native_client_sdk/src/tools/lib/quote.py

   1 #!/usr/bin/env python
   2 # Copyright 2014 The Chromium Authors. All rights reserved.
   3 # Use of this source code is governed by a BSD-style license that can be
   4 # found in the LICENSE file.
   5
   6 import re
   7
   8 def quote(input_str, specials, escape='\\'):
   9   """Returns a quoted version of |str|, where every character in the
  10   iterable |specials| (usually a set or a string) and the escape
  11   character |escape| is replaced by the original character preceded by
  12   the escape character."""
  13
  14   assert len(escape) == 1
  15
  16   # Since escape is used in replacement pattern context, so we need to
  17   # ensure that it stays a simple literal and cannot affect the \1
  18   # that will follow it.
  19   if escape == '\\':
  20     escape = '\\\\'
  21   if len(specials) > 0:
  22     return re.sub(r'(' + r'|'.join(specials)+r'|'+escape + r')',
  23                   escape + r'\1', input_str)
  24   return re.sub(r'(' + escape + r')', escape + r'\1', input_str)
  25
  26
  27 def unquote(input_str, specials, escape='\\'):
  28   """Splits the input string |input_str| where special characters in
  29   the input |specials| are, if not quoted by |escape|, used as
  30   delimiters to split the string.  The returned value is a list of
  31   strings of alternating non-specials and specials used to break the
  32   string. The list will always begin with a possibly empty string of
  33   non-specials, but may end with either specials or non-specials."""
  34
  35   assert len(escape) == 1
  36
  37   out = []
  38   cur_out = []
  39   cur_special = False
  40   lit_next = False
  41   for c in input_str:
  42     if cur_special:
  43       lit_next = (c == escape)
  44       if c not in specials or lit_next:
  45         cur_special = False
  46         out.append(''.join(cur_out))
  47         if not lit_next:
  48           cur_out = [c]
  49         else:
  50           cur_out = []
  51       else:
  52         cur_out.append(c)
  53     else:
  54       if lit_next:
  55         cur_out.append(c)
  56         lit_next = False
  57       else:
  58         lit_next = c == escape
  59         if c not in specials:
  60           if not lit_next:
  61             cur_out.append(c)
  62         else:
  63           out.append(''.join(cur_out))
  64           cur_out = [c]
  65           cur_special = True
  66   out.append(''.join(cur_out))
  67   return out