view contrib/casesmash.py @ 50244:07d030b38097 stable

rust-dirstate-v2: don't write dirstate if data file has changed

This fixes the following race:
    - process A reads the dirstate
    - process B reads and writes the dirstate
    - process A writes the dirstate

This either resulted in losing what process B had just written or a crash
because the `uuid` had changed and we were trying to write to a file that
doesn't exist. More explanations inside.

This doesn't fix the issue for dirstate-v1, a later patch addresses it.

import __builtin__
import os
from mercurial import util


def lowerwrap(scope, funcname):
    f = getattr(scope, funcname)

    def wrap(fname, *args, **kwargs):
        d, base = os.path.split(fname)
        try:
            files = os.listdir(d or '.')
        except OSError:
            files = []
        if base in files:
            return f(fname, *args, **kwargs)
        for fn in files:
            if fn.lower() == base.lower():
                return f(os.path.join(d, fn), *args, **kwargs)
        return f(fname, *args, **kwargs)

    scope.__dict__[funcname] = wrap


def normcase(path):
    return path.lower()


os.path.normcase = normcase

for f in 'file open'.split():
    lowerwrap(__builtin__, f)

for f in "chmod chown open lstat stat remove unlink".split():
    lowerwrap(os, f)

for f in "exists lexists".split():
    lowerwrap(os.path, f)

lowerwrap(util, 'posixfile')