crunch_scripts/subst.py

   1 import os
   2 import glob
   3
   4 def search(c):
   5     DEFAULT = 0
   6     DOLLAR = 1
   7
   8     i = 0
   9     state = DEFAULT
  10     start = None
  11     depth = 0
  12     while i < len(c):
  13         if c[i] == '\\':
  14             i += 1
  15         elif state == DEFAULT:
  16             if c[i] == '$':
  17                 state = DOLLAR
  18                 if depth == 0:
  19                     start = i
  20             elif c[i] == ')':
  21                 if depth == 1:
  22                     return [start, i]
  23                 if depth > 0:
  24                     depth -= 1
  25         elif state == DOLLAR:
  26             if c[i] == '(':
  27                 depth += 1
  28             state = DEFAULT
  29         i += 1
  30     if depth != 0:
  31         raise Exception("Substitution error, mismatched parentheses {}".format(c))
  32     return None
  33
  34 def sub_file(v):
  35     return os.path.join(os.environ['TASK_KEEPMOUNT'], v)
  36
  37 def sub_dir(v):
  38     d = os.path.dirname(v)
  39     if d == '':
  40         d = v
  41     return os.path.join(os.environ['TASK_KEEPMOUNT'], d)
  42
  43 def sub_basename(v):
  44     return os.path.splitext(os.path.basename(v))[0]
  45
  46 def sub_glob(v):
  47     return glob.glob(v)[0]
  48
  49 default_subs = {"file ": sub_file,
  50                 "dir ": sub_dir,
  51                 "basename ": sub_basename,
  52                 "glob ": sub_glob}
  53
  54 def do_substitution(p, c, subs=default_subs):
  55     while True:
  56         #print("c is", c)
  57         m = search(c)
  58         if m != None:
  59             v = do_substitution(p, c[m[0]+2 : m[1]])
  60             var = True
  61             for sub in subs:
  62                 if v.startswith(sub):
  63                     r = subs[sub](v[len(sub):])
  64                     var = False
  65                     break
  66             if var:
  67                 r = p[v]
  68
  69             c = c[:m[0]] + r + c[m[1]+1:]
  70         else:
  71             return c