Replace the remaining UTF-16-mode StringBuilder instances in LibWeb
with Utf16StringBuilder when they assemble Utf16String values or UTF-16
text views. This keeps those paths in UTF-16 throughout and uses
explicit ASCII append helpers for ASCII-only pieces.
Keep StringBuilder in place for JSON, markup, CSS serialization, and
other byte-oriented string construction paths.
Move the layout tree from GC allocation to refcounted ownership so
removed layout and paint subtrees are destroyed synchronously instead
of waiting for the next GC sweep. This dramatically reduces GC memory
usage peaks after layout tree churn and makes it easier for memory use
to fall back after large document updates.
Update layout factories, tree traversal, SVG layout node creation,
paintable back-pointers, and pseudo-element layout links to use RefPtr
ownership.
Make display: contents follow the same shape as Blink and WebKit: the
element itself does not create a layout node, and its children are
flattened into the nearest layout parent. Wrap direct non-whitespace
text in an anonymous inline node when the boxless element contributes
inherited style to that text.
Use an internal inline wrapper for display: contents pseudo-elements
so generated content can still participate in layout, painting, hit
testing, and pseudo-element queries. Keep CSSOM reporting the computed
display value from the pseudo style, not the internal wrapper.
Remove the retained out-of-tree layout node list and its testing hook,
since the flattened model does not need a side owner for boxless
elements. Add coverage for inherited text style, dynamic insertion
order, pseudo-element hit testing, and computed style queries.
Stop creating unattached DOM Text nodes for string items in generated
CSS content. These text nodes are layout artifacts, so store their text
directly in a GeneratedTextNode instead of pretending they have DOM
backing.
Teach text shaping and first-letter splitting to read text through the
layout text source while keeping DOM-specific behavior behind an
optional DOM text accessor. This preserves generated first-letter
handling without rooting fake DOM nodes.
Add crash coverage for generated content surviving GC and rebaseline
layout dumps that now identify generated text explicitly.
Move ComputedProperties and CascadedProperties out of the GC. They no
longer contain strong references to GC-managed data.
Keep computed styles alive from DOM elements and animation updates with
RefPtr. Pass style into layout constructors by reference, since layout
only copies the values it needs while building nodes.
Use GC::Weak for cascade source links, so entries no longer keep the
style declaration or shadow root alive.
Previously, the text searched by find-in-page was gathered from each
text node's rendered string, which still contains uncollapsed
whitespace. We now collapse runs of whitespace to a single space and
trim leading and trailing whitespace per block when building the
searchable text, while keeping each character mapped back to its DOM
position so matches still resolve to correct ranges.
We now apply first letter styles by splitting text with a first-letter
style applied into 2 `TextSliceNode` objects. The
`DOM::Text` layout node always points at the non first-letter slice
and the first-letter slice is reachable via
`TextSliceNode::first_letter_slice()`.
First letter splitting works by `TreeBuilder` walking a block
container's inline descendants to find the first typographic letter
unit per the pattern given in css-pseudo level 4, which is then
wrapped in an anonymous inline box styled with the `::first-letter`
computed properties.
Consumers that map between DOM offsets and layout geometry
are updated to visit all slices of a `DOM::Text` through
`TextOffsetMapping`.
The Paintable tree and its supplemental painting data structures were
GC allocated because that was the easiest way to manage it and avoid
leaks introduced by ref cycles. This included the Paintable subclasses
themselves plus StackingContext, ChromeWidget, Scrollbar, ResizeHandle,
and scroll-frame state.
We are now trying to reduce GC allocation churn on layout and painting
updates, so keeping this short-lived rendering tree outside the JS heap
is a better fit. Move Paintable to RefCountedTreeNode, make painting
helpers ref-counted or weakly reference Paintables, and update the
layout and event-handler call sites to use RefPtr/WeakPtr ownership.
Move the inline dom_node() method to Viewport.cpp so the header no
longer needs the full Document definition. Add explicit includes to
files that relied on the transitive dependency.
This migrates TextNode::text_for_rendering() to Utf16String and deals
with the fallout. As a consequence, this effectively reverts commit
3df83dade8.
The layout test expecation file updates are because we now express text
lengths and offsets in UTF-16 code units.
The selection-over-multiple-code-units expectation file update actually
represents a correctness fix. Our result now matches Firefox.
We were passing in byte offsets instead of UTF-16 code unit offsets,
which could lead to crashes if the offsets found exceeded the number of
code units in text fragments on the page.
Fixes#4908.
Co-authored-by: Tim Ledbetter <tim.ledbetter@ladybird.org>
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
