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# coding: utf-8
"""Compatibility tricks for Python 3. Mainly to do with unicode."""
import functools
import os
import sys
import re
import shutil
import types
import platform
from .encoding import DEFAULT_ENCODING
def no_code(x, encoding=None):
return x
def decode(s, encoding=None):
encoding = encoding or DEFAULT_ENCODING
return s.decode(encoding, "replace")
def encode(u, encoding=None):
encoding = encoding or DEFAULT_ENCODING
return u.encode(encoding, "replace")
def cast_unicode(s, encoding=None):
if isinstance(s, bytes):
return decode(s, encoding)
return s
def cast_bytes(s, encoding=None):
if not isinstance(s, bytes):
return encode(s, encoding)
return s
def buffer_to_bytes(buf):
"""Cast a buffer object to bytes"""
if not isinstance(buf, bytes):
buf = bytes(buf)
return buf
def _modify_str_or_docstring(str_change_func):
@functools.wraps(str_change_func)
def wrapper(func_or_str):
if isinstance(func_or_str, string_types):
func = None
doc = func_or_str
else:
func = func_or_str
doc = func.__doc__
# PYTHONOPTIMIZE=2 strips docstrings, so they can disappear unexpectedly
if doc is not None:
doc = str_change_func(doc)
if func:
func.__doc__ = doc
return func
return doc
return wrapper
def safe_unicode(e):
"""unicode(e) with various fallbacks. Used for exceptions, which may not be
safe to call unicode() on.
"""
try:
return unicode_type(e)
except UnicodeError:
pass
try:
return str_to_unicode(str(e))
except UnicodeError:
pass
try:
return str_to_unicode(repr(e))
except UnicodeError:
pass
return u'Unrecoverably corrupt evalue'
# shutil.which from Python 3.4
def _shutil_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.
This is a backport of shutil.which from Python 3.4
"""
# Check that a given file can be accessed with the correct mode.
# Additionally check that `file` is not a directory, as on Windows
# directories pass the os.access check.
def _access_check(fn, mode):
return (os.path.exists(fn) and os.access(fn, mode)
and not os.path.isdir(fn))
# If we're given a path with a directory part, look it up directly rather
# than referring to PATH directories. This includes checking relative to the
# current directory, e.g. ./script
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":
# The current directory takes precedence on Windows.
if not os.curdir in path:
path.insert(0, os.curdir)
# PATHEXT is necessary to check on Windows.
pathext = os.environ.get("PATHEXT", "").split(os.pathsep)
# See if the given file matches any of the expected path extensions.
# This will allow us to short circuit when given "python.exe".
# If it does match, only test that one, otherwise we have to try
# others.
if any(cmd.lower().endswith(ext.lower()) for ext in pathext):
files = [cmd]
else:
files = [cmd + ext for ext in pathext]
else:
# On other platforms you don't have things like PATHEXT to tell you
# what file suffixes are executable, so just pass on cmd as-is.
files = [cmd]
seen = set()
for dir in path:
normdir = os.path.normcase(dir)
if not normdir in seen:
seen.add(normdir)
for thefile in files:
name = os.path.join(dir, thefile)
if _access_check(name, mode):
return name
return None
if sys.version_info[0] >= 3:
PY3 = True
# keep reference to builtin_mod because the kernel overrides that value
# to forward requests to a frontend.
def input(prompt=''):
return builtin_mod.input(prompt)
builtin_mod_name = "builtins"
import builtins as builtin_mod
str_to_unicode = no_code
unicode_to_str = no_code
str_to_bytes = encode
bytes_to_str = decode
cast_bytes_py2 = no_code
cast_unicode_py2 = no_code
buffer_to_bytes_py2 = no_code
string_types = (str,)
unicode_type = str
which = shutil.which
def isidentifier(s, dotted=False):
if dotted:
return all(isidentifier(a) for a in s.split("."))
return s.isidentifier()
xrange = range
def iteritems(d): return iter(d.items())
def itervalues(d): return iter(d.values())
getcwd = os.getcwd
MethodType = types.MethodType
def execfile(fname, glob, loc=None, compiler=None):
loc = loc if (loc is not None) else glob
with open(fname, 'rb') as f:
compiler = compiler or compile
exec(compiler(f.read(), fname, 'exec'), glob, loc)
# Refactor print statements in doctests.
_print_statement_re = re.compile(r"\bprint (?P<expr>.*)$", re.MULTILINE)
def _print_statement_sub(match):
expr = match.groups('expr')
return "print(%s)" % expr
@_modify_str_or_docstring
def doctest_refactor_print(doc):
"""Refactor 'print x' statements in a doctest to print(x) style. 2to3
unfortunately doesn't pick up on our doctests.
Can accept a string or a function, so it can be used as a decorator."""
return _print_statement_re.sub(_print_statement_sub, doc)
# Abstract u'abc' syntax:
@_modify_str_or_docstring
def u_format(s):
""""{u}'abc'" --> "'abc'" (Python 3)
Accepts a string or a function, so it can be used as a decorator."""
return s.format(u='')
def get_closure(f):
"""Get a function's closure attribute"""
return f.__closure__
else:
PY3 = False
# keep reference to builtin_mod because the kernel overrides that value
# to forward requests to a frontend.
def input(prompt=''):
return builtin_mod.raw_input(prompt)
builtin_mod_name = "__builtin__"
import __builtin__ as builtin_mod
str_to_unicode = decode
unicode_to_str = encode
str_to_bytes = no_code
bytes_to_str = no_code
cast_bytes_py2 = cast_bytes
cast_unicode_py2 = cast_unicode
buffer_to_bytes_py2 = buffer_to_bytes
string_types = (str, unicode)
unicode_type = unicode
import re
_name_re = re.compile(r"[a-zA-Z_][a-zA-Z0-9_]*$")
def isidentifier(s, dotted=False):
if dotted:
return all(isidentifier(a) for a in s.split("."))
return bool(_name_re.match(s))
xrange = xrange
def iteritems(d): return d.iteritems()
def itervalues(d): return d.itervalues()
getcwd = os.getcwdu
def MethodType(func, instance):
return types.MethodType(func, instance, type(instance))
def doctest_refactor_print(func_or_str):
return func_or_str
def get_closure(f):
"""Get a function's closure attribute"""
return f.func_closure
which = _shutil_which
# Abstract u'abc' syntax:
@_modify_str_or_docstring
def u_format(s):
""""{u}'abc'" --> "u'abc'" (Python 2)
Accepts a string or a function, so it can be used as a decorator."""
return s.format(u='u')
if sys.platform == 'win32':
def execfile(fname, glob=None, loc=None, compiler=None):
loc = loc if (loc is not None) else glob
scripttext = builtin_mod.open(fname).read()+ '\n'
# compile converts unicode filename to str assuming
# ascii. Let's do the conversion before calling compile
if isinstance(fname, unicode):
filename = unicode_to_str(fname)
else:
filename = fname
compiler = compiler or compile
exec(compiler(scripttext, filename, 'exec'), glob, loc)
else:
def execfile(fname, glob=None, loc=None, compiler=None):
if isinstance(fname, unicode):
filename = fname.encode(sys.getfilesystemencoding())
else:
filename = fname
where = [ns for ns in [glob, loc] if ns is not None]
if compiler is None:
builtin_mod.execfile(filename, *where)
else:
scripttext = builtin_mod.open(fname).read().rstrip() + '\n'
exec(compiler(scripttext, filename, 'exec'), glob, loc)
PY2 = not PY3
PYPY = platform.python_implementation() == "PyPy"
def annotate(**kwargs):
"""Python 3 compatible function annotation for Python 2."""
if not kwargs:
raise ValueError('annotations must be provided as keyword arguments')
def dec(f):
if hasattr(f, '__annotations__'):
for k, v in kwargs.items():
f.__annotations__[k] = v
else:
f.__annotations__ = kwargs
return f
return dec
# Parts below taken from six:
# Copyright (c) 2010-2013 Benjamin Peterson
#
# 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.
def with_metaclass(meta, *bases):
"""Create a base class with a metaclass."""
return meta("_NewBase", bases, {})