Struct FileBoundaryFoldProvider 

pub struct FileBoundaryFoldProvider { /* private fields */ }

M.8: computes one open [lattice_core::Fold] per distinct source [BufferId] (file), spanning the composed-row range from the first to the last excerpt belonging to that file. Registered alongside ExcerptFoldProvider by MultibufferMode::on_activate. Enables collapsing all excerpts from a file to its header row with za.

PD.5a: the fold’s identity is derived from the source path, not its BufferId. recompute_folds carries closed/open state across a rebuild by matching identity, and a refreshing provider re-reads its files under fresh BufferId::next() values — so a BufferId-derived identity changes on every refresh, the match misses, and every file the user had collapsed springs back open. The path is what the user was collapsing, so it is what the identity should track.

Implementations

impl FileBoundaryFoldProvider

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

Trait Implementations

impl FoldSource for FileBoundaryFoldProvider

fn id(&self) -> ProviderId

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

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

Produce the current fold ranges. Called by the host on recompute, so it should be cheap (read already-computed state; no I/O).