Struct ExcerptFoldProvider 

pub struct ExcerptFoldProvider { /* private fields */ }

M.7: computes one open [lattice_core::Fold] per excerpt in the composed multibuffer. Registered as a [lattice_core::FoldSource] by MultibufferMode::on_activate via FoldOverlayService; the FoldSourceAdapter in lattice-host gates compute_folds to calls where FoldContext::buffer_id matches this multibuffer’s buffer ID.

Implementations

impl ExcerptFoldProvider

pub fn new(handle: MultibufferDocumentHandle, buffer_id: BufferId) -> Self

Trait Implementations

impl FoldSource for ExcerptFoldProvider

fn compute_folds(&self) -> Vec<Fold>

One fold per excerpt — except a single-line one, which is not a fold at all (OA.4c).

A fold whose start_line == end_line can never hide anything: closed, it shows its head, which is the whole of it. Emitting one is not merely wasteful, it is actively wrong, because innermost_fold_idx picks the fold with the greatest start_line — so a degenerate per-excerpt fold SHADOWS the group fold that actually contains the row, and <Tab> toggles something with no visible effect while the block stays closed.

That is what one-line agenda rows (OA.1) turned this into: before them an agenda excerpt spanned its planning line, so every fold here was a real two-line one. The report was “<Tab> doesn’t work cleanly, only <S-Tab> seems to work” — <S-Tab> sets every fold at once, so it was unaffected.

Generic, not agenda-shaped: project search with context_lines = 0 produces one-line excerpts too.

fn id(&self) -> ProviderId

This source’s stable id: the same on every call, and distinct from every other registered source’s (see [ProviderId]).