| Current File : //lib64/python3.6/site-packages/psutil/_compat.py |
# 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."""
import collections
import functools
import os
import sys
__all__ = ["PY3", "long", "xrange", "unicode", "basestring", "u", "b",
"callable", "lru_cache", "which"]
PY3 = sys.version_info[0] == 3
if PY3:
long = int
xrange = range
unicode = str
basestring = str
def u(s):
return s
def b(s):
return s.encode("latin-1")
else:
long = long
xrange = xrange
unicode = unicode
basestring = basestring
def u(s):
return unicode(s, "unicode_escape")
def b(s):
return s
# removed in 3.0, reintroduced in 3.2
try:
callable = callable
except NameError:
def callable(obj):
return any("__call__" in klass.__dict__ for klass in type(obj).__mro__)
# --- 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=(object(), ),
fasttypes=set((int, str, frozenset, type(None))),
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 = dict()
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