#! /usr/bin/env python

# This script is obsolete -- it is kept for historical purposes only.

#

# Fix Python source files to use the new class definition syntax, i.e.,

# the syntax used in Python versions before 0.9.8:

#       class C() = base(), base(), ...: ...

# is changed to the current syntax:

#       class C(base, base, ...): ...

#

# The script uses heuristics to find class definitions that usually

# work but occasionally can fail; carefully check the output!

#

# Command line arguments are files or directories to be processed.

# Directories are searched recursively for files whose name looks

# like a python module.

# Symbolic links are always ignored (except as explicit directory

# arguments).  Of course, the original file is kept as a back-up

# (with a "~" attached to its name).

#

# Changes made are reported to stdout in a diff-like format.

#

# Undoubtedly you can do this using find and sed or perl, but this is

# a nice example of Python code that recurses down a directory tree

# and uses regular expressions.  Also note several subtleties like

# preserving the file's mode and avoiding to even write a temp file

# when no changes are needed for a file.

#

# NB: by changing only the function fixline() you can turn this

# into a program for a different change to Python programs...

import sys

import re

import os

from stat import *

err = sys.stderr.write

dbg = err

rep = sys.stdout.write

def main():

    bad = 0

    if not sys.argv[1:]: # No arguments

        err('usage: ' + sys.argv[0] + ' file-or-directory ...\n')

        sys.exit(2)

    for arg in sys.argv[1:]:

        if os.path.isdir(arg):

            if recursedown(arg): bad = 1

        elif os.path.islink(arg):

            err(arg + ': will not process symbolic links\n')

            bad = 1

        else:

            if fix(arg): bad = 1

    sys.exit(bad)

ispythonprog = re.compile('^[a-zA-Z0-9_]+\.py$')

def ispython(name):

    return ispythonprog.match(name) >= 0

def recursedown(dirname):

    dbg('recursedown(%r)\n' % (dirname,))

    bad = 0

    try:

        names = os.listdir(dirname)

    except os.error, msg:

        err('%s: cannot list directory: %r\n' % (dirname, msg))

        return 1

    names.sort()

    subdirs = []

    for name in names:

        if name in (os.curdir, os.pardir): continue

        fullname = os.path.join(dirname, name)

        if os.path.islink(fullname): pass

        elif os.path.isdir(fullname):

            subdirs.append(fullname)

        elif ispython(name):

            if fix(fullname): bad = 1

    for fullname in subdirs:

        if recursedown(fullname): bad = 1

    return bad

def fix(filename):

##  dbg('fix(%r)\n' % (filename,))

    try:

        f = open(filename, 'r')

    except IOError, msg:

        err('%s: cannot open: %r\n' % (filename, msg))

        return 1

    head, tail = os.path.split(filename)

    tempname = os.path.join(head, '@' + tail)

    g = None

    # If we find a match, we rewind the file and start over but

    # now copy everything to a temp file.

    lineno = 0

    while 1:

        line = f.readline()

        if not line: break

        lineno = lineno + 1

        while line[-2:] == '\\\n':

            nextline = f.readline()

            if not nextline: break

            line = line + nextline

            lineno = lineno + 1

        newline = fixline(line)

        if newline != line:

            if g is None:

                try:

                    g = open(tempname, 'w')

                except IOError, msg:

                    f.close()

                    err('%s: cannot create: %r\n' % (tempname, msg))

                    return 1

                f.seek(0)

                lineno = 0

                rep(filename + ':\n')

                continue # restart from the beginning

            rep(repr(lineno) + '\n')

            rep('< ' + line)

            rep('> ' + newline)

        if g is not None:

            g.write(newline)

    # End of file

    f.close()

    if not g: return 0 # No changes

    # Finishing touch -- move files

    # First copy the file's mode to the temp file

    try:

        statbuf = os.stat(filename)

        os.chmod(tempname, statbuf[ST_MODE] & 07777)

    except os.error, msg:

        err('%s: warning: chmod failed (%r)\n' % (tempname, msg))

    # Then make a backup of the original file as filename~

    try:

        os.rename(filename, filename + '~')

    except os.error, msg:

        err('%s: warning: backup failed (%r)\n' % (filename, msg))

    # Now move the temp file to the original file

    try:

        os.rename(tempname, filename)

    except os.error, msg:

        err('%s: rename failed (%r)\n' % (filename, msg))

        return 1

    # Return succes

    return 0

# This expression doesn't catch *all* class definition headers,

# but it's pretty darn close.

classexpr = '^([ \t]*class +[a-zA-Z0-9_]+) *( *) *((=.*)?):'

classprog = re.compile(classexpr)

# Expressions for finding base class expressions.

baseexpr = '^ *(.*) *( *) *$'

baseprog = re.compile(baseexpr)

def fixline(line):

    if classprog.match(line) < 0: # No 'class' keyword -- no change

        return line

    (a0, b0), (a1, b1), (a2, b2) = classprog.regs[:3]

    # a0, b0 = Whole match (up to ':')

    # a1, b1 = First subexpression (up to classname)

    # a2, b2 = Second subexpression (=.*)

    head = line[:b1]

    tail = line[b0:] # Unmatched rest of line

    if a2 == b2: # No base classes -- easy case

        return head + ':' + tail

    # Get rid of leading '='

    basepart = line[a2+1:b2]

    # Extract list of base expressions

    bases = basepart.split(',')

    # Strip trailing '()' from each base expression

    for i in range(len(bases)):

        if baseprog.match(bases[i]) >= 0:

            x1, y1 = baseprog.regs[1]

            bases[i] = bases[i][x1:y1]

    # Join the bases back again and build the new line

    basepart = ', '.join(bases)

    return head + '(' + basepart + '):' + tail

if __name__ == '__main__':

    main()