232351 - make a stub implementation of nsIDocumentObserver

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

I think it might be good to have a stub implementation of nsIDocumentObserver
that implementors of nsIDocumentObserver within content and layout can derive
from (instead of directly from nsIDocumentObserver).

It would have empty implementations (using the existing macros) of all the
nsIDocumentObserver methods, but the nsISupports methods would still be pure
virtual.  (I'd probably want to call it nsStubDocumentObserver or
nsDocumentObserverStub.)

This would have two advantages:
 * it would reduce code size
 * it would hopefully reduce CPU cache misses and perhaps even missed branch
prediction, since (to some degree) instead of calling a bunch of different
functions when looping over observers, we'd repeatedly call the same function.

Thoughts?

Comment 1

[Boris Zbarsky [:bzbarsky]]

Sounds pretty good to me.

Comment 2

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

jst also suggested the possibility of inline virtual functions on
nsIDocumentObserver, but neither of us is sure exactly what that would do.

We're leaning towards nsStubDocumentObserver.

Comment 3

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

Yeah, i think a nsStubDocumentObserver would be the safest too. We should still
keep the macros in nsIDocumentObserver.h though, since we have documentobservers
outside of gklayout, such as transformiix and inspector.

Comment 4

[Brendan Eich [:brendan]]

This is a total language-geek nit: nsStubDocumentObserver is slightly verb-ier
than the clearly-noun-phrase nsDocumentObserverStub, and I think for concrete
class names, noun phrases win.

/be

Comment 5

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Attachment: patch

Comment 6

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Comment on attachment 140035 [details] [diff] [review]
patch

I think I prefer nsStubDocumentObserver -- it's no verbier than
nsIDocumentObserver itself.

Comment 7

[Johnny Stenback (:jst)]

Comment on attachment 140035 [details] [diff] [review]
patch

r=jst

Comment 8

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Fix checked in to trunk, 2004-01-28 13:01/02/04 -0800.

Comment 9

[[e-mail]]

/me would have just called it nsDocumentObserver ;-)

Comment 10

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Attachment: missed one

Comment 11

[Johnny Stenback (:jst)]

Comment on attachment 140118 [details] [diff] [review]
missed one

r+sr=jst

Comment 12

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Comment on attachment 140118 [details] [diff] [review]
missed one

Checked in to trunk, 2004-01-28 17:45 -0800.