1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
|
#!/usr/bin/env python3
# Change the #! line (shebang) occurring in Python scripts. The new interpreter
# pathname must be given with a -i option.
#
# Command line arguments are files or directories to be processed.
# Directories are searched recursively for files whose name looks
# like a python module.
# Symbolic links are always ignored (except as explicit directory
# arguments).
# The original file is kept as a back-up (with a "~" attached to its name),
# -n flag can be used to disable this.
# Sometimes you may find shebangs with flags such as `#! /usr/bin/env python -si`.
# Normally, pathfix overwrites the entire line, including the flags.
# To change interpreter and keep flags from the original shebang line, use -k.
# Undoubtedly you can do this using find and sed or perl, but this is
# a nice example of Python code that recurses down a directory tree
# and uses regular expressions. Also note several subtleties like
# preserving the file's mode and avoiding to even write a temp file
# when no changes are needed for a file.
#
# NB: by changing only the function fixfile() you can turn this
# into a program for a different change to Python programs...
import sys
import re
import os
from stat import *
import getopt
err = sys.stderr.write
dbg = err
rep = sys.stdout.write
new_interpreter = None
preserve_timestamps = False
create_backup = True
keep_flags = False
def main():
global new_interpreter
global preserve_timestamps
global create_backup
global keep_flags
usage = ('usage: %s -i /interpreter -p -n -k file-or-directory ...\n' %
sys.argv[0])
try:
opts, args = getopt.getopt(sys.argv[1:], 'i:kpn')
except getopt.error as msg:
err(str(msg) + '\n')
err(usage)
sys.exit(2)
for o, a in opts:
if o == '-i':
new_interpreter = a.encode()
if o == '-p':
preserve_timestamps = True
if o == '-n':
create_backup = False
if o == '-k':
keep_flags = True
if not new_interpreter or not new_interpreter.startswith(b'/') or \
not args:
err('-i option or file-or-directory missing\n')
err(usage)
sys.exit(2)
bad = 0
for arg in args:
if os.path.isdir(arg):
if recursedown(arg): bad = 1
elif os.path.islink(arg):
err(arg + ': will not process symbolic links\n')
bad = 1
else:
if fix(arg): bad = 1
sys.exit(bad)
ispythonprog = re.compile(r'^[a-zA-Z0-9_]+\.py$')
def ispython(name):
return bool(ispythonprog.match(name))
def recursedown(dirname):
dbg('recursedown(%r)\n' % (dirname,))
bad = 0
try:
names = os.listdir(dirname)
except OSError as msg:
err('%s: cannot list directory: %r\n' % (dirname, msg))
return 1
names.sort()
subdirs = []
for name in names:
if name in (os.curdir, os.pardir): continue
fullname = os.path.join(dirname, name)
if os.path.islink(fullname): pass
elif os.path.isdir(fullname):
subdirs.append(fullname)
elif ispython(name):
if fix(fullname): bad = 1
for fullname in subdirs:
if recursedown(fullname): bad = 1
return bad
def fix(filename):
## dbg('fix(%r)\n' % (filename,))
try:
f = open(filename, 'rb')
except IOError as msg:
err('%s: cannot open: %r\n' % (filename, msg))
return 1
with f:
line = f.readline()
fixed = fixline(line)
if line == fixed:
rep(filename+': no change\n')
return
head, tail = os.path.split(filename)
tempname = os.path.join(head, '@' + tail)
try:
g = open(tempname, 'wb')
except IOError as msg:
err('%s: cannot create: %r\n' % (tempname, msg))
return 1
with g:
rep(filename + ': updating\n')
g.write(fixed)
BUFSIZE = 8*1024
while 1:
buf = f.read(BUFSIZE)
if not buf: break
g.write(buf)
# Finishing touch -- move files
mtime = None
atime = None
# First copy the file's mode to the temp file
try:
statbuf = os.stat(filename)
mtime = statbuf.st_mtime
atime = statbuf.st_atime
os.chmod(tempname, statbuf[ST_MODE] & 0o7777)
except OSError as msg:
err('%s: warning: chmod failed (%r)\n' % (tempname, msg))
# Then make a backup of the original file as filename~
if create_backup:
try:
os.rename(filename, filename + '~')
except OSError as msg:
err('%s: warning: backup failed (%r)\n' % (filename, msg))
else:
try:
os.remove(filename)
except OSError as msg:
err('%s: warning: removing failed (%r)\n' % (filename, msg))
# Now move the temp file to the original file
try:
os.rename(tempname, filename)
except OSError as msg:
err('%s: rename failed (%r)\n' % (filename, msg))
return 1
if preserve_timestamps:
if atime and mtime:
try:
os.utime(filename, (atime, mtime))
except OSError as msg:
err('%s: reset of timestamp failed (%r)\n' % (filename, msg))
return 1
# Return success
return 0
def parse_shebang(shebangline):
shebangline = shebangline.rstrip(b'\n')
start = shebangline.find(b' -')
if start == -1:
return b''
return shebangline[start:]
def fixline(line):
if not line.startswith(b'#!'):
return line
if b"python" not in line:
return line
flags = b''
if keep_flags:
flags = parse_shebang(line)
return b'#! ' + new_interpreter + flags + b'\n'
if __name__ == '__main__':
main()
|
