[Dovecot] dovecot dspam plugin using libdspam

[Trever L. Adams]

Johannes Berg wrote:
> Note that passing dspam the signature is likely more efficient. There
> are two possibilities:
>  (1) dspam extracts the signature
>      -> dovecot is more efficient at extracting headers because of cache
>  (2) dspam uses the mail
>      -> it has to re-tokenize etc which afaik it doesn't if you give it
>         the signature and it loads things from disk
>
> johannes
>   
This is correct, the signature is attached, so to say, to a already 
tokenized version of the message. This is a large part of the overhead 
of dspam. Also, to do a retrain, you need a pristine message. So if a 
signature has been attached or any headers added in any way since it was 
processed by dspam it won't be a true retrain.

We want to use signatures if it is present, if not, then we can use the 
raw message. I would suggest the code do an if on the present of the 
signature. I haven't yet looked a the code. Maybe tomorrow. (I am a bit 
behind on my schedule.)

Trever