1479398 - The is_root() fast-path could be faster.

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, enhancement)

Description

[Emilio Cobos Álvarez (:emilio)]

I thought that bug 1478985 wouldn't make a difference in common cases since we already need to poke at the element and such for looking up in the selector maps.

But is_root right now pokes at the parent in the common case. That can be faster.

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1479398: Micro-optimize is_root to avoid poking at the parent in the common case. r=xidorn

We can discard the common case of an element having another element or document
fragment parent, which is the common case.

Then we can discard detached subtrees looking at is_in_document().

The only case where we have a non-content parent is the document case:

  https://searchfox.org/mozilla-central/rev/033d45ca70ff32acf04286244644d19308c359d5/dom/base/Element.cpp#1683

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/89fcb03e210c
Micro-optimize is_root to avoid poking at the parent in the common case. r=xidorn

Comment 3

[Pulsebot]

Backout by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/951af7075518
Back out changeset 89fcb03e210c because it's not reviewed yet. r=backout

Comment 4

[Phabricator Automation]

Comment on attachment 8995933 [details]
Bug 1479398: Micro-optimize is_root to avoid poking at the parent in the common case. r=xidorn

Xidorn Quan [:xidorn] UTC+10 has approved the revision.

https://phabricator.services.mozilla.com/D2505

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/7197c675f225
Micro-optimize is_root to avoid poking at the parent in the common case. r=xidorn

Comment 6

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/7197c675f225