Tools/scripts/pathfix.py

   1 #! /usr/bin/env python
   2
   3 # Change the #! line occurring in Python scripts.  The new interpreter
   4 # pathname must be given with a -i option.
   5 #
   6 # Command line arguments are files or directories to be processed.
   7 # Directories are searched recursively for files whose name looks
   8 # like a python module.
   9 # Symbolic links are always ignored (except as explicit directory
  10 # arguments).  Of course, the original file is kept as a back-up
  11 # (with a "~" attached to its name).
  12 #
  13 # Undoubtedly you can do this using find and sed or perl, but this is
  14 # a nice example of Python code that recurses down a directory tree
  15 # and uses regular expressions.  Also note several subtleties like
  16 # preserving the file's mode and avoiding to even write a temp file
  17 # when no changes are needed for a file.
  18 #
  19 # NB: by changing only the function fixfile() you can turn this
  20 # into a program for a different change to Python programs...
  21
  22 import sys
  23 import re
  24 import os
  25 from stat import *
  26 import getopt
  27
  28 err = sys.stderr.write
  29 dbg = err
  30 rep = sys.stdout.write
  31
  32 new_interpreter = None
  33
  34 def main():
  35     global new_interpreter
  36     usage = ('usage: %s -i /interpreter file-or-directory ...\n' %
  37              sys.argv[0])
  38     try:
  39         opts, args = getopt.getopt(sys.argv[1:], 'i:')
  40     except getopt.error, msg:
  41         err(msg + '\n')
  42         err(usage)
  43         sys.exit(2)
  44     for o, a in opts:
  45         if o == '-i':
  46             new_interpreter = a
  47     if not new_interpreter or new_interpreter[0] != '/' or not args:
  48         err('-i option or file-or-directory missing\n')
  49         err(usage)
  50         sys.exit(2)
  51     bad = 0
  52     for arg in args:
  53         if os.path.isdir(arg):
  54             if recursedown(arg): bad = 1
  55         elif os.path.islink(arg):
  56             err(arg + ': will not process symbolic links\n')
  57             bad = 1
  58         else:
  59             if fix(arg): bad = 1
  60     sys.exit(bad)
  61
  62 ispythonprog = re.compile('^[a-zA-Z0-9_]+\.py$')
  63 def ispython(name):
  64     return ispythonprog.match(name) >= 0
  65
  66 def recursedown(dirname):
  67     dbg('recursedown(%r)\n' % (dirname,))
  68     bad = 0
  69     try:
  70         names = os.listdir(dirname)
  71     except os.error, msg:
  72         err('%s: cannot list directory: %r\n' % (dirname, msg))
  73         return 1
  74     names.sort()
  75     subdirs = []
  76     for name in names:
  77         if name in (os.curdir, os.pardir): continue
  78         fullname = os.path.join(dirname, name)
  79         if os.path.islink(fullname): pass
  80         elif os.path.isdir(fullname):
  81             subdirs.append(fullname)
  82         elif ispython(name):
  83             if fix(fullname): bad = 1
  84     for fullname in subdirs:
  85         if recursedown(fullname): bad = 1
  86     return bad
  87
  88 def fix(filename):
  89 ##  dbg('fix(%r)\n' % (filename,))
  90     try:
  91         f = open(filename, 'r')
  92     except IOError, msg:
  93         err('%s: cannot open: %r\n' % (filename, msg))
  94         return 1
  95     line = f.readline()
  96     fixed = fixline(line)
  97     if line == fixed:
  98         rep(filename+': no change\n')
  99         f.close()
 100         return
 101     head, tail = os.path.split(filename)
 102     tempname = os.path.join(head, '@' + tail)
 103     try:
 104         g = open(tempname, 'w')
 105     except IOError, msg:
 106         f.close()
 107         err('%s: cannot create: %r\n' % (tempname, msg))
 108         return 1
 109     rep(filename + ': updating\n')
 110     g.write(fixed)
 111     BUFSIZE = 8*1024
 112     while 1:
 113         buf = f.read(BUFSIZE)
 114         if not buf: break
 115         g.write(buf)
 116     g.close()
 117     f.close()
 118
 119     # Finishing touch -- move files
 120
 121     # First copy the file's mode to the temp file
 122     try:
 123         statbuf = os.stat(filename)
 124         os.chmod(tempname, statbuf[ST_MODE] & 07777)
 125     except os.error, msg:
 126         err('%s: warning: chmod failed (%r)\n' % (tempname, msg))
 127     # Then make a backup of the original file as filename~
 128     try:
 129         os.rename(filename, filename + '~')
 130     except os.error, msg:
 131         err('%s: warning: backup failed (%r)\n' % (filename, msg))
 132     # Now move the temp file to the original file
 133     try:
 134         os.rename(tempname, filename)
 135     except os.error, msg:
 136         err('%s: rename failed (%r)\n' % (filename, msg))
 137         return 1
 138     # Return succes
 139     return 0
 140
 141 def fixline(line):
 142     if not line.startswith('#!'):
 143         return line
 144     if "python" not in line:
 145         return line
 146     return '#! %s\n' % new_interpreter
 147
 148 if __name__ == '__main__':
 149     main()