Struct UnchangedFoldSource 

pub struct UnchangedFoldSource { /* private fields */ }

D-fix.5 (2026-06-26): per-buffer, per-side unchanged-fold source — vimdiff foldmethod=diff / VS Code “Collapse Unchanged Regions”.

Where HunkFoldSource folds the hunks (open by default — za collapses a change), this folds their complement: the unchanged gaps between hunks, minus a context-line window around each change, closed by default so a diff opens showing only the changes. The two coexist on the same buffer over disjoint line regions.

Both sides, in lockstep. diff-mode::on_activate registers one per participant buffer (resolving each side’s slot via DiffSubsystem::participant_slot), so a side-by-side :diffsplit / openDiff folds the baseline and current panes symmetrically — the scroll-bound panes stay vertically aligned (folding only one side would desync them).

Option-gated, read live at compute_folds time from the ConfigRegistry service: ui.diff.fold-unchanged (default on) + ui.diff.context (default 6). No config service / option absent ⇒ the safe defaults (fold on, context 6) — never a panic.

Implementations

impl UnchangedFoldSource

pub fn new( session: Arc<DiffSession>, buffer_id: BufferId, slot: usize, config: Option<Arc<ConfigRegistry>>, ) -> UnchangedFoldSource

Build a source for session at slot, namespaced by buffer_id (distinct from the buffer’s hunk-fold source via UNCHANGED_FOLD_NAMESPACE). config is the ConfigRegistry service handle the mode pulls in on_activate (or None ⇒ defaults).

Trait Implementations

impl FoldSource for UnchangedFoldSource

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).