python/samba/common.py

   1 # Samba common functions
   2 #
   3 # Copyright (C) Matthieu Patou <mat@matws.net>
   4 # Copyright (C) Lumir Balhar <lbalhar@redhat.com> 2017
   5 #
   6 # This program is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; either version 3 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 #
  19
  20
  21 def cmp(x, y):
  22     """
  23     Replacement for built-in function cmp that was removed in Python 3
  24
  25     Compare the two objects x and y and return an integer according to
  26     the outcome. The return value is negative if x < y, zero if x == y
  27     and strictly positive if x > y.
  28     """
  29
  30     return (x > y) - (x < y)
  31
  32
  33 def confirm(msg, forced=False, allow_all=False):
  34     """confirm an action with the user
  35
  36     :param msg: A string to print to the user
  37     :param forced: Are the answer forced
  38     """
  39     if forced:
  40         print("%s [YES]" % msg)
  41         return True
  42
  43     mapping = {
  44         'Y': True,
  45         'YES': True,
  46         '': False,
  47         'N': False,
  48         'NO': False,
  49     }
  50
  51     prompt = '[y/N]'
  52
  53     if allow_all:
  54         mapping['ALL'] = 'ALL'
  55         mapping['NONE'] = 'NONE'
  56         prompt = '[y/N/all/none]'
  57
  58     while True:
  59         v = input(msg + ' %s ' % prompt)
  60         v = v.upper()
  61         if v in mapping:
  62             return mapping[v]
  63         print("Unknown response '%s'" % v)
  64
  65
  66 def normalise_int32(ivalue):
  67     """normalise a ldap integer to signed 32 bit"""
  68     if int(ivalue) & 0x80000000 and int(ivalue) > 0:
  69         return str(int(ivalue) - 0x100000000)
  70     return str(ivalue)
  71
  72
  73 # Sometimes in PY3 we have variables whose content can be 'bytes' or
  74 # 'str' and we can't be sure which. Generally this is because the
  75 # code variable can be initialised (or reassigned) a value from different
  76 # api(s) or functions depending on complex conditions or logic. Or another
  77 # common case is in PY2 the variable is 'type <str>' and in PY3 it is
  78 # 'class <str>' and the function to use e.g. b64encode requires 'bytes'
  79 # in PY3. In such cases it would be nice to avoid excessive testing in
  80 # the client code. Calling such a helper function should be avoided
  81 # if possible but sometimes this just isn't possible.
  82 # If a 'str' object is passed in it is encoded using 'utf8' or if 'bytes'
  83 # is passed in it is returned unchanged.
  84 # Using this function is PY2/PY3 code should ensure in most cases
  85 # the PY2 code runs unchanged in PY2 whereas the code in PY3 possibly
  86 # encodes the variable (see PY2 implementation of this function below)
  87 def get_bytes(bytesorstring):
  88     tmp = bytesorstring
  89     if isinstance(bytesorstring, str):
  90         tmp = bytesorstring.encode('utf8')
  91     elif not isinstance(bytesorstring, bytes):
  92         raise ValueError('Expected bytes or string for %s:%s' % (type(bytesorstring), bytesorstring))
  93     return tmp
  94
  95 # helper function to get a string from a variable that maybe 'str' or
  96 # 'bytes' if 'bytes' then it is decoded using 'utf8'. If 'str' is passed
  97 # it is returned unchanged
  98 # Using this function is PY2/PY3 code should ensure in most cases
  99 # the PY2 code runs unchanged in PY2 whereas the code in PY3 possibly
 100 # decodes the variable (see PY2 implementation of this function below)
 101 def get_string(bytesorstring):
 102     tmp = bytesorstring
 103     if isinstance(bytesorstring, bytes):
 104         tmp = bytesorstring.decode('utf8')
 105     elif not isinstance(bytesorstring, str):
 106         raise ValueError('Expected bytes or string for %s:%s' % (type(bytesorstring), bytesorstring))
 107     return tmp