Tools/scripts/classfix.py

   1 #! /usr/local/bin/python
   2
   3 # Fix Python source files to use the new class definition syntax, i.e.,
   4 #       class C() = base(), base(), ...: ...
   5 # is changed to
   6 #       class C(base, base, ...): ...
   7 # The script uses heuristics to find class definitions that usually
   8 # work but occasionally can fail; carefully check the output!
   9 #
  10 # Command line arguments are files or directories to be processed.
  11 # Directories are searched recursively for files whose name looks
  12 # like a python module.
  13 # Symbolic links are always ignored (except as explicit directory
  14 # arguments).  Of course, the original file is kept as a back-up
  15 # (with a "~" attached to its name).
  16 #
  17 # Changes made are reported to stdout in a diff-like format.
  18 #
  19 # Undoubtedly you can do this using find and sed or perl, but this is
  20 # a nice example of Python code that recurses down a directory tree
  21 # and uses regular expressions.  Also note several subtleties like
  22 # preserving the file's mode and avoiding to even write a temp file
  23 # when no changes are needed for a file.
  24 #
  25 # NB: by changing only the function fixline() you can turn this
  26 # into a program for a different change to Python programs...
  27
  28 import sys
  29 import regex
  30 import os
  31 from stat import *
  32
  33 err = sys.stderr.write
  34 dbg = err
  35 rep = sys.stdout.write
  36
  37 def main():
  38         bad = 0
  39         if not sys.argv[1:]: # No arguments
  40                 err('usage: ' + sys.argv[0] + ' file-or-directory ...\n')
  41                 sys.exit(2)
  42         for arg in sys.argv[1:]:
  43                 if os.path.isdir(arg):
  44                         if recursedown(arg): bad = 1
  45                 elif os.path.islink(arg):
  46                         err(arg + ': will not process symbolic links\n')
  47                         bad = 1
  48                 else:
  49                         if fix(arg): bad = 1
  50         sys.exit(bad)
  51
  52 ispythonprog = regex.compile('^[a-zA-Z0-9_]+\.py$')
  53 def ispython(name):
  54         return ispythonprog.match(name) >= 0
  55
  56 def recursedown(dirname):
  57         dbg('recursedown(' + `dirname` + ')\n')
  58         bad = 0
  59         try:
  60                 names = os.listdir(dirname)
  61         except os.error, msg:
  62                 err(dirname + ': cannot list directory: ' + `msg` + '\n')
  63                 return 1
  64         names.sort()
  65         subdirs = []
  66         for name in names:
  67                 if name in (os.curdir, os.pardir): continue
  68                 fullname = os.path.join(dirname, name)
  69                 if os.path.islink(fullname): pass
  70                 elif os.path.isdir(fullname):
  71                         subdirs.append(fullname)
  72                 elif ispython(name):
  73                         if fix(fullname): bad = 1
  74         for fullname in subdirs:
  75                 if recursedown(fullname): bad = 1
  76         return bad
  77
  78 def fix(filename):
  79 ##      dbg('fix(' + `filename` + ')\n')
  80         try:
  81                 f = open(filename, 'r')
  82         except IOError, msg:
  83                 err(filename + ': cannot open: ' + `msg` + '\n')
  84                 return 1
  85         head, tail = os.path.split(filename)
  86         tempname = os.path.join(head, '@' + tail)
  87         g = None
  88         # If we find a match, we rewind the file and start over but
  89         # now copy everything to a temp file.
  90         lineno = 0
  91         while 1:
  92                 line = f.readline()
  93                 if not line: break
  94                 lineno = lineno + 1
  95                 while line[-2:] == '\\\n':
  96                         nextline = f.readline()
  97                         if not nextline: break
  98                         line = line + nextline
  99                         lineno = lineno + 1
 100                 newline = fixline(line)
 101                 if newline != line:
 102                         if g is None:
 103                                 try:
 104                                         g = open(tempname, 'w')
 105                                 except IOError, msg:
 106                                         f.close()
 107                                         err(tempname+': cannot create: '+\
 108                                             `msg`+'\n')
 109                                         return 1
 110                                 f.seek(0)
 111                                 lineno = 0
 112                                 rep(filename + ':\n')
 113                                 continue # restart from the beginning
 114                         rep(`lineno` + '\n')
 115                         rep('< ' + line)
 116                         rep('> ' + newline)
 117                 if g is not None:
 118                         g.write(newline)
 119
 120         # End of file
 121         f.close()
 122         if not g: return 0 # No changes
 123
 124         # Finishing touch -- move files
 125
 126         # First copy the file's mode to the temp file
 127         try:
 128                 statbuf = os.stat(filename)
 129                 os.chmod(tempname, statbuf[ST_MODE] & 07777)
 130         except os.error, msg:
 131                 err(tempname + ': warning: chmod failed (' + `msg` + ')\n')
 132         # Then make a backup of the original file as filename~
 133         try:
 134                 os.rename(filename, filename + '~')
 135         except os.error, msg:
 136                 err(filename + ': warning: backup failed (' + `msg` + ')\n')
 137         # Now move the temp file to the original file
 138         try:
 139                 os.rename(tempname, filename)
 140         except os.error, msg:
 141                 err(filename + ': rename failed (' + `msg` + ')\n')
 142                 return 1
 143         # Return succes
 144         return 0
 145
 146 # This expression doesn't catch *all* class definition headers,
 147 # but it's pretty darn close.
 148 classexpr = '^\([ \t]*class +[a-zA-Z0-9_]+\) *( *) *\(\(=.*\)?\):'
 149 classprog = regex.compile(classexpr)
 150
 151 # Expressions for finding base class expressions.
 152 baseexpr = '^ *\(.*\) *( *) *$'
 153 baseprog = regex.compile(baseexpr)
 154
 155 import string
 156
 157 def fixline(line):
 158         if classprog.match(line) < 0: # No 'class' keyword -- no change
 159                 return line
 160
 161         (a0, b0), (a1, b1), (a2, b2) = classprog.regs[:3]
 162         # a0, b0 = Whole match (up to ':')
 163         # a1, b1 = First subexpression (up to classname)
 164         # a2, b2 = Second subexpression (=.*)
 165         head = line[:b1]
 166         tail = line[b0:] # Unmatched rest of line
 167
 168         if a2 == b2: # No base classes -- easy case
 169                 return head + ':' + tail
 170
 171         # Get rid of leading '='
 172         basepart = line[a2+1:b2]
 173
 174         # Extract list of base expressions
 175         bases = string.splitfields(basepart, ',')
 176
 177         # Strip trailing '()' from each base expression
 178         for i in range(len(bases)):
 179                 if baseprog.match(bases[i]) >= 0:
 180                         x1, y1 = baseprog.regs[1]
 181                         bases[i] = bases[i][x1:y1]
 182
 183         # Join the bases back again and build the new line
 184         basepart = string.joinfields(bases, ', ')
 185
 186         return head + '(' + basepart + '):' + tail
 187
 188 main()