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1#! /usr/bin/env python
2
3# Fix Python source files to avoid using
4#       def method(self, (arg1, ..., argn)):
5# instead of the more rational
6#       def method(self, arg1, ..., argn):
7#
8# Command line arguments are files or directories to be processed.
9# Directories are searched recursively for files whose name looks
10# like a python module.
11# Symbolic links are always ignored (except as explicit directory
12# arguments).  Of course, the original file is kept as a back-up
13# (with a "~" attached to its name).
14# It complains about binaries (files containing null bytes)
15# and about files that are ostensibly not Python files: if the first
16# line starts with '#!' and does not contain the string 'python'.
17#
18# Changes made are reported to stdout in a diff-like format.
19#
20# Undoubtedly you can do this using find and sed or perl, but this is
21# a nice example of Python code that recurses down a directory tree
22# and uses regular expressions.  Also note several subtleties like
23# preserving the file's mode and avoiding to even write a temp file
24# when no changes are needed for a file.
25#
26# NB: by changing only the function fixline() you can turn this
27# into a program for a different change to Python programs...
28
29import sys
30import re
31import os
32from stat import *
33
34err = sys.stderr.write
35dbg = err
36rep = sys.stdout.write
37
38def main():
39    bad = 0
40    if not sys.argv[1:]: # No arguments
41        err('usage: ' + sys.argv[0] + ' file-or-directory ...\n')
42        sys.exit(2)
43    for arg in sys.argv[1:]:
44        if os.path.isdir(arg):
45            if recursedown(arg): bad = 1
46        elif os.path.islink(arg):
47            err(arg + ': will not process symbolic links\n')
48            bad = 1
49        else:
50            if fix(arg): bad = 1
51    sys.exit(bad)
52
53ispythonprog = re.compile('^[a-zA-Z0-9_]+\.py$')
54def ispython(name):
55    return ispythonprog.match(name) >= 0
56
57def recursedown(dirname):
58    dbg('recursedown(%r)\n' % (dirname,))
59    bad = 0
60    try:
61        names = os.listdir(dirname)
62    except os.error, msg:
63        err('%s: cannot list directory: %r\n' % (dirname, msg))
64        return 1
65    names.sort()
66    subdirs = []
67    for name in names:
68        if name in (os.curdir, os.pardir): continue
69        fullname = os.path.join(dirname, name)
70        if os.path.islink(fullname): pass
71        elif os.path.isdir(fullname):
72            subdirs.append(fullname)
73        elif ispython(name):
74            if fix(fullname): bad = 1
75    for fullname in subdirs:
76        if recursedown(fullname): bad = 1
77    return bad
78
79def fix(filename):
80##  dbg('fix(%r)\n' % (filename,))
81    try:
82        f = open(filename, 'r')
83    except IOError, msg:
84        err('%s: cannot open: %r\n' % (filename, msg))
85        return 1
86    head, tail = os.path.split(filename)
87    tempname = os.path.join(head, '@' + tail)
88    g = None
89    # If we find a match, we rewind the file and start over but
90    # now copy everything to a temp file.
91    lineno = 0
92    while 1:
93        line = f.readline()
94        if not line: break
95        lineno = lineno + 1
96        if g is None and '\0' in line:
97            # Check for binary files
98            err(filename + ': contains null bytes; not fixed\n')
99            f.close()
100            return 1
101        if lineno == 1 and g is None and line[:2] == '#!':
102            # Check for non-Python scripts
103            words = line[2:].split()
104            if words and re.search('[pP]ython', words[0]) < 0:
105                msg = filename + ': ' + words[0]
106                msg = msg + ' script; not fixed\n'
107                err(msg)
108                f.close()
109                return 1
110        while line[-2:] == '\\\n':
111            nextline = f.readline()
112            if not nextline: break
113            line = line + nextline
114            lineno = lineno + 1
115        newline = fixline(line)
116        if newline != line:
117            if g is None:
118                try:
119                    g = open(tempname, 'w')
120                except IOError, msg:
121                    f.close()
122                    err('%s: cannot create: %r\n' % (tempname, msg))
123                    return 1
124                f.seek(0)
125                lineno = 0
126                rep(filename + ':\n')
127                continue # restart from the beginning
128            rep(repr(lineno) + '\n')
129            rep('< ' + line)
130            rep('> ' + newline)
131        if g is not None:
132            g.write(newline)
133
134    # End of file
135    f.close()
136    if not g: return 0 # No changes
137
138    # Finishing touch -- move files
139
140    # First copy the file's mode to the temp file
141    try:
142        statbuf = os.stat(filename)
143        os.chmod(tempname, statbuf[ST_MODE] & 07777)
144    except os.error, msg:
145        err('%s: warning: chmod failed (%r)\n' % (tempname, msg))
146    # Then make a backup of the original file as filename~
147    try:
148        os.rename(filename, filename + '~')
149    except os.error, msg:
150        err('%s: warning: backup failed (%r)\n' % (filename, msg))
151    # Now move the temp file to the original file
152    try:
153        os.rename(tempname, filename)
154    except os.error, msg:
155        err('%s: rename failed (%r)\n' % (filename, msg))
156        return 1
157    # Return succes
158    return 0
159
160
161fixpat = '^[ \t]+def +[a-zA-Z0-9_]+ *( *self *, *(( *(.*) *)) *) *:'
162fixprog = re.compile(fixpat)
163
164def fixline(line):
165    if fixprog.match(line) >= 0:
166        (a, b), (c, d) = fixprog.regs[1:3]
167        line = line[:a] + line[c:d] + line[b:]
168    return line
169
170if __name__ == '__main__':
171    main()
172