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 main()