Struct PaneVersionStore 

pub struct PaneVersionStore { /* private fields */ }

A history of pane-tree versions with replay-free undo/redo.

undo/redo/current are O(1) — they move or read a cursor over a Vec of immutable version roots. Applying a new operation truncates any redo branch (matching the canonical timeline) and appends a new version.

Implementations

impl PaneVersionStore

pub fn new(initial: VersionedPaneTree) -> Self

Create a store seeded with an initial version (the baseline).

pub fn with_max_versions( initial: VersionedPaneTree, max_versions: usize, ) -> Self

Create a store with a bounded retention window.

When the retained version count exceeds max_versions, the oldest versions are pruned (which discards the ability to undo into them, the same posture as the canonical timeline’s entry limit). 0 is unbounded.

pub fn set_max_versions(&mut self, max_versions: usize) -> usize

Install a retention bound and immediately enforce it, pruning the oldest versions if the store currently exceeds max_versions.

Unlike with_max_versions this acts on an existing store, so a retention policy can re-bound it retroactively. The newest versions (including the current one) are always kept, so the current state — and therefore current’s state hash — is never discarded. Returns the number of versions pruned by this call. 0 is unbounded.

pub fn apply( &mut self, operation: &PaneOperation, ) -> Result<&VersionedPaneTree, PersistentApplyError>

Apply an operation to the current version, appending a new version.

Errors

Propagates the PersistentApplyError from the underlying apply.

pub fn undo(&mut self) -> bool

Move to the previous version. Returns false at the oldest retained version.

pub fn redo(&mut self) -> bool

Move to the next version. Returns false at the newest version.

pub fn current(&self) -> &VersionedPaneTree

The current version.

pub fn version_count(&self) -> usize

Number of retained versions.

pub const fn cursor(&self) -> usize

Current cursor index.

pub const fn can_undo(&self) -> bool

Whether undo would succeed.

pub fn can_redo(&self) -> bool

Whether redo would succeed.

pub const fn pruned(&self) -> usize

Number of versions pruned by the retention bound so far.

pub fn report(&self) -> PaneVersioningReport

Compute a structural-sharing and memory-retention report.

pub fn retention(&self) -> PaneVersionRetention

Compute a deterministic retained-memory byte model over the distinct nodes physically held by all retained versions.

The model mirrors the canonical timeline’s retention_diagnostics methodology — size_of struct estimates plus measured string payload bytes — so the two strategies are directly comparable. Because shared subtrees are counted once (via Arc pointer identity), node bytes scale with distinct nodes, not the logical node total.

Trait Implementations

impl Clone for PaneVersionStore

fn clone(&self) -> PaneVersionStore

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PaneVersionStore

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.