302090 - nsXULTemplateBuilder : Refresh boolean parameter request (synchronous or asynchronous) for RDF reloading and XUL Elements

Status: NEW

(Core :: XUL, defect)

Description

[Stephane Berthelot]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; fr-FR; rv:1.7.10) Gecko/20050716 Firefox/1.0.6
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; fr-FR; rv:1.7.10) Gecko/20050716 Firefox/1.0.6

When updating a live RDF source (generated in PHP) with element.builder.refresh()
I just after select an item in the XUL menulist that has the datasource with
element.selectedIndex=0;
It seems the datasource loads asynchronously then the selection comes to early
and the menupopup is not generated. Having a boolean argument (that is directly
passed to the datasource.Refresh(boolean async)
http://lxr.mozilla.org/mozilla/source/content/xul/templates/src/nsXULTemplateBuilder.cpp#269
function could allow a javascript function to wait for the load completion and
select items after)

I have tried with a Listener but it seems it still arrives too fast (before
completion on menupopup nodes generation) and trying to get the datasource
object to call Resfresh(true) on it requires more evelated privileges (which I
think shouldn't be needed for that kind of operation)

By the way I also get "Error : uncaught exception: [Exception... "Component
returned failure code: 0x80004005 (NS_ERROR_FAILURE)
[nsIMenuBoxObject.activeChild]"  nsresult: "0x80004005 (NS_ERROR_FAILURE)" 
location: "JS frame :: chrome://global/content/bindings/menulist.xml ::
onxblpopupshowing :: line 43"  data: no]" at first time opening the popup after
having reloaded the datasource...

Reproducible: Always

Steps to Reproduce:
(see details also)
1. Design a menulist/menupopup with template and a dynamic RDF datasource
2. Call a javascript function to reload the datasource (element.builder.refresh())
3. make a selection on the same element quicly after (element.selectedIndex=0)

Actual Results:  
(see details)
Got "Error : uncaught exception: [Exception... "Component returned failure code:
0x80004005 (NS_ERROR_FAILURE) [nsIMenuBoxObject.activeChild]"  nsresult:
"0x80004005 (NS_ERROR_FAILURE)"  location: "JS frame ::
chrome://global/content/bindings/menulist.xml :: onxblpopupshowing :: line 43" 
data: no]"
and the item is not selected (selectedIndex==-1)

Expected Results:  
Wait for datasource refresh completion. Maybe allow to prepare items in
menupopup children nodes (not lazily, a method would be great for that) then
allow directly after those calls to set selectedIndex without having to require
more privileges to get the datasource and attach an observer to it ...

I would personnaly change to
http://lxr.mozilla.org/mozilla/source/content/xul/templates/src/nsXULTemplateBuilder.cpp#254

-nsXULTemplateBuilder::Refresh()
+nsXULTemplateBuilder::Refresh(PRBOOL aBlocking)

-          rds->Refresh(PR_FALSE);
+          rds->Refresh(aBlocking);

Comment 1

[Boris Zbarsky [:bzbarsky]]

Neil, is this something we want to support?

Comment 2

[Neil Deakin]

The refresh method is supposed to be temporary until rdf becomes scriptable. Adding support for blocking refresh will mean that a remote site can block the UI. If that's acceptable, then I don't see any reason not to support this change.