from __future__ import nested_scopes
import os, time

def watch_directories (paths, func, delay=0.2):


    all_files = {}
    def f (unused, dirname, files):
        for filename in files:
            path = os.path.join(dirname, filename)

            try:
                t = os.stat(path)
            except os.error:
                # A file has been deleted between os.path.walk()
                continue

            mtime = remaining_files.get(path)
            if mtime:
                # Record this file as having been seen
                del remaining_files[path]
                # File's mtime has been changed since we last looked at it.
                if t.st_mtime > mtime:
                    changed_list.append(path)
            else:
                # No recorded modification time, so it must be
                # a brand new file.
                changed_list.append(path)
            all_files[path] = t.st_mtime

    # Main loop
    rescan = False
    while True: #scan forever
        changed_list = []
        remaining_files = all_files.copy()
        all_files = {}
        for path in paths:
            os.path.walk(path, f, None)
        removed_list = remaining_files.keys()
        if rescan:
            rescan = False
        elif changed_list or removed_list:
            rescan = func(changed_list, removed_list)
            print 'Changed Files', changed_list
            print 'Removed', removed_list
        time.sleep(delay)


import os
if __name__ == '__main__':
    def f (changed_files, removed_files):
        os.nice(10)
        print 'Changed Files', changed_files
        print 'Removed', removed_files
    while True:
        try:
            watch_directories('/home/crmpicco/', f, 1)
            ##watch_directories('.', f, 1)
        except KeyboardInterrupt:
            print "I cant be stopped (unless you try a lot)"