Mini Shell
# Copyright (c) 2009, Giampaolo Rodola'. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Module which provides compatibility with older Python versions.
This is more future-compatible rather than the opposite (prefer latest
Python 3 way of doing things).
"""
import collections
import contextlib
import errno
import functools
import os
import sys
import types
__all__ = [
# constants
"PY3",
# builtins
"long", "range", "super", "unicode", "basestring",
# literals
"u", "b",
# collections module
"lru_cache",
# shutil module
"which", "get_terminal_size",
# contextlib module
"redirect_stderr",
# python 3 exceptions
"FileNotFoundError", "PermissionError", "ProcessLookupError",
"InterruptedError", "ChildProcessError", "FileExistsError"]
PY3 = sys.version_info[0] >= 3
_SENTINEL = object()
if PY3:
long = int
xrange = range
unicode = str
basestring = str
range = range
def u(s):
return s
def b(s):
return s.encode("latin-1")
else:
long = long
range = xrange
unicode = unicode
basestring = basestring
def u(s):
return unicode(s, "unicode_escape")
def b(s):
return s
# --- builtins
# Python 3 super().
# Taken from "future" package.
# Credit: Ryan Kelly
if PY3:
super = super
else:
_builtin_super = super
def super(type_=_SENTINEL, type_or_obj=_SENTINEL, framedepth=1):
"""Like Python 3 builtin super(). If called without any arguments
it attempts to infer them at runtime.
"""
if type_ is _SENTINEL:
f = sys._getframe(framedepth)
try:
# Get the function's first positional argument.
type_or_obj = f.f_locals[f.f_code.co_varnames[0]]
except (IndexError, KeyError):
raise RuntimeError('super() used in a function with no args')
try:
# Get the MRO so we can crawl it.
mro = type_or_obj.__mro__
except (AttributeError, RuntimeError):
try:
mro = type_or_obj.__class__.__mro__
except AttributeError:
raise RuntimeError('super() used in a non-newstyle class')
for type_ in mro:
# Find the class that owns the currently-executing method.
for meth in type_.__dict__.values():
# Drill down through any wrappers to the underlying func.
# This handles e.g. classmethod() and staticmethod().
try:
while not isinstance(meth, types.FunctionType):
if isinstance(meth, property):
# Calling __get__ on the property will invoke
# user code which might throw exceptions or
# have side effects
meth = meth.fget
else:
try:
meth = meth.__func__
except AttributeError:
meth = meth.__get__(type_or_obj, type_)
except (AttributeError, TypeError):
continue
if meth.func_code is f.f_code:
break # found
else:
# Not found. Move onto the next class in MRO.
continue
break # found
else:
raise RuntimeError('super() called outside a method')
# Dispatch to builtin super().
if type_or_obj is not _SENTINEL:
return _builtin_super(type_, type_or_obj)
return _builtin_super(type_)
# --- exceptions
if PY3:
FileNotFoundError = FileNotFoundError # NOQA
PermissionError = PermissionError # NOQA
ProcessLookupError = ProcessLookupError # NOQA
InterruptedError = InterruptedError # NOQA
ChildProcessError = ChildProcessError # NOQA
FileExistsError = FileExistsError # NOQA
else:
# https://github.com/PythonCharmers/python-future/blob/exceptions/
# src/future/types/exceptions/pep3151.py
import platform
def _instance_checking_exception(base_exception=Exception):
def wrapped(instance_checker):
class TemporaryClass(base_exception):
def __init__(self, *args, **kwargs):
if len(args) == 1 and isinstance(args[0], TemporaryClass):
unwrap_me = args[0]
for attr in dir(unwrap_me):
if not attr.startswith('__'):
setattr(self, attr, getattr(unwrap_me, attr))
else:
super(TemporaryClass, self).__init__(*args, **kwargs) # noqa
class __metaclass__(type):
def __instancecheck__(cls, inst):
return instance_checker(inst)
def __subclasscheck__(cls, classinfo):
value = sys.exc_info()[1]
return isinstance(value, cls)
TemporaryClass.__name__ = instance_checker.__name__
TemporaryClass.__doc__ = instance_checker.__doc__
return TemporaryClass
return wrapped
@_instance_checking_exception(EnvironmentError)
def FileNotFoundError(inst):
return getattr(inst, 'errno', _SENTINEL) == errno.ENOENT
@_instance_checking_exception(EnvironmentError)
def ProcessLookupError(inst):
return getattr(inst, 'errno', _SENTINEL) == errno.ESRCH
@_instance_checking_exception(EnvironmentError)
def PermissionError(inst):
return getattr(inst, 'errno', _SENTINEL) in (
errno.EACCES, errno.EPERM)
@_instance_checking_exception(EnvironmentError)
def InterruptedError(inst):
return getattr(inst, 'errno', _SENTINEL) == errno.EINTR
@_instance_checking_exception(EnvironmentError)
def ChildProcessError(inst):
return getattr(inst, 'errno', _SENTINEL) == errno.ECHILD
@_instance_checking_exception(EnvironmentError)
def FileExistsError(inst):
return getattr(inst, 'errno', _SENTINEL) == errno.EEXIST
if platform.python_implementation() != "CPython":
try:
raise OSError(errno.EEXIST, "perm")
except FileExistsError:
pass
except OSError:
raise RuntimeError(
"broken or incompatible Python implementation, see: "
"https://github.com/giampaolo/psutil/issues/1659")
# --- stdlib additions
# py 3.2 functools.lru_cache
# Taken from: http://code.activestate.com/recipes/578078
# Credit: Raymond Hettinger
try:
from functools import lru_cache
except ImportError:
try:
from threading import RLock
except ImportError:
from dummy_threading import RLock
_CacheInfo = collections.namedtuple(
"CacheInfo", ["hits", "misses", "maxsize", "currsize"])
class _HashedSeq(list):
__slots__ = ('hashvalue', )
def __init__(self, tup, hash=hash):
self[:] = tup
self.hashvalue = hash(tup)
def __hash__(self):
return self.hashvalue
def _make_key(args, kwds, typed,
kwd_mark=(_SENTINEL, ),
fasttypes=set((int, str, frozenset, type(None))), # noqa
sorted=sorted, tuple=tuple, type=type, len=len):
key = args
if kwds:
sorted_items = sorted(kwds.items())
key += kwd_mark
for item in sorted_items:
key += item
if typed:
key += tuple(type(v) for v in args)
if kwds:
key += tuple(type(v) for k, v in sorted_items)
elif len(key) == 1 and type(key[0]) in fasttypes:
return key[0]
return _HashedSeq(key)
def lru_cache(maxsize=100, typed=False):
"""Least-recently-used cache decorator, see:
http://docs.python.org/3/library/functools.html#functools.lru_cache.
"""
def decorating_function(user_function):
cache = {}
stats = [0, 0]
HITS, MISSES = 0, 1
make_key = _make_key
cache_get = cache.get
_len = len
lock = RLock()
root = []
root[:] = [root, root, None, None]
nonlocal_root = [root]
PREV, NEXT, KEY, RESULT = 0, 1, 2, 3
if maxsize == 0:
def wrapper(*args, **kwds):
result = user_function(*args, **kwds)
stats[MISSES] += 1
return result
elif maxsize is None:
def wrapper(*args, **kwds):
key = make_key(args, kwds, typed)
result = cache_get(key, root)
if result is not root:
stats[HITS] += 1
return result
result = user_function(*args, **kwds)
cache[key] = result
stats[MISSES] += 1
return result
else:
def wrapper(*args, **kwds):
if kwds or typed:
key = make_key(args, kwds, typed)
else:
key = args
lock.acquire()
try:
link = cache_get(key)
if link is not None:
root, = nonlocal_root
link_prev, link_next, key, result = link
link_prev[NEXT] = link_next
link_next[PREV] = link_prev
last = root[PREV]
last[NEXT] = root[PREV] = link
link[PREV] = last
link[NEXT] = root
stats[HITS] += 1
return result
finally:
lock.release()
result = user_function(*args, **kwds)
lock.acquire()
try:
root, = nonlocal_root
if key in cache:
pass
elif _len(cache) >= maxsize:
oldroot = root
oldroot[KEY] = key
oldroot[RESULT] = result
root = nonlocal_root[0] = oldroot[NEXT]
oldkey = root[KEY]
root[KEY] = root[RESULT] = None
del cache[oldkey]
cache[key] = oldroot
else:
last = root[PREV]
link = [last, root, key, result]
last[NEXT] = root[PREV] = cache[key] = link
stats[MISSES] += 1
finally:
lock.release()
return result
def cache_info():
"""Report cache statistics."""
lock.acquire()
try:
return _CacheInfo(stats[HITS], stats[MISSES], maxsize,
len(cache))
finally:
lock.release()
def cache_clear():
"""Clear the cache and cache statistics."""
lock.acquire()
try:
cache.clear()
root = nonlocal_root[0]
root[:] = [root, root, None, None]
stats[:] = [0, 0]
finally:
lock.release()
wrapper.__wrapped__ = user_function
wrapper.cache_info = cache_info
wrapper.cache_clear = cache_clear
return functools.update_wrapper(wrapper, user_function)
return decorating_function
# python 3.3
try:
from shutil import which
except ImportError:
def which(cmd, mode=os.F_OK | os.X_OK, path=None):
"""Given a command, mode, and a PATH string, return the path which
conforms to the given mode on the PATH, or None if there is no such
file.
`mode` defaults to os.F_OK | os.X_OK. `path` defaults to the result
of os.environ.get("PATH"), or can be overridden with a custom search
path.
"""
def _access_check(fn, mode):
return (os.path.exists(fn) and os.access(fn, mode) and
not os.path.isdir(fn))
if os.path.dirname(cmd):
if _access_check(cmd, mode):
return cmd
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:
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
Zerion Mini Shell 1.0