Python 3 wrapper for os.stat_result

mystat.py

import os, stat, math
import pwd, grp
from datetime import datetime

'''
Wrapper for os.stat_result, which contains all the information I usually need, 
in a form that is simple to interact with.

For example:
    x = FileStat( '/path/to/file.zip' )

    # permissions
    if not x.perm['urw']:
        print 'Needs read+write permission!'

    # size
    if x.size['GB'] > 1:
        print 'File is too big'

    print(x.size) # auto-select correct unit

    # user/group info
    x.owner.name 
    x.group.id
    print(x.owner) # prints: name (id)

'''

# ------------------------------------------------------------------------

class _FileSize:
    __slots__ = ('bytes', 'scale', 'units')

    def __init__(self, bsize):
        self.bytes = bsize 
        self.scale = math.log(max([ bsize, 1 ]))
        self.scale = int(self.scale // math.log(1024))
        self.units = ['B','kB','MB','GB','TB','PB']

    def __getitem__(self, key):
        try:
            if isinstance(key,str):
                s = self.units.index(key)
            else:
                s = int(key)
        except:
            raise ValueError('Unknown scale: {}'.format(key))

        return self.bytes / 1024**s

    def __str__(self):
        s = min([ len(self.units)-1, self.scale ]) 
        return '%.2f %s' % ( self[s], self.units[s] )

# ----------  =====  ----------

class _FileTime:
    # access, modify, create/metadata
    __slots__ = ('a', 'm', 'c')

    def __init__(self, a,m,c, convert=False):
        if convert:
            self.a = datetime.fromtimestamp(a)
            self.m = datetime.fromtimestamp(m)
            self.c = datetime.fromtimestamp(c)
        else:
            self.a = a
            self.m = m
            self.c = c

# ------------------------------------------------------------------------

class _FileOwner:
    __slots__ = ('id', 'name')

    def __init__(self,uid):
        self.id = uid 
        self.name = pwd.getpwuid(uid).pw_name

    def __str__(self):
        return '%s (%d)' % (self.name, self.id)

# ----------  =====  ----------

class _FileGroup:
    __slots__ = ('id', 'name')

    def __init__(self, gid):
        self.id = gid 
        self.name = grp.getgrgid(gid).gr_name

    def __str__(self):
        return '%s (%d)' % (self.name, self.id)

# ----------  =====  ----------

class _FilePerm:
    __slots__ = ('mode', 'octal', 'code')

    def __init__(self, mode):
        self.mode = mode 
        self.octal = oct(stat.S_IMODE(mode))
        self.code = {
            'u': {'r': stat.S_IRUSR, 'w': stat.S_IWUSR, 'x': stat.S_IXUSR},
            'g': {'r': stat.S_IRGRP, 'w': stat.S_IWGRP, 'x': stat.S_IXGRP},
            'o': {'r': stat.S_IROTH, 'w': stat.S_IWOTH, 'x': stat.S_IXOTH},
        }

    def __getitem__(self, key):
        """
        Key should be: ur, ux, urw, grw
        I.e. first letter owner, rest permission
        """
        x = key[0]
        k = key[1:]
        for y in k:
            if not bool(self.mode & self.code[x][y]):
                return False 

        return True

    def __str__(self):
        return str(self.octal)

# ------------------------------------------------------------------------

class FileStat:
    __slots__ = ('perm', 'size', 'owner', 'group', 'time')
    
    def __init__(self, fstat, convert=False):
        if isinstance(fstat,str):
            fstat = os.stat(fstat)

        # see also: 
        #   st_rsize on OSX
        #   st_birthtime on FreeBSD

        self.size = _FileSize( fstat.st_size ) 
        self.perm = _FilePerm( fstat.st_mode )
        self.owner = _FileOwner( fstat.st_uid )
        self.group = _FileGroup( fstat.st_gid )
        self.time = _FileTime( fstat.st_atime, fstat.st_mtime, fstat.st_ctime )