Having Servo's FontFaceRule owning Gecko's nsCSSFontFaceRule object opens an
untracked edge, because we generally don't track the reference through Servo
objects, so there is a chance that nsCSSFontFaceRule can form a undroppable
reference cycle.
This patch adds a workaround that we track @font-face rule twice in CSS rule
list. This is not perfect, but the idea is that, if someone wants to put some
reference on the @font-face rule, the rule itself and its parent list should
have been constructed in the CSSOM tree. If they are not there, we are
probably safe from cycle reference.
For @font-face rule, that assumption isn't strictly true. Script can still
get a font-face rule via layout inspector's nsIDOMFontFace::rule. If some
script puts an object which references the stylesheet of the rule or any of
its parent rule / rule list into font-face rule's expando, we would leak
again... But as far as that is an internal interface, we are probably safe?
MozReview-Commit-ID: DDMJh3mxDCH
--HG--
extra : rebase_source : 646fcf076195151e6890ebffb7597e58c8a7d522
An explanation of the Mozilla Source Code Directory Structure and links to
project pages with documentation can be found at:
https://developer.mozilla.org/en/Mozilla_Source_Code_Directory_Structure
For information on how to build Mozilla from the source code, see:
https://developer.mozilla.org/en/docs/Build_Documentation
To have your bug fix / feature added to Mozilla, you should create a patch and
submit it to Bugzilla (https://bugzilla.mozilla.org). Instructions are at:
https://developer.mozilla.org/en/docs/Creating_a_patch
https://developer.mozilla.org/en/docs/Getting_your_patch_in_the_tree
If you have a question about developing Mozilla, and can't find the solution
on https://developer.mozilla.org, you can try asking your question in a
mozilla.* Usenet group, or on IRC at irc.mozilla.org. [The Mozilla news groups
are accessible on Google Groups, or news.mozilla.org with a NNTP reader.]
You can download nightly development builds from the Mozilla FTP server.
Keep in mind that nightly builds, which are used by Mozilla developers for
testing, may be buggy. Firefox nightlies, for example, can be found at:
https://archive.mozilla.org/pub/firefox/nightly/latest-mozilla-central/
- or -
https://nightly.mozilla.org/
9558f57119