cola/compat.py

   1 # pylint: disable=unused-import,redefined-builtin,undefined-variable
   2 from __future__ import absolute_import, division, print_function, unicode_literals
   3 import os
   4 import sys
   5
   6 try:
   7     import urllib2 as parse  # noqa
   8 except ImportError:
   9     # Python 3
  10     from urllib import parse  # noqa
  11
  12
  13 PY_VERSION = sys.version_info[:2]  # (2, 7)
  14 PY_VERSION_MAJOR = PY_VERSION[0]
  15 PY2 = PY_VERSION_MAJOR == 2
  16 PY3 = PY_VERSION_MAJOR >= 3
  17 PY26_PLUS = PY2 and sys.version_info[1] >= 6
  18 WIN32 = sys.platform in {'win32', 'cygwin'}
  19 ENCODING = 'utf-8'
  20
  21
  22 if PY3:
  23
  24     def bstr(value, encoding=ENCODING):
  25         return bytes(value, encoding=encoding)
  26
  27 elif PY26_PLUS:
  28     bstr = bytes
  29 else:
  30     # Python <= 2.5
  31     bstr = str
  32
  33
  34 if PY3:
  35
  36     def bchr(i):
  37         return bytes([i])
  38
  39     int_types = (int,)
  40     maxsize = sys.maxsize
  41     ustr = str
  42     uchr = chr
  43 else:
  44     bchr = chr
  45     maxsize = 2**31
  46     ustr = unicode  # noqa
  47     uchr = unichr  # noqa
  48     int_types = (int, long)  # noqa
  49
  50 # Qt's max 32-bit signed integer range (-2147483648 to 2147483647)
  51 maxint = (2**31) - 1
  52
  53
  54 def setenv(key, value):
  55     """Compatibility wrapper for setting environment variables
  56
  57     Why?  win32 requires putenv().  UNIX only requires os.environ.
  58     """
  59     if not PY3 and isinstance(value, ustr):
  60         value = value.encode(ENCODING, 'replace')
  61     os.environ[key] = value
  62     os.putenv(key, value)
  63
  64
  65 def unsetenv(key):
  66     """Compatibility wrapper for unsetting environment variables"""
  67     os.environ.pop(key, None)
  68     if hasattr(os, 'unsetenv'):
  69         os.unsetenv(key)
  70
  71
  72 def no_op(value):
  73     """Return the value as-is"""
  74     return value
  75
  76
  77 def byte_offset_to_int_converter():
  78     """Return a function to convert byte string offsets into ints
  79
  80     Indexing into python3 bytes returns ints, Python2 returns str.
  81     Thus, on Python2 we need to use `ord()` to convert the byte into
  82     an integer.  It's already an int on Python3, so we use no_op there.
  83     """
  84     if PY2:
  85         result = ord
  86     else:
  87         result = no_op
  88     return result