[Opensim-dev] Proposal to eliminate the name, description and invType fields from the assets db

[Sean Dague]

On Mon, Jun 23, 2008 at 11:13:09PM +0100, Justin Clark-Casey wrote:
<snip>
> If asset uuids are hashes, then they can disappear from the user and 
> program's view.  Outside of OpenSim, there is no need to manipulate 
> uuids in this scenario - collections of objects or scenes can be 
> structured in any way that the external program pleases.  Instead of 
> getting asset uuids on import, the importing process calculates the 
> necessary uuids from data, and can ask the asset service whether these 
> already exist without needing to actually obtain the blobs.
> 
> I think that it's possible to experiment with the hashing idea without 
> requiring the whole system to change.  Indeed, because of the very 
> import scenario outlined above, I may well try using it for importing 
> object archives.  This shouldn't impact the rest of the system since, of 
> course, the chances of collision are small.

Before we do this, we should make sure to actually do the version 5 uuid
implementation, which isn't just sha1, as it does some reserved bytes to
make sure that you can tell from the UUID what version generated it.

My suggestion, which came out on IRC, is that we create a singleton UUID
generator class that can be configed on construction as to which type to
generate.  Then we create version 4 (random, what we have today) and
version 5 (sha1 based on content) implementations (anyone that wants to
implement versions 1 - 3 is welcomed to).

UUID assignment would come in the form: UUID.Create(assetdata).

We'll always need UUID type 4 support for prims and other mutable
structures, as type 5 doesn't really make any sense.  But for assetid
assignment we can do this in a user configurable manner.  Also, because
the uuids are namespaced correctly, we can easily distinguish which were
created in which model.

Honestly, this is all probably a bit down the road.  But looking at the
UUID RFC is a good place to check out some of the peer reviewed models
for generating UUIDs.

    -Sean

-- 
__________________________________________________________________

Sean Dague                                       Mid-Hudson Valley
sean at dague dot net                            Linux Users Group
http://dague.net                                 http://mhvlug.org

There is no silver bullet.  Plus, werewolves make better neighbors
than zombies, and they tend to keep the vampire population down.
__________________________________________________________________
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
URL: <http://opensimulator.org/pipermail/opensim-dev/attachments/20080623/ce293a1b/attachment-0001.pgp>