Mercurial > hg
view mercurial/dirstateutils/timestamp.py @ 48397:8d585aa9becf
dirstate: drop comparison primitive on the timestamp class
All comparison are now managed without using operator :
- the status mtime comparisons is handled by the DirstateItem,
- the fixup reliability check,
- the update "hack".
So we no longer needs the operator and should discourage its usage.
Differential Revision: https://phab.mercurial-scm.org/D11841
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
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date | Tue, 23 Nov 2021 19:27:17 +0100 |
parents | 9ae0353c9f5d |
children | 111098af6356 |
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# Copyright Mercurial Contributors # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import functools import os import stat from .. import error rangemask = 0x7FFFFFFF @functools.total_ordering class timestamp(tuple): """ A Unix timestamp with optional nanoseconds precision, modulo 2**31 seconds. A 2-tuple containing: `truncated_seconds`: seconds since the Unix epoch, truncated to its lower 31 bits `subsecond_nanoseconds`: number of nanoseconds since `truncated_seconds`. When this is zero, the sub-second precision is considered unknown. """ def __new__(cls, value): truncated_seconds, subsec_nanos = value value = (truncated_seconds & rangemask, subsec_nanos) return super(timestamp, cls).__new__(cls, value) def __eq__(self, other): raise error.ProgrammingError( 'timestamp should never be compared directly' ) def __gt__(self, other): raise error.ProgrammingError( 'timestamp should never be compared directly' ) def get_fs_now(vfs): """return a timestamp for "now" in the current vfs This will raise an exception if no temporary files could be created. """ tmpfd, tmpname = vfs.mkstemp() try: return mtime_of(os.fstat(tmpfd)) finally: os.close(tmpfd) vfs.unlink(tmpname) def zero(): """ Returns the `timestamp` at the Unix epoch. """ return tuple.__new__(timestamp, (0, 0)) def mtime_of(stat_result): """ Takes an `os.stat_result`-like object and returns a `timestamp` object for its modification time. """ try: # TODO: add this attribute to `osutil.stat` objects, # see `mercurial/cext/osutil.c`. # # This attribute is also not available on Python 2. nanos = stat_result.st_mtime_ns except AttributeError: # https://docs.python.org/2/library/os.html#os.stat_float_times # "For compatibility with older Python versions, # accessing stat_result as a tuple always returns integers." secs = stat_result[stat.ST_MTIME] subsec_nanos = 0 else: billion = int(1e9) secs = nanos // billion subsec_nanos = nanos % billion return timestamp((secs, subsec_nanos)) def reliable_mtime_of(stat_result, present_mtime): """same as `mtime_of`, but return None if the date might be ambiguous A modification time is reliable if it is older than "present_time" (or sufficiently in the futur). Otherwise a concurrent modification might happens with the same mtime. """ file_mtime = mtime_of(stat_result) file_second = file_mtime[0] boundary_second = present_mtime[0] # If the mtime of the ambiguous file is younger (or equal) to the starting # point of the `status` walk, we cannot garantee that another, racy, write # will not happen right after with the same mtime and we cannot cache the # information. # # However is the mtime is far away in the future, this is likely some # mismatch between the current clock and previous file system operation. So # mtime more than one days in the future are considered fine. if boundary_second <= file_second < (3600 * 24 + boundary_second): return None else: return file_mtime