--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/mercurial/thirdparty/attr/_make.py Sun Oct 01 04:14:16 2017 -0700
@@ -0,0 +1,1059 @@
+from __future__ import absolute_import, division, print_function
+
+import hashlib
+import linecache
+
+from operator import itemgetter
+
+from . import _config
+from ._compat import PY2, iteritems, isclass, iterkeys, metadata_proxy
+from .exceptions import (
+ DefaultAlreadySetError,
+ FrozenInstanceError,
+ NotAnAttrsClassError,
+)
+
+
+# This is used at least twice, so cache it here.
+_obj_setattr = object.__setattr__
+_init_convert_pat = "__attr_convert_{}"
+_init_factory_pat = "__attr_factory_{}"
+_tuple_property_pat = " {attr_name} = property(itemgetter({index}))"
+_empty_metadata_singleton = metadata_proxy({})
+
+
+class _Nothing(object):
+ """
+ Sentinel class to indicate the lack of a value when ``None`` is ambiguous.
+
+ All instances of `_Nothing` are equal.
+ """
+ def __copy__(self):
+ return self
+
+ def __deepcopy__(self, _):
+ return self
+
+ def __eq__(self, other):
+ return other.__class__ == _Nothing
+
+ def __ne__(self, other):
+ return not self == other
+
+ def __repr__(self):
+ return "NOTHING"
+
+ def __hash__(self):
+ return 0xdeadbeef
+
+
+NOTHING = _Nothing()
+"""
+Sentinel to indicate the lack of a value when ``None`` is ambiguous.
+"""
+
+
+def attr(default=NOTHING, validator=None,
+ repr=True, cmp=True, hash=None, init=True,
+ convert=None, metadata={}):
+ """
+ Create a new attribute on a class.
+
+ .. warning::
+
+ Does *not* do anything unless the class is also decorated with
+ :func:`attr.s`!
+
+ :param default: A value that is used if an ``attrs``-generated ``__init__``
+ is used and no value is passed while instantiating or the attribute is
+ excluded using ``init=False``.
+
+ If the value is an instance of :class:`Factory`, its callable will be
+ used to construct a new value (useful for mutable datatypes like lists
+ or dicts).
+
+ If a default is not set (or set manually to ``attr.NOTHING``), a value
+ *must* be supplied when instantiating; otherwise a :exc:`TypeError`
+ will be raised.
+
+ The default can also be set using decorator notation as shown below.
+
+ :type default: Any value.
+
+ :param validator: :func:`callable` that is called by ``attrs``-generated
+ ``__init__`` methods after the instance has been initialized. They
+ receive the initialized instance, the :class:`Attribute`, and the
+ passed value.
+
+ The return value is *not* inspected so the validator has to throw an
+ exception itself.
+
+ If a ``list`` is passed, its items are treated as validators and must
+ all pass.
+
+ Validators can be globally disabled and re-enabled using
+ :func:`get_run_validators`.
+
+ The validator can also be set using decorator notation as shown below.
+
+ :type validator: ``callable`` or a ``list`` of ``callable``\ s.
+
+ :param bool repr: Include this attribute in the generated ``__repr__``
+ method.
+ :param bool cmp: Include this attribute in the generated comparison methods
+ (``__eq__`` et al).
+ :param hash: Include this attribute in the generated ``__hash__``
+ method. If ``None`` (default), mirror *cmp*'s value. This is the
+ correct behavior according the Python spec. Setting this value to
+ anything else than ``None`` is *discouraged*.
+ :type hash: ``bool`` or ``None``
+ :param bool init: Include this attribute in the generated ``__init__``
+ method. It is possible to set this to ``False`` and set a default
+ value. In that case this attributed is unconditionally initialized
+ with the specified default value or factory.
+ :param callable convert: :func:`callable` that is called by
+ ``attrs``-generated ``__init__`` methods to convert attribute's value
+ to the desired format. It is given the passed-in value, and the
+ returned value will be used as the new value of the attribute. The
+ value is converted before being passed to the validator, if any.
+ :param metadata: An arbitrary mapping, to be used by third-party
+ components. See :ref:`extending_metadata`.
+
+ .. versionchanged:: 17.1.0 *validator* can be a ``list`` now.
+ .. versionchanged:: 17.1.0
+ *hash* is ``None`` and therefore mirrors *cmp* by default .
+ """
+ if hash is not None and hash is not True and hash is not False:
+ raise TypeError(
+ "Invalid value for hash. Must be True, False, or None."
+ )
+ return _CountingAttr(
+ default=default,
+ validator=validator,
+ repr=repr,
+ cmp=cmp,
+ hash=hash,
+ init=init,
+ convert=convert,
+ metadata=metadata,
+ )
+
+
+def _make_attr_tuple_class(cls_name, attr_names):
+ """
+ Create a tuple subclass to hold `Attribute`s for an `attrs` class.
+
+ The subclass is a bare tuple with properties for names.
+
+ class MyClassAttributes(tuple):
+ __slots__ = ()
+ x = property(itemgetter(0))
+ """
+ attr_class_name = "{}Attributes".format(cls_name)
+ attr_class_template = [
+ "class {}(tuple):".format(attr_class_name),
+ " __slots__ = ()",
+ ]
+ if attr_names:
+ for i, attr_name in enumerate(attr_names):
+ attr_class_template.append(_tuple_property_pat.format(
+ index=i,
+ attr_name=attr_name,
+ ))
+ else:
+ attr_class_template.append(" pass")
+ globs = {"itemgetter": itemgetter}
+ eval(compile("\n".join(attr_class_template), "", "exec"), globs)
+ return globs[attr_class_name]
+
+
+def _transform_attrs(cls, these):
+ """
+ Transforms all `_CountingAttr`s on a class into `Attribute`s and saves the
+ list in `__attrs_attrs__`.
+
+ If *these* is passed, use that and don't look for them on the class.
+ """
+ super_cls = []
+ for c in reversed(cls.__mro__[1:-1]):
+ sub_attrs = getattr(c, "__attrs_attrs__", None)
+ if sub_attrs is not None:
+ super_cls.extend(a for a in sub_attrs if a not in super_cls)
+ if these is None:
+ ca_list = [(name, attr)
+ for name, attr
+ in cls.__dict__.items()
+ if isinstance(attr, _CountingAttr)]
+ else:
+ ca_list = [(name, ca)
+ for name, ca
+ in iteritems(these)]
+
+ non_super_attrs = [
+ Attribute.from_counting_attr(name=attr_name, ca=ca)
+ for attr_name, ca
+ in sorted(ca_list, key=lambda e: e[1].counter)
+ ]
+ attr_names = [a.name for a in super_cls + non_super_attrs]
+
+ AttrsClass = _make_attr_tuple_class(cls.__name__, attr_names)
+
+ cls.__attrs_attrs__ = AttrsClass(super_cls + [
+ Attribute.from_counting_attr(name=attr_name, ca=ca)
+ for attr_name, ca
+ in sorted(ca_list, key=lambda e: e[1].counter)
+ ])
+
+ had_default = False
+ for a in cls.__attrs_attrs__:
+ if these is None and a not in super_cls:
+ setattr(cls, a.name, a)
+ if had_default is True and a.default is NOTHING and a.init is True:
+ raise ValueError(
+ "No mandatory attributes allowed after an attribute with a "
+ "default value or factory. Attribute in question: {a!r}"
+ .format(a=a)
+ )
+ elif had_default is False and \
+ a.default is not NOTHING and \
+ a.init is not False:
+ had_default = True
+
+
+def _frozen_setattrs(self, name, value):
+ """
+ Attached to frozen classes as __setattr__.
+ """
+ raise FrozenInstanceError()
+
+
+def _frozen_delattrs(self, name):
+ """
+ Attached to frozen classes as __delattr__.
+ """
+ raise FrozenInstanceError()
+
+
+def attributes(maybe_cls=None, these=None, repr_ns=None,
+ repr=True, cmp=True, hash=None, init=True,
+ slots=False, frozen=False, str=False):
+ r"""
+ A class decorator that adds `dunder
+ <https://wiki.python.org/moin/DunderAlias>`_\ -methods according to the
+ specified attributes using :func:`attr.ib` or the *these* argument.
+
+ :param these: A dictionary of name to :func:`attr.ib` mappings. This is
+ useful to avoid the definition of your attributes within the class body
+ because you can't (e.g. if you want to add ``__repr__`` methods to
+ Django models) or don't want to.
+
+ If *these* is not ``None``, ``attrs`` will *not* search the class body
+ for attributes.
+
+ :type these: :class:`dict` of :class:`str` to :func:`attr.ib`
+
+ :param str repr_ns: When using nested classes, there's no way in Python 2
+ to automatically detect that. Therefore it's possible to set the
+ namespace explicitly for a more meaningful ``repr`` output.
+ :param bool repr: Create a ``__repr__`` method with a human readable
+ represantation of ``attrs`` attributes..
+ :param bool str: Create a ``__str__`` method that is identical to
+ ``__repr__``. This is usually not necessary except for
+ :class:`Exception`\ s.
+ :param bool cmp: Create ``__eq__``, ``__ne__``, ``__lt__``, ``__le__``,
+ ``__gt__``, and ``__ge__`` methods that compare the class as if it were
+ a tuple of its ``attrs`` attributes. But the attributes are *only*
+ compared, if the type of both classes is *identical*!
+ :param hash: If ``None`` (default), the ``__hash__`` method is generated
+ according how *cmp* and *frozen* are set.
+
+ 1. If *both* are True, ``attrs`` will generate a ``__hash__`` for you.
+ 2. If *cmp* is True and *frozen* is False, ``__hash__`` will be set to
+ None, marking it unhashable (which it is).
+ 3. If *cmp* is False, ``__hash__`` will be left untouched meaning the
+ ``__hash__`` method of the superclass will be used (if superclass is
+ ``object``, this means it will fall back to id-based hashing.).
+
+ Although not recommended, you can decide for yourself and force
+ ``attrs`` to create one (e.g. if the class is immutable even though you
+ didn't freeze it programmatically) by passing ``True`` or not. Both of
+ these cases are rather special and should be used carefully.
+
+ See the `Python documentation \
+ <https://docs.python.org/3/reference/datamodel.html#object.__hash__>`_
+ and the `GitHub issue that led to the default behavior \
+ <https://github.com/python-attrs/attrs/issues/136>`_ for more details.
+ :type hash: ``bool`` or ``None``
+ :param bool init: Create a ``__init__`` method that initialiazes the
+ ``attrs`` attributes. Leading underscores are stripped for the
+ argument name. If a ``__attrs_post_init__`` method exists on the
+ class, it will be called after the class is fully initialized.
+ :param bool slots: Create a slots_-style class that's more
+ memory-efficient. See :ref:`slots` for further ramifications.
+ :param bool frozen: Make instances immutable after initialization. If
+ someone attempts to modify a frozen instance,
+ :exc:`attr.exceptions.FrozenInstanceError` is raised.
+
+ Please note:
+
+ 1. This is achieved by installing a custom ``__setattr__`` method
+ on your class so you can't implement an own one.
+
+ 2. True immutability is impossible in Python.
+
+ 3. This *does* have a minor a runtime performance :ref:`impact
+ <how-frozen>` when initializing new instances. In other words:
+ ``__init__`` is slightly slower with ``frozen=True``.
+
+ 4. If a class is frozen, you cannot modify ``self`` in
+ ``__attrs_post_init__`` or a self-written ``__init__``. You can
+ circumvent that limitation by using
+ ``object.__setattr__(self, "attribute_name", value)``.
+
+ .. _slots: https://docs.python.org/3.5/reference/datamodel.html#slots
+
+ .. versionadded:: 16.0.0 *slots*
+ .. versionadded:: 16.1.0 *frozen*
+ .. versionadded:: 16.3.0 *str*, and support for ``__attrs_post_init__``.
+ .. versionchanged::
+ 17.1.0 *hash* supports ``None`` as value which is also the default
+ now.
+ """
+ def wrap(cls):
+ if getattr(cls, "__class__", None) is None:
+ raise TypeError("attrs only works with new-style classes.")
+
+ if repr is False and str is True:
+ raise ValueError(
+ "__str__ can only be generated if a __repr__ exists."
+ )
+
+ if slots:
+ # Only need this later if we're using slots.
+ if these is None:
+ ca_list = [name
+ for name, attr
+ in cls.__dict__.items()
+ if isinstance(attr, _CountingAttr)]
+ else:
+ ca_list = list(iterkeys(these))
+ _transform_attrs(cls, these)
+
+ # Can't just re-use frozen name because Python's scoping. :(
+ # Can't compare function objects because Python 2 is terrible. :(
+ effectively_frozen = _has_frozen_superclass(cls) or frozen
+ if repr is True:
+ cls = _add_repr(cls, ns=repr_ns)
+ if str is True:
+ cls.__str__ = cls.__repr__
+ if cmp is True:
+ cls = _add_cmp(cls)
+
+ if hash is not True and hash is not False and hash is not None:
+ raise TypeError(
+ "Invalid value for hash. Must be True, False, or None."
+ )
+ elif hash is False or (hash is None and cmp is False):
+ pass
+ elif hash is True or (hash is None and cmp is True and frozen is True):
+ cls = _add_hash(cls)
+ else:
+ cls.__hash__ = None
+
+ if init is True:
+ cls = _add_init(cls, effectively_frozen)
+ if effectively_frozen is True:
+ cls.__setattr__ = _frozen_setattrs
+ cls.__delattr__ = _frozen_delattrs
+ if slots is True:
+ # slots and frozen require __getstate__/__setstate__ to work
+ cls = _add_pickle(cls)
+ if slots is True:
+ cls_dict = dict(cls.__dict__)
+ cls_dict["__slots__"] = tuple(ca_list)
+ for ca_name in ca_list:
+ # It might not actually be in there, e.g. if using 'these'.
+ cls_dict.pop(ca_name, None)
+ cls_dict.pop("__dict__", None)
+
+ qualname = getattr(cls, "__qualname__", None)
+ cls = type(cls)(cls.__name__, cls.__bases__, cls_dict)
+ if qualname is not None:
+ cls.__qualname__ = qualname
+
+ return cls
+
+ # attrs_or class type depends on the usage of the decorator. It's a class
+ # if it's used as `@attributes` but ``None`` if used # as `@attributes()`.
+ if maybe_cls is None:
+ return wrap
+ else:
+ return wrap(maybe_cls)
+
+
+if PY2:
+ def _has_frozen_superclass(cls):
+ """
+ Check whether *cls* has a frozen ancestor by looking at its
+ __setattr__.
+ """
+ return (
+ getattr(
+ cls.__setattr__, "__module__", None
+ ) == _frozen_setattrs.__module__ and
+ cls.__setattr__.__name__ == _frozen_setattrs.__name__
+ )
+else:
+ def _has_frozen_superclass(cls):
+ """
+ Check whether *cls* has a frozen ancestor by looking at its
+ __setattr__.
+ """
+ return cls.__setattr__ == _frozen_setattrs
+
+
+def _attrs_to_tuple(obj, attrs):
+ """
+ Create a tuple of all values of *obj*'s *attrs*.
+ """
+ return tuple(getattr(obj, a.name) for a in attrs)
+
+
+def _add_hash(cls, attrs=None):
+ """
+ Add a hash method to *cls*.
+ """
+ if attrs is None:
+ attrs = [a
+ for a in cls.__attrs_attrs__
+ if a.hash is True or (a.hash is None and a.cmp is True)]
+
+ def hash_(self):
+ """
+ Automatically created by attrs.
+ """
+ return hash(_attrs_to_tuple(self, attrs))
+
+ cls.__hash__ = hash_
+ return cls
+
+
+def _add_cmp(cls, attrs=None):
+ """
+ Add comparison methods to *cls*.
+ """
+ if attrs is None:
+ attrs = [a for a in cls.__attrs_attrs__ if a.cmp]
+
+ def attrs_to_tuple(obj):
+ """
+ Save us some typing.
+ """
+ return _attrs_to_tuple(obj, attrs)
+
+ def eq(self, other):
+ """
+ Automatically created by attrs.
+ """
+ if other.__class__ is self.__class__:
+ return attrs_to_tuple(self) == attrs_to_tuple(other)
+ else:
+ return NotImplemented
+
+ def ne(self, other):
+ """
+ Automatically created by attrs.
+ """
+ result = eq(self, other)
+ if result is NotImplemented:
+ return NotImplemented
+ else:
+ return not result
+
+ def lt(self, other):
+ """
+ Automatically created by attrs.
+ """
+ if isinstance(other, self.__class__):
+ return attrs_to_tuple(self) < attrs_to_tuple(other)
+ else:
+ return NotImplemented
+
+ def le(self, other):
+ """
+ Automatically created by attrs.
+ """
+ if isinstance(other, self.__class__):
+ return attrs_to_tuple(self) <= attrs_to_tuple(other)
+ else:
+ return NotImplemented
+
+ def gt(self, other):
+ """
+ Automatically created by attrs.
+ """
+ if isinstance(other, self.__class__):
+ return attrs_to_tuple(self) > attrs_to_tuple(other)
+ else:
+ return NotImplemented
+
+ def ge(self, other):
+ """
+ Automatically created by attrs.
+ """
+ if isinstance(other, self.__class__):
+ return attrs_to_tuple(self) >= attrs_to_tuple(other)
+ else:
+ return NotImplemented
+
+ cls.__eq__ = eq
+ cls.__ne__ = ne
+ cls.__lt__ = lt
+ cls.__le__ = le
+ cls.__gt__ = gt
+ cls.__ge__ = ge
+
+ return cls
+
+
+def _add_repr(cls, ns=None, attrs=None):
+ """
+ Add a repr method to *cls*.
+ """
+ if attrs is None:
+ attrs = [a for a in cls.__attrs_attrs__ if a.repr]
+
+ def repr_(self):
+ """
+ Automatically created by attrs.
+ """
+ real_cls = self.__class__
+ if ns is None:
+ qualname = getattr(real_cls, "__qualname__", None)
+ if qualname is not None:
+ class_name = qualname.rsplit(">.", 1)[-1]
+ else:
+ class_name = real_cls.__name__
+ else:
+ class_name = ns + "." + real_cls.__name__
+
+ return "{0}({1})".format(
+ class_name,
+ ", ".join(a.name + "=" + repr(getattr(self, a.name))
+ for a in attrs)
+ )
+ cls.__repr__ = repr_
+ return cls
+
+
+def _add_init(cls, frozen):
+ """
+ Add a __init__ method to *cls*. If *frozen* is True, make it immutable.
+ """
+ attrs = [a for a in cls.__attrs_attrs__
+ if a.init or a.default is not NOTHING]
+
+ # We cache the generated init methods for the same kinds of attributes.
+ sha1 = hashlib.sha1()
+ sha1.update(repr(attrs).encode("utf-8"))
+ unique_filename = "<attrs generated init {0}>".format(
+ sha1.hexdigest()
+ )
+
+ script, globs = _attrs_to_script(
+ attrs,
+ frozen,
+ getattr(cls, "__attrs_post_init__", False),
+ )
+ locs = {}
+ bytecode = compile(script, unique_filename, "exec")
+ attr_dict = dict((a.name, a) for a in attrs)
+ globs.update({
+ "NOTHING": NOTHING,
+ "attr_dict": attr_dict,
+ })
+ if frozen is True:
+ # Save the lookup overhead in __init__ if we need to circumvent
+ # immutability.
+ globs["_cached_setattr"] = _obj_setattr
+ eval(bytecode, globs, locs)
+ init = locs["__init__"]
+
+ # In order of debuggers like PDB being able to step through the code,
+ # we add a fake linecache entry.
+ linecache.cache[unique_filename] = (
+ len(script),
+ None,
+ script.splitlines(True),
+ unique_filename
+ )
+ cls.__init__ = init
+ return cls
+
+
+def _add_pickle(cls):
+ """
+ Add pickle helpers, needed for frozen and slotted classes
+ """
+ def _slots_getstate__(obj):
+ """
+ Play nice with pickle.
+ """
+ return tuple(getattr(obj, a.name) for a in fields(obj.__class__))
+
+ def _slots_setstate__(obj, state):
+ """
+ Play nice with pickle.
+ """
+ __bound_setattr = _obj_setattr.__get__(obj, Attribute)
+ for a, value in zip(fields(obj.__class__), state):
+ __bound_setattr(a.name, value)
+
+ cls.__getstate__ = _slots_getstate__
+ cls.__setstate__ = _slots_setstate__
+ return cls
+
+
+def fields(cls):
+ """
+ Returns the tuple of ``attrs`` attributes for a class.
+
+ The tuple also allows accessing the fields by their names (see below for
+ examples).
+
+ :param type cls: Class to introspect.
+
+ :raise TypeError: If *cls* is not a class.
+ :raise attr.exceptions.NotAnAttrsClassError: If *cls* is not an ``attrs``
+ class.
+
+ :rtype: tuple (with name accesors) of :class:`attr.Attribute`
+
+ .. versionchanged:: 16.2.0 Returned tuple allows accessing the fields
+ by name.
+ """
+ if not isclass(cls):
+ raise TypeError("Passed object must be a class.")
+ attrs = getattr(cls, "__attrs_attrs__", None)
+ if attrs is None:
+ raise NotAnAttrsClassError(
+ "{cls!r} is not an attrs-decorated class.".format(cls=cls)
+ )
+ return attrs
+
+
+def validate(inst):
+ """
+ Validate all attributes on *inst* that have a validator.
+
+ Leaves all exceptions through.
+
+ :param inst: Instance of a class with ``attrs`` attributes.
+ """
+ if _config._run_validators is False:
+ return
+
+ for a in fields(inst.__class__):
+ v = a.validator
+ if v is not None:
+ v(inst, a, getattr(inst, a.name))
+
+
+def _attrs_to_script(attrs, frozen, post_init):
+ """
+ Return a script of an initializer for *attrs* and a dict of globals.
+
+ The globals are expected by the generated script.
+
+ If *frozen* is True, we cannot set the attributes directly so we use
+ a cached ``object.__setattr__``.
+ """
+ lines = []
+ if frozen is True:
+ lines.append(
+ # Circumvent the __setattr__ descriptor to save one lookup per
+ # assignment.
+ "_setattr = _cached_setattr.__get__(self, self.__class__)"
+ )
+
+ def fmt_setter(attr_name, value_var):
+ return "_setattr('%(attr_name)s', %(value_var)s)" % {
+ "attr_name": attr_name,
+ "value_var": value_var,
+ }
+
+ def fmt_setter_with_converter(attr_name, value_var):
+ conv_name = _init_convert_pat.format(attr_name)
+ return "_setattr('%(attr_name)s', %(conv)s(%(value_var)s))" % {
+ "attr_name": attr_name,
+ "value_var": value_var,
+ "conv": conv_name,
+ }
+ else:
+ def fmt_setter(attr_name, value):
+ return "self.%(attr_name)s = %(value)s" % {
+ "attr_name": attr_name,
+ "value": value,
+ }
+
+ def fmt_setter_with_converter(attr_name, value_var):
+ conv_name = _init_convert_pat.format(attr_name)
+ return "self.%(attr_name)s = %(conv)s(%(value_var)s)" % {
+ "attr_name": attr_name,
+ "value_var": value_var,
+ "conv": conv_name,
+ }
+
+ args = []
+ attrs_to_validate = []
+
+ # This is a dictionary of names to validator and converter callables.
+ # Injecting this into __init__ globals lets us avoid lookups.
+ names_for_globals = {}
+
+ for a in attrs:
+ if a.validator:
+ attrs_to_validate.append(a)
+ attr_name = a.name
+ arg_name = a.name.lstrip("_")
+ has_factory = isinstance(a.default, Factory)
+ if has_factory and a.default.takes_self:
+ maybe_self = "self"
+ else:
+ maybe_self = ""
+ if a.init is False:
+ if has_factory:
+ init_factory_name = _init_factory_pat.format(a.name)
+ if a.convert is not None:
+ lines.append(fmt_setter_with_converter(
+ attr_name,
+ init_factory_name + "({0})".format(maybe_self)))
+ conv_name = _init_convert_pat.format(a.name)
+ names_for_globals[conv_name] = a.convert
+ else:
+ lines.append(fmt_setter(
+ attr_name,
+ init_factory_name + "({0})".format(maybe_self)
+ ))
+ names_for_globals[init_factory_name] = a.default.factory
+ else:
+ if a.convert is not None:
+ lines.append(fmt_setter_with_converter(
+ attr_name,
+ "attr_dict['{attr_name}'].default"
+ .format(attr_name=attr_name)
+ ))
+ conv_name = _init_convert_pat.format(a.name)
+ names_for_globals[conv_name] = a.convert
+ else:
+ lines.append(fmt_setter(
+ attr_name,
+ "attr_dict['{attr_name}'].default"
+ .format(attr_name=attr_name)
+ ))
+ elif a.default is not NOTHING and not has_factory:
+ args.append(
+ "{arg_name}=attr_dict['{attr_name}'].default".format(
+ arg_name=arg_name,
+ attr_name=attr_name,
+ )
+ )
+ if a.convert is not None:
+ lines.append(fmt_setter_with_converter(attr_name, arg_name))
+ names_for_globals[_init_convert_pat.format(a.name)] = a.convert
+ else:
+ lines.append(fmt_setter(attr_name, arg_name))
+ elif has_factory:
+ args.append("{arg_name}=NOTHING".format(arg_name=arg_name))
+ lines.append("if {arg_name} is not NOTHING:"
+ .format(arg_name=arg_name))
+ init_factory_name = _init_factory_pat.format(a.name)
+ if a.convert is not None:
+ lines.append(" " + fmt_setter_with_converter(attr_name,
+ arg_name))
+ lines.append("else:")
+ lines.append(" " + fmt_setter_with_converter(
+ attr_name,
+ init_factory_name + "({0})".format(maybe_self)
+ ))
+ names_for_globals[_init_convert_pat.format(a.name)] = a.convert
+ else:
+ lines.append(" " + fmt_setter(attr_name, arg_name))
+ lines.append("else:")
+ lines.append(" " + fmt_setter(
+ attr_name,
+ init_factory_name + "({0})".format(maybe_self)
+ ))
+ names_for_globals[init_factory_name] = a.default.factory
+ else:
+ args.append(arg_name)
+ if a.convert is not None:
+ lines.append(fmt_setter_with_converter(attr_name, arg_name))
+ names_for_globals[_init_convert_pat.format(a.name)] = a.convert
+ else:
+ lines.append(fmt_setter(attr_name, arg_name))
+
+ if attrs_to_validate: # we can skip this if there are no validators.
+ names_for_globals["_config"] = _config
+ lines.append("if _config._run_validators is True:")
+ for a in attrs_to_validate:
+ val_name = "__attr_validator_{}".format(a.name)
+ attr_name = "__attr_{}".format(a.name)
+ lines.append(" {}(self, {}, self.{})".format(
+ val_name, attr_name, a.name))
+ names_for_globals[val_name] = a.validator
+ names_for_globals[attr_name] = a
+ if post_init:
+ lines.append("self.__attrs_post_init__()")
+
+ return """\
+def __init__(self, {args}):
+ {lines}
+""".format(
+ args=", ".join(args),
+ lines="\n ".join(lines) if lines else "pass",
+ ), names_for_globals
+
+
+class Attribute(object):
+ """
+ *Read-only* representation of an attribute.
+
+ :attribute name: The name of the attribute.
+
+ Plus *all* arguments of :func:`attr.ib`.
+ """
+ __slots__ = (
+ "name", "default", "validator", "repr", "cmp", "hash", "init",
+ "convert", "metadata",
+ )
+
+ def __init__(self, name, default, validator, repr, cmp, hash, init,
+ convert=None, metadata=None):
+ # Cache this descriptor here to speed things up later.
+ bound_setattr = _obj_setattr.__get__(self, Attribute)
+
+ bound_setattr("name", name)
+ bound_setattr("default", default)
+ bound_setattr("validator", validator)
+ bound_setattr("repr", repr)
+ bound_setattr("cmp", cmp)
+ bound_setattr("hash", hash)
+ bound_setattr("init", init)
+ bound_setattr("convert", convert)
+ bound_setattr("metadata", (metadata_proxy(metadata) if metadata
+ else _empty_metadata_singleton))
+
+ def __setattr__(self, name, value):
+ raise FrozenInstanceError()
+
+ @classmethod
+ def from_counting_attr(cls, name, ca):
+ inst_dict = {
+ k: getattr(ca, k)
+ for k
+ in Attribute.__slots__
+ if k not in (
+ "name", "validator", "default",
+ ) # exclude methods
+ }
+ return cls(name=name, validator=ca._validator, default=ca._default,
+ **inst_dict)
+
+ # Don't use _add_pickle since fields(Attribute) doesn't work
+ def __getstate__(self):
+ """
+ Play nice with pickle.
+ """
+ return tuple(getattr(self, name) if name != "metadata"
+ else dict(self.metadata)
+ for name in self.__slots__)
+
+ def __setstate__(self, state):
+ """
+ Play nice with pickle.
+ """
+ bound_setattr = _obj_setattr.__get__(self, Attribute)
+ for name, value in zip(self.__slots__, state):
+ if name != "metadata":
+ bound_setattr(name, value)
+ else:
+ bound_setattr(name, metadata_proxy(value) if value else
+ _empty_metadata_singleton)
+
+
+_a = [Attribute(name=name, default=NOTHING, validator=None,
+ repr=True, cmp=True, hash=(name != "metadata"), init=True)
+ for name in Attribute.__slots__]
+
+Attribute = _add_hash(
+ _add_cmp(_add_repr(Attribute, attrs=_a), attrs=_a),
+ attrs=[a for a in _a if a.hash]
+)
+
+
+class _CountingAttr(object):
+ """
+ Intermediate representation of attributes that uses a counter to preserve
+ the order in which the attributes have been defined.
+
+ *Internal* data structure of the attrs library. Running into is most
+ likely the result of a bug like a forgotten `@attr.s` decorator.
+ """
+ __slots__ = ("counter", "_default", "repr", "cmp", "hash", "init",
+ "metadata", "_validator", "convert")
+ __attrs_attrs__ = tuple(
+ Attribute(name=name, default=NOTHING, validator=None,
+ repr=True, cmp=True, hash=True, init=True)
+ for name
+ in ("counter", "_default", "repr", "cmp", "hash", "init",)
+ ) + (
+ Attribute(name="metadata", default=None, validator=None,
+ repr=True, cmp=True, hash=False, init=True),
+ )
+ cls_counter = 0
+
+ def __init__(self, default, validator, repr, cmp, hash, init, convert,
+ metadata):
+ _CountingAttr.cls_counter += 1
+ self.counter = _CountingAttr.cls_counter
+ self._default = default
+ # If validator is a list/tuple, wrap it using helper validator.
+ if validator and isinstance(validator, (list, tuple)):
+ self._validator = and_(*validator)
+ else:
+ self._validator = validator
+ self.repr = repr
+ self.cmp = cmp
+ self.hash = hash
+ self.init = init
+ self.convert = convert
+ self.metadata = metadata
+
+ def validator(self, meth):
+ """
+ Decorator that adds *meth* to the list of validators.
+
+ Returns *meth* unchanged.
+
+ .. versionadded:: 17.1.0
+ """
+ if self._validator is None:
+ self._validator = meth
+ else:
+ self._validator = and_(self._validator, meth)
+ return meth
+
+ def default(self, meth):
+ """
+ Decorator that allows to set the default for an attribute.
+
+ Returns *meth* unchanged.
+
+ :raises DefaultAlreadySetError: If default has been set before.
+
+ .. versionadded:: 17.1.0
+ """
+ if self._default is not NOTHING:
+ raise DefaultAlreadySetError()
+
+ self._default = Factory(meth, takes_self=True)
+
+ return meth
+
+
+_CountingAttr = _add_cmp(_add_repr(_CountingAttr))
+
+
+@attributes(slots=True, init=False)
+class Factory(object):
+ """
+ Stores a factory callable.
+
+ If passed as the default value to :func:`attr.ib`, the factory is used to
+ generate a new value.
+
+ :param callable factory: A callable that takes either none or exactly one
+ mandatory positional argument depending on *takes_self*.
+ :param bool takes_self: Pass the partially initialized instance that is
+ being initialized as a positional argument.
+
+ .. versionadded:: 17.1.0 *takes_self*
+ """
+ factory = attr()
+ takes_self = attr()
+
+ def __init__(self, factory, takes_self=False):
+ """
+ `Factory` is part of the default machinery so if we want a default
+ value here, we have to implement it ourselves.
+ """
+ self.factory = factory
+ self.takes_self = takes_self
+
+
+def make_class(name, attrs, bases=(object,), **attributes_arguments):
+ """
+ A quick way to create a new class called *name* with *attrs*.
+
+ :param name: The name for the new class.
+ :type name: str
+
+ :param attrs: A list of names or a dictionary of mappings of names to
+ attributes.
+ :type attrs: :class:`list` or :class:`dict`
+
+ :param tuple bases: Classes that the new class will subclass.
+
+ :param attributes_arguments: Passed unmodified to :func:`attr.s`.
+
+ :return: A new class with *attrs*.
+ :rtype: type
+
+ .. versionadded:: 17.1.0 *bases*
+ """
+ if isinstance(attrs, dict):
+ cls_dict = attrs
+ elif isinstance(attrs, (list, tuple)):
+ cls_dict = dict((a, attr()) for a in attrs)
+ else:
+ raise TypeError("attrs argument must be a dict or a list.")
+
+ return attributes(**attributes_arguments)(type(name, bases, cls_dict))
+
+
+# These are required by whithin this module so we define them here and merely
+# import into .validators.
+
+
+@attributes(slots=True, hash=True)
+class _AndValidator(object):
+ """
+ Compose many validators to a single one.
+ """
+ _validators = attr()
+
+ def __call__(self, inst, attr, value):
+ for v in self._validators:
+ v(inst, attr, value)
+
+
+def and_(*validators):
+ """
+ A validator that composes multiple validators into one.
+
+ When called on a value, it runs all wrapped validators.
+
+ :param validators: Arbitrary number of validators.
+ :type validators: callables
+
+ .. versionadded:: 17.1.0
+ """
+ vals = []
+ for validator in validators:
+ vals.extend(
+ validator._validators if isinstance(validator, _AndValidator)
+ else [validator]
+ )
+
+ return _AndValidator(tuple(vals))