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 regex
  31 import getopt
  32 import string
  33
  34 defs = []
  35 undefs = []
  36
  37 def main():
  38         opts, args = getopt.getopt(sys.argv[1:], 'D:U:')
  39         for o, a in opts:
  40                 if o == '-D':
  41                         defs.append(a)
  42                 if o == '-U':
  43                         undefs.append(a)
  44         if not args:
  45                 args = ['-']
  46         for file in args:
  47                 if file == '-':
  48                         process(sys.stdin, sys.stdout)
  49                 else:
  50                         f = open(file, 'r')
  51                         process(f, sys.stdout)
  52                         f.close()
  53
  54 def process(fpi, fpo):
  55         keywords = ('if', 'ifdef', 'ifndef', 'else', 'endif')
  56         ok = 1
  57         stack = []
  58         while 1:
  59                 line = fpi.readline()
  60                 if not line: break
  61                 while line[-2:] == '\\\n':
  62                         nextline = fpi.readline()
  63                         if not nextline: break
  64                         line = line + nextline
  65                 tmp = string.strip(line)
  66                 if tmp[:1] != '#':
  67                         if ok: fpo.write(line)
  68                         continue
  69                 tmp = string.strip(tmp[1:])
  70                 words = string.split(tmp)
  71                 keyword = words[0]
  72                 if keyword not in keywords:
  73                         if ok: fpo.write(line)
  74                         continue
  75                 if keyword in ('ifdef', 'ifndef') and len(words) == 2:
  76                         if keyword == 'ifdef':
  77                                 ko = 1
  78                         else:
  79                                 ko = 0
  80                         word = words[1]
  81                         if word in defs:
  82                                 stack.append((ok, ko, word))
  83                                 if not ko: ok = 0
  84                         elif word in undefs:
  85                                 stack.append((ok, not ko, word))
  86                                 if ko: ok = 0
  87                         else:
  88                                 stack.append((ok, -1, word))
  89                                 if ok: fpo.write(line)
  90                 elif keyword == 'if':
  91                         stack.append((ok, -1, ''))
  92                         if ok: fpo.write(line)
  93                 elif keyword == 'else' and stack:
  94                         s_ok, s_ko, s_word = stack[-1]
  95                         if s_ko < 0:
  96                                 if ok: fpo.write(line)
  97                         else:
  98                                 s_ko = not s_ko
  99                                 ok = s_ok
 100                                 if not s_ko: ok = 0
 101                                 stack[-1] = s_ok, s_ko, s_word
 102                 elif keyword == 'endif' and stack:
 103                         s_ok, s_ko, s_word = stack[-1]
 104                         if s_ko < 0:
 105                                 if ok: fpo.write(line)
 106                         del stack[-1]
 107                         ok = s_ok
 108                 else:
 109                         sys.stderr.write('Unknown keyword %s\n' % keyword)
 110         if stack:
 111                 sys.stderr.write('stack: %s\n' % stack)
 112
 113 main()