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 regex
  24 import os
  25 from stat import *
  26 import string
  27 import getopt
  28
  29 err = sys.stderr.write
  30 dbg = err
  31 rep = sys.stdout.write
  32
  33 new_interpreter = None
  34
  35 def main():
  36         global new_interpreter
  37         usage = ('usage: %s -i /interpreter file-or-directory ...\n' %
  38                  sys.argv[0])
  39         try:
  40                 opts, args = getopt.getopt(sys.argv[1:], 'i:')
  41         except getopt.error, msg:
  42                 err(msg + '\n')
  43                 err(usage)
  44                 sys.exit(2)
  45         for o, a in opts:
  46                 if o == '-i':
  47                         new_interpreter = a
  48         if not new_interpreter or new_interpreter[0] != '/' or not args:
  49                 err('-i option or file-or-directory missing\n')
  50                 err(usage)
  51                 sys.exit(2)
  52         bad = 0
  53         for arg in args:
  54                 if os.path.isdir(arg):
  55                         if recursedown(arg): bad = 1
  56                 elif os.path.islink(arg):
  57                         err(arg + ': will not process symbolic links\n')
  58                         bad = 1
  59                 else:
  60                         if fix(arg): bad = 1
  61         sys.exit(bad)
  62
  63 ispythonprog = regex.compile('^[a-zA-Z0-9_]+\.py$')
  64 def ispython(name):
  65         return ispythonprog.match(name) >= 0
  66
  67 def recursedown(dirname):
  68         dbg('recursedown(' + `dirname` + ')\n')
  69         bad = 0
  70         try:
  71                 names = os.listdir(dirname)
  72         except os.error, msg:
  73                 err(dirname + ': cannot list directory: ' + `msg` + '\n')
  74                 return 1
  75         names.sort()
  76         subdirs = []
  77         for name in names:
  78                 if name in (os.curdir, os.pardir): continue
  79                 fullname = os.path.join(dirname, name)
  80                 if os.path.islink(fullname): pass
  81                 elif os.path.isdir(fullname):
  82                         subdirs.append(fullname)
  83                 elif ispython(name):
  84                         if fix(fullname): bad = 1
  85         for fullname in subdirs:
  86                 if recursedown(fullname): bad = 1
  87         return bad
  88
  89 def fix(filename):
  90 ##      dbg('fix(' + `filename` + ')\n')
  91         try:
  92                 f = open(filename, 'r')
  93         except IOError, msg:
  94                 err(filename + ': cannot open: ' + `msg` + '\n')
  95                 return 1
  96         line = f.readline()
  97         fixed = fixline(line)
  98         if line == fixed:
  99                 rep(filename+': no change\n')
 100                 f.close()
 101                 return
 102         head, tail = os.path.split(filename)
 103         tempname = os.path.join(head, '@' + tail)
 104         try:
 105                 g = open(tempname, 'w')
 106         except IOError, msg:
 107                 f.close()
 108                 err(tempname+': cannot create: '+`msg`+'\n')
 109                 return 1
 110         rep(filename + ': updating\n')
 111         g.write(fixed)
 112         BUFSIZE = 8*1024
 113         while 1:
 114                 buf = f.read(BUFSIZE)
 115                 if not buf: break
 116                 g.write(buf)
 117         g.close()
 118         f.close()
 119
 120         # Finishing touch -- move files
 121
 122         # First copy the file's mode to the temp file
 123         try:
 124                 statbuf = os.stat(filename)
 125                 os.chmod(tempname, statbuf[ST_MODE] & 07777)
 126         except os.error, msg:
 127                 err(tempname + ': warning: chmod failed (' + `msg` + ')\n')
 128         # Then make a backup of the original file as filename~
 129         try:
 130                 os.rename(filename, filename + '~')
 131         except os.error, msg:
 132                 err(filename + ': warning: backup failed (' + `msg` + ')\n')
 133         # Now move the temp file to the original file
 134         try:
 135                 os.rename(tempname, filename)
 136         except os.error, msg:
 137                 err(filename + ': rename failed (' + `msg` + ')\n')
 138                 return 1
 139         # Return succes
 140         return 0
 141
 142 def fixline(line):
 143         if line[:2] != '#!':
 144                 return line
 145         if string.find(line, "python") < 0:
 146                 return line
 147         return '#! %s\n' % new_interpreter
 148
 149 main()