This is because recent viewers (3.2.1, 3.3.4) and probably earlier ones using the http GetTexture capability will sometimes make such invalid range requests.
This appears to happen if the viewer's estimate of texture sizes at discard levels > 0 (chiefly 2) exceeds the total texture size.
I believe this does not normally happen but can occur for dynamic textures with are large but mainly blank.
If this happens, returning a RequestedRangeNotSatisfiable will cause the viewer to not render the texture at the final resolution.
However, returning a PartialContent (or OK) even with 0 data will allow the viewer to render the final texture.
This is to avoid logging a 'slow' request when the source of delay is the viewer in processing a response.
This is not something we can do much about on the server end - it's server-side delay that we're interested in.
To ensure consistency, this commit also had to refactor and simplify inbound non-poll network request handling, though there should be no functional change.
IOSHttpResponse no longer exposes the Send() method, only classes in OpenSim.Framework.Servers.HttpServer should be doing this.
Only the GetTextureHandler was sending its own response. Now it leaves this to BaseHttpServer, like all other core handlers.
This is required for the substitution of different HTTP servers or the newer HttpServer.dll without having to commit to a particular implementation.
This is also required to write regression tests that involve the HTTP layer.
If you need to recompile, all you need to do is replace OSHttpRequest/OSHttpResponse references with IOSHttpRequest/IOSHttpResponse.
NotFound is obviously wrong, and this change stops viewer 3.2.2 (and v probably earlier) complaining in the log about missing textures that are actually present.
We still return PartialContent even if the range requested is a superset of the data range as per httpd's behaviour
https://issues.apache.org/bugzilla/show_bug.cgi?id=51878
Viewer 3.2.2 and very probably earlier appear happy with this.
Whether fixing this NotFound bug has any practical effect apart from resolve viewer log messages is unknown.
Leaving them at UUID.Zero meant that when a viewer 2 logged into a region that had been freshly created, it received UUID.Zero for these textures, and hence display the land as plain white.
On a simulator restart, the problem would go away since when the database adapators loaded the new region settings, RegionSettings itself has code to use default textures instead of UUID.Zero.
This commit resolves the problem by saving the default texture UUIDs instead of Zero.
However, we currently have to do this in a roundabout way by resaving once the RegionSettings have been created by the database for the first time. This needless complexity should be addressed.
This change will also have the effect of replacing any existing UUID.Zero terrain textures with the default ones.
However, this shouldn't have any effect since the UUID.Zeros were already being replaced in memory with those same UUIDs.
Justin Clark-Casey (justincc)