IOExtensionPoint

class IOExtensionPoint(*args, **kwargs)

GIOExtensionPoint provides a mechanism for modules to extend the functionality of the library or application that loaded it in an organized fashion.

An extension point is identified by a name, and it may optionally require that any implementation must be of a certain type (or derived thereof). Use register to register an extension point, and set_required_type to set a required type.

A module can implement an extension point by specifying the Type that implements the functionality. Additionally, each implementation of an extension point has a name, and a priority. Use implement to implement an extension point.

GIOExtensionPoint *ep;

// Register an extension point
ep = g_io_extension_point_register ("my-extension-point");
g_io_extension_point_set_required_type (ep, MY_TYPE_EXAMPLE);

  // Implement an extension point
  G_DEFINE_TYPE (MyExampleImpl, my_example_impl, MY_TYPE_EXAMPLE)
  g_io_extension_point_implement ("my-extension-point",
                                  my_example_impl_get_type (),
                                  "my-example",
                                  10);


It is up to the code that registered the extension point how
it uses the implementations that have been associated with it.
Depending on the use case, it may use all implementations, or
only the one with the highest priority, or pick a specific
one by name.

To avoid opening all modules just to find out what extension
points they implement, GIO makes use of a caching mechanism,
see `gio-querymodules <gio-querymodules.html>`_.
You are expected to run this command after installing a
GIO module.

The ``GIO_EXTRA_MODULES`` environment variable can be used to
specify additional directories to automatically load modules
from. This environment variable has the same syntax as the
``PATH``. If two modules have the same base name in different
directories, then the latter one will be ignored. If additional
directories are specified GIO will load modules from the built-in
directory last.

Methods

class IOExtensionPoint

get_extension_by_name(name: str) → IOExtension

Finds a IOExtension for an extension point by name.

Parameters:

name – the name of the extension to get

get_extensions() → list[IOExtension]

Gets a list of all extensions that implement this extension point. The list is sorted by priority, beginning with the highest priority.

get_required_type() → type

Gets the required type for extension_point.

implement(extension_point_name: str, type: type, extension_name: str, priority: int) → IOExtension

Registers type as extension for the extension point with name extension_point_name.

If type has already been registered as an extension for this extension point, the existing IOExtension object is returned.

Parameters:

• extension_point_name – the name of the extension point

• type – the Type to register as extension

• extension_name – the name for the extension

• priority – the priority for the extension

lookup(name: str) → IOExtensionPoint

Looks up an existing extension point.

Parameters:

name – the name of the extension point

register(name: str) → IOExtensionPoint

Registers an extension point.

Parameters:

name – The name of the extension point

set_required_type(type: type) → None

Sets the required type for extension_point to type. All implementations must henceforth have this type.

Parameters:

type – the Type to require