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
   9 import os
  10
  11 def 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
  54 def 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
  60 if __name__ == "__main__":
  61     main()