cola/compat.py

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