419 lines
12 KiB
Python
419 lines
12 KiB
Python
# util/compat.py
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# Copyright (C) 2005-2019 the SQLAlchemy authors and contributors
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# <see AUTHORS file>
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#
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# This module is part of SQLAlchemy and is released under
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# the MIT License: http://www.opensource.org/licenses/mit-license.php
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"""Handle Python version/platform incompatibilities."""
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import collections
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import contextlib
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import inspect
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import operator
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import sys
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py36 = sys.version_info >= (3, 6)
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py33 = sys.version_info >= (3, 3)
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py35 = sys.version_info >= (3, 5)
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py32 = sys.version_info >= (3, 2)
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py3k = sys.version_info >= (3, 0)
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py2k = sys.version_info < (3, 0)
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py265 = sys.version_info >= (2, 6, 5)
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jython = sys.platform.startswith("java")
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pypy = hasattr(sys, "pypy_version_info")
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win32 = sys.platform.startswith("win")
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cpython = not pypy and not jython # TODO: something better for this ?
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contextmanager = contextlib.contextmanager
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dottedgetter = operator.attrgetter
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namedtuple = collections.namedtuple
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next = next # noqa
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FullArgSpec = collections.namedtuple(
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"FullArgSpec",
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[
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"args",
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"varargs",
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"varkw",
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"defaults",
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"kwonlyargs",
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"kwonlydefaults",
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"annotations",
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],
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)
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try:
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import threading
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except ImportError:
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import dummy_threading as threading # noqa
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# work around http://bugs.python.org/issue2646
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if py265:
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safe_kwarg = lambda arg: arg # noqa
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else:
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safe_kwarg = str
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def inspect_getfullargspec(func):
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"""Fully vendored version of getfullargspec from Python 3.3."""
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if inspect.ismethod(func):
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func = func.__func__
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if not inspect.isfunction(func):
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raise TypeError("{!r} is not a Python function".format(func))
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co = func.__code__
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if not inspect.iscode(co):
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raise TypeError("{!r} is not a code object".format(co))
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nargs = co.co_argcount
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names = co.co_varnames
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nkwargs = co.co_kwonlyargcount if py3k else 0
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args = list(names[:nargs])
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kwonlyargs = list(names[nargs : nargs + nkwargs])
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nargs += nkwargs
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varargs = None
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if co.co_flags & inspect.CO_VARARGS:
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varargs = co.co_varnames[nargs]
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nargs = nargs + 1
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varkw = None
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if co.co_flags & inspect.CO_VARKEYWORDS:
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varkw = co.co_varnames[nargs]
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return FullArgSpec(
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args,
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varargs,
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varkw,
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func.__defaults__,
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kwonlyargs,
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func.__kwdefaults__ if py3k else None,
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func.__annotations__ if py3k else {},
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)
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if py3k:
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import base64
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import builtins
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import configparser
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import itertools
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import pickle
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from functools import reduce
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from io import BytesIO as byte_buffer
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from io import StringIO
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from itertools import zip_longest
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from urllib.parse import (
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quote_plus,
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unquote_plus,
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parse_qsl,
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quote,
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unquote,
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)
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string_types = (str,)
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binary_types = (bytes,)
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binary_type = bytes
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text_type = str
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int_types = (int,)
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iterbytes = iter
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itertools_filterfalse = itertools.filterfalse
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itertools_filter = filter
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itertools_imap = map
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exec_ = getattr(builtins, "exec")
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import_ = getattr(builtins, "__import__")
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print_ = getattr(builtins, "print")
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def b(s):
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return s.encode("latin-1")
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def b64decode(x):
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return base64.b64decode(x.encode("ascii"))
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def b64encode(x):
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return base64.b64encode(x).decode("ascii")
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def decode_backslashreplace(text, encoding):
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return text.decode(encoding, errors="backslashreplace")
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def cmp(a, b):
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return (a > b) - (a < b)
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def reraise(tp, value, tb=None, cause=None):
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if cause is not None:
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assert cause is not value, "Same cause emitted"
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value.__cause__ = cause
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if value.__traceback__ is not tb:
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raise value.with_traceback(tb)
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raise value
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def u(s):
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return s
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def ue(s):
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return s
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if py32:
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callable = callable # noqa
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else:
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def callable(fn): # noqa
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return hasattr(fn, "__call__")
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else:
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import base64
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import ConfigParser as configparser # noqa
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import itertools
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from StringIO import StringIO # noqa
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from cStringIO import StringIO as byte_buffer # noqa
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from itertools import izip_longest as zip_longest # noqa
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from urllib import quote # noqa
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from urllib import quote_plus # noqa
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from urllib import unquote # noqa
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from urllib import unquote_plus # noqa
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from urlparse import parse_qsl # noqa
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try:
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import cPickle as pickle
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except ImportError:
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import pickle # noqa
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string_types = (basestring,) # noqa
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binary_types = (bytes,)
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binary_type = str
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text_type = unicode # noqa
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int_types = int, long # noqa
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callable = callable # noqa
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cmp = cmp # noqa
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reduce = reduce # noqa
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b64encode = base64.b64encode
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b64decode = base64.b64decode
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itertools_filterfalse = itertools.ifilterfalse
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itertools_filter = itertools.ifilter
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itertools_imap = itertools.imap
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def b(s):
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return s
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def exec_(func_text, globals_, lcl=None):
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if lcl is None:
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exec("exec func_text in globals_")
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else:
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exec("exec func_text in globals_, lcl")
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def iterbytes(buf):
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return (ord(byte) for byte in buf)
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def import_(*args):
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if len(args) == 4:
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args = args[0:3] + ([str(arg) for arg in args[3]],)
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return __import__(*args)
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def print_(*args, **kwargs):
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fp = kwargs.pop("file", sys.stdout)
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if fp is None:
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return
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for arg in enumerate(args):
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if not isinstance(arg, basestring): # noqa
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arg = str(arg)
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fp.write(arg)
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def u(s):
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# this differs from what six does, which doesn't support non-ASCII
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# strings - we only use u() with
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# literal source strings, and all our source files with non-ascii
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# in them (all are tests) are utf-8 encoded.
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return unicode(s, "utf-8") # noqa
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def ue(s):
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return unicode(s, "unicode_escape") # noqa
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def decode_backslashreplace(text, encoding):
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try:
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return text.decode(encoding)
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except UnicodeDecodeError:
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# regular "backslashreplace" for an incompatible encoding raises:
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# "TypeError: don't know how to handle UnicodeDecodeError in
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# error callback"
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return repr(text)[1:-1].decode()
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def safe_bytestring(text):
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# py2k only
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if not isinstance(text, string_types):
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return unicode(text).encode("ascii", errors="backslashreplace")
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elif isinstance(text, unicode):
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return text.encode("ascii", errors="backslashreplace")
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else:
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return text
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# not as nice as that of Py3K, but at least preserves
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# the code line where the issue occurred
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exec(
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"def reraise(tp, value, tb=None, cause=None):\n"
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" if cause is not None:\n"
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" assert cause is not value, 'Same cause emitted'\n"
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" raise tp, value, tb\n"
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)
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if py35:
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from inspect import formatannotation
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def inspect_formatargspec(
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args,
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varargs=None,
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varkw=None,
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defaults=None,
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kwonlyargs=(),
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kwonlydefaults={},
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annotations={},
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formatarg=str,
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formatvarargs=lambda name: "*" + name,
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formatvarkw=lambda name: "**" + name,
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formatvalue=lambda value: "=" + repr(value),
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formatreturns=lambda text: " -> " + text,
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formatannotation=formatannotation,
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):
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"""Copy formatargspec from python 3.7 standard library.
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Python 3 has deprecated formatargspec and requested that Signature
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be used instead, however this requires a full reimplementation
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of formatargspec() in terms of creating Parameter objects and such.
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Instead of introducing all the object-creation overhead and having
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to reinvent from scratch, just copy their compatibility routine.
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Utimately we would need to rewrite our "decorator" routine completely
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which is not really worth it right now, until all Python 2.x support
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is dropped.
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"""
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def formatargandannotation(arg):
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result = formatarg(arg)
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if arg in annotations:
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result += ": " + formatannotation(annotations[arg])
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return result
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specs = []
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if defaults:
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firstdefault = len(args) - len(defaults)
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for i, arg in enumerate(args):
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spec = formatargandannotation(arg)
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if defaults and i >= firstdefault:
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spec = spec + formatvalue(defaults[i - firstdefault])
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specs.append(spec)
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if varargs is not None:
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specs.append(formatvarargs(formatargandannotation(varargs)))
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else:
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if kwonlyargs:
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specs.append("*")
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if kwonlyargs:
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for kwonlyarg in kwonlyargs:
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spec = formatargandannotation(kwonlyarg)
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if kwonlydefaults and kwonlyarg in kwonlydefaults:
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spec += formatvalue(kwonlydefaults[kwonlyarg])
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specs.append(spec)
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if varkw is not None:
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specs.append(formatvarkw(formatargandannotation(varkw)))
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result = "(" + ", ".join(specs) + ")"
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if "return" in annotations:
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result += formatreturns(formatannotation(annotations["return"]))
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return result
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elif py2k:
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from inspect import formatargspec as _inspect_formatargspec
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def inspect_formatargspec(*spec, **kw):
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# convert for a potential FullArgSpec from compat.getfullargspec()
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return _inspect_formatargspec(*spec[0:4], **kw) # noqa
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else:
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from inspect import formatargspec as inspect_formatargspec # noqa
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# Fix deprecation of accessing ABCs straight from collections module
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# (which will stop working in 3.8).
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if py33:
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import collections.abc as collections_abc
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else:
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import collections as collections_abc # noqa
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@contextlib.contextmanager
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def nested(*managers):
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"""Implement contextlib.nested, mostly for unit tests.
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As tests still need to run on py2.6 we can't use multiple-with yet.
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Function is removed in py3k but also emits deprecation warning in 2.7
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so just roll it here for everyone.
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"""
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exits = []
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vars_ = []
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exc = (None, None, None)
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try:
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for mgr in managers:
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exit_ = mgr.__exit__
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enter = mgr.__enter__
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vars_.append(enter())
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exits.append(exit_)
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yield vars_
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except:
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exc = sys.exc_info()
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finally:
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while exits:
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exit_ = exits.pop() # noqa
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try:
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if exit_(*exc):
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exc = (None, None, None)
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except:
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exc = sys.exc_info()
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if exc != (None, None, None):
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reraise(exc[0], exc[1], exc[2])
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def raise_from_cause(exception, exc_info=None):
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if exc_info is None:
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exc_info = sys.exc_info()
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exc_type, exc_value, exc_tb = exc_info
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cause = exc_value if exc_value is not exception else None
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reraise(type(exception), exception, tb=exc_tb, cause=cause)
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def with_metaclass(meta, *bases):
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"""Create a base class with a metaclass.
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Drops the middle class upon creation.
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Source: http://lucumr.pocoo.org/2013/5/21/porting-to-python-3-redux/
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"""
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class metaclass(meta):
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__call__ = type.__call__
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__init__ = type.__init__
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def __new__(cls, name, this_bases, d):
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if this_bases is None:
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return type.__new__(cls, name, (), d)
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return meta(name, bases, d)
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return metaclass("temporary_class", None, {})
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