-object

Create an object using a native object from an object of the same type found elsewhere. See also Gnome::N::TopLevelSupportClass.

multi method new ( N-Object() :$native-object! )

new-application

Creates a new Gnome::Gio::Application instance.

If non-undefined, the application id must be valid. See .id-is-valid().

If no application ID is given then some features of Gnome::Gio::Application (most notably application uniqueness) will be disabled.

method new-application ( Str $application-id, UInt $flags --> Gnome::Gio::Application \)

  • $application-id; the application id.

  • $flags; the application flags.

Methods

activate

Activates the application.

In essence, this results in the activate signal being emitted in the primary instance.

The application must be registered before calling this function.

method activate ( )

add-main-option This function is not yet available

Add an option to be handled by $application.

Calling this function is the equivalent of calling .add-main-option-entries() with a single Gnome::Glib::N-OptionEntry that has its arg_data member set to undefined.

The parsed arguments will be packed into a Gnome::Glib::N-VariantDict which is passed to handle-local-options. If G_APPLICATION_HANDLES_COMMAND_LINE is set, then it will also be sent to the primary instance. See .add-main-option-entries() for more details.

See Gnome::Glib::N-OptionEntry for more documentation of the arguments.

method add-main-option ( Str $long-name, Int() $short-name, UInt $flags, GOptionArg  $arg, Str $description, Str $arg-description )

  • $long-name; the long name of an option used to specify it in a commandline.

  • $short-name; the short name of an option.

  • $flags; flags from Gnome::Glib::T-option.

  • $arg; the type of the option, as a Gnome::Glib::T-option.

  • $description; the description for the option in `--help` output.

  • $arg-description; the placeholder to use for the extra argument parsed by the option in `--help` output.

add-main-option-entries

Adds main option entries to be handled by $application.

This function is comparable to g_option_context_add_main_entries().

After the commandline arguments are parsed, the handle-local-options signal will be emitted. At this point, the application can inspect the values pointed to by $arg-data in the given GOptionEntrys.

Unlike GOptionContext, Gnome::Gio::Application supports giving a undefined $arg-data for a non-callback Gnome::Glib::N-OptionEntry. This results in the argument in question being packed into a Gnome::Glib::N-VariantDict which is also passed to handle-local-options, where it can be inspected and modified. If G_APPLICATION_HANDLES_COMMAND_LINE is set, then the resulting dictionary is sent to the primary instance, where .command-line-get-options-dict() will return it. As it has been passed outside the process at this point, the types of all values in the options dict must be checked before being used. This "packing" is done according to the type of the argument -- booleans for normal flags, strings for strings, bytestrings for filenames, etc. The packing only occurs if the flag is given (ie: we do not pack a "false" Gnome::Glib::N-Variant in the case that a flag is missing).

In general, it is recommended that all commandline arguments are parsed locally. The options dictionary should then be used to transmit the result of the parsing to the primary instance, where g_variant_dict_lookup() can be used. For local options, it is possible to either use $arg-data in the usual way, or to consult (and potentially remove) the option from the options dictionary.

This function is new in GLib 2.40. Before then, the only real choice was to send all of the commandline arguments (options and all) to the primary instance for handling. Gnome::Gio::Application ignored them completely on the local side. Calling this function "opts in" to the new behaviour, and in particular, means that unrecognised options will be treated as errors. Unrecognised options have never been ignored when G_APPLICATION_HANDLES_COMMAND_LINE is unset.

If handle-local-options needs to see the list of filenames, then the use of G_OPTION_REMAINING is recommended. If $arg-data is undefined then G_OPTION_REMAINING can be used as a key into the options dictionary. If you do use G_OPTION_REMAINING then you need to handle these arguments for yourself because once they are consumed, they will no longer be visible to the default handling (which treats them as filenames to be opened).

It is important to use the proper GVariant format when retrieving the options with g_variant_dict_lookup():

  • for G_OPTION_ARG_NONE, use b

  • for G_OPTION_ARG_STRING, use `&s`

  • for G_OPTION_ARG_INT, use i

  • for %G_OPTION_ARG_INT64, use x

  • for G_OPTION_ARG_DOUBLE, use d

  • for G_OPTION_ARG_FILENAME, use `^&ay`

  • for G_OPTION_ARG_STRING_ARRAY, use `^a&s`

  • for G_OPTION_ARG_FILENAME_ARRAY, use `^a&ay`

method add-main-option-entries ( N-Object $entries )

  • $entries; the main options for the application

add-option-group

Adds a Gnome::Glib::N-OptionGroup to the commandline handling of $application.

This function is comparable to g_option_context_add_group().

Unlike .add-main-option-entries(), this function does not deal with undefined $arg-data and never transmits options to the primary instance.

The reason for that is because, by the time the options arrive at the primary instance, it is typically too late to do anything with them. Taking the GTK option group as an example: GTK will already have been initialised by the time the command-line handler runs. In the case that this is not the first-running instance of the application, the existing instance may already have been running for a very long time.

This means that the options from Gnome::Glib::N-OptionGroup are only really usable in the case that the instance of the application being run is the first instance. Passing options like `--display=` or `--gdk-debug=` on future runs will have no effect on the existing primary instance.

Calling this function will cause the options in the supplied option group to be parsed, but it does not cause you to be "opted in" to the new functionality whereby unrecognised options are rejected even if G_APPLICATION_HANDLES_COMMAND_LINE was given.

method add-option-group ( N-Object $group )

  • $group; (transfer ownership: full) a Gnome::Glib::N-OptionGroup

bind-busy-property

Marks $application as busy (see .mark-busy()) while $property on $object is True.

The binding holds a reference to $application while it is active, but not to $object. Instead, the binding is destroyed when $object is finalized.

method bind-busy-property ( gpointer $object, Str $property )

  • $object; a Gnome::GObject::Object.

  • $property; the name of a boolean property of $object.

get-application-id

Gets the unique identifier for $application.

method get-application-id (--> Str )

Return value; the identifier for $application, owned by $application.

get-dbus-connection

Gets the Gnome::Gio::DBusConnection being used by the application, or undefined.

If Gnome::Gio::Application is using its D-Bus backend then this function will return the Gnome::Gio::DBusConnection being used for uniqueness and communication with the desktop environment and other instances of the application.

If Gnome::Gio::Application is not using D-Bus then this function will return undefined. This includes the situation where the D-Bus backend would normally be in use but we were unable to connect to the bus.

This function must not be called before the application has been registered. See .get-is-registered().

method get-dbus-connection (--> N-Object )

Return value; a Gnome::Gio::DBusConnection, or undefined.

get-dbus-object-path

Gets the D-Bus object path being used by the application, or undefined.

If Gnome::Gio::Application is using its D-Bus backend then this function will return the D-Bus object path that Gnome::Gio::Application is using. If the application is the primary instance then there is an object published at this path. If the application is not the primary instance then the result of this function is undefined.

If Gnome::Gio::Application is not using D-Bus then this function will return undefined. This includes the situation where the D-Bus backend would normally be in use but we were unable to connect to the bus.

This function must not be called before the application has been registered. See .get-is-registered().

method get-dbus-object-path (--> Str )

Return value; the object path, or undefined.

get-flags

Gets the flags for $application.

See Gnome::Gio::T-ioenums.

method get-flags (--> UInt )

Return value; the flags for $application.

get-inactivity-timeout

Gets the current inactivity timeout for the application.

This is the amount of time (in milliseconds) after the last call to .release() before the application stops running.

method get-inactivity-timeout (--> UInt )

Return value; the timeout, in milliseconds.

get-is-busy

Gets the application's current busy state, as set through .mark-busy() or .bind-busy-property().

method get-is-busy (--> Bool )

Return value; True if $application is currently marked as busy.

get-is-registered

Checks if $application is registered.

An application is registered if .register() has been successfully called.

method get-is-registered (--> Bool )

Return value; True if $application is registered.

get-is-remote

Checks if $application is remote.

If $application is remote then it means that another instance of application already exists (the 'primary' instance). Calls to perform actions on $application will result in the actions being performed by the primary instance.

The value of this property cannot be accessed before .register() has been called. See .get-is-registered().

method get-is-remote (--> Bool )

Return value; True if $application is remote.

get-resource-base-path

Gets the resource base path of $application.

See .set-resource-base-path() for more information.

method get-resource-base-path (--> Str )

Return value; the base resource path, if one is set.

get-version

Gets the version of $application.

method get-version (--> Str )

Return value; the version of $application.

hold

Increases the use count of $application.

Use this function to indicate that the application has a reason to continue to run. For example, .hold() is called by GTK when a toplevel window is on the screen.

To cancel the hold, call .release().

method hold ( )

mark-busy

Increases the busy count of $application.

Use this function to indicate that the application is busy, for instance while a long running operation is pending.

The busy state will be exposed to other processes, so a session shell will use that information to indicate the state to the user (e.g. with a spinner).

To cancel the busy indication, use .unmark-busy().

The application must be registered before calling this function.

method mark-busy ( )

open

Opens the given files.

In essence, this results in the open signal being emitted in the primary instance. $n-files must be greater than zero. $hint is simply passed through to the open signal. It is intended to be used by applications that have multiple modes for opening files (eg: "view" vs "edit", etc). Unless you have a need for this functionality, you should use "".

The application must be registered before calling this function and it must have the G_APPLICATION_HANDLES_OPEN flag set.

method open ( N-Object() $files, Int() $n-files, Str $hint )

  • $files; an array of GFiles to open.

  • $n-files; the length of the $files array.

  • $hint; a hint (or ""), but never undefined.

quit

Immediately quits the application.

Upon return to the mainloop, .run() will return, calling only the 'shutdown' function before doing so.

The hold count is ignored. Take care if your code has called .hold() on the application and is therefore still expecting it to exist. (Note that you may have called .hold() indirectly, for example through gtk_application_add_window().)

The result of calling .run() again after it returns is unspecified.

method quit ( )

register

Attempts registration of the application.

This is the point at which the application discovers if it is the primary instance or merely acting as a remote for an already-existing primary instance. This is implemented by attempting to acquire the application identifier as a unique bus name on the session bus using GDBus.

If there is no application ID or if G_APPLICATION_NON_UNIQUE was given, then this process will always become the primary instance.

Due to the internal architecture of GDBus, method calls can be dispatched at any time (even if a main loop is not running). For this reason, you must ensure that any object paths that you wish to register are registered before calling this function.

If the application has already been registered then True is returned with no work performed.

The startup signal is emitted if registration succeeds and $application is the primary instance (including the non-unique case).

In the event of an error (such as $cancellable being cancelled, or a failure to connect to the session bus), False is returned and $error is set appropriately.

Note: the return value of this function is not an indicator that this instance is or is not the primary instance of the application. See .get-is-remote() for that.

method register ( N-Object() $cancellable, CArray[N-Error] $err --> Bool )

  • $cancellable; a Gnome::Gio::Cancellable, or undefined.

  • $err; Error object. When defined, an error can be returned when there is one. Use Pointer when you want to ignore the error. .

Return value; True if registration succeeded.

release

Decrease the use count of $application.

When the use count reaches zero, the application will stop running.

Never call this function except to cancel the effect of a previous call to .hold().

method release ( )

run

Runs the application.

This function is intended to be run from main() and its return value is intended to be returned by main(). Although you are expected to pass the $argc, $argv parameters from main() to this function, it is possible to pass undefined if $argv is not available or commandline handling is not required. Note that on Windows, $argc and $argv are ignored, and g_win32_get_command_line() is called internally (for proper support of Unicode commandline arguments).

Gnome::Gio::Application will attempt to parse the commandline arguments. You can add commandline flags to the list of recognised options by way of .add-main-option-entries(). After this, the handle-local-options signal is emitted, from which the application can inspect the values of its GOptionEntrys.

I<handle-local-options> is a good place to handle options

such as `--version`, where an immediate reply from the local process is desired (instead of communicating with an already-running instance). A handle-local-options handler can stop further processing by returning a non-negative value, which then becomes the exit status of the process.

What happens next depends on the flags: if G_APPLICATION_HANDLES_COMMAND_LINE was specified then the remaining commandline arguments are sent to the primary instance, where a command-line signal is emitted. Otherwise, the remaining commandline arguments are assumed to be a list of files. If there are no files listed, the application is activated via the activate signal. If there are one or more files, and G_APPLICATION_HANDLES_OPEN was specified then the files are opened via the open signal.

If you are interested in doing more complicated local handling of the commandline then you should implement your own Gnome::Gio::Application subclass and override local_command_line(). In this case, you most likely want to return True from your local_command_line() implementation to suppress the default handling. See gapplication-example-cmdline2.c for an example.

If, after the above is done, the use count of the application is zero then the exit status is returned immediately. If the use count is non-zero then the default main context is iterated until the use count falls to zero, at which point 0 is returned.

If the G_APPLICATION_IS_SERVICE flag is set, then the service will run for as much as 10 seconds with a use count of zero while waiting for the message that caused the activation to arrive. After that, if the use count falls to zero the application will exit immediately, except in the case that .set-inactivity-timeout() is in use.

This function sets the prgname (g_set_prgname()), if not already set, to the basename of argv[0].

Much like g_main_loop_run(), this function will acquire the main context for the duration that the application is running.

Since 2.40, applications that are not explicitly flagged as services or launchers (ie: neither G_APPLICATION_IS_SERVICE or G_APPLICATION_IS_LAUNCHER are given as flags) will check (from the default handler for local_command_line) if "--gapplication-service" was given in the command line. If this flag is present then normal commandline processing is interrupted and the G_APPLICATION_IS_SERVICE flag is set. This provides a "compromise" solution whereby running an application directly from the commandline will invoke it in the normal way (which can be useful for debugging) while still allowing applications to be D-Bus activated in service mode. The D-Bus service file should invoke the executable with "--gapplication-service" as the sole commandline argument. This approach is suitable for use by most graphical applications but should not be used from applications like editors that need precise control over when processes invoked via the commandline will exit and what their exit status will be.

method run ( Int() $argc, Array[Str] $argv --> Int )

  • $argc; the argc from main() (or 0 if $argv is undefined).

  • $argv; the argv from main(), or undefined.

Return value; the exit status.

send-notification

Sends a notification on behalf of $application to the desktop shell. There is no guarantee that the notification is displayed immediately, or even at all.

Notifications may persist after the application exits. It will be D-Bus-activated when the notification or one of its actions is activated.

Modifying $notification after this call has no effect. However, the object can be reused for a later call to this function. $id may be any string that uniquely identifies the event for the application. It does not need to be in any special format. For example, "new-message" might be appropriate for a notification about new messages.

If a previous notification was sent with the same $id, it will be replaced with $notification and shown again as if it was a new notification. This works even for notifications sent from a previous execution of the application, as long as $id is the same string. $id may be undefined, but it is impossible to replace or withdraw notifications without an id.

If $notification is no longer relevant, it can be withdrawn with .withdraw-notification().

It is an error to call this function if $application has no application ID.

method send-notification ( Str $id, N-Object() $notification )

  • $id; id of the notification, or undefined.

  • $notification; the Gnome::Gio::Notification to send.

set-action-group

Note: The native version of this routine is deprecated in gio-lib() since version 2.32

This used to be how actions were associated with a Gnome::Gio::Application. Now there is Gnome::Gio::R-ActionMap for that.

method set-action-group ( N-Object() $action-group )

  • $action-group; a Gnome::Gio::R-ActionGroup, or undefined.

set-application-id

Sets the unique identifier for $application.

The application id can only be modified if $application has not yet been registered.

If non-undefined, the application id must be valid. See .id-is-valid().

method set-application-id ( Str $application-id )

  • $application-id; the identifier for $application.

set-default

Sets or unsets the default application for the process, as returned by .get-default().

This function does not take its own reference on $application. If $application is destroyed then the default application will revert back to undefined.

method set-default ( )

set-flags

Sets the flags for $application.

The flags can only be modified if $application has not yet been registered.

See Gnome::Gio::T-ioenums.

method set-flags ( UInt $flags )

  • $flags; the flags for $application.

set-inactivity-timeout

Sets the current inactivity timeout for the application.

This is the amount of time (in milliseconds) after the last call to .release() before the application stops running.

This call has no side effects of its own. The value set here is only used for next time .release() drops the use count to zero. Any timeouts currently in progress are not impacted.

method set-inactivity-timeout ( UInt() $inactivity-timeout )

  • $inactivity-timeout; the timeout, in milliseconds.

set-option-context-description

Adds a description to the $application option context.

See g_option_context_set_description() for more information.

method set-option-context-description ( Str $description )

  • $description; a string to be shown in `--help` output after the list of options, or undefined.

set-option-context-parameter-string

Sets the parameter string to be used by the commandline handling of $application.

This function registers the argument to be passed to g_option_context_new() when the internal GOptionContext of $application is created.

See g_option_context_new() for more information about $parameter-string.

method set-option-context-parameter-string ( Str $parameter-string )

  • $parameter-string; a string which is displayed in the first line of `--help` output, after the usage summary programname [OPTION...]`..

set-option-context-summary

Adds a summary to the $application option context.

See g_option_context_set_summary() for more information.

method set-option-context-summary ( Str $summary )

  • $summary; a string to be shown in `--help` output before the list of options, or undefined.

set-resource-base-path

Sets (or unsets) the base resource path of $application.

The path is used to automatically load various application resources such as menu layouts and action descriptions. The various types of resources will be found at fixed names relative to the given base path.

By default, the resource base path is determined from the application ID by prefixing '/' and replacing each '.' with '/'. This is done at the time that the Gnome::Gio::Application object is constructed. Changes to the application ID after that point will not have an impact on the resource base path.

As an example, if the application has an ID of "org.example.app" then the default resource base path will be "/org/example/app". If this is a GtkApplication (and you have not manually changed the path) then Gtk will then search for the menus of the application at "/org/example/app/gtk/menus.ui".

See Gnome::Gio::N-Resource for more information about adding resources to your application.

You can disable automatic resource loading functionality by setting the path to undefined.

Changing the resource base path once the application is running is not recommended. The point at which the resource path is consulted for forming paths for various purposes is unspecified. When writing a sub-class of Gnome::Gio::Application you should either set the Gnome::Gio::Application:resource-base-path property at construction time, or call this function during the instance initialization. Alternatively, you can call this function in the GApplicationClass.startup virtual function, before chaining up to the parent implementation.

method set-resource-base-path ( Str $resource-path )

  • $resource-path; the resource path to use.

set-version

Sets the version number of $application. This will be used to implement a `--version` command line argument

The application version can only be modified if $application has not yet been registered.

method set-version ( Str $version )

  • $version; the version of $application.

unbind-busy-property

Destroys a binding between $property and the busy state of $application that was previously created with .bind-busy-property().

method unbind-busy-property ( gpointer $object, Str $property )

  • $object; a Gnome::GObject::Object.

  • $property; the name of a boolean property of $object.

unmark-busy

Decreases the busy count of $application.

When the busy count reaches zero, the new state will be propagated to other processes.

This function must only be called to cancel the effect of a previous call to .mark-busy().

method unmark-busy ( )

withdraw-notification

Withdraws a notification that was sent with .send-notification().

This call does nothing if a notification with $id doesn't exist or the notification was never sent.

This function works even for notifications sent in previous executions of this application, as long $id is the same as it was for the sent notification.

Note that notifications are dismissed when the user clicks on one of the buttons in a notification or triggers its default action, so there is no need to explicitly withdraw the notification in that case.

method withdraw-notification ( Str $id )

  • $id; id of a previously sent notification.

Functions

get-default

Returns the default Gnome::Gio::Application instance for this process.

Normally there is only one Gnome::Gio::Application per process and it becomes the default when it is created. You can exercise more control over this by using .set-default().

If there is no default application then undefined is returned.

method get-default (--> N-Object )

Return value; the default application for this process, or undefined.

id-is-valid

Checks if $application-id is a valid application identifier.

A valid ID is required for calls to .new-application() and .set-application-id().

Application identifiers follow the same format as [D-Bus well-known bus names](https://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus). For convenience, the restrictions on application identifiers are reproduced here:

  • Application identifiers are composed of 1 or more elements separated by a period (`.`) character. All elements must contain at least one character.

  • Each element must only contain the ASCII characters `[A-Z][a-z][0-9]_-`, with `-` discouraged in new application identifiers. Each element must not begin with a digit.

  • Application identifiers must contain at least one `.` (period) character (and thus at least two elements).

  • Application identifiers must not begin with a `.` (period) character.

  • Application identifiers must not exceed 255 characters.

Note that the hyphen (`-`) character is allowed in application identifiers, but is problematic or not allowed in various specifications and APIs that refer to D-Bus, such as [Flatpak application IDs](http://docs.flatpak.org/en/latest/introduction.html#identifiers), the [DBusActivatable interface in the Desktop Entry Specification](https://specifications.freedesktop.org/desktop-entry-spec/desktop-entry-spec-latest.html#dbus), and the convention that an application's "main" interface and object path resemble its application identifier and bus name. To avoid situations that require special-case handling, it is recommended that new application identifiers consistently replace hyphens with underscores.

Like D-Bus interface names, application identifiers should start with the reversed DNS domain name of the author of the interface (in lower-case), and it is conventional for the rest of the application identifier to consist of words run together, with initial capital letters.

As with D-Bus interface names, if the author's DNS domain name contains hyphen/minus characters they should be replaced by underscores, and if it contains leading digits they should be escaped by prepending an underscore. For example, if the owner of 7-zip.org used an application identifier for an archiving application, it might be named org._7_zip.Archiver`.

method id-is-valid ( Str $application-id --> Bool )

  • $application-id; a potential application identifier.

Return value; True if $application-id is valid.

Signals

activate

The activate signal is emitted on the primary instance when an activation occurs. See .activate().

method handler (
  Int :$_handle_id,
  N-GObject :$_native-object,
  Gnome::Gio::Application :$_widget,
  *C<user>-options
)

  • $_handle_id; The registered event handler id.

  • $_native-object; The native object provided by the Raku object which registered this event. This a native Gnome::Gio::Application object.

  • $_widget; The object which registered the signal. User code may have left the object going out of scope.

  • user-options; A list of named arguments provided at the .register-signal() method from Gnome::GObject::Object.

command-line

The command-line signal is emitted on the primary instance when a commandline is not handled locally. See .run() and the Gnome::Gio::ApplicationCommandLine documentation for more information.

method handler (
   $command-line,
  Int :$_handle_id,
  N-GObject :$_native-object,
  Gnome::Gio::Application :$_widget,
  *C<user>-options
  --> gint
)

  • $command-line; a Gnome::Gio::ApplicationCommandLine representing the passed commandline.

  • $_handle_id; The registered event handler id.

  • $_native-object; The native object provided by the Raku object which registered this event. This a native Gnome::Gio::Application object.

  • $_widget; The object which registered the signal. User code may have left the object going out of scope.

  • user-options; A list of named arguments provided at the .register-signal() method from Gnome::GObject::Object.

Return value; An integer that is set as the exit status for the calling process. See .command-line-set-exit-status().

handle-local-options

The handle-local-options signal is emitted on the local instance after the parsing of the commandline options has occurred.

You can add options to be recognised during commandline option parsing using .add-main-option-entries() and .add-option-group().

Signal handlers can inspect $options (along with values pointed to from the $arg-data of an installed GOptionEntrys) in order to decide to perform certain actions, including direct local handling (which may be useful for options like --version).

In the event that the application is marked G_APPLICATION_HANDLES_COMMAND_LINE the "normal processing" will send the $options dictionary to the primary instance where it can be read with .command-line-get-options-dict(). The signal handler can modify the dictionary before returning, and the modified dictionary will be sent.

In the event that G_APPLICATION_HANDLES_COMMAND_LINE is not set, "normal processing" will treat the remaining uncollected command line arguments as filenames or URIs. If there are no arguments, the application is activated by .activate(). One or more arguments results in a call to .open().

If you want to handle the local commandline arguments for yourself by converting them to calls to .open() or g_action_group_activate_action() then you must be sure to register the application first. You should probably not call .activate() for yourself, however: just return -1 and allow the default handler to do it for you. This will ensure that the `--gapplication-service` switch works properly (i.e. no activation in that case).

Note that this signal is emitted from the default implementation of local_command_line(). If you override that function and don't chain up then this signal will never be emitted.

You can override local_command_line() if you need more powerful capabilities than what is provided here, but this should not normally be required.

method handler (
   $options,
  Int :$_handle_id,
  N-GObject :$_native-object,
  Gnome::Gio::Application :$_widget,
  *C<user>-options
  --> gint
)

  • $options; the options dictionary.

  • $_handle_id; The registered event handler id.

  • $_native-object; The native object provided by the Raku object which registered this event. This a native Gnome::Gio::Application object.

  • $_widget; The object which registered the signal. User code may have left the object going out of scope.

  • user-options; A list of named arguments provided at the .register-signal() method from Gnome::GObject::Object.

Return value; an exit code. If you have handled your options and want to exit the process, return a non-negative option, 0 for success, and a positive value for failure. To continue, return -1 to let the default option processing continue.

name-lost

The name-lost signal is emitted only on the registered primary instance when a new instance has taken over. This can only happen if the application is using the G_APPLICATION_ALLOW_REPLACEMENT flag.

The default handler for this signal calls .quit().

method handler (
  Int :$_handle_id,
  N-GObject :$_native-object,
  Gnome::Gio::Application :$_widget,
  *C<user>-options
  --> gboolean
)

  • $_handle_id; The registered event handler id.

  • $_native-object; The native object provided by the Raku object which registered this event. This a native Gnome::Gio::Application object.

  • $_widget; The object which registered the signal. User code may have left the object going out of scope.

  • user-options; A list of named arguments provided at the .register-signal() method from Gnome::GObject::Object.

Return value; True if the signal has been handled

open

The open signal is emitted on the primary instance when there are files to open. See .open() for more information.

method handler (
  gpointer $files,
  gint $n-files,
  Str $hint,
  Int :$_handle_id,
  N-GObject :$_native-object,
  Gnome::Gio::Application :$_widget,
  *C<user>-options
)

  • $files; an array of GFiles.

  • $n-files; the length of $files.

  • $hint; a hint provided by the calling instance.

  • $_handle_id; The registered event handler id.

  • $_native-object; The native object provided by the Raku object which registered this event. This a native Gnome::Gio::Application object.

  • $_widget; The object which registered the signal. User code may have left the object going out of scope.

  • user-options; A list of named arguments provided at the .register-signal() method from Gnome::GObject::Object.

shutdown

The shutdown signal is emitted only on the registered primary instance immediately after the main loop terminates.

method handler (
  Int :$_handle_id,
  N-GObject :$_native-object,
  Gnome::Gio::Application :$_widget,
  *C<user>-options
)

  • $_handle_id; The registered event handler id.

  • $_native-object; The native object provided by the Raku object which registered this event. This a native Gnome::Gio::Application object.

  • $_widget; The object which registered the signal. User code may have left the object going out of scope.

  • user-options; A list of named arguments provided at the .register-signal() method from Gnome::GObject::Object.

startup

The startup signal is emitted on the primary instance immediately after registration. See .register().

method handler (
  Int :$_handle_id,
  N-GObject :$_native-object,
  Gnome::Gio::Application :$_widget,
  *C<user>-options
)

  • $_handle_id; The registered event handler id.

  • $_native-object; The native object provided by the Raku object which registered this event. This a native Gnome::Gio::Application object.

  • $_widget; The object which registered the signal. User code may have left the object going out of scope.

  • user-options; A list of named arguments provided at the .register-signal() method from Gnome::GObject::Object.