Source Code for Module zeroinstall.support.escaping

 1  """Functions for escaping and unescaping strings (for URLs, filenames, etc). 
 2   
 3  The underscore escaping functions are useful when generating directory names 
 4  which should be reasonably human-readable, and not contain characters which are 
 5  likely to confuse programs (e.g. ":" doesn't work on Windows, "#" confuses 
 6  cmake, "=" confuses Java, [:;,] confuse anything that uses these as list item 
 7  separators, etc. 
 8   
 9  See also L{zeroinstall.injector.model.escape} for an older escaping scheme. 
10   
11  @since: 1.13 
12  """ 
13   
14  import re 
15   
16  # Copyright (C) 2012, Thomas Leonard 
17  # See the README file for details, or visit http://0install.net. 
18   
19 -def _under_escape(m): 
20          """@rtype: str""" 
21          c = m.group(0) 
22          if c == '/': 
23                  return '__' 
24          else: 
25                  return '_%x_' % ord(c) 
26   
27 -def _ununder_escape(m): 
28          """@rtype: str""" 
29          c = m.group(1) 
30          if c == "": 
31                  return "/" 
32          else: 
33                  return chr(int(m.group(1), 16)) 
34   
35  _troublesome_re = re.compile(r'[]\\[^_`\0-,/:-@{|}~\x7f]') 
36   
37 -def underscore_escape(src): 
38          """Escape troublesome characters in 'src'. 
39          The result is a valid file leaf name (i.e. does not contain / etc). 
40          Letters, digits and characters > 127 are copied unmodified. 
41          '/' becomes '__'. Other characters become '_code_', where code is the 
42          lowercase hex value of the character in Unicode. 
43          @param src: the string to escape 
44          @type src: str 
45          @return: the escaped string 
46          @rtype: str""" 
47          escaped = re.sub(_troublesome_re, _under_escape, src) 
48   
49          # Avoid creating hidden files, or specials (. and ..) 
50          if escaped.startswith("."): 
51                  return "_2e_" + escaped[1:] 
52   
53          return escaped 
54   
55  _escaped_code_re = re.compile('_([0-9a-fA-F]*)_') 
56   
57 -def ununderscore_escape(escaped): 
58          """@type escaped: str 
59          @rtype: str""" 
60          return _escaped_code_re.sub(_ununder_escape, escaped) 
61