1445229 - [css-grid] Store the number of grid items per span-length to avoid iterating them again

Status: RESOLVED FIXED

(Core :: Layout, enhancement, P3)

Description

[Mats Palmgren (inactive)]

Just a little optimization on top of bug 1425599.

Comment 1

[Mats Palmgren (inactive)]

Attachment: [css-grid] Store the number of grid items per span-length to avoid iterating them again

Comment 2

[Mats Palmgren (inactive)]

Attachment: [css-grid] Store the number of grid items per span-length to avoid iterating them again (idempotent change)

Comment 3

[Daniel Holbert [:dholbert]]

Comment on attachment 8958421 [details] [diff] [review]
[css-grid] Store the number of grid items per span-length to avoid iterating them again (idempotent change)

Review of attachment 8958421 [details] [diff] [review]:
-----------------------------------------------------------------

r=me, one optional nit:

::: layout/generic/nsGridContainerFrame.cpp
@@ +4360,4 @@
>            uint32_t len = 2 * span;
> +          perSpanData.SetCapacity(len);
> +          for (uint32_t i = perSpanData.Length(); i < len; ++i) {
> +            perSpanData.AppendElement(PerSpanData{0, TrackSize::StateBits(0)});

If you gave PerSpanData a default constructor with ": mItemCount(0), mStateBits(0)" (somewhat useful on its own merits as an uninitialized-data foolproofing measure), then you could replace this whole "if" clause with a single nsTArray::SetLength() call, like so:

  if (span >= perSpanData.Length()) {
    perSpanData.SetLength(2 * span);
  }

(Because nsTArray::SetLength automatically invokes the default constructor for new elements that it appends.)

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/023c4f7e7d76
[css-grid] Store the number of grid items per span-length to avoid iterating them again (idempotent change).  r=dholbert

Comment 5

[Mats Palmgren (inactive)]

(In reply to Daniel Holbert [:dholbert] from comment #3)
>   if (span >= perSpanData.Length()) {
>     perSpanData.SetLength(2 * span);

Yeah, that's much better, thanks!

Comment 6

[Raul Gurzau (:RaulG)]

https://hg.mozilla.org/mozilla-central/rev/023c4f7e7d76