80 lines
1.4 KiB
Python
80 lines
1.4 KiB
Python
# SPDX-License-Identifier: MIT
|
|
|
|
"""
|
|
Commonly used hooks for on_setattr.
|
|
"""
|
|
|
|
from __future__ import absolute_import, division, print_function
|
|
|
|
from . import _config
|
|
from .exceptions import FrozenAttributeError
|
|
|
|
|
|
def pipe(*setters):
|
|
"""
|
|
Run all *setters* and return the return value of the last one.
|
|
|
|
.. versionadded:: 20.1.0
|
|
"""
|
|
|
|
def wrapped_pipe(instance, attrib, new_value):
|
|
rv = new_value
|
|
|
|
for setter in setters:
|
|
rv = setter(instance, attrib, rv)
|
|
|
|
return rv
|
|
|
|
return wrapped_pipe
|
|
|
|
|
|
def frozen(_, __, ___):
|
|
"""
|
|
Prevent an attribute to be modified.
|
|
|
|
.. versionadded:: 20.1.0
|
|
"""
|
|
raise FrozenAttributeError()
|
|
|
|
|
|
def validate(instance, attrib, new_value):
|
|
"""
|
|
Run *attrib*'s validator on *new_value* if it has one.
|
|
|
|
.. versionadded:: 20.1.0
|
|
"""
|
|
if _config._run_validators is False:
|
|
return new_value
|
|
|
|
v = attrib.validator
|
|
if not v:
|
|
return new_value
|
|
|
|
v(instance, attrib, new_value)
|
|
|
|
return new_value
|
|
|
|
|
|
def convert(instance, attrib, new_value):
|
|
"""
|
|
Run *attrib*'s converter -- if it has one -- on *new_value* and return the
|
|
result.
|
|
|
|
.. versionadded:: 20.1.0
|
|
"""
|
|
c = attrib.converter
|
|
if c:
|
|
return c(new_value)
|
|
|
|
return new_value
|
|
|
|
|
|
NO_OP = object()
|
|
"""
|
|
Sentinel for disabling class-wide *on_setattr* hooks for certain attributes.
|
|
|
|
Does not work in `pipe` or within lists.
|
|
|
|
.. versionadded:: 20.1.0
|
|
"""
|