view tests/lockdelay.py @ 51905:c564be351754

rev-branch-cache: stop truncating cache file

Truncating the file prevent the safe use of mmap. So instead of overwrite the
existing data. If more than 20% of the file is to be overwritten, we rewrite the
whole file instead.

Such whole rewrite is done by replacing the old one with a new one, so mmap of
the old file would be affected.

This prepare a more aggressive use of mmap in later patches.

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


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