"""Widget Settings and Settings Handlers
Settings are used to declare widget attributes that persist through sessions.
When widget is removed or saved to a schema file, its settings are packed,
serialized and stored. When a new widget is created, values of attributes
marked as settings are read from disk. When schema is loaded, attribute values
are set to one stored in schema.
Each widget has its own SettingsHandler that takes care of serializing and
storing of settings and SettingProvider that is incharge of reading and
writing the setting values.
All widgets extending from OWBaseWidget use SettingsHandler, unless they
declare otherwise. SettingsHandler ensures that setting attributes
are replaced with default (last used) setting values when the widget is
initialized and stored when the widget is removed.
Widgets with settings whose values depend on the widget inputs use
settings handlers based on ContextHandler. These handlers have two
additional methods, open_context and close_context.
open_context is called when widgets receives new data. It finds a suitable
context and sets the widget attributes to the values stored in context.
If no suitable context exists, a new one is created and values from widget
are copied to it.
close_context stores values that were last used on the widget to the context
so they can be used alter. It should be called before widget starts modifying
(initializing) the value of the setting attributes.
"""
import sys
import copy
import itertools
import os
import logging
import pickle
import pprint
import warnings
from operator import itemgetter
from typing import Any, Optional, Tuple
from orangewidget.gui import OWComponent
log = logging.getLogger(__name__)
__all__ = [
"Setting", "SettingsHandler", "SettingProvider",
"ContextSetting", "Context", "ContextHandler", "IncompatibleContext",
"SettingsPrinter", "rename_setting", "widget_settings_dir"
]
_IMMUTABLES = (str, int, bytes, bool, float, tuple)
VERSION_KEY = "__version__"
# protocol v4 is supported since Python 3.4, protocol v5 since Python 3.8
PICKLE_PROTOCOL = 4
__WIDGET_SETTINGS_DIR = None # type: Optional[Tuple[str, str]]
def set_widget_settings_dir_components(basedir: str, versionstr: str) -> None:
"""
Set the directory path components where widgets save their settings.
This overrides the global current application name/version derived paths.
Note
----
This should be set early in the application startup before any
`OWBaseWidget` subclasses are imported (because it is needed at class
definition time).
Parameters
----------
basedir: str
The application specific data directory.
versionstr: str
The application version string for the versioned path component.
See Also
--------
widget_settings_dir
"""
global __WIDGET_SETTINGS_DIR
__WIDGET_SETTINGS_DIR = (basedir, versionstr)
def widget_settings_dir(versioned=True) -> str:
"""
Return the effective directory where widgets save their settings.
This is a composed path based on a application specific data directory
and application version string (if `versioned` is True) with a final
'widgets' path component added (e.g. `'~/.local/share/MyApp/9.9.9/widgets'`)
By default `QCoreApplication.applicationName` and
`QCoreApplication.applicationVersion` are used to derive suitable paths
(with a fallback if they are not set).
Note
----
If the application sets the `applicationName`/`applicationVersion`, it
should do this early in the application startup before any
`OWBaseWidget` subclasses are imported (because it is needed at class
definition time).
Use `set_widget_settings_dir_components` to override the default paths.
Parameters
----------
versioned: bool
Should the returned path include the application version component.
See Also
--------
set_widget_settings_dir_components
"""
if __WIDGET_SETTINGS_DIR is None:
from orangewidget.workflow.config import data_dir
return os.path.join(data_dir(versioned), "widgets")
else:
base, version = __WIDGET_SETTINGS_DIR
if versioned:
return os.path.join(base, version, "widgets")
else:
return os.path.join(base, "widgets")
class Setting:
"""Description of a setting.
"""
# Settings are automatically persisted to disk
packable = True
# Setting is only persisted to schema (default value does not change)
schema_only = False
def __new__(cls, default, *args, **kwargs):
"""A misleading docstring for providing type hints for Settings
:type: default: T
:rtype: T
"""
return super().__new__(cls)
def __init__(self, default, **data):
self.name = None # Name gets set in widget's meta class
self.default = default
self.__dict__.update(data)
def __str__(self):
return '{0} "{1}"'.format(self.__class__.__name__, self.name)
__repr__ = __str__
def __getnewargs__(self):
return (self.default, )
# Pylint ignores type annotations in assignments. For
#
# x: int = Setting(0)
#
# it ignores `int` and assumes x is of type `Setting`. Annotations in
# comments ( # type: int) also don't work. The only way to annotate x is
#
# x: int
# x = Setting(0)
#
# but we don't want to clutter the code with extra lines of annotations. Hence
# we disable checking the type of `Setting` by confusing pylint with an extra
# definition that is never executed.
if 1 == 0:
class Setting: # pylint: disable=function-redefined
pass
def _apply_setting(setting: Setting, instance: OWComponent, value: Any):
"""
Set `setting` of widget `instance` to the given `value`, in place if
possible.
If old and new values are of the same type, and the type is either a list
or has methods `clear` and `update`, setting is updated in place. Otherwise
the function calls `setattr`.
Even if the target is update this way, call setattr (effectively calling
instance.target = instance.target) to trigger any automatic updates related
to this attribute).
"""
target = getattr(instance, setting.name, None)
if type(target) is type(value):
if isinstance(value, list):
target[:] = value
value = target
elif hasattr(value, "clear") and hasattr(value, "update"):
target.clear()
target.update(value)
value = target
setattr(instance, setting.name, value)
class SettingProvider:
"""A hierarchical structure keeping track of settings belonging to
a class and child setting providers.
At instantiation, it creates a dict of all Setting and SettingProvider
members of the class. This dict is used to get/set values of settings
from/to the instances of the class this provider belongs to.
"""
def __init__(self, provider_class):
""" Construct a new instance of SettingProvider.
Traverse provider_class members and store all instances of
Setting and SettingProvider.
Parameters
----------
provider_class : class
class containing settings definitions
"""
self.name = ""
self.provider_class = provider_class
self.providers = {}
""":type: dict[str, SettingProvider]"""
self.settings = {}
""":type: dict[str, Setting]"""
self.initialization_data = None
for name in dir(provider_class):
value = getattr(provider_class, name, None)
if isinstance(value, Setting):
value = copy.deepcopy(value)
value.name = name
self.settings[name] = value
if isinstance(value, SettingProvider):
value = copy.deepcopy(value)
value.name = name
self.providers[name] = value
def initialize(self, instance, data=None):
"""Initialize instance settings to their default values.
Mutable values are (shallow) copied before they are assigned to the
widget. Immutable are used as-is.
Parameters
----------
instance : OWBaseWidget
widget instance to initialize
data : Optional[dict]
optional data used to override the defaults
(used when settings are loaded from schema)
"""
if data is None and self.initialization_data is not None:
data = self.initialization_data
self._initialize_settings(instance, data)
self._initialize_providers(instance, data)
def reset_to_original(self, instance):
self._initialize_settings(instance, None)
self._initialize_providers(instance, None)
def _initialize_settings(self, instance, data):
if data is None:
data = {}
for name, setting in self.settings.items():
value = data.get(name, setting.default)
if isinstance(value, _IMMUTABLES):
setattr(instance, name, value)
else:
setattr(instance, name, copy.copy(value))
def _initialize_providers(self, instance, data):
if not data:
return
for name, provider in self.providers.items():
if name not in data:
continue
member = getattr(instance, name, None)
if member is None or isinstance(member, SettingProvider):
provider.store_initialization_data(data[name])
else:
provider.initialize(member, data[name])
def store_initialization_data(self, initialization_data):
"""Store initialization data for later use.
Used when settings handler is initialized, but member for this
provider does not exists yet (because handler.initialize is called in
__new__, but member will be created in __init__.
Parameters
----------
initialization_data : dict
data to be used for initialization when the component is created
"""
self.initialization_data = initialization_data
@staticmethod
def _default_packer(setting, instance):
"""A simple packet that yields setting name and value.
Parameters
----------
setting : Setting
instance : OWBaseWidget
"""
if setting.packable:
if hasattr(instance, setting.name):
yield setting.name, getattr(instance, setting.name)
else:
warnings.warn("{0} is declared as setting on {1} "
"but not present on instance."
.format(setting.name, instance))
def pack(self, instance, packer=None):
"""Pack instance settings in a name:value dict.
Parameters
----------
instance : OWBaseWidget
widget instance
packer: callable (Setting, OWBaseWidget) -> Generator[(str, object)]
optional packing function
it will be called with setting and instance parameters and
should yield (name, value) pairs that will be added to the
packed_settings.
"""
if packer is None:
packer = self._default_packer
packed_settings = dict(itertools.chain(
*(packer(setting, instance) for setting in self.settings.values())
))
packed_settings.update({
name: provider.pack(getattr(instance, name), packer)
for name, provider in self.providers.items()
if hasattr(instance, name)
})
return packed_settings
def unpack(self, instance, data):
"""Restore settings from data to the instance.
Parameters
----------
instance : OWBaseWidget
instance to restore settings to
data : dict
packed data
"""
for setting, _data, inst in self.traverse_settings(data, instance):
if setting.name in _data and inst is not None:
_apply_setting(setting, inst, _data[setting.name])
def get_provider(self, provider_class):
"""Return provider for provider_class.
If this provider matches, return it, otherwise pass
the call to child providers.
Parameters
----------
provider_class : class
"""
if issubclass(provider_class, self.provider_class):
return self
for subprovider in self.providers.values():
provider = subprovider.get_provider(provider_class)
if provider:
return provider
return None
def traverse_settings(self, data=None, instance=None):
"""Generator of tuples (setting, data, instance) for each setting
in this and child providers..
Parameters
----------
data : dict
dictionary with setting values
instance : OWBaseWidget
instance matching setting_provider
"""
data = data if data is not None else {}
for setting in self.settings.values():
yield setting, data, instance
for provider in self.providers.values():
data_ = data.get(provider.name, {})
instance_ = getattr(instance, provider.name, None)
for setting, component_data, component_instance in \
provider.traverse_settings(data_, instance_):
yield setting, component_data, component_instance
class SettingsHandler:
"""Reads widget setting files and passes them to appropriate providers."""
def __init__(self):
"""Create a setting handler template.
Used in class definition. Bound instance will be created
when SettingsHandler.create is called.
"""
self.widget_class = None
self.provider = None
""":type: SettingProvider"""
self.defaults = {}
self.known_settings = {}
@staticmethod
def create(widget_class, template=None):
"""Create a new settings handler based on the template and bind it to
widget_class.
Parameters
----------
widget_class : class
template : SettingsHandler
SettingsHandler to copy setup from
Returns
-------
SettingsHandler
"""
if template is None:
template = SettingsHandler()
setting_handler = copy.copy(template)
setting_handler.defaults = {}
setting_handler.bind(widget_class)
return setting_handler
def bind(self, widget_class):
"""Bind settings handler instance to widget_class.
Parameters
----------
widget_class : class
"""
self.widget_class = widget_class
self.provider = SettingProvider(widget_class)
self.known_settings = {}
self.analyze_settings(self.provider, "")
self.read_defaults()
def analyze_settings(self, provider, prefix):
"""Traverse through all settings known to the provider
and analyze each of them.
Parameters
----------
provider : SettingProvider
prefix : str
prefix the provider is registered to handle
"""
for setting in provider.settings.values():
self.analyze_setting(prefix, setting)
for name, sub_provider in provider.providers.items():
new_prefix = '{0}{1}.'.format(prefix or '', name)
self.analyze_settings(sub_provider, new_prefix)
def analyze_setting(self, prefix, setting):
"""Perform any initialization task related to setting.
Parameters
----------
prefix : str
setting : Setting
"""
self.known_settings[prefix + setting.name] = setting
def read_defaults(self):
"""Read (global) defaults for this widget class from a file.
Opens a file and calls :obj:`read_defaults_file`. Derived classes
should overload the latter."""
filename = self._get_settings_filename()
if os.path.isfile(filename):
settings_file = open(filename, "rb")
try:
self.read_defaults_file(settings_file)
# Unpickling exceptions can be of any type
# pylint: disable=broad-except
except Exception as ex:
warnings.warn("Could not read defaults for widget {0}\n"
"The following error occurred:\n\n{1}"
.format(self.widget_class, ex))
finally:
settings_file.close()
def read_defaults_file(self, settings_file):
"""Read (global) defaults for this widget class from a file.
Parameters
----------
settings_file : file-like object
"""
defaults = pickle.load(settings_file)
self.defaults = {
key: value
for key, value in defaults.items()
if not isinstance(value, Setting)
}
self._migrate_settings(self.defaults)
# remove schema_only settings introduced by the migration
self._remove_schema_only(self.defaults)
def write_defaults(self):
"""Write (global) defaults for this widget class to a file.
Opens a file and calls :obj:`write_defaults_file`. Derived classes
should overload the latter."""
filename = self._get_settings_filename()
os.makedirs(os.path.dirname(filename), exist_ok=True)
try:
settings_file = open(filename, "wb")
try:
self.write_defaults_file(settings_file)
except (EOFError, IOError, pickle.PicklingError) as ex:
log.error("Could not write default settings for %s (%s).",
self.widget_class, ex)
settings_file.close()
os.remove(filename)
else:
settings_file.close()
except PermissionError as ex:
log.error("Could not write default settings for %s (%s).",
self.widget_class, type(ex).__name__)
def write_defaults_file(self, settings_file):
"""Write defaults for this widget class to a file
Parameters
----------
settings_file : file-like object
"""
defaults = dict(self.defaults)
defaults[VERSION_KEY] = self.widget_class.settings_version
pickle.dump(defaults, settings_file, protocol=PICKLE_PROTOCOL)
def _get_settings_filename(self):
"""Return the name of the file with default settings for the widget"""
return os.path.join(widget_settings_dir(),
"{0.__module__}.{0.__qualname__}.pickle"
.format(self.widget_class))
def initialize(self, instance, data=None):
"""
Initialize widget's settings.
Replace all instance settings with their default values.
Parameters
----------
instance : OWBaseWidget
data : dict or bytes that unpickle into a dict
values used to override the defaults
"""
provider = self._select_provider(instance)
if isinstance(data, bytes):
data = pickle.loads(data)
self._migrate_settings(data)
if provider is self.provider:
data = self._add_defaults(data)
provider.initialize(instance, data)
def reset_to_original(self, instance):
provider = self._select_provider(instance)
provider.reset_to_original(instance)
def _migrate_settings(self, settings):
"""Ask widget to migrate settings to the latest version."""
if settings:
try:
self.widget_class.migrate_settings(
settings, settings.pop(VERSION_KEY, 0))
except Exception: # pylint: disable=broad-except
sys.excepthook(*sys.exc_info())
settings.clear()
def _select_provider(self, instance):
provider = self.provider.get_provider(instance.__class__)
if provider is None:
message = "{0} has not been declared as setting provider in {1}. " \
"Settings will not be saved/loaded properly. Defaults will be used instead." \
.format(instance.__class__, self.widget_class)
warnings.warn(message)
provider = SettingProvider(instance.__class__)
return provider
def _add_defaults(self, data):
if data is None:
return self.defaults
new_data = self.defaults.copy()
new_data.update(data)
return new_data
def _remove_schema_only(self, settings_dict):
for setting, data, _ in self.provider.traverse_settings(data=settings_dict):
if setting.schema_only:
data.pop(setting.name, None)
def _prepare_defaults(self, widget):
self.defaults = self.provider.pack(widget)
self._remove_schema_only(self.defaults)
def pack_data(self, widget):
"""
Pack the settings for the given widget. This method is used when
saving schema, so that when the schema is reloaded the widget is
initialized with its proper data and not the class-based defaults.
See :obj:`SettingsHandler.initialize` for detailed explanation of its
use.
Inherited classes add other data, in particular widget-specific
local contexts.
Parameters
----------
widget : OWBaseWidget
"""
widget.settingsAboutToBePacked.emit()
packed_settings = self.provider.pack(widget)
packed_settings[VERSION_KEY] = self.widget_class.settings_version
return packed_settings
def update_defaults(self, widget):
"""
Writes widget instance's settings to class defaults. Called when the
widget is deleted.
Parameters
----------
widget : OWBaseWidget
"""
widget.settingsAboutToBePacked.emit()
self._prepare_defaults(widget)
self.write_defaults()
def fast_save(self, widget, name, value):
"""Store the (changed) widget's setting immediately to the context.
Parameters
----------
widget : OWBaseWidget
name : str
value : object
"""
if name in self.known_settings:
setting = self.known_settings[name]
if not setting.schema_only:
setting.default = value
def reset_settings(self, instance):
"""Reset widget settings to defaults
Parameters
----------
instance : OWBaseWidget
"""
for setting, _, inst in self.provider.traverse_settings(instance=instance):
if setting.packable:
_apply_setting(setting, inst, setting.default)
class ContextSetting(Setting):
"""Description of a context dependent setting"""
OPTIONAL = 0
REQUIRED = 2
# Context settings are not persisted, but are stored in context instead.
packable = False
# These flags are not general - they assume that the setting has to do
# something with the attributes. Large majority does, so this greatly
# simplifies the declaration of settings in widget at no (visible)
# cost to those settings that don't need it
def __init__(self, default, *, required=2,
exclude_attributes=False, exclude_metas=False, **data):
super().__init__(default, **data)
self.exclude_attributes = exclude_attributes
self.exclude_metas = exclude_metas
self.required = required
class Context:
"""Class for data that defines context and
values that should be applied to widget if given context
is encountered."""
def __init__(self, **argkw):
self.values = {}
self.__dict__.update(argkw)
def __eq__(self, other):
return self.__dict__ == other.__dict__
class ContextHandler(SettingsHandler):
"""Base class for setting handlers that can handle contexts.
Classes deriving from it need to implement method `match`.
"""
NO_MATCH = 0
MATCH = 1
PERFECT_MATCH = 2
MAX_SAVED_CONTEXTS = 50
def __init__(self):
super().__init__()
self.global_contexts = []
self.known_settings = {}
def initialize(self, instance, data=None):
"""Initialize the widget: call the inherited initialization and
add an attribute 'context_settings' to the widget. This method
does not open a context."""
instance.current_context = None
super().initialize(instance, data)
if data and "context_settings" in data:
instance.context_settings = data["context_settings"]
self._migrate_contexts(instance.context_settings)
else:
instance.context_settings = []
def read_defaults_file(self, settings_file):
"""Call the inherited method, then read global context from the
pickle."""
super().read_defaults_file(settings_file)
self.global_contexts = pickle.load(settings_file)
self._migrate_contexts(self.global_contexts)
# remove schema_only settings introduced by the migration
for context in self.global_contexts:
self._remove_schema_only(context.values)
def _migrate_contexts(self, contexts):
i = 0
while i < len(contexts):
context = contexts[i]
try:
self.widget_class.migrate_context(
context, context.values.pop(VERSION_KEY, 0))
except IncompatibleContext:
del contexts[i]
except Exception: # pylint: disable=broad-except
sys.excepthook(*sys.exc_info())
del contexts[i]
else:
i += 1
def write_defaults_file(self, settings_file):
"""Call the inherited method, then add global context to the pickle."""
super().write_defaults_file(settings_file)
def add_version(context):
context = copy.copy(context)
context.values = dict(context.values)
context.values[VERSION_KEY] = self.widget_class.settings_version
return context
pickle.dump([add_version(context) for context in self.global_contexts],
settings_file, protocol=PICKLE_PROTOCOL)
def pack_data(self, widget):
"""Call the inherited method, then add local contexts to the dict."""
data = super().pack_data(widget)
self.settings_from_widget(widget)
context_settings = [copy.copy(context) for context in
widget.context_settings]
for context in context_settings:
context.values[VERSION_KEY] = self.widget_class.settings_version
data["context_settings"] = context_settings
return data
def update_defaults(self, widget):
"""
Reimplemented from SettingsHandler
Merge the widgets local contexts into the global contexts and persist
the settings (including the contexts) to disk.
"""
widget.settingsAboutToBePacked.emit()
self.settings_from_widget(widget)
globs = self.global_contexts
assert widget.context_settings is not globs
new_contexts = []
for context in widget.context_settings:
context = copy.deepcopy(context)
self._remove_schema_only(context.values)
if context not in globs:
new_contexts.append(context)
globs[:0] = reversed(new_contexts)
del globs[self.MAX_SAVED_CONTEXTS:]
# Save non-context settings. Do not call super().update_defaults, so that
# settingsAboutToBePacked is emitted once.
self._prepare_defaults(widget)
self.write_defaults()
def new_context(self, *args):
"""Create a new context."""
return Context()
def open_context(self, widget, *args):
"""Open a context by finding one and setting the widget data or
creating one and fill with the data from the widget."""
widget.current_context, is_new = \
self.find_or_create_context(widget, *args)
if is_new:
self.settings_from_widget(widget, *args)
else:
self.settings_to_widget(widget, *args)
def match(self, context, *args):
"""Return the degree to which the stored `context` matches the data
passed in additional arguments).
When match returns 0 (ContextHandler.NO_MATCH), the context will not
be used. When it returns ContextHandler.PERFECT_MATCH, the context
is a perfect match so no further search is necessary.
If imperfect matching is not desired, match should only
return ContextHandler.NO_MATCH or ContextHandler.PERFECT_MATCH.
Derived classes must overload this method.
"""
raise NotImplementedError
def find_or_create_context(self, widget, *args):
"""Find the best matching context or create a new one if nothing
useful is found. The returned context is moved to or added to the top
of the context list."""
# First search the contexts that were already used in this widget instance
best_context, best_score = self.find_context(widget.context_settings, args, move_up=True)
# If the exact data was used, reuse the context
if best_score == self.PERFECT_MATCH:
return best_context, False
# Otherwise check if a better match is available in global_contexts
best_context, best_score = self.find_context(self.global_contexts, args,
best_score, best_context)
if best_context:
context = self.clone_context(best_context, *args)
else:
context = self.new_context(*args)
# Store context in widget instance. It will be pushed to global_contexts
# when (if) update defaults is called.
self.add_context(widget.context_settings, context)
return context, best_context is None
def find_context(self, known_contexts, args, best_score=0, best_context=None, move_up=False):
"""Search the given list of contexts and return the context
which best matches the given args.
best_score and best_context can be used to provide base_values.
"""
best_idx = None
for i, context in enumerate(known_contexts):
score = self.match(context, *args)
if score > best_score: # NO_MATCH is not OK!
best_context, best_score, best_idx = context, score, i
if score == self.PERFECT_MATCH:
break
if best_idx is not None and move_up:
self.move_context_up(known_contexts, best_idx)
return best_context, best_score
@staticmethod
def move_context_up(contexts, index):
"""Move the context to the top of the list"""
contexts.insert(0, contexts.pop(index))
def add_context(self, contexts, setting):
"""Add the context to the top of the list."""
contexts.insert(0, setting)
del contexts[self.MAX_SAVED_CONTEXTS:]
def clone_context(self, old_context, *args):
"""Construct a copy of the context settings suitable for the context
described by additional arguments. The method is called by
find_or_create_context with the same arguments. A class that overloads
:obj:`match` to accept additional arguments must also overload
:obj:`clone_context`."""
context = self.new_context(*args)
context.values = copy.deepcopy(old_context.values)
traverse = self.provider.traverse_settings
for setting, data, _ in traverse(data=context.values):
if not isinstance(setting, ContextSetting):
continue
self.filter_value(setting, data, *args)
return context
@staticmethod
def filter_value(setting, data, *args):
"""Remove values related to setting that are invalid given args."""
def close_context(self, widget):
"""Close the context by calling :obj:`settings_from_widget` to write
any relevant widget settings to the context."""
if widget.current_context is None:
return
self.settings_from_widget(widget)
widget.current_context = None
def settings_to_widget(self, widget, *args):
"""Apply context settings stored in currently opened context
to the widget.
"""
context = widget.current_context
if context is None:
return
widget.retrieveSpecificSettings()
for setting, data, instance in \
self.provider.traverse_settings(data=context.values, instance=widget):
if not isinstance(setting, ContextSetting) or setting.name not in data:
continue
value = self.decode_setting(setting, data[setting.name], *args)
_apply_setting(setting, instance, value)
def settings_from_widget(self, widget, *args):
"""Update the current context with the setting values from the widget.
"""
context = widget.current_context
if context is None:
return
widget.storeSpecificSettings()
def packer(setting, instance):
if isinstance(setting, ContextSetting) and hasattr(instance, setting.name):
value = getattr(instance, setting.name)
yield setting.name, self.encode_setting(context, setting, value)
context.values = self.provider.pack(widget, packer=packer)
def fast_save(self, widget, name, value):
"""Update value of `name` setting in the current context to `value`
"""
setting = self.known_settings.get(name)
if isinstance(setting, ContextSetting):
context = widget.current_context
if setting.schema_only or context is None:
return
value = self.encode_setting(context, setting, value)
self.update_packed_data(context.values, name, value)
else:
super().fast_save(widget, name, value)
@staticmethod
def update_packed_data(data, name, value):
"""Updates setting value stored in data dict"""
*prefixes, name = name.split('.')
for prefix in prefixes:
data = data.setdefault(prefix, {})
data[name] = value
def encode_setting(self, context, setting, value):
"""Encode value to be stored in settings dict"""
return copy.copy(value)
def decode_setting(self, setting, value, *args):
"""Decode settings value from the setting dict format"""
return value
class IncompatibleContext(Exception):
"""Raised when a required variable in context is not available in data."""
class SettingsPrinter(pprint.PrettyPrinter):
"""Pretty Printer that knows how to properly format Contexts."""
def _format(self, obj, stream, indent, allowance, context, level):
if not isinstance(obj, Context):
super()._format(obj, stream, indent, allowance, context, level)
return
stream.write("Context(")
for key, value in sorted(obj.__dict__.items(), key=itemgetter(0)):
if key == "values":
continue
stream.write(key)
stream.write("=")
stream.write(self._repr(value, context, level + 1))
stream.write(",\n")
stream.write(" " * (indent + 8))
stream.write("values=")
stream.write(" ")
self._format(obj.values, stream, indent+15,
allowance+1, context, level + 1)
stream.write(")")
def rename_setting(settings, old_name, new_name):
"""
Rename setting from `old_name` to `new_name`. Used in migrations.
The argument `settings` can be `dict` or `Context`.
"""
if isinstance(settings, Context):
rename_setting(settings.values, old_name, new_name)
else:
settings[new_name] = settings.pop(old_name)