tools/sort-headers.py

   1 #!/usr/bin/env python
   2 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   3 # Use of this source code is governed by a BSD-style license that can be
   4 # found in the LICENSE file.
   5
   6 """Given a filename as an argument, sort the #include/#imports in that file.
   7
   8 Shows a diff and prompts for confirmation before doing the deed.
   9 Works great with tools/git/for-all-touched-files.py.
  10 """
  11
  12 import optparse
  13 import os
  14 import sys
  15 import termios
  16 import tty
  17
  18
  19 def YesNo(prompt):
  20   """Prompts with a yes/no question, returns True if yes."""
  21   print prompt,
  22   sys.stdout.flush()
  23   # http://code.activestate.com/recipes/134892/
  24   fd = sys.stdin.fileno()
  25   old_settings = termios.tcgetattr(fd)
  26   ch = 'n'
  27   try:
  28     tty.setraw(sys.stdin.fileno())
  29     ch = sys.stdin.read(1)
  30   finally:
  31     termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
  32   print ch
  33   return ch in ('Y', 'y')
  34
  35
  36 def IncludeCompareKey(line):
  37   """Sorting comparator key used for comparing two #include lines.
  38   Returns the filename without the #include/#import prefix.
  39   """
  40   line = line.lower()
  41   for prefix in ('#include ', '#import '):
  42     if line.startswith(prefix):
  43       line = line[len(prefix):]
  44       break
  45
  46   # The win32 api has all sorts of implicit include order dependencies :-/
  47   # Give a few headers special sort keys that make sure they appear before all
  48   # other headers.
  49   if line.startswith('<windows.h>'):  # Must be before e.g. shellapi.h
  50     return '0'
  51   if line.startswith('<unknwn.h>'):  # Must be before e.g. intshcut.h
  52     return '1'
  53
  54   # C++ system headers should come after C system headers.
  55   if line.startswith('<'):
  56     if line.find('.h>') != -1:
  57       return '2' + line
  58     else:
  59       return '3' + line
  60
  61   return '4' + line
  62
  63
  64 def IsInclude(line):
  65   """Returns True if the line is an #include/#import line."""
  66   return line.startswith('#include ') or line.startswith('#import ')
  67
  68
  69 def SortHeader(infile, outfile):
  70   """Sorts the headers in infile, writing the sorted file to outfile."""
  71   for line in infile:
  72     if IsInclude(line):
  73       headerblock = []
  74       while IsInclude(line):
  75         headerblock.append(line)
  76         line = infile.next()
  77       for header in sorted(headerblock, key=IncludeCompareKey):
  78         outfile.write(header)
  79       # Intentionally fall through, to write the line that caused
  80       # the above while loop to exit.
  81     outfile.write(line)
  82
  83
  84 def FixFileWithConfirmFunction(filename, confirm_function):
  85   """Creates a fixed version of the file, invokes |confirm_function|
  86   to decide whether to use the new file, and cleans up.
  87
  88   |confirm_function| takes two parameters, the original filename and
  89   the fixed-up filename, and returns True to use the fixed-up file,
  90   false to not use it.
  91   """
  92   fixfilename = filename + '.new'
  93   infile = open(filename, 'r')
  94   outfile = open(fixfilename, 'w')
  95   SortHeader(infile, outfile)
  96   infile.close()
  97   outfile.close()  # Important so the below diff gets the updated contents.
  98
  99   try:
 100     if confirm_function(filename, fixfilename):
 101       os.rename(fixfilename, filename)
 102   finally:
 103     try:
 104       os.remove(fixfilename)
 105     except OSError:
 106       # If the file isn't there, we don't care.
 107       pass
 108
 109
 110 def DiffAndConfirm(filename, should_confirm):
 111   """Shows a diff of what the tool would change the file named
 112   filename to.  Shows a confirmation prompt if should_confirm is true.
 113   Saves the resulting file if should_confirm is false or the user
 114   answers Y to the confirmation prompt.
 115   """
 116   def ConfirmFunction(filename, fixfilename):
 117     diff = os.system('diff -u %s %s' % (filename, fixfilename))
 118     if diff >> 8 == 0:  # Check exit code.
 119       print '%s: no change' % filename
 120       return False
 121
 122     return (not should_confirm or YesNo('Use new file (y/N)?'))
 123
 124   FixFileWithConfirmFunction(filename, ConfirmFunction)
 125
 126
 127 def main():
 128   parser = optparse.OptionParser(usage='%prog filename1 filename2 ...')
 129   parser.add_option('-f', '--force', action='store_false', default=True,
 130                     dest='should_confirm',
 131                     help='Turn off confirmation prompt.')
 132   opts, filenames = parser.parse_args()
 133
 134   if len(filenames) < 1:
 135     parser.print_help()
 136     return 1
 137
 138   for filename in filenames:
 139     DiffAndConfirm(filename, opts.should_confirm)
 140
 141
 142 if __name__ == '__main__':
 143   sys.exit(main())