297810 - de-singleton RDF/XML datasources

Status: RESOLVED WONTFIX

(Core Graveyard :: RDF, defect)

Description

[Axel Hecht]

As I laid out in my XTech talk, I'd like to drop handling RDF/XML data sources as
singletons in the RDF service.

This does not touch the built-in datasources like bookmarks or localstore.

This should help with error reporting in general and fix bugs like bug 279335.

I'd like to land this in an alpha as it may break extensions, though only those
that rely on a RDF/XML datasource to bridge data between windows or something
like that.

Comment 1

[Axel Hecht]

I have a patch for this, and it breaks:

XPFE sidebar. This should be more or less easy to fix. I don't think that the 
code will suddenly turn out nice and pretty, but still.

Help viewer. Evil hacks like a mother of a sith. Help viewer is loading
datasources blocking and then adds the URLs to the databases attr, relying on GC 
not kicking in inbetween. May be a safe bet, but still.

Basically, they try to get synchronous loads for templates, which we don't
expose. Neil, what would you prefer, a synchronous="true" attr on the template,
or should I try to create a "ensureLoaded(aTimeOut)" or so method on 
datasources? I'm not comfortable with the latter, as I don't know, if it will
be as trivial as I hope or just uncover other bugs.

Comment 2

[Neil Deakin (away until Sept 6)]

The attribute is better, but it could just be an extra flag as in
flags="dont-build-content load-synchronous"

Comment 3

[Jeff Walden (gone starting June 8)]

(In reply to comment #1)
> I have a patch for this, and it breaks:
> 
> Help viewer. Evil hacks like a mother of a sith. Help viewer is loading
> datasources blocking and then adds the URLs to the databases attr, relying on
> GC not kicking in inbetween. May be a safe bet, but still.

You shouldn't have to worry about Help viewer for long.  The way Help viewer
loads and searches through datasources is going to be substantially changed once
bug 296012 is fixed, which I want to do immediately after bug 295817.  It's been
a little bit since I looked at the patch, but my recollection is that it does
away with using an attribute in favor of storing everything in one composite
datasource in the tree.database property for each <tree/>.  Feel free to look at
it and make comments if you want, but recognize that it'll go through some
intense reformatting after bug 295817 lands.  The logic used in a final patch,
however, should remain mostly the same as what's in the current patch.

Comment 4

[Jeff Walden (gone starting June 8)]

(In reply to comment #3)
> You shouldn't have to worry about Help viewer for long.

I should clarify that I'm referring primarily to the toolkit Help viewer here,
but in the interests of maintaining Help content pack cross-appness I'll
eventually patch SeaMonkey Help for bug 296012 as well.  SeaMonkey is a much
smaller concern than toolkit, however, so SeaMonkey Help's definitely not going
to get any love until bug 296012 is fixed in toolkit Help.