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# -*- coding: utf-8 -*-
# Copyright (c) 2010 Mark Sandstrom
# Copyright (c) 2011-2013 Raphaël Barrois
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
import collections
#: String for splitting an attribute name into a
#: (subfactory_name, subfactory_field) tuple.
ATTR_SPLITTER = '__'
def extract_dict(prefix, kwargs, pop=True, exclude=()):
"""Extracts all values beginning with a given prefix from a dict.
Can either 'pop' or 'get' them;
Args:
prefix (str): the prefix to use for lookups
kwargs (dict): the dict from which values should be extracted
pop (bool): whether to use pop (True) or get (False)
exclude (iterable): list of prefixed keys that shouldn't be extracted
Returns:
A new dict, containing values from kwargs and beginning with
prefix + ATTR_SPLITTER. That full prefix is removed from the keys
of the returned dict.
"""
prefix = prefix + ATTR_SPLITTER
extracted = {}
for key in list(kwargs):
if key in exclude:
continue
if key.startswith(prefix):
new_key = key[len(prefix):]
if pop:
value = kwargs.pop(key)
else:
value = kwargs[key]
extracted[new_key] = value
return extracted
def multi_extract_dict(prefixes, kwargs, pop=True, exclude=()):
"""Extracts all values from a given list of prefixes.
Extraction will start with longer prefixes.
Args:
prefixes (str list): the prefixes to use for lookups
kwargs (dict): the dict from which values should be extracted
pop (bool): whether to use pop (True) or get (False)
exclude (iterable): list of prefixed keys that shouldn't be extracted
Returns:
dict(str => dict): a dict mapping each prefix to the dict of extracted
key/value.
"""
results = {}
exclude = list(exclude)
for prefix in sorted(prefixes, key=lambda x: -len(x)):
extracted = extract_dict(prefix, kwargs, pop=pop, exclude=exclude)
results[prefix] = extracted
exclude.extend(
['%s%s%s' % (prefix, ATTR_SPLITTER, key) for key in extracted])
return results
def import_object(module_name, attribute_name):
"""Import an object from its absolute path.
Example:
>>> import_object('datetime', 'datetime')
<type 'datetime.datetime'>
"""
module = __import__(module_name, {}, {}, [attribute_name], 0)
return getattr(module, attribute_name)
def log_pprint(args=(), kwargs=None):
kwargs = kwargs or {}
return ', '.join(
[str(arg) for arg in args] +
['%s=%r' % item for item in kwargs.items()]
)
class ResetableIterator(object):
"""An iterator wrapper that can be 'reset()' to its start."""
def __init__(self, iterator, **kwargs):
super(ResetableIterator, self).__init__(**kwargs)
self.iterator = iter(iterator)
self.past_elements = collections.deque()
self.next_elements = collections.deque()
def __iter__(self):
while True:
if self.next_elements:
yield self.next_elements.popleft()
else:
value = next(self.iterator)
self.past_elements.append(value)
yield value
def reset(self):
self.next_elements.clear()
self.next_elements.extend(self.past_elements)
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