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| 1 | +#! /usr/local/bin/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 | +prog = regex.compile('\(#![ \t]*\)\(/[^ \t\n]*\)\(.*\n\)') |
| 143 | + |
| 144 | +def fixline(line): |
| 145 | + if prog.match(line) < 0: |
| 146 | + return line |
| 147 | + head, tail = prog.group(1, 3) |
| 148 | + return head + new_interpreter + tail |
| 149 | + |
| 150 | +main() |
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