Implement the first Rust tree builder pass around the tokenizer and the
LibWeb DOM host hooks. Cover the document setup, insertion-mode
dispatch, ordinary body insertion, basic table handling, active
formatting element reconstruction, and foreign-content routing.
Leave the C++ parser available at runtime so the new path can be tested
against the old implementation while the remaining tree-construction
algorithms are filled in.
Add the C++ and Rust scaffolding that lets the tree builder live in
Rust while the DOM remains owned by LibWeb. Keep the exported surface
small: Rust stores parser state, and C++ provides node creation,
insertion, script, template, and GC hooks.
Route dump-html-tree through the selectable parser backend so the new
implementation can be exercised beside the existing parser while it is
being brought up.
Replace the FFI tokenizer state transmute with an explicit conversion
from the incoming numeric value. The old code range-checked against the
last state before transmuting, which matched today's contiguous enum but
left the conversion dependent on that layout detail.
Returning early for unknown values keeps the FFI boundary tolerant while
removing a source of possible invalid enum discriminants.
Replace the C++ HTML tokenizer with a Rust implementation behind the
existing HTMLTokenizer API.
Keep the parser-facing integration points for streaming input,
insertion points, document.write(), EOF insertion, parser aborts,
speculative parser input, and last start tag tracking. The generated
FFI handle stays an implementation detail of HTMLTokenizer, so callers
keep a single tokenizer class.
Preserve duplicate attributes through FFI so C++ token normalization can
record the duplicate-attribute signal used by CSP nonce checks. Keep
bulk tag-name and attribute scans capped at the active insertion point
so streamed parser input is spliced at the right offset.
Use generated DAFSA tables for named character references and intern
common tag and attribute names to reduce FFI marshalling overhead. This
also fixes attribute name source positions, nested old insertion points,
and aborted fast-path handling.
TestHTMLTokenizer covers duplicate attributes and insertion points in
fast tag-name, attribute-name, and quoted-value scans. A CSP text test
covers duplicate nonce attributes on parser-created script elements.
The tokenizer dump fixtures still match, TestHTMLTokenizer passes, and
the full release test-web run passes with 6981 tests and 226 skipped.
