Re: Composing tasks and protected objects

[Florian Weimer <fw@deneb.enyo.de>]

* Jeffrey Carter:

> You need all calls to go the same way. Right now you're trying to do 
> something like
>
> +----------+          +----------+          +----------+
> |          |          |          |          |          |
> |     Q    |<--Get----|  Server  |<--Shut---|     ?    |
> |          |          |          |   Down   |          |
> |          |          |          |<--Reload-|          |
> |          |          |          |          |          |
> +----------+          +----------+          +----------+
>
> where arrows indicate direction of call. This won't work, but it will 
> work if you can turn that call to Get around. For this, you need a 
> forwarder between the Queue and Server:
>
> +----------+       +----------+       +----------+       +----------+
> |          |       |          |       |          |       |          |
> |     Q    |<-Get--| Forwarder|--Msg->|  Server  |<-Etc--|     ?    |
> |          |       |          |       |          |       |          |
> +----------+       +----------+       +----------+       +----------+

This introduces overhead in terms of an additional task, and the
Forwarder and Server are strongly coupled (unless you manually write
wrappers, because access-to-entry types are missing).