Windows support

[John Goerzen <jgoerzen@xxxxxxxxxxxx>]

Hello,

Recently, I have had at least three different people approach me about
Windows support for OfflineIMAP, and I would like to be a little more clear
about my own plans for that.

Personally, I have no problem with OfflineIMAP supporting Windows.  However,
I do not run Windows myself.  Therefore, anybody adding Windows support to
OfflineIMAP will have to be reponsible for writing it *and maintaining it*
as time goes by.

The main problem on Windows seems to be that of colons in Maildir filenames. 
As that is specified in the Maildir spec, at present there seems to be no
Windows readers that can use Maildirs.  OfflineIMAP could be trivially
modified to use a non-colon character on Windows, but then all other
Maildir-using software would also have to be so modified.

Another (better?) solution would be to extend OfflineIMAP to support mboxes. 
This involves a lot of trickiness, though, as mboxes are tough to really get
right.  Locking issues are complex at best, and more realistically,
nightmarish.  We will also have to add the OfflineIMAP metadata to something
like an X-OfflineIMAP header to each message (this metadata consists of UID,
folder, etc.).

Because of all this, I am not going to write mbox support for OfflineIMAP
myself anytime soon.  However, if someone else writes reliable mbox support
("reliable" meaning doing the right thing in terms of locking, metadata,
robustness in the face of a crash, compatibility, etc.), then I will add
the code and maintain it in the future.

-- John