Struct FileTreeMode 

pub struct FileTreeMode;

Major mode for file-tree buffers. Read-only contribution (ReadOnly = true); any buffer whose major is file-tree-mode rejects mutating operators.

Implementations

impl FileTreeMode

pub fn mode_id() -> ModeId

Trait Implementations

impl Mode for FileTreeMode

fn target_buffer_kind(&self) -> Option<BufferKind>

H.2: file-tree buffers (BufferKind::FileTree) dispatch to this major via the registry’s kind index.

fn options(&self) -> OptionOverrideSet

Number = false is per-major, not per-listing (2026-08-16): a tree is a navigation surface and hides line numbers like every other tree UI, while oil is an ordinary editable buffer that keeps them. It used to sit on the shared directory-listing-mode, which forced the tree’s answer onto oil. It lives here now, next to ReadOnly, which is per-major for the same reason.

fn invocation_runner(&self) -> Option<ModeId>

2026-05-26: claim invocation dispatch for file-tree panes via Editor::run_file_tree_invocation.

fn action_handlers(&self) -> Vec<ActionHandlerContribution>

LM.4: the navigation/open chord bodies, mode-owned (they were the host’s do_file_tree_follow + the do_oil_navigate_up file-tree branch, reached through the shared Help | FileTree input-gate). Each reads the tree’s entries from the ActionContext’s buffer-locals (LM.1) and the row under the cursor, then hands the host an Effect (the diff/oil pattern). Bound globally at boot; each names its own view (ctx.buffer_id) so many trees stay independent (design §3.2).

type Guard = ()

Owned cleanup token returned by Self::on_activate.

fn id(&self) -> ModeId

Canonical identity. Same value every call.

fn kind(&self) -> ModeKind

Major or minor. Read at registration and on every activation call (activate_major on a minor, or vice versa, is ModeActivationError::WrongKind).

fn required_capabilities(&self) -> CapabilitySet

Capabilities the mode requires. Validated at activation; missing capability ⇒ ModeActivationError::MissingCapability, never silent skip.

fn keymap(&self) -> Keymap

Keymap chord → command additions / overrides.

fn on_activate( &self, _ctx: ModeContext, ) -> Pin<Box<dyn Future<Output = Result<(), ModeActivationError>> + Send + '_>>

Lifecycle. Called once per (buffer, activation) cycle after the registry has applied the declarative contributions. Returns an owned Guard carrying every resource the mode allocated. The dispatcher stashes the Guard until deactivation, at which point dropping it performs cleanup via the Guard’s Drop impl.

fn target_language(&self) -> Option<&str>

For major modes, the language this mode is the default major for, by canonical name (Lang::name() — "rust", "org") (OM.1). The peer of target_buffer_kind for the dispatch path BufferKind::Document takes: language detection rather than kind dispatch.

fn decorations(&self) -> Vec<DecorationProvider>

Decoration providers (gutter / inline / overlay / statusline). Stub — reserved for the WIT plugin path (M.10).

fn gutter_decorations(&self, _ctx: &DecorationCtx<'_>) -> Vec<GutterDecoration>

Gutter sign decorations this mode contributes while active. Called once per pane per frame with a DecorationCtx carrying relevant render-state snapshots (diff sign map, LSP diagnostics arc). Returns per-line GutterDecoration values; the renderer partitions them by variant into the appropriate gutter column. Default: empty (no contribution).

fn completion_sources(&self) -> Vec<CompletionSourceContribution>

Insert-mode completion sources this mode contributes while active on a buffer. Empty by default; minors that own a completion source (lsp-completion-mode, snippet-completion-mode, buffer-words-mode, tree-sitter-completion-mode, path-completion-mode, plugin sources) override.

fn conflicts_with(&self) -> &[ModeId]

Modes this one cannot be active alongside.

fn implies(&self) -> &[ModeId]

Minor modes activating this mode also activates. Used by relative-line-numbers-mode ⇒ line-numbers-mode, and by read-only majors ⇒ read-only-mode.

fn presents_extensions(&self) -> &[&'static str]

File extensions (lowercase, no dot) this major PRESENTS rather than edits — the file is never loaded as text.

fn mirrors_option(&self) -> Option<&'static str>

Declarative mirror hint for “this mode is the on/off switch for a typed option of the same observable state”. Some(canonical_name) ⇒ a host-driven cascade keeps the mode’s active state and the option’s value in sync.

fn refresh_action(&self) -> Option<&'static str>

Which of this mode’s own actions refreshes its view, or None (the default) when the mode backs nothing refreshable (RV.1, 2026-08-10).

fn fold_toggle_action(&self) -> Option<&'static str>

Which of this mode’s actions <Tab> fires, and the declaration that pulls in foldable-view-mode — the shared minor owning the chord.

fn refresh_on_open(&self) -> bool

Should re-opening this view re-run its refresh?

fn activation_policy(&self) -> ActivationPolicy

A minor mode’s default auto-activation policy (MA.1; mode-architecture.md §7.4). The host’s minor-activation resolver reads this for every registered minor when a buffer enters a major mode, and activates those whose policy admits the entered major. The default is ActivationPolicy::Manual — auto-activate nowhere until the mode or the user opts in. Ignored for major modes (a buffer’s major is chosen by the major resolver, not this allowlist).

fn editable_tail(&self) -> Option<EditableTail>

The mode’s editable tail on an otherwise read-only buffer, or None (the default) for a fully read-only / fully writable buffer (AU‑3).