cache.py not windows friendly

[accident12123]

we won't get into why I found this but fcntl is not available on windows so the import fcntl errors out.

[wagnerrp]

This might be fixed by 4663490, but the msvcrt locking mechanism is completely untested.

[accident12123]

some problems...

the code should have been:

    LOCK_EX = msvcrt.LK_NBLCK
    LOCK_SH = msvcrt.LK_NBLCK

[accident12123]

prepending /tmp/ to the start of a path isn't windows \tmp\ path friendly.. os.path.join should fix that up quick.

also there might be driveletter: or unc \ formatting for an absolute path

[accident12123]

Now that I have it running, I'm getting permission errors:

\cache_file.py", line 60, in enter
msvcrt.locking(self.fileobj.fileno(), self.operation, self.size)
IOError: [Errno 13] Permission denied

[wagnerrp]

Now that I'm thinking about it, those locks should probably be LK_LOCK, so it waits for dedicated access rather than outright fails.

The filename handling does need to be improved, as at current, only caches located in a user's home directory with a '~' would pass the logic. I assume Windows absolute paths would either start with ":" or "\server"?

[accident12123]

I would think c:, \server and \path would all be valid.. but it's going to need a default also I think /tmp/ wouldn't work.

[wagnerrp]

263d868 adds an independent chunk of logic for Windows systems, based off the module import test. Variables are replaced into the path, and anything starting with lettered drives and ':', or a UNC server are passed through. Everything else gets the %TEMP% directory prepended. That still leaves the issue as to why locking itself is not working.

[accident12123]

I'm still getting a bunch of permissions denied on the windows side.... didn't really have the time to look closer at it.