[webkit-changes] [WebKit/WebKit] a8f7b2: [IFC][Partial layout] Exit line layout when curren...

[Alan Baradlay]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: a8f7b254c9857b3c870acb19cfb352444b20e8ca
      https://github.com/WebKit/WebKit/commit/a8f7b254c9857b3c870acb19cfb352444b20e8ca
  Author: Alan Baradlay <zalan at apple.com>
  Date:   2023-03-17 (Fri, 17 Mar 2023)

  Changed paths:
    M Source/WebCore/layout/formattingContexts/inline/InlineFormattingContext.cpp
    M Source/WebCore/layout/formattingContexts/inline/display/InlineDisplayBox.h
    M Source/WebCore/layout/formattingContexts/inline/invalidation/InlineDamage.h
    M Source/WebCore/layout/formattingContexts/inline/invalidation/InlineInvalidation.cpp
    M Source/WebCore/layout/formattingContexts/inline/invalidation/InlineInvalidation.h
    M Source/WebCore/layout/integration/inline/LayoutIntegrationInlineContentBuilder.cpp
    M Source/WebCore/layout/integration/inline/LayoutIntegrationLineLayout.cpp

  Log Message:
  -----------
  [IFC][Partial layout] Exit line layout when current line ends exactly where it ended at the previous layout
https://bugs.webkit.org/show_bug.cgi?id=253582

Reviewed by Antti Koivisto.

During partial layout, we may find ourselves laying out lines beyond the damaged position and yet producing the same set of display boxes.
This patch implements an exit strategy for such partial layouts by looking at the trailing position of the freshly laid out line.
If we see no change at the trailing position, we assume running line layout on the subsequent line would produce
the same set of display boxes that we already have (note that this is limited to text only content, no floats, no special first/last lines etc).

This is not yet functional as m_trailingDisplayBoxes is not populated.

* Source/WebCore/layout/formattingContexts/inline/InlineFormattingContext.cpp:
(WebCore::Layout::InlineFormattingContext::layoutInFlowContent):
(WebCore::Layout::InlineFormattingContext::layoutInFlowContentForIntegration):
(WebCore::Layout::InlineFormattingContext::computedIntrinsicWidthConstraintsForIntegration):
(WebCore::Layout::mayExitFromPartialLayout):
(WebCore::Layout::InlineFormattingContext::lineLayout):
(WebCore::Layout::InlineFormattingContext::computedIntrinsicWidthConstraints):
* Source/WebCore/layout/formattingContexts/inline/display/InlineDisplayBox.h:
(WebCore::InlineDisplay::operator==):
* Source/WebCore/layout/formattingContexts/inline/invalidation/InlineDamage.h:
(WebCore::Layout::InlineDamage::start const):
(WebCore::Layout::InlineDamage::setDamagedPosition):
(WebCore::Layout::InlineDamage::trailingContentForLine const):
(WebCore::Layout::InlineDamage::~InlineDamage):
(WebCore::Layout::InlineDamage::reset):
(WebCore::Layout::InlineDamage::contentPosition const): Deleted.
* Source/WebCore/layout/formattingContexts/inline/invalidation/InlineInvalidation.cpp:
(WebCore::Layout::InlineInvalidation::updateInlineDamage):
(WebCore::Layout::InlineInvalidation::textInserted):
(WebCore::Layout::InlineInvalidation::textWillBeRemoved):
(WebCore::Layout::InlineInvalidation::inlineLevelBoxInserted):
(WebCore::Layout::InlineInvalidation::inlineLevelBoxWillBeRemoved):
* Source/WebCore/layout/formattingContexts/inline/invalidation/InlineInvalidation.h:
* Source/WebCore/layout/integration/inline/LayoutIntegrationInlineContentBuilder.cpp:
(WebCore::LayoutIntegration::InlineContentBuilder::build const):
* Source/WebCore/layout/integration/inline/LayoutIntegrationLineLayout.cpp:
(WebCore::LayoutIntegration::LineLayout::layout):

Canonical link: https://commits.webkit.org/261790@main