lib/bup/xstat.py

   1 """Enhanced stat operations for bup."""
   2 import os
   3 from bup import _helpers
   4
   5
   6 try:
   7     _have_utimensat = _helpers.utimensat
   8 except AttributeError, e:
   9     _have_utimensat = False
  10
  11
  12 def timespec_to_nsecs((ts_s, ts_ns)):
  13     # c.f. _helpers.c: timespec_vals_to_py_ns()
  14     if ts_ns < 0 or ts_ns > 999999999:
  15         raise Exception('invalid timespec nsec value')
  16     return ts_s * 10**9 + ts_ns
  17
  18
  19 def nsecs_to_timespec(ns):
  20     """Return (s, ns) where ns is always non-negative
  21     and t = s + ns / 10e8""" # metadata record rep (and libc rep)
  22     ns = int(ns)
  23     return (ns / 10**9, ns % 10**9)
  24
  25
  26 def fstime_floor_secs(ns):
  27     """Return largest integer not greater than ns / 10e8."""
  28     return int(ns) / 10**9;
  29
  30
  31 def fstime_to_timespec(ns):
  32     return nsecs_to_timespec(ns)
  33
  34
  35 if _have_utimensat:
  36     def lutime(path, times):
  37         atime = nsecs_to_timespec(times[0])
  38         mtime = nsecs_to_timespec(times[1])
  39         _helpers.utimensat(_helpers.AT_FDCWD, path, (atime, mtime),
  40                            _helpers.AT_SYMLINK_NOFOLLOW)
  41     def utime(path, times):
  42         atime = nsecs_to_timespec(times[0])
  43         mtime = nsecs_to_timespec(times[1])
  44         _helpers.utimensat(_helpers.AT_FDCWD, path, (atime, mtime), 0)
  45 else:
  46     def lutime(path, times):
  47         return None
  48
  49     def utime(path, times):
  50         atime = fstime_floor_secs(times[0])
  51         mtime = fstime_floor_secs(times[1])
  52         os.utime(path, (atime, mtime))
  53
  54
  55 class stat_result:
  56     @staticmethod
  57     def from_xstat_rep(st):
  58         result = stat_result()
  59         (result.st_mode,
  60          result.st_ino,
  61          result.st_dev,
  62          result.st_nlink,
  63          result.st_uid,
  64          result.st_gid,
  65          result.st_rdev,
  66          result.st_size,
  67          result.st_atime,
  68          result.st_mtime,
  69          result.st_ctime) = st
  70         result.st_atime = timespec_to_nsecs(result.st_atime)
  71         result.st_mtime = timespec_to_nsecs(result.st_mtime)
  72         result.st_ctime = timespec_to_nsecs(result.st_ctime)
  73         return result
  74
  75
  76 def stat(path):
  77     return stat_result.from_xstat_rep(_helpers.stat(path))
  78
  79
  80 def fstat(path):
  81     return stat_result.from_xstat_rep(_helpers.fstat(path))
  82
  83
  84 def lstat(path):
  85     return stat_result.from_xstat_rep(_helpers.lstat(path))