tests/lockdelay.py

rust: Add a log file rotation utility

This is ported to Rust from `mercurial/loggingutil.py`.

The "builder" pattern is used to make it visible at call sites what the two
numeric parameters mean. In Python they might simply by keyword arguments.

Differential Revision: https://phab.mercurial-scm.org/D10010

# Dummy extension that adds a delay after acquiring a lock.
#
# This extension can be used to test race conditions between lock acquisition.

from __future__ import absolute_import

import os
import time


def reposetup(ui, repo):
    class delayedlockrepo(repo.__class__):
        def lock(self, wait=True):
            delay = float(os.environ.get('HGPRELOCKDELAY', '0.0'))
            if delay:
                time.sleep(delay)
            res = super(delayedlockrepo, self).lock(wait=wait)
            delay = float(os.environ.get('HGPOSTLOCKDELAY', '0.0'))
            if delay:
                time.sleep(delay)
            return res

    repo.__class__ = delayedlockrepo