contrib/casesmash.py

context: don't use util.cachefunc due to cycle creation (issue5043)

util.cachefunc stores all arguments as the cache key. For filectxfn
functions, the arguments include the memctx instance. This creates a
cycle where memctx._filectxfn references self. This causes a memory
leak.

We break the cycle by implementing our own memoizing function that
only uses the path as the cache key. Since each memctx has its own
cache instance, there is no concern about invalid cache hits.

import os, __builtin__
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')