/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
 22import sys
 23import re
 24import os
 25from stat import *
 26import getopt
 27
 28err = sys.stderr.write
 29dbg = err
 30rep = sys.stdout.write
 31
 32new_interpreter = None
 33
 34def 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
 62ispythonprog = re.compile('^[a-zA-Z0-9_]+\.py$')
 63def ispython(name):
 64    return ispythonprog.match(name) >= 0
 65
 66def 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
 88def 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
141def 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
148if __name__ == '__main__':
149    main()