172058 - Split up nsIDocumentObserver

Status: RESOLVED INVALID

(Core :: DOM: Core & HTML, task, P5)

Description

[John Keiser (jkeiser)]

Most nsIDocumentObservers don't care about all the 20 notifications on that
interface, yet we send the notifications for all of them to every observer (most
of whom just return NS_OK; from nearly all the functions).  We should fix that.

Comment 1

[John Keiser (jkeiser)]

Two possibilities we have come up with:
(a) pass a flag when you register as an observer saying what notifications you
want to receive;
(b) break it down into a few smaller, saner observer interfaces where people are
more likely to listen to all or most of the events

I prefer (b) breaking it down.

Here is a VERY ROUGH START at this that should be sort of reasonable:
nsIDocumentContentChangeObserver {
  BeginUpdate
  EndUpdate
  ContentChanged
  ContentStatesChanged
  AttributeChanged
  ContentAppended
  ContentInserted
  ContentRemoved
  ContentReplaced
}

nsIDocumentStyleObserver {
  StyleSheetAdded
  StyleSheetRemoved
  StyleSheetDisabledStateChanged
  StyleRuleChanged
  StyleRuleAdded
  StyleRuleRemoved
}

nsIDocumentObserver {
  BeginLoad
  EndLoad
  BeginReflow
  EndReflow
  DocumentWillBeDestroyed
}

The positioning of StyleSheetAdded/Removed/Disabled, and ContentStatesChanged,
may be wrong--this is a rough sketch that seems to fit things pretty well
without being totally horrible.  BeginReflow/EndReflow, however, seem like they
should be notifications from the PresShell, though, another possible change.

Comment 2

[Firefox Bug Husbandry Bot]

https://bugzilla.mozilla.org/show_bug.cgi?id=1472046

Move all DOM bugs that haven’t been updated in more than 3 years and has no one currently assigned to P5.

If you have questions, please contact :mdaly.

Comment 3

[Hsin-Yi Tsai (she/her) [:hsinyi]]

The code has changed a lot, and many parts have been moved to other .idl files.