478 lines
15 KiB
Python
478 lines
15 KiB
Python
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# Copyright (c) 2009, Giampaolo Rodola'. All rights reserved.
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# Use of this source code is governed by a BSD-style license that can be
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# found in the LICENSE file.
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"""Module which provides compatibility with older Python versions.
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This is more future-compatible rather than the opposite (prefer latest
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Python 3 way of doing things).
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"""
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import collections
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import contextlib
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import errno
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import functools
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import os
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import sys
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import types
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# fmt: off
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__all__ = [
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# constants
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"PY3",
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# builtins
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"long", "range", "super", "unicode", "basestring",
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# literals
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"b",
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# collections module
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"lru_cache",
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# shutil module
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"which", "get_terminal_size",
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# contextlib module
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"redirect_stderr",
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# python 3 exceptions
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"FileNotFoundError", "PermissionError", "ProcessLookupError",
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"InterruptedError", "ChildProcessError", "FileExistsError",
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]
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# fmt: on
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PY3 = sys.version_info[0] >= 3
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_SENTINEL = object()
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if PY3:
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long = int
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xrange = range
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unicode = str
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basestring = str
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range = range
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def b(s):
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return s.encode("latin-1")
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else:
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long = long
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range = xrange
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unicode = unicode
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basestring = basestring
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def b(s):
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return s
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# --- builtins
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# Python 3 super().
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# Taken from "future" package.
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# Credit: Ryan Kelly
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if PY3:
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super = super
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else:
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_builtin_super = super
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def super(type_=_SENTINEL, type_or_obj=_SENTINEL, framedepth=1):
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"""Like Python 3 builtin super(). If called without any arguments
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it attempts to infer them at runtime.
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"""
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if type_ is _SENTINEL:
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f = sys._getframe(framedepth)
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try:
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# Get the function's first positional argument.
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type_or_obj = f.f_locals[f.f_code.co_varnames[0]]
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except (IndexError, KeyError):
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msg = 'super() used in a function with no args'
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raise RuntimeError(msg)
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try:
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# Get the MRO so we can crawl it.
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mro = type_or_obj.__mro__
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except (AttributeError, RuntimeError):
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try:
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mro = type_or_obj.__class__.__mro__
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except AttributeError:
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msg = 'super() used in a non-newstyle class'
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raise RuntimeError(msg)
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for type_ in mro:
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# Find the class that owns the currently-executing method.
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for meth in type_.__dict__.values():
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# Drill down through any wrappers to the underlying func.
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# This handles e.g. classmethod() and staticmethod().
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try:
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while not isinstance(meth, types.FunctionType):
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if isinstance(meth, property):
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# Calling __get__ on the property will invoke
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# user code which might throw exceptions or
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# have side effects
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meth = meth.fget
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else:
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try:
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meth = meth.__func__
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except AttributeError:
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meth = meth.__get__(type_or_obj, type_)
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except (AttributeError, TypeError):
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continue
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if meth.func_code is f.f_code:
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break # found
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else:
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# Not found. Move onto the next class in MRO.
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continue
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break # found
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else:
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msg = 'super() called outside a method'
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raise RuntimeError(msg)
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# Dispatch to builtin super().
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if type_or_obj is not _SENTINEL:
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return _builtin_super(type_, type_or_obj)
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return _builtin_super(type_)
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# --- exceptions
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if PY3:
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FileNotFoundError = FileNotFoundError # NOQA
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PermissionError = PermissionError # NOQA
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ProcessLookupError = ProcessLookupError # NOQA
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InterruptedError = InterruptedError # NOQA
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ChildProcessError = ChildProcessError # NOQA
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FileExistsError = FileExistsError # NOQA
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else:
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# https://github.com/PythonCharmers/python-future/blob/exceptions/
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# src/future/types/exceptions/pep3151.py
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import platform
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def _instance_checking_exception(base_exception=Exception):
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def wrapped(instance_checker):
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class TemporaryClass(base_exception):
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def __init__(self, *args, **kwargs):
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if len(args) == 1 and isinstance(args[0], TemporaryClass):
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unwrap_me = args[0]
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for attr in dir(unwrap_me):
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if not attr.startswith('__'):
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setattr(self, attr, getattr(unwrap_me, attr))
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else:
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super(TemporaryClass, self).__init__( # noqa
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*args, **kwargs
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)
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class __metaclass__(type):
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def __instancecheck__(cls, inst):
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return instance_checker(inst)
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def __subclasscheck__(cls, classinfo):
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value = sys.exc_info()[1]
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return isinstance(value, cls)
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TemporaryClass.__name__ = instance_checker.__name__
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TemporaryClass.__doc__ = instance_checker.__doc__
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return TemporaryClass
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return wrapped
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@_instance_checking_exception(EnvironmentError)
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def FileNotFoundError(inst):
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return getattr(inst, 'errno', _SENTINEL) == errno.ENOENT
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@_instance_checking_exception(EnvironmentError)
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def ProcessLookupError(inst):
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return getattr(inst, 'errno', _SENTINEL) == errno.ESRCH
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@_instance_checking_exception(EnvironmentError)
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def PermissionError(inst):
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return getattr(inst, 'errno', _SENTINEL) in (errno.EACCES, errno.EPERM)
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@_instance_checking_exception(EnvironmentError)
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def InterruptedError(inst):
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return getattr(inst, 'errno', _SENTINEL) == errno.EINTR
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@_instance_checking_exception(EnvironmentError)
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def ChildProcessError(inst):
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return getattr(inst, 'errno', _SENTINEL) == errno.ECHILD
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@_instance_checking_exception(EnvironmentError)
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def FileExistsError(inst):
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return getattr(inst, 'errno', _SENTINEL) == errno.EEXIST
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if platform.python_implementation() != "CPython":
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try:
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raise OSError(errno.EEXIST, "perm")
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except FileExistsError:
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pass
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except OSError:
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msg = (
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"broken or incompatible Python implementation, see: "
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"https://github.com/giampaolo/psutil/issues/1659"
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)
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raise RuntimeError(msg)
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# --- stdlib additions
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# py 3.2 functools.lru_cache
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# Taken from: http://code.activestate.com/recipes/578078
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# Credit: Raymond Hettinger
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try:
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from functools import lru_cache
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except ImportError:
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try:
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from threading import RLock
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except ImportError:
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from dummy_threading import RLock
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_CacheInfo = collections.namedtuple(
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"CacheInfo", ["hits", "misses", "maxsize", "currsize"]
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)
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class _HashedSeq(list):
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__slots__ = ('hashvalue',)
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def __init__(self, tup, hash=hash):
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self[:] = tup
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self.hashvalue = hash(tup)
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def __hash__(self):
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return self.hashvalue
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def _make_key(
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args,
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kwds,
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typed,
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kwd_mark=(_SENTINEL,),
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fasttypes=set((int, str, frozenset, type(None))), # noqa
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sorted=sorted,
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tuple=tuple,
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type=type,
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len=len,
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):
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key = args
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if kwds:
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sorted_items = sorted(kwds.items())
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key += kwd_mark
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for item in sorted_items:
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key += item
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if typed:
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key += tuple(type(v) for v in args)
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if kwds:
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key += tuple(type(v) for k, v in sorted_items)
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elif len(key) == 1 and type(key[0]) in fasttypes:
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return key[0]
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return _HashedSeq(key)
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def lru_cache(maxsize=100, typed=False):
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"""Least-recently-used cache decorator, see:
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http://docs.python.org/3/library/functools.html#functools.lru_cache.
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"""
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def decorating_function(user_function):
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cache = {}
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stats = [0, 0]
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HITS, MISSES = 0, 1
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make_key = _make_key
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cache_get = cache.get
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_len = len
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lock = RLock()
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root = []
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root[:] = [root, root, None, None]
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nonlocal_root = [root]
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PREV, NEXT, KEY, RESULT = 0, 1, 2, 3
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if maxsize == 0:
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def wrapper(*args, **kwds):
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result = user_function(*args, **kwds)
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stats[MISSES] += 1
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return result
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elif maxsize is None:
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def wrapper(*args, **kwds):
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key = make_key(args, kwds, typed)
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result = cache_get(key, root)
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if result is not root:
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stats[HITS] += 1
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return result
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result = user_function(*args, **kwds)
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cache[key] = result
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stats[MISSES] += 1
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return result
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else:
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def wrapper(*args, **kwds):
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if kwds or typed:
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key = make_key(args, kwds, typed)
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else:
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key = args
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lock.acquire()
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try:
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link = cache_get(key)
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if link is not None:
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(root,) = nonlocal_root
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link_prev, link_next, key, result = link
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link_prev[NEXT] = link_next
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link_next[PREV] = link_prev
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last = root[PREV]
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last[NEXT] = root[PREV] = link
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link[PREV] = last
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link[NEXT] = root
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stats[HITS] += 1
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return result
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finally:
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lock.release()
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result = user_function(*args, **kwds)
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lock.acquire()
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try:
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(root,) = nonlocal_root
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if key in cache:
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pass
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elif _len(cache) >= maxsize:
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oldroot = root
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oldroot[KEY] = key
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oldroot[RESULT] = result
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root = nonlocal_root[0] = oldroot[NEXT]
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oldkey = root[KEY]
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root[KEY] = root[RESULT] = None
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del cache[oldkey]
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cache[key] = oldroot
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else:
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last = root[PREV]
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link = [last, root, key, result]
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last[NEXT] = root[PREV] = cache[key] = link
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stats[MISSES] += 1
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finally:
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lock.release()
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return result
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def cache_info():
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"""Report cache statistics."""
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lock.acquire()
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try:
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return _CacheInfo(
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stats[HITS], stats[MISSES], maxsize, len(cache)
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)
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finally:
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lock.release()
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def cache_clear():
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"""Clear the cache and cache statistics."""
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lock.acquire()
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try:
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cache.clear()
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root = nonlocal_root[0]
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root[:] = [root, root, None, None]
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stats[:] = [0, 0]
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finally:
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lock.release()
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wrapper.__wrapped__ = user_function
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wrapper.cache_info = cache_info
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wrapper.cache_clear = cache_clear
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return functools.update_wrapper(wrapper, user_function)
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return decorating_function
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# python 3.3
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try:
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from shutil import which
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except ImportError:
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def which(cmd, mode=os.F_OK | os.X_OK, path=None):
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"""Given a command, mode, and a PATH string, return the path which
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conforms to the given mode on the PATH, or None if there is no such
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file.
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`mode` defaults to os.F_OK | os.X_OK. `path` defaults to the result
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of os.environ.get("PATH"), or can be overridden with a custom search
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path.
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"""
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def _access_check(fn, mode):
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return (
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os.path.exists(fn)
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and os.access(fn, mode)
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|
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and not os.path.isdir(fn)
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)
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if os.path.dirname(cmd):
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if _access_check(cmd, mode):
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return cmd
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|
return None
|
||
|
|
|
||
|
|
if path is None:
|
||
|
|
path = os.environ.get("PATH", os.defpath)
|
||
|
|
if not path:
|
||
|
|
return None
|
||
|
|
path = path.split(os.pathsep)
|
||
|
|
|
||
|
|
if sys.platform == "win32":
|
||
|
|
if os.curdir not in path:
|
||
|
|
path.insert(0, os.curdir)
|
||
|
|
|
||
|
|
pathext = os.environ.get("PATHEXT", "").split(os.pathsep)
|
||
|
|
if any(cmd.lower().endswith(ext.lower()) for ext in pathext):
|
||
|
|
files = [cmd]
|
||
|
|
else:
|
||
|
|
files = [cmd + ext for ext in pathext]
|
||
|
|
else:
|
||
|
|
files = [cmd]
|
||
|
|
|
||
|
|
seen = set()
|
||
|
|
for dir in path:
|
||
|
|
normdir = os.path.normcase(dir)
|
||
|
|
if normdir not in seen:
|
||
|
|
seen.add(normdir)
|
||
|
|
for thefile in files:
|
||
|
|
name = os.path.join(dir, thefile)
|
||
|
|
if _access_check(name, mode):
|
||
|
|
return name
|
||
|
|
return None
|
||
|
|
|
||
|
|
|
||
|
|
# python 3.3
|
||
|
|
try:
|
||
|
|
from shutil import get_terminal_size
|
||
|
|
except ImportError:
|
||
|
|
|
||
|
|
def get_terminal_size(fallback=(80, 24)):
|
||
|
|
try:
|
||
|
|
import fcntl
|
||
|
|
import struct
|
||
|
|
import termios
|
||
|
|
except ImportError:
|
||
|
|
return fallback
|
||
|
|
else:
|
||
|
|
try:
|
||
|
|
# This should work on Linux.
|
||
|
|
res = struct.unpack(
|
||
|
|
'hh', fcntl.ioctl(1, termios.TIOCGWINSZ, '1234')
|
||
|
|
)
|
||
|
|
return (res[1], res[0])
|
||
|
|
except Exception: # noqa: BLE001
|
||
|
|
return fallback
|
||
|
|
|
||
|
|
|
||
|
|
# python 3.3
|
||
|
|
try:
|
||
|
|
from subprocess import TimeoutExpired as SubprocessTimeoutExpired
|
||
|
|
except ImportError:
|
||
|
|
|
||
|
|
class SubprocessTimeoutExpired(Exception):
|
||
|
|
pass
|
||
|
|
|
||
|
|
|
||
|
|
# python 3.5
|
||
|
|
try:
|
||
|
|
from contextlib import redirect_stderr
|
||
|
|
except ImportError:
|
||
|
|
|
||
|
|
@contextlib.contextmanager
|
||
|
|
def redirect_stderr(new_target):
|
||
|
|
original = sys.stderr
|
||
|
|
try:
|
||
|
|
sys.stderr = new_target
|
||
|
|
yield new_target
|
||
|
|
finally:
|
||
|
|
sys.stderr = original
|