[Dovecot] IMAP move extension support

[Timo Sirainen]

On 26.3.2011, at 23.56, Nikolay Shopik wrote:

>> Little chance at the moment. It's not easy. It's actually very difficult. I would want to create "doveadm move" command, but I think I'll just make that to be a copy+expunge as well.

doveadm move command is in hg.

> Forgot to ask, will be "copy+expunge" actually atomic operation? This is currently problem with copy+expunge from email client at least.

It's not atomic, but its behavior should be close enough for it to not matter. If copying fails, nothing is moved. If copying succeeds, those messages are expunged. Duplicates happen only if doveadm crashes between those actions. (If moving from multiple source mailboxes it can get messier.)