Convert Picasa star ratings to XMP format

PicasaToXMP.py

#!/usr/bin/python
# prerequisite: http://www.exiv2.org/download.html

import sys
import os.path
import re
import subprocess

def process_ini(fname):
#	print "found ini " + fname + "\n"
	dirname = os.path.dirname(fname)
	f = open(fname,"r")
	curfile = ""
	for line in f.readlines():
		line = line.rstrip()
		match = re.search(r'^\[(.*)\]$', line, re.M)
		if match:
			curfile = dirname + "/" + match.group(1)
#			print "found file name " + curfile
		else:
			match = re.search(r'^star=yes$', line, re.M)
			if match:
				# exiv2 -M"add Xmp.xmp.Rating XmpText 4"
				# print "found star file " + curfile + "\n"
				retVal = subprocess.call(['exiv2', '-Madd Xmp.xmp.Rating XmpText 5', curfile])
				if retVal != 0:
					write_error(curfile +"\t error writing metadata")
	f.close()

def process_dir(dir):
#	print "Processing ", dir
	if os.path.basename(dir) == "Originals" or os.path.basename(dir) == ".picasaoriginals":
		return
	if os.path.exists(dir + "/" + ".picasa.ini"):
		process_ini(dir + "/" + ".picasa.ini")
	elif os.path.exists(dir + "/" + "Picasa.ini"):
		process_ini(dir + "/" + "Picasa.ini")
	for filename in os.listdir(dir):
		if os.path.isdir(dir + "/" + filename):
			process_dir(dir + "/" + filename)

def write_error(str):
	global ERRFILE, errfile_path
	if ERRFILE == 0:
		ERRFILE = open(errfile_path, 'w')
	if ERRFILE != 0:
		ERRFILE.write(str + "\n")

# setup
homedir = "."
if len(sys.argv) == 2:
	homedir = sys.argv[1];
elif len(sys.argv) != 1:
	print "usage: PicasaToXMP.py [directory]"
homedir = os.path.realpath(homedir)

# errors
ERRFILE = 0;
errfile_path = homedir + "/" + "PicasaToXMP.ERROR.txt"

# execute
process_dir(homedir)

if ERRFILE != 0:
	ERRFILE.close();
	print "Errors encountered. Error log saved in:\n" + errfile_path + "\n"