On Mon, Feb 3, 2014 at 12:07 AM, Chris Angelico <ros...@gmail.com> wrote: > On Mon, Feb 3, 2014 at 10:40 AM, Roy Smith <r...@panix.com> wrote: >> I'm reasonably sure you posted this as humor, but there is some truth in >> what you said. In the crypto/security domain, you often want to keep a >> key or cleartext around only for the time it's needed, and scrub the >> memory it was occupying as soon as it is no longer in use. >> >> I don't know how you would do that in Python. > > I did, but you're right. > > It's fundamentally not possible in pure Python, because there's no way > to flag a block of memory as "do not page this to disk". For what > you're talking about to be at all possible, you would need support > from the language, from the OS, and possibly from the CPU as well. I'm > sure this sort of thing exists, but if it does, it'll probably be > something that Python itself wouldn't concern itself with - you'd get > it via openssl or something. > > There have been occasional times I've wanted an "explicit destruction" > feature. Rather than the facetious exception I listed above, it'd be > better to have all those references (including the original one in a, > since there's nothing special about that) turn into some kind of "null > state" - either None, or a special object that marks itself as a > destructed/destroyed (terminology debates aside) object. With custom > types, I can mark them off with a special flag, and check that all the > time; but I can't, for instance, have a dict that maps some lookup > keyword to its output file, and then destroy output files to remove > all their references from everywhere in the dict. (I have had > something along these lines, a bit more complicated than this, but not > in Python.)
Can't you get close to that using weakrefs? I'll admit that care is required. N. -- https://mail.python.org/mailman/listinfo/python-list
