Re: DO Proxy
Re: DO Proxy
- Subject: Re: DO Proxy
- From: Ovidiu Predescu <email@hidden>
- Date: Tue, 14 May 2002 08:43:15 -0700
On Tue, 14 May 2002 08:11:45 -0500, Timothy Ritchey <email@hidden> wrote:
>
>
On Monday, May 13, 2002, at 11:10 PM, Ovidiu Predescu wrote:
>
>> 2) Add a third app C. If C connects to B and asks for X, it will
>
>> establish its own connection to A. B can disappear, and C's proxy to X
>
>> will keep on trucking.
>
>
>
> I wonder how this is possible, since C has a proxy to X in A. If you
>
> pass the proxy to X from C back into A, A should get its own object,
>
> and not a proxy. Is this last proxy a proxy to C's proxy to A, if you
>
> understand what I mean ;)? Something doesn't sound right to me if
>
> this is the case, as it contradicts the way the so-called "triangle
>
> connection" works in DO.
>
>
C's proxy to X in A has its own direct connection. It does not go
>
through B any more. I am almost 100% positive on this, as I quit app B,
>
and the connection to X in A continued to work. You mention triangle
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connection in quotes as if this is a known entity. I haven't run across
>
this in any documentation anywhere. Might you know where I could find
>
some docs on how DO is implemented, or its specs?
There are no such docs AFAIK, but you can understand how this could
possibly work if you are familiar with the Objective-C runtime and the
Mach messaging system, although solutions using TCP/IP sockets can be
easily built.
If you want to look at a real DO implementation, check out the one in
GNUstep, look in the gstep-base library, the Foundation
implementation.
>
> But since in the case of a proxy to a
>
> proxy the receiver's class is the Proxy class, it is impossible to
>
> obtain this information.
>
>
The current implementation seems to not create proxy-to-proxy. The proxy
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in C identifies itself properly as class X. I also hooked into the
>
connection creation notification, and can see a new connection
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appear/disappear as C retains and releases its proxy.
OK.
>
> The GNU Objective-C runtime helps in such a case since the selector
>
> has the method signature information associated with it. Nevertheless,
>
> the correct solution is to short-circuit the triangle connection by
>
> creating a direct connection.
>
>
If my experiment worked, this happens in the background automatically.
Yes, it does, you don't see it unless you register for the proper
notifications probably. If I remember well, in NeXTSTEP/OPENSTEP, the
delegate used to be notified about such things.
Regards,
--
Ovidiu Predescu <email@hidden>
>
>> I'm in the job market again, check out my resume and qualifications at:
http://www.geocities.com/SiliconValley/Monitor/7464/ (GNU, Emacs, other stuff)
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