# SPDX-License-Identifier: MIT

"""

Commonly used hooks for on_setattr.

"""

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

# Sentinel for disabling class-wide *on_setattr* hooks for certain attributes.

# autodata stopped working, so the docstring is inlined in the API docs.

NO_OP = object()