def source(self):
'''The source of objects from this token.
If then token is a top-level one and is related with a
``is_instance(token, SomeClass)`` filter and
``SomeClass.this_instances`` is a collection, this collection will be
the source.
If the token is a top-level token but the test described above fails,
the we use the `gc` module to get every possible object in the Python's
memory.
If the token is not a top-level token, we simply use the attribute's
name from the parent token current value.
'''
from xoutil.types import is_collection
cls = self._token_class
this_instances = getattr(cls, 'this_instances', None)
if is_collection(this_instances):
if not self.only or defined(cls, self.only):
return iter(this_instances)
else:
return []
else:
return self._build_source()
def getargvalues(frame):
'''Inspects the given frame for arguments and returns a dictionary that
maps parameters names to arguments values. If an `*` argument was passed
then the key on the returning dictionary would be formatted as
`<name-of-*-param>[index]`.
For example in the function::
>>> def autocontained(a, limit, *margs, **ks):
... import sys
... return getargvalues(sys._getframe())
>>> autocontained(1, 12)['limit']
12
>>> autocontained(1, 2, -10, -11)['margs[0]']
-10
'''
from xoutil.types import is_collection
from xoutil.iterators import flatten
pos, args, kwds, values = inspect.getargvalues(frame)
res = {}
for keys in pos:
if not is_collection(keys):
keys = (keys,)
res.update({key: values[key] for key in flatten(keys)})
if args:
i = 0
for item in values[args]:
res['%s[%s]' % (args, i)] = item
i += 1
if kwds:
res.update(values[kwds])
return res
def iterate_over(source, *keys):
'''Yields pairs of (key, value) for of all `keys` in `source`.
If any `key` is missing from `source` is ignored (not yielded).
If `source` is a `collection <xoutil.types.is_collection>`:func:, iterate
over each of the items searching for any of keys. This is not recursive.
If no `keys` are provided, return an "empty" iterator -- i.e will raise
StopIteration upon calling `next`.
.. versionadded:: 1.5.2
'''
from xoutil.types import is_collection
def inner(source):
get = smart_getter(source)
for key in keys:
val = get(key, Unset)
if val is not Unset:
yield key, val
def when_collection(source):
from xoutil.iterators import map
for generator in map(inner, source):
for key, val in generator:
yield key, val
if is_collection(source):
res = when_collection(source)
else:
res = inner(source)
return res
def push(queues, items):
from xoutil.types import is_collection
is_queryobject = IQueryObject.providedBy
if not is_collection(items):
items = (items, )
for item in items:
if is_expression(item):
queues.append([item])
elif is_queryobject(item):
queues.extend([f] for f in item.filters)
def pop_first_of(source, *keys, **kwargs):
'''Similar to :func:`get_first_of` using as `source` either an object or a
mapping and deleting the first attribute or key.
Examples::
>>> somedict = dict(bar='bar-dict', eggs='eggs-dict')
>>> class Foo(object): pass
>>> foo = Foo()
>>> foo.bar = 'bar-obj'
>>> foo.eggs = 'eggs-obj'
>>> pop_first_of((somedict, foo), 'eggs')
'eggs-dict'
>>> pop_first_of((somedict, foo), 'eggs')
'eggs-obj'
>>> pop_first_of((somedict, foo), 'eggs') is None
True
>>> pop_first_of((foo, somedict), 'bar')
'bar-obj'
>>> pop_first_of((foo, somedict), 'bar')
'bar-dict'
>>> pop_first_of((foo, somedict), 'bar') is None
True
'''
from xoutil.types import is_collection
def inner(source):
get = smart_getter_and_deleter(source)
res, i = Unset, 0
while (res is Unset) and (i < len(keys)):
res = get(keys[i], Unset)
i += 1
return res
if is_collection(source):
res = Unset
source = iter(source)
probe = next(source, None)
while res is Unset and probe:
res = inner(probe)
probe = next(source, None)
else:
res = inner(source)
return res if res is not Unset else kwargs.get('default', None)
def test_iscollection():
from xoutil.eight import range
from xoutil.types import is_collection
from xoutil.collections import UserList, UserDict
assert is_collection('all strings are iterable') is False
assert is_collection(1) is False
assert is_collection(range(1)) is True
assert is_collection({}) is False
assert is_collection(tuple()) is True
assert is_collection(set()) is True
assert is_collection(a for a in range(100)) is True
class Foobar(UserList):
pass
assert is_collection(Foobar()) is True
class Foobar(UserDict):
pass
assert is_collection(Foobar()) is False
def concatfiles(*files):
'''Concat several files to a single one.
Each positional argument must be either:
- a file-like object (ready to be passed to :func:`shutil.copyfileobj`)
- a string, the file path.
The last positional argument is the target. If it's file-like object it
must be open for writing, and the caller is the responsible for closing
it.
Alternatively if there are only two positional arguments and the first is
a collection, the sources will be the members of the first argument.
'''
import shutil
from xoutil.eight import string_types
from xoutil.types import is_collection
if len(files) < 2:
raise TypeError('At least 2 files must be passed to concatfiles.')
elif len(files) == 2:
files, target = files[0], files[1]
if not is_collection(files):
files = [files]
else:
files, target = files[:-1], files[-1]
if isinstance(target, string_types):
target, opened = open(target, 'wb'), True
else:
opened = False
try:
for f in files:
if isinstance(f, string_types):
fh = open(f, 'rb')
closefh = True
else:
fh = f
closefh = False
try:
shutil.copyfileobj(fh, target)
finally:
if closefh:
fh.close()
finally:
if opened:
target.close()
def first_n(iterable, n=1, fill=Unset):
'''Takes the first `n` items from iterable.
If there are less than `n` items in the iterable and `fill` is
:class:`~xoutil.types.Unset`, a StopIteration exception is raised;
otherwise it's used as a filling pattern as explained below.
:param iterable: An iterable from which the first `n` items should be
collected.
:param n: The number of items to collect
:type n: int
:param fill: The filling pattern to use. It may be:
- a collection, in which case `first_n` fills the last items
by cycling over `fill`.
- anything else is used as the filling pattern by repeating.
:returns: The first `n` items from `iterable`, probably with a filling
pattern at the end.
:rtype: generator object
.. versionadded:: 1.2.0
.. versionchanged:: 1.4.0 The notion of collection for the `fill`
argument uses :class:`xoutil.types.is_collection`
instead of probing for the ``__iter__`` method.
'''
if fill is not Unset:
from xoutil.types import is_collection
from itertools import cycle, repeat, chain
if is_collection(fill):
fill = cycle(fill)
else:
fill = repeat(fill)
seq = chain(iterable, fill)
else:
seq = iter(iterable)
while n > 0:
yield next(seq)
n -= 1
def slides(iterable, width=2, fill=None):
'''Creates a sliding window of a given `width` over an iterable::
>>> list(slides(range(1, 11)))
[(1, 2), (3, 4), (5, 6), (7, 8), (9, 10)]
If the iterator does not yield a width-aligned number of items, the last
slice returned is filled with `fill` (by default None)::
>>> list(slides(range(1, 11), width=3)) # doctest: +ELLIPSIS
[(1, 2, 3), (4, 5, 6), (7, 8, 9), (10, None, None)]
.. versionchanged:: 1.4.0 If the `fill` argument is a collection is cycled
over to get the filling, just like in :func:`first_n`.
.. versionchanged:: 1.4.2 The `fill` argument now defaults to None,
instead of Unset.
'''
from itertools import cycle, repeat
from xoutil.types import is_collection
pos = 0
res = []
iterator = iter(iterable)
current = next(iterator, Unset)
while current is not Unset:
if pos < width:
res.append(current)
current = next(iterator, Unset)
pos = pos + 1
else:
yield tuple(res)
res = []
pos = 0
if res:
if is_collection(fill):
fill = cycle(fill)
else:
fill = repeat(fill)
while pos < width:
res.append(next(fill))
pos += 1
yield tuple(res)
def smart_copy(*args, **kwargs):
'''Copies the first apparition of attributes (or keys) from `sources` to
`target`.
:param sources: The objects from which to extract keys or attributes.
:param target: The object to fill.
:param defaults: Default values for the attributes to be copied as
explained below. Defaults to False.
:type defaults: Either a bool, a dictionary, an iterable or a callable.
Every `sources` and `target` are always positional arguments. There should
be at least one source. `target` will always be the last positional
argument.
If `defaults` is a dictionary or an iterable then only the names provided
by itering over `defaults` will be copied. If `defaults` is a dictionary,
and one of its key is not found in any of the `sources`, then the value of
the key in the dictionary is copied to `target` unless:
- It's the value :class:`xoutil.types.Required` or an instance of Required.
- An exception object
- A sequence with is first value being a subclass of Exception. In which
case :class:`xoutil.data.adapt_exception` is used.
In these cases a KeyError is raised if the key is not found in the
sources.
If `default` is an iterable and a key is not found in any of the sources,
None is copied to `target`.
If `defaults` is a callable then it should receive one positional
arguments for the current `attribute name` and several keyword arguments
(we pass ``source``) and return either True or False if the attribute
should be copied.
If `defaults` is False (or None) only the attributes that do not start
with a "_" are copied, if it's True all attributes are copied.
When `target` is not a mapping only valid Python identifiers will be
copied.
Each `source` is considered a mapping if it's an instance of
`collections.Mapping` or a `MappingProxyType`.
The `target` is considered a mapping if it's an instance of
`collections.MutableMapping`.
:returns: `target`.
.. versionchanged:: 1.7.0 `defaults` is now keyword only.
'''
from collections import MutableMapping
from xoutil.types import is_collection, is_mapping, Required
from xoutil.data import adapt_exception
from xoutil.validators.identifiers import is_valid_identifier
defaults = kwargs.pop('defaults', False)
if kwargs:
raise TypeError('smart_copy does not accept a "%s" keyword argument'
% kwargs.keys()[0])
sources, target = args[:-1], args[-1]
if not sources:
raise TypeError('smart_copy requires at least one source')
if isinstance(target, (bool, type(None), int, float, str_base)):
raise TypeError('target should be a mutable object, not %s' %
type(target))
if isinstance(target, MutableMapping):
def setter(key, val):
target[key] = val
else:
def setter(key, val):
if is_valid_identifier(key):
setattr(target, key, val)
_mapping = is_mapping(defaults)
if _mapping or is_collection(defaults):
for key, val in ((key, get_first_of(sources, key, default=Unset))
for key in defaults):
if val is Unset:
if _mapping:
val = defaults.get(key, None)
else:
val = None
exc = adapt_exception(val, key=key)
if exc or val is Required or isinstance(val, Required):
raise KeyError(key)
setter(key, val)
else:
keys = []
for source in sources:
get = smart_getter(source)
if is_mapping(source):
items = (name for name in source)
else:
items = dir(source)
for key in items:
private = isinstance(key, str_base) and key.startswith('_')
if (defaults is False or defaults is None) and private:
copy = False
elif callable(defaults):
copy = defaults(key, source=source)
else:
copy = True
if key not in keys:
keys.append(key)
if copy:
setter(key, get(key))
return target
