cola/core.py

   1 """This module provides core functions for handling unicode and UNIX quirks
   2
   3 OSX and others are known to interrupt system calls
   4
   5     http://en.wikipedia.org/wiki/PCLSRing
   6     http://en.wikipedia.org/wiki/Unix_philosophy#Worse_is_better
   7
   8 The {read,write,wait}_nointr functions handle this situation
   9 """
  10 import errno
  11
  12 # Some files are not in UTF-8; some other aren't in any codification.
  13 # Remember that GIT doesn't care about encodings (saves binary data)
  14 _encoding_tests = [
  15     'utf-8',
  16     'iso-8859-15',
  17     'windows1252',
  18     'ascii',
  19     # <-- add encodings here
  20 ]
  21
  22 def decode(enc):
  23     """decode(encoded_string) returns an unencoded unicode string
  24     """
  25     for encoding in _encoding_tests:
  26         try:
  27             return unicode(enc.decode(encoding))
  28         except:
  29             pass
  30     # this shouldn't ever happen... FIXME
  31     return unicode(enc)
  32
  33 def encode(unenc):
  34     """encode(unencoded_string) returns a string encoded in utf-8
  35     """
  36     return unenc.encode('utf-8', 'replace')
  37
  38 def read_nointr(fh):
  39     """Read from a filehandle and retry when interrupted"""
  40     while True:
  41         try:
  42             content = fh.read()
  43             break
  44         except IOError, e:
  45             if e.errno == errno.EINTR:
  46                 continue
  47             raise e
  48         except OSError, e:
  49             if e.errno == errno.EINTR:
  50                 continue
  51             raise e
  52     return content
  53
  54 def write_nointr(fh, content):
  55     """Write to a filehandle and retry when interrupted"""
  56     while True:
  57         try:
  58             content = fh.write(content)
  59             break
  60         except IOError, e:
  61             if e.errno == errno.EINTR:
  62                 continue
  63             raise e
  64         except OSError, e:
  65             if e.errno == errno.EINTR:
  66                 continue
  67             raise e
  68     return content
  69
  70 def wait_nointr(proc):
  71     """Wait on a subprocess and retry when interrupted"""
  72     while True:
  73         try:
  74             status = proc.wait()
  75             break
  76         except IOError, e:
  77             if e.errno == errno.EINTR:
  78                 continue
  79             raise e
  80         except OSError, e:
  81             if e.errno == errno.EINTR:
  82                 continue
  83             raise e
  84     return status