1507305 - Give Servo the ability to serialize computed shorthands

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, enhancement)

Description

[Emilio Cobos Álvarez (:emilio)]

I wrote this for bug 775618, but it applies to all our other shorthands.

Need a bit more care with mask and text-decoration, but this introduces the infrastructure, and improves consistency of serialization, in particular with calc(), where Servo follows the Spec but Gecko doesn't.

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1507305 - Add a mechanism to serialize shorthands for getComputedStyle().

This implements the mechanism reusing the animation machinery for now, so it
asserts in a few cases that this wouldn't handle correctly.

For shorthands that have colors and other bits we'd need a more sophisticated
mechanism with a bit more code (that resolves colors and such), but it'd look
something like this regardless, and we should have this in any case.

Comment 2

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1507305 - Use Servo to serialize most of the already-exposed shorthands.

Skip mask and text-decoration for now since there's a single test-case failing
for each that seem worth fixing in a different bug:

 * For mask, there's the case of setting mask: url(foo.svg#bar), which we test
   we serialize absolutely. But given we're uncomputing it we don't serialize
   the resolved URL. Chrome doesn't either so we could just change the test, but
   even if we decided to do it we probably should do it in a separate bug.

 * For text-decoration, we need to resolve the value, when it's an interpolation
   between currentcolor and other color. Right now that returns the empty string
   which is not great:

     https://searchfox.org/mozilla-central/rev/d850d799a0009f851b5535580e0a8b4bb2c591d7/servo/components/style/values/specified/color.rs#194

   So I need to come up with something. Probably we need to implement the "hard"
   version of the serialization code that doesn't reuse the animation machinery.

   Definitely a separate bug though.

While at it, also serialize all <position> longhands with Servo, so that I can
clean up the tests.

Comment 3

[Emilio Cobos Álvarez (:emilio)]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=c56002c2f29091bf70f89db6a9ba9160100e44fe

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/5201cfe20675
Add a mechanism to serialize shorthands for getComputedStyle(). r=heycam

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/76aa81358d76
Use Servo to serialize most of the already-exposed shorthands. r=heycam

Comment 6

[Eliza Balazs [:ebalazs_]]

https://hg.mozilla.org/mozilla-central/rev/5201cfe20675
https://hg.mozilla.org/mozilla-central/rev/76aa81358d76