1#! /usr/bin/env python3
2# Check that all ".pyc" files exist and are up-to-date
3# Uses module 'os'
4
5import sys
6import os
7from stat import ST_MTIME
8import importlib.util
9
10# PEP 3147 compatibility (PYC Repository Directories)
11cache_from_source = (importlib.util.cache_from_source if sys.implementation.cache_tag
12                     else lambda path: path + 'c')
13
14
15def main():
16    if len(sys.argv) > 1:
17        verbose = (sys.argv[1] == '-v')
18        silent = (sys.argv[1] == '-s')
19    else:
20        verbose = silent = False
21    MAGIC = importlib.util.MAGIC_NUMBER
22    if not silent:
23        print('Using MAGIC word', repr(MAGIC))
24    for dirname in sys.path:
25        try:
26            names = os.listdir(dirname)
27        except OSError:
28            print('Cannot list directory', repr(dirname))
29            continue
30        if not silent:
31            print('Checking ', repr(dirname), '...')
32        for name in sorted(names):
33            if name.endswith('.py'):
34                name = os.path.join(dirname, name)
35                try:
36                    st = os.stat(name)
37                except OSError:
38                    print('Cannot stat', repr(name))
39                    continue
40                if verbose:
41                    print('Check', repr(name), '...')
42                name_c = cache_from_source(name)
43                try:
44                    with open(name_c, 'rb') as f:
45                        magic_str = f.read(4)
46                        mtime_str = f.read(4)
47                except IOError:
48                    print('Cannot open', repr(name_c))
49                    continue
50                if magic_str != MAGIC:
51                    print('Bad MAGIC word in ".pyc" file', end=' ')
52                    print(repr(name_c))
53                    continue
54                mtime = get_long(mtime_str)
55                if mtime in {0, -1}:
56                    print('Bad ".pyc" file', repr(name_c))
57                elif mtime != st[ST_MTIME]:
58                    print('Out-of-date ".pyc" file', end=' ')
59                    print(repr(name_c))
60
61
62def get_long(s):
63    if len(s) != 4:
64        return -1
65    return s[0] + (s[1] << 8) + (s[2] << 16) + (s[3] << 24)
66
67
68if __name__ == '__main__':
69    main()
70