/Demo/scripts/mkrcs.py

 1#! /usr/bin/env python
 2
 3# A rather specialized script to make sure that a symbolic link named
 4# RCS exists pointing to a real RCS directory in a parallel tree
 5# referenced as RCStree in an ancestor directory.
 6# (I use this because I like my RCS files to reside on a physically
 7# different machine).
 8
 9import os
10
11def main():
12    rcstree = 'RCStree'
13    rcs = 'RCS'
14    if os.path.islink(rcs):
15        print '%r is a symlink to %r' % (rcs, os.readlink(rcs))
16        return
17    if os.path.isdir(rcs):
18        print '%r is an ordinary directory' % (rcs,)
19        return
20    if os.path.exists(rcs):
21        print '%r is a file?!?!' % (rcs,)
22        return
23    #
24    p = os.getcwd()
25    up = ''
26    down = ''
27    # Invariants:
28    # (1) join(p, down) is the current directory
29    # (2) up is the same directory as p
30    # Ergo:
31    # (3) join(up, down) is the current directory
32    #print 'p =', repr(p)
33    while not os.path.isdir(os.path.join(p, rcstree)):
34        head, tail = os.path.split(p)
35        #print 'head = %r; tail = %r' % (head, tail)
36        if not tail:
37            print 'Sorry, no ancestor dir contains %r' % (rcstree,)
38            return
39        p = head
40        up = os.path.join(os.pardir, up)
41        down = os.path.join(tail, down)
42        #print 'p = %r; up = %r; down = %r' % (p, up, down)
43    there = os.path.join(up, rcstree)
44    there = os.path.join(there, down)
45    there = os.path.join(there, rcs)
46    if os.path.isdir(there):
47        print '%r already exists' % (there, )
48    else:
49        print 'making %r' % (there,)
50        makedirs(there)
51    print 'making symlink %r -> %r' % (rcs, there)
52    os.symlink(there, rcs)
53
54def makedirs(p):
55    if not os.path.isdir(p):
56        head, tail = os.path.split(p)
57        makedirs(head)
58        os.mkdir(p, 0777)
59
60if __name__ == "__main__":
61    main()