output_rows (in tui::history) walks the raw tool output, ANSI-strips
each line, classifies path/URL-like rows, and wraps the rest to the
current viewport width. selected_output_indices then computes the
head/tail/importance subset that the compact Live view shows. Both
functions are pure, but they are called on every render frame for
every visible tool cell. For a 4 KB tool output on a 120 FPS render
loop that is 2-6 redundant walks per frame, per cell, and the
function is called from a non-trivial number of cells across
exec, tool, command, and review history.
Add tui::output_rows_cache, a thread-local, content-addressed cache
keyed on (content_hash, width) for the rows and (content_hash, width,
line_limit) for the indices. The cache stores the wrapped
Vec<OutputRow> plus a per-line-limit map of selected indices on a
single entry, so a single key lookup satisfies both render steps.
render_preserved_output_mode now consults the cache for both the
rows and the indices; on a hit, neither the per-line ANSI strip nor
the importance-ranking pass runs. The cache is bounded (default
capacity 256) with insertion-order eviction. The OutputRow struct
gains PartialEq + Eq + pub fields so the cache module can store and
hash it without exposing private internals.
Tests: 6 new unit tests cover the hit/miss path, width invalidation,
content invalidation, indices per-line_limit caching, capacity
eviction, and hash stability. The wider tui::history test suite (68
tests) still passes.
HUQIANTAO
3b0ef3f63c