A script to aid in refactoring a git-managed codebase

rfr.py

#!/opt/pypy/bin/pypy

# easy project refactoring.

import os
import shutil
from subprocess import Popen

def build_parser():
    """
    Returns an argparse.ArgumentParser instance to parse the command line
    arguments for rfr
    """
    import argparse
    description = "A simple refactoring tool"
    parser = argparse.ArgumentParser(description=description)
    parser.add_argument('--dry-run', '-d',  dest='dry_run', action='store_true',
                        default=False, help='Print expected output but do not actually move or edit any files')
    parser.add_argument('--ignore-binary', '-i',  dest='ignore_binary', action='store_true',
                        default=False, help='Don\'t warn about binary file content matches')
    parser.add_argument('oldstring', metavar='OLDSTRING', action='store',
                        help='a string that you wish to replace both inside of files and in file/directory names')
    parser.add_argument('newstring', metavar='NEWSTRING', action='store',
                        help='a string that you wish to replace OLDSTRING with')
    parser.add_argument('directory', metavar='DIRECTORY', nargs='?',
                        default=os.getcwd(), help='a directory to search in (default cwd)')
    return parser

if __name__ == '__main__':
    parser = build_parser()
    args = parser.parse_args()

    # first, ensure that no instances of newstring exist already
    for dirpath, dirnames, filenames in os.walk(args.directory):
        if '.git' in dirnames:
            dirnames.remove('.git')
        for dirname in dirnames:
            if dirname.find(args.oldstring) >= 0:
                olddir = os.path.join(dirpath, dirname)
                newdir = os.path.join(dirpath, dirname.replace(args.oldstring, args.newstring))
                if not os.path.exists(newdir):
                    if not args.dry_run:
                        pargs = ['/bin/sh -c "cd %s && git mv %s %s"' % (args.directory, olddir, newdir)]
                        p = Popen(pargs, shell=True)
                        p.communicate()
                    print "Renamed directory %s to %s" % (olddir, newdir)
                else:
                    print "Warning: could not rename directory %s to %s, path already exists" % (olddir, newdir)

    for dirpath, dirnames, filenames in os.walk(args.directory):
        if '.git' in dirnames:
            dirnames.remove('.git')
        for filename in filenames:
            if filename.find(args.oldstring) >= 0:
                oldfile = os.path.join(dirpath, filename)
                newfile = os.path.join(dirpath, filename.replace(args.oldstring, args.newstring))

                if not os.path.exists(newfile):
                    if not args.dry_run:
                        pargs = ['/bin/sh -c "cd %s && git mv %s %s"' % (args.directory, oldfile, newfile)]
                        p = Popen(args, shell=True)
                        p.communicate()
                    print "Renamed file %s to %s" % (oldfile, newfile)
                else:
                    print "Warning: could not rename file %s to %s, path already exists" % (oldfile, newfile)

    for dirpath, dirnames, filenames in os.walk(args.directory):
        if '.git' in dirnames:
            dirnames.remove('.git')
        for filename in filenames:
            newfile = os.path.join(dirpath, filename)
            f = open(newfile, 'r+b')
            old_file_contents = f.read()
            f.close()
            new_file_contents = old_file_contents.replace(args.oldstring, args.newstring)
            if new_file_contents.find('\000') >= 0:
                if not args.ignore_binary and old_file_contents != new_file_contents:
                    print "Warning, binary file %s contains match. I won't modify it but I thought you should know..." % newfile
            else:
                if old_file_contents != new_file_contents:
                    if not args.dry_run:
                        f = open(newfile, 'w+b')
                        f.write(new_file_contents)
                        f.close()
                    print "Replacements made in %s" % newfile