72899 - fix GetHasSubFolders() and fix nsMsgFolderDataSource::createFolderChildNode to use it

Status: RESOLVED FIXED

(MailNews Core :: Database, defect)

Description

[(not reading, please use [e-mail] instead)]

we only want the first child, we can speed this up.

Comment 1

[(not reading, please use [e-mail] instead)]

to fix this, I think we want to rewrite createFolderChildNode() to call the 
existing GetHasSubFolders() (which is part of the nsIFolder interface)

but it may not be that simple.

currently, to determine if we have subfolders in createFolderChildNode(), we call 
GetSubFolders()

In the case of news (and probably imap, and local)  GetSubFolders() is overriden 
to discover the subfolders if not initialized.

if we call GetHasSubFolders() directly (which is not overriden) will just return 
the count of mSubFolders, but will not initalize it.

now GetHasSubFolders() is scarying me.  

querying for "hassubfolders" in lxr, it is called in a few places.

we should probably override it (just like we override GetSubFolders()).

for news (and in most cases), GetHasSubFolder() would be overriden like this:

if (!mInitialized) {
	// call GetSubFolders() to initialize mSubFolders
}
// now set the return result, based on the count of mSubFolders

if we do that, then we could fix createFolderChildNode()

comments?

Comment 2

[(not reading, please use [e-mail] instead)]

talking to bienvenu, we need nsMsgFolder::GetHasSubFolders() to call
GetSubFolders().  

we need to do this, otherwise mSubFolders might not be properly initialized. 
(GetSubFolders() will initialize if it needs to.)

fixing nsMsgFolderDataSource::createFolderChildNode() to call GetHasSubFolders()
will be prettier, but it will do what it does now, and call GetSubFolders().

Comment 3

[Håkan Waara]

But still, isn't it inefficent to get a whole array just to use the first element?

Comment 4

[[e-mail] (gone - use [e-mail] instead)]

Would this be a big performance win?  Cavin, might this be something you and 
Seth have already investigated?

Comment 5

[(not reading, please use [e-mail] instead)]

sorry for the spam.  making bugzilla reflect reality as I'm not working on these bugs.  filter on FOOBARCHEESE to remove these in bulk.

Comment 6

[David :Bienvenu]

this is now fixed because GetHasSubfolders creates an enumerator and checks if the enumerator has any elements.