Update Python3 bytecode timestamps

update_bytecode_timestamps.py

#!/usr/bin/python3

# Python scripts which reads all Python bytecode files (pyc) and clears
# the timestamp (set to 0)
# This is useful for OSTree which clears modification time of all source
# files. Processed bytecode files are then not considered stale anymore.

import sys, os
import marshal
import importlib.util

rootdir = str(sys.argv[1])

def set_mtime(name, newtime):
    with open(name, 'r+b') as fd:
        fd.seek(0)
        magic = fd.read(4) # python version specific magic num
        #date = fd.read(4)  # mtime of py file...

        if (magic != importlib.util.MAGIC_NUMBER):
            print('bad magic number in {!r}: {!r}'.format(name, magic))
            return

        # Replace timestamp
        fd.seek(4)
        fd.write(int.to_bytes(newtime, 4, 'little'))

def main(rootdir):
    for root,d_names,f_names in os.walk(rootdir):
        for f in f_names:
            if f.endswith(".pyc"):
                set_mtime(os.path.join(root, f), 0)


if __name__ == '__main__':
   main(rootdir)