Class: Gio::SettingsBackend

Inherits:
Object
  • Object
show all
Defined in:
(unknown)

Overview

Class structure for GSettings::Backend.

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.default ⇒ Gio::SettingsBackend

Returns the default GSettings::Backend. It is possible to override
the default by setting the GSETTINGS_BACKEND environment variable
to the name of a settings backend.

The user gets a reference to the backend.

Returns:

  • (Gio::SettingsBackend) —

    the default GSettings::Backend,
    which will be a dummy (memory) settings backend if no other settings
    backend is available.

.flatten_tree(tree, path, keys, values) ⇒ nil

Calculate the longest common prefix of all keys in a tree and write
out an array of the key names relative to that prefix and,
optionally, the value to store at each of those keys.

You must free the value returned in path, keys and values using
g_free(). You should not attempt to free or unref the contents of
keys or values.

Parameters:

  • tree (GLib::Tree) —

    a #GTree containing the changes

  • path (String) —

    the location to save the path

  • keys (Array<String>) —

    the
    location to save the relative keys

  • values (Array<GLib::Variant>) —

    the location to save the values, or nil

Returns:

  • (nil)

Instance Method Details

#changed(key, origin_tag) ⇒ nil

Signals that a single key has possibly changed. Backend
implementations should call this if a key has possibly changed its
value.

key must be a valid key (ie starting with a slash, not containing
'//', and not ending with a slash).

The implementation must call this function during any call to
g_settings_backend_write(), before the call returns (except in the
case that no keys are actually changed and it cares to detect this
fact). It may not rely on the existence of a mainloop for
dispatching the signal later.

The implementation may call this function at any other time it likes
in response to other events (such as changes occurring outside of the
program). These calls may originate from a mainloop or may originate
in response to any other action (including from calls to
g_settings_backend_write()).

In the case that this call is in response to a call to
g_settings_backend_write() then origin_tag must be set to the same
value that was passed to that call.

Parameters:

  • key (String) —

    the name of the key

  • origin_tag (GObject) —

    the origin tag

Returns:

  • (nil)

#changed_tree(tree, origin_tag) ⇒ nil

This call is a convenience wrapper. It gets the list of changes from
tree, computes the longest common prefix and calls
g_settings_backend_changed().

Parameters:

  • tree (GLib::Tree) —

    a #GTree containing the changes

  • origin_tag (GObject) —

    the origin tag

Returns:

  • (nil)

#keys_changed(path, items, origin_tag) ⇒ nil

Signals that a list of keys have possibly changed. Backend
implementations should call this if keys have possibly changed their
values.

path must be a valid path (ie starting and ending with a slash and
not containing '//'). Each string in items must form a valid key
name when path is prefixed to it (ie: each item must not start or
end with '/' and must not contain '//').

The meaning of this signal is that any of the key names resulting
from the contatenation of path with each item in items may have
changed.

The same rules for when notifications must occur apply as per
g_settings_backend_changed(). These two calls can be used
interchangeably if exactly one item has changed (although in that
case g_settings_backend_changed() is definitely preferred).

For efficiency reasons, the implementation should strive for path to
be as long as possible (ie: the longest common prefix of all of the
keys that were changed) but this is not strictly required.

Parameters:

  • path (String) —

    the path containing the changes

  • items (Array<String>) —

    the nil-terminated list of changed keys

  • origin_tag (GObject) —

    the origin tag

Returns:

  • (nil)

#path_changed(path, origin_tag) ⇒ nil

Signals that all keys below a given path may have possibly changed.
Backend implementations should call this if an entire path of keys
have possibly changed their values.

path must be a valid path (ie starting and ending with a slash and
not containing '//').

The meaning of this signal is that any of the key which has a name
starting with path may have changed.

The same rules for when notifications must occur apply as per
g_settings_backend_changed(). This call might be an appropriate
reasponse to a 'reset' call but implementations are also free to
explicitly list the keys that were affected by that call if they can
easily do so.

For efficiency reasons, the implementation should strive for path to
be as long as possible (ie: the longest common prefix of all of the
keys that were changed) but this is not strictly required. As an
example, if this function is called with the path of "/" then every
single key in the application will be notified of a possible change.

Parameters:

  • path (String) —

    the path containing the changes

  • origin_tag (GObject) —

    the origin tag

Returns:

  • (nil)

#path_writable_changed(path) ⇒ nil

Signals that the writability of all keys below a given path may have
changed.

Since GSettings performs no locking operations for itself, this call
will always be made in response to external events.

Parameters:

  • path (String) —

    the name of the path

Returns:

  • (nil)

#writable_changed(key) ⇒ nil

Signals that the writability of a single key has possibly changed.

Since GSettings performs no locking operations for itself, this call
will always be made in response to external events.

Parameters:

  • key (String) —

    the name of the key

Returns:

  • (nil)