1620490 - Break DoFlexLayout() into smaller pieces

Status: RESOLVED FIXED

(Core :: Layout: Flexbox, task)

Description

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

Currently, DoFlexLayout() roughly does three things in the following order.

1. Runs the flex layout algorithm, generates flex lines and flex items, and computes all the information.
2. Performs the final reflow for all children based on the data in step 1.
3. Computes flex container's final size based on data in step 1 and 2.

I'd like to extract step 2 and step 3 into some helpers. When the flex container needs to split, the data computed in step 1 might need not be computed again in the flex container's continuations.

In doing so, this part of the flex container's Reflow() will be more like

DoFlexLayout(...)
if (restart flex layout) {
  DoFlexLayout(...)
}

ReflowChilden(...)
ComputeFinalSize(...)

Comment 1

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

Attachment: Bug 1620490 Part 1 - Rename ResolveFlexContainerMainSize to ComputeMainSize, and make it a flex container method.

For two reasons,

1. Change the naming to make it consistent with ComputeCrossSize.

2. Make it a flex container methods because it likely needs to call
   nsSplittableFrame::GetEffectiveComputedBSize() later when we consider
   fragmentation. If not, it doesn't harm anyway.

Comment 2

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

Attachment: Bug 1620490 Part 2 - Delete unused SortChildrenIfNeeded() declaration.

The implementation was deleted in Bug 812687
https://hg.mozilla.org/mozilla-central/rev/173a4f49dfe3

Depends on D65778

Comment 3

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

Attachment: Bug 1620490 Part 3 - Export some data computed in DoFlexLayout.

This is a preparation patch for a later part. I want to extract the
computation of flex container's ReflowOutput into a helper method, and
call the helper in Reflow().

Depends on D65779

Comment 4

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

Attachment: Bug 1620490 Part 4 - Move the helper methods that handle ComputedFlexContainerInfo into protected section.

They are helpers for DoFlexLayout, which don't need to be public.

Depends on D65780

Comment 5

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

Attachment: Bug 1620490 Part 5 - Make CreateOrClearFlexContainerInfo() return the container info pointer, and use the pointer in DoFlexLayout.

Also, move UpdateFlexLineAndItemInfo() from the end of DoFlexLayout() to
the end of Reflow() because I'm going to extract the computation of
final size of flex container into a helper method in a later patch, and
call it Reflow() just after DoFlexLayout().

Depends on D65782

Comment 6

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

Attachment: Bug 1620490 Part 6 - Extract the computation of flex container's final size into a helper method.

Also, remove unused ReflowOutput from DoFlexLayout's argument.

Depends on D65783

Comment 7

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

Attachment: Bug 1620490 Part 7 - Extract the final reflow for flex container's children into a method.

Depends on D65784

Comment 8

[Daniel Holbert [:dholbert]]

Thanks for doing this!

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d74c415aa322
Part 1 - Rename ResolveFlexContainerMainSize to ComputeMainSize, and make it a flex container method. r=dholbert
https://hg.mozilla.org/integration/autoland/rev/d4bda3643a1d
Part 2 - Delete unused SortChildrenIfNeeded() declaration. r=dholbert
https://hg.mozilla.org/integration/autoland/rev/ae1ed37843e9
Part 3 - Export some data computed in DoFlexLayout. r=dholbert
https://hg.mozilla.org/integration/autoland/rev/ae329f32dda9
Part 4 - Move the helper methods that handle ComputedFlexContainerInfo into protected section. r=dholbert
https://hg.mozilla.org/integration/autoland/rev/fdfb108df9e8
Part 5 - Make CreateOrClearFlexContainerInfo() return the container info pointer, and use the pointer in DoFlexLayout. r=dholbert
https://hg.mozilla.org/integration/autoland/rev/7c8aecf26754
Part 6 - Extract the computation of flex container's final size into a helper method. r=dholbert
https://hg.mozilla.org/integration/autoland/rev/25601cd5859a
Part 7 - Extract the final reflow for flex container's children into a method. r=dholbert

Comment 10

[Alexandru Michis [:malexandru]]

https://hg.mozilla.org/mozilla-central/rev/d74c415aa322
https://hg.mozilla.org/mozilla-central/rev/d4bda3643a1d
https://hg.mozilla.org/mozilla-central/rev/ae1ed37843e9
https://hg.mozilla.org/mozilla-central/rev/ae329f32dda9
https://hg.mozilla.org/mozilla-central/rev/fdfb108df9e8
https://hg.mozilla.org/mozilla-central/rev/7c8aecf26754
https://hg.mozilla.org/mozilla-central/rev/25601cd5859a