1# Copyright 2015-2017 Google Inc. All Rights Reserved. 2# 3# Licensed under the Apache License, Version 2.0 (the "License"); 4# you may not use this file except in compliance with the License. 5# You may obtain a copy of the License at 6# 7# http://www.apache.org/licenses/LICENSE-2.0 8# 9# Unless required by applicable law or agreed to in writing, software 10# distributed under the License is distributed on an "AS IS" BASIS, 11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12# See the License for the specific language governing permissions and 13# limitations under the License. 14"""Utilities for Python2 / Python3 compatibility.""" 15 16import io 17import os 18import sys 19 20PY3 = sys.version_info[0] >= 3 21PY36 = sys.version_info[0] >= 3 and sys.version_info[1] >= 6 22 23if PY3: 24 StringIO = io.StringIO 25 BytesIO = io.BytesIO 26 27 import codecs 28 29 def open_with_encoding(filename, mode, encoding, newline=''): # pylint: disable=unused-argument 30 return codecs.open(filename, mode=mode, encoding=encoding) 31 32 import functools 33 lru_cache = functools.lru_cache 34 35 range = range 36 ifilter = filter 37 raw_input = input 38 39 import configparser 40 41 # Mappings from strings to booleans (such as '1' to True, 'false' to False, 42 # etc.) 43 CONFIGPARSER_BOOLEAN_STATES = configparser.ConfigParser.BOOLEAN_STATES 44else: 45 import __builtin__ 46 import cStringIO 47 StringIO = BytesIO = cStringIO.StringIO 48 49 open_with_encoding = io.open 50 51 # Python 2.7 doesn't have a native LRU cache, so do nothing. 52 def lru_cache(maxsize=128, typed=False): 53 54 def fake_wrapper(user_function): 55 return user_function 56 57 return fake_wrapper 58 59 range = xrange 60 61 from itertools import ifilter 62 raw_input = raw_input 63 64 import ConfigParser as configparser 65 CONFIGPARSER_BOOLEAN_STATES = configparser.ConfigParser._boolean_states # pylint: disable=protected-access 66 67 68def EncodeAndWriteToStdout(s, encoding='utf-8'): 69 """Encode the given string and emit to stdout. 70 71 The string may contain non-ascii characters. This is a problem when stdout is 72 redirected, because then Python doesn't know the encoding and we may get a 73 UnicodeEncodeError. 74 75 Arguments: 76 s: (string) The string to encode. 77 encoding: (string) The encoding of the string. 78 """ 79 if PY3: 80 sys.stdout.buffer.write(s.encode(encoding)) 81 elif sys.platform == 'win32': 82 # On python 2 and Windows universal newline transformation will be in 83 # effect on stdout. Python 2 will not let us avoid the easily because 84 # it happens based on whether the file handle is opened in O_BINARY or 85 # O_TEXT state. However we can tell Windows itself to change the current 86 # mode, and python 2 will follow suit. However we must take care to change 87 # the mode on the actual external stdout not just the current sys.stdout 88 # which may have been monkey-patched inside the python environment. 89 import msvcrt # pylint: disable=g-import-not-at-top 90 if sys.__stdout__ is sys.stdout: 91 msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY) 92 sys.stdout.write(s.encode(encoding)) 93 else: 94 sys.stdout.write(s.encode(encoding)) 95 96 97if PY3: 98 unicode = str # pylint: disable=redefined-builtin,invalid-name 99else: 100 101 def unicode(s): # pylint: disable=invalid-name 102 """Force conversion of s to unicode.""" 103 return __builtin__.unicode(s, 'utf-8') 104 105 106# In Python 3.2+, readfp is deprecated in favor of read_file, which doesn't 107# exist in Python 2 yet. To avoid deprecation warnings, subclass ConfigParser to 108# fix this - now read_file works across all Python versions we care about. 109class ConfigParser(configparser.ConfigParser): 110 if not PY3: 111 112 def read_file(self, fp, source=None): 113 self.readfp(fp, filename=source) 114