################
Session Tracking
################

Some plugins may want to save state when the user closes Builder.
The `Ide.SessionAddin` allows for saving and restoring state of an `Ide.Page` when a project is closed or re-opened.

.. code-block:: python3

   # my_plugin.py

   import gi

   from gi.repository import GObject
   from gi.repository import Gio
   from gi.repository import Ide

   class MySessionAddin(Ide.Object, Ide.SessionAddin):

       def get_autosave_properties(self):
           return ['uri', 'current-directory']

       def can_save_page(self, page):
           return issubclass(page, My.CustomPage)

       def do_save_page_async(self, page, cancellable, callback, data):
           # Create our async task
           task = Ide.Task.new(self, cancellable, callback)

           # State is saved as a variant
           task.result = GLib.Variant.new_int(123)

           # Now complete task
           task.return_boolean(True)

       def do_save_finish(self, task):
           if task.propagate_boolean():
               return task.result

       def do_restore_page_async(self, state, cancellable, callback, data):
           # Create our async task
           task = Ide.Task.new(self, cancellable, callback)

           # state is a GLib.Variant matching what we saved
           # unpack state here

           my_page = My.CustomPage.new(data_from_state)

           # Now complete task
           task.return_pointer(my_page)

       def do_restore_finish(self, task):
           return task.propagate_pointer()