1559546 - Use atoms for grid line names.

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, task, P3)

Description

[Emilio Cobos Álvarez (:emilio)]

The style system already atomizes all CustomIdent values, which means that we're
just wasting memory and CPU by doing string copies all over the place.

This also simplifies further changes to use as much of the
rust data structures as possible.

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1559546 - Allow to construct StyleAtom objects from C++. r=heycam

I'm going to need it in an upcoming patch.

Comment 2

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1559546 - Use atoms for grid line names. r=mats,#style

The style system already atomizes all CustomIdent values, which means that we're
just wasting memory and CPU by doing string copies all over the place.

This patch fixes it. This also simplifies further changes to use as much of the
rust data structures as possible.

I had to switch from nsTHashtable to mozilla::HashTable because the former
doesn't handle well non-default-constructible structs (like NamedLine, which
now has a StyleAtom, which is not default-constructible).

Depends on D35118

Comment 3

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1559546 - Introduce nsAtom::IsEmpty. r=njn

Both for symmetry with other string APIs, and also to prevent footguns (since I
debugged for a while a typo where I wrote nsGkAtoms::empty rather than
nsGkAtoms::_empty).

We could use null here, but that will not be possible in the future when I use
the rust representation of more grid data structures (at least without
increasing memory usage).

So I think I'll keep using ::_empty as a signaling value for "no grid
identifier".

Depends on D35119

Comment 4

[Emilio Cobos Álvarez (:emilio)]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=0cec38ebbc23233415a9a0c0b6041a5fda9b3247

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1e5b608b1442
Allow to construct StyleAtom objects from C++. r=heycam
https://hg.mozilla.org/integration/autoland/rev/acf98e967abe
Use atoms for grid line names. r=mats
https://hg.mozilla.org/integration/autoland/rev/8567a308ac7a
Introduce nsAtom::IsEmpty. r=njn

Comment 6

[Raul Gurzau (:RaulG)]

https://hg.mozilla.org/mozilla-central/rev/1e5b608b1442
https://hg.mozilla.org/mozilla-central/rev/acf98e967abe
https://hg.mozilla.org/mozilla-central/rev/8567a308ac7a