Tools/scripts/ifdef.py

   1 #! /usr/bin/env python
   2
   3 # Selectively preprocess #ifdef / #ifndef statements.
   4 # Usage:
   5 # ifdef [-Dname] ... [-Uname] ... [file] ...
   6 #
   7 # This scans the file(s), looking for #ifdef and #ifndef preprocessor
   8 # commands that test for one of the names mentioned in the -D and -U
   9 # options.  On standard output it writes a copy of the input file(s)
  10 # minus those code sections that are suppressed by the selected
  11 # combination of defined/undefined symbols.  The #if(n)def/#else/#else
  12 # lines themselfs (if the #if(n)def tests for one of the mentioned
  13 # names) are removed as well.
  14
  15 # Features: Arbitrary nesting of recognized and unrecognized
  16 # preprocesor statements works correctly.  Unrecognized #if* commands
  17 # are left in place, so it will never remove too much, only too
  18 # little.  It does accept whitespace around the '#' character.
  19
  20 # Restrictions: There should be no comments or other symbols on the
  21 # #if(n)def lines.  The effect of #define/#undef commands in the input
  22 # file or in included files is not taken into account.  Tests using
  23 # #if and the defined() pseudo function are not recognized.  The #elif
  24 # command is not recognized.  Improperly nesting is not detected.
  25 # Lines that look like preprocessor commands but which are actually
  26 # part of comments or string literals will be mistaken for
  27 # preprocessor commands.
  28
  29 import sys
  30 import getopt
  31
  32 defs = []
  33 undefs = []
  34
  35 def main():
  36     opts, args = getopt.getopt(sys.argv[1:], 'D:U:')
  37     for o, a in opts:
  38         if o == '-D':
  39             defs.append(a)
  40         if o == '-U':
  41             undefs.append(a)
  42     if not args:
  43         args = ['-']
  44     for filename in args:
  45         if filename == '-':
  46             process(sys.stdin, sys.stdout)
  47         else:
  48             f = open(filename, 'r')
  49             process(f, sys.stdout)
  50             f.close()
  51
  52 def process(fpi, fpo):
  53     keywords = ('if', 'ifdef', 'ifndef', 'else', 'endif')
  54     ok = 1
  55     stack = []
  56     while 1:
  57         line = fpi.readline()
  58         if not line: break
  59         while line[-2:] == '\\\n':
  60             nextline = fpi.readline()
  61             if not nextline: break
  62             line = line + nextline
  63         tmp = line.strip()
  64         if tmp[:1] != '#':
  65             if ok: fpo.write(line)
  66             continue
  67         tmp = tmp[1:].strip()
  68         words = tmp.split()
  69         keyword = words[0]
  70         if keyword not in keywords:
  71             if ok: fpo.write(line)
  72             continue
  73         if keyword in ('ifdef', 'ifndef') and len(words) == 2:
  74             if keyword == 'ifdef':
  75                 ko = 1
  76             else:
  77                 ko = 0
  78             word = words[1]
  79             if word in defs:
  80                 stack.append((ok, ko, word))
  81                 if not ko: ok = 0
  82             elif word in undefs:
  83                 stack.append((ok, not ko, word))
  84                 if ko: ok = 0
  85             else:
  86                 stack.append((ok, -1, word))
  87                 if ok: fpo.write(line)
  88         elif keyword == 'if':
  89             stack.append((ok, -1, ''))
  90             if ok: fpo.write(line)
  91         elif keyword == 'else' and stack:
  92             s_ok, s_ko, s_word = stack[-1]
  93             if s_ko < 0:
  94                 if ok: fpo.write(line)
  95             else:
  96                 s_ko = not s_ko
  97                 ok = s_ok
  98                 if not s_ko: ok = 0
  99                 stack[-1] = s_ok, s_ko, s_word
 100         elif keyword == 'endif' and stack:
 101             s_ok, s_ko, s_word = stack[-1]
 102             if s_ko < 0:
 103                 if ok: fpo.write(line)
 104             del stack[-1]
 105             ok = s_ok
 106         else:
 107             sys.stderr.write('Unknown keyword %s\n' % keyword)
 108     if stack:
 109         sys.stderr.write('stack: %s\n' % stack)
 110
 111 if __name__ == '__main__':
 112     main()