Also fixes access time being set on assets rather than XAssetsMeta
This is to try and be somewhat consistent with other service tables that are mainly in this style.
No migration is supplied, since nobody should be using this service yet except on a test basis.
This only happens if access time is older than 30 days currently, in order to reduce database updates.
The idea is to give some idea of assets which haven't been accessed for a very, very long time.
These might conceivably be deleteable, though this will be a risk due to caching at other points in the chain.
This is actually currently much less useable on the xasset service since access time is on metadata rather than the data itself.
And many metadata entries may point to the same data. Probably need to address this.
On balance, I still think this is useful because asset names and descriptions can sometimes be helpful in determining what things are.
Even though they are never subsequently (inventory names/descriptions are always used instead).
The asset data plugin now implements IXAssetData rather than IAssetData so the ordinary AssetService should no longer pick it up.
This replaces the changes in 92b1ade. There is no longer any need to adjust your StandaloneCommon.ini/Robust.ini/Robust.HG.ini files.
This may explain very recent issues in the last few weeks where textures have been disappearing or turning white (as they were going to different places).
Unfortunately, you will need to rollback to an earlier database backup or reupload the textures.
.NET 4.0 added the method Stream.CopyTo(stream, bufferSize). For .NET 3.5
and before, WebUtil defined an extension method for Stream with the signature
Stream.CopyTo(stream, maxBytesToCopy). The meaning of the second parameter
is different in the two forms and depending on which compiler and/or
runtime you use, you could get one form or the other. Crashes ensue.
This change renames the WebUtil stream copy method to something that
cannot be confused with the new CopyTo method defined in .NET 4.0.
This should not currently be used in any circumstances except for experimentation.
Database tables used by this plugin can still change at any time with no migration path.
Some successful collision attacks have been carried out on sha1 with speculation that more are possible.
http://en.wikipedia.org/wiki/Cryptographic_hash_function#Cryptographic_hash_algorithms
No successful attacks have been shown on sha256, which makes it less likely that anybody will be able to engineer an asset hash collision in the future.
Tradeoff is more storage required for hashes, and more cpu to hash, though this is neglible compared to db operations and network access.
Whether this is worthwhile is debatable since here we are not transmitting data over a network
In addition, jpeg2000 (the biggest data hog) is already a compressed image format.
May not remain.
This is an extremely crude implemenation which almost works by accident. Nevertheless it does work.
It can be tested with the instructions at http://opensimulator.org/wiki/Feature_Proposals/Deduplicating_Asset_Service#Testing
It does not interact at all with the existing asset service or any data stored there.
This code is subject to change without notice and should not be used for anything other than gawking.
Justin Clark-Casey (justincc)