Jiffy.py 文件源码

def get_next_max_usn(self, drive):
        '''On windows/ntfs this is 'next usn' - the usn index to latest change made. 
        Also returns max_usn since enumdata requires an upper boundary. Not needed
        when using readjournal.
        fsutil usn queryjournal result: 

        Usn Journal ID   : 0x01d2a26e17dbc5e8
        First Usn        : 0x0000000000000000
        Next Usn         : 0x0000000000acddf0     <--- index #2
        Lowest Valid Usn : 0x0000000000000000
        Max Usn          : 0x7fffffffffff0000     <--- index #4
        .
        .                                      '''

        if 'win' in sys.platform and drive == '/':
            ''' using '/' on windows works for scandir but not for fsutil'''
            drive='c:'
        else:
            # Removing trailing slashes
            drive=drive.split(':')[0]+':'  

        journal_specs=Popen(('fsutil', 'usn', 'queryjournal', drive), stdout=PIPE).communicate()[0].split('\r\n')
        next_usn=journal_specs[2].split(': ')[1]
        max_usn=journal_specs[4].split(': ')[1]

        return next_usn, max_usn         #int(next_usn, 16), int(max_usn, 16)