8479 - alter RDF observer ownership to allow JS implementation

Status: VERIFIED FIXED

(Core Graveyard :: RDF, defect, P3)

Description

[Chris Waterson]

The "composite datasource" composes together (and owns) indivdual datasources.
It "spies" on those datasources by registering itself as an "observer" with
each datasource. In order to avoid a leak in this case, I set up the ownership
model s.t. a datasource holds a "weak" (not addref-ed) reference on an
observer. XPConnect is not set up to handle this. Nor can it be, if it is to
remain safe from dangling pointers.

Brendan reminded me that I could in fact allow an observer to refcount its
observee, and can break the circularity in "composite datasource" by
special-casing its Release() method. Specifically, Release() will detect
refcount == num-datasources, and know that these remaining references are the
circular "back links" from the datasource observers.

Comment 1

[Chris Waterson]

Fixed. Landed RDF_19990617_BRANCH.

Comment 2

[phillip]

code level fix, marking verified. reopen if i'm wrong here...