# perftweaks.py
#
# Copyright 2015 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""extension for tweaking Mercurial features to improve performance."""

from mercurial import tags, merge
from mercurial.extensions import wrapcommand, wrapfunction
from mercurial.i18n import _
import os

testedwith = 'internal'

def extsetup(ui):
    wrapfunction(tags, '_readtagcache', _readtagcache)
    wrapfunction(merge, '_checkcollision', _checkcollision)

def _readtagcache(orig, ui, repo):
    """Disables reading tags if the repo is known to not contain any."""
    if ui.configbool('perftweaks', 'disabletags'):
        return (None, None, None, {}, False)

    return orig(ui, repo)

def _checkcollision(orig, repo, wmf, actions):
    """Disables case collision checking since it is known to be very slow."""
    if repo.ui.configbool('perftweaks', 'disablecasecheck'):
        return
    orig(repo, wmf, actions)