Struct ZwinderStateManager 

pub struct ZwinderStateManager { /* private fields */ }

A compressed, density-tiered, byte-budgeted history of frame-keyed save-states. See the module docs for the design.

Implementations

impl ZwinderStateManager

pub fn new(budget_bytes: usize, keyframe_interval: u32) -> Self

Create an empty manager with a compressed byte budget and keyframe interval. Frame 0 is always an anchor (the power-on base must never be evicted). keyframe_interval of 0 is treated as 1 (every entry a keyframe).

pub fn store(&mut self, frame: u64, snapshot: &[u8], cursor: u64)

Store (or replace) the save-state for frame, compressing it. cursor is the editor/playhead frame — eviction protects the dense neighbourhood around it. Enforces the byte budget after inserting.

Anchored frames are always stored as self-contained keyframes (so they never depend on a neighbour that eviction might thin). A non-anchor frame is a delta against the nearest preceding keyframe, unless none exists at-or-before it or the keyframe interval is due — then it is promoted to a keyframe.

pub fn nearest_at_or_before( &self, target: u64, ) -> Option<Result<(u64, Vec<u8>), ZwinderError>>

Decode and return the nearest cached state at or before target, as (frame, snapshot_bytes). None if nothing at-or-before target is cached.

Errors

Returns ZwinderError if the entry (or the keyframe a delta depends on) can’t be reconstructed.

pub fn get(&self, frame: u64) -> Option<Result<Vec<u8>, ZwinderError>>

Decode and return the cached state for exactly frame, if present.

Errors

Returns ZwinderError if the entry can’t be reconstructed.

pub fn has(&self, frame: u64) -> bool

true if a state is cached for exactly frame.

pub fn invalidate_after(&mut self, frame: u64)

Drop every cached state strictly after frame (the InvalidateAfter operation — an edit at frame invalidates the downstream tail). Anchor registrations after frame are kept (a later recapture re-pins them), but their stored state is dropped.

pub fn add_anchor(&mut self, frame: u64)

Register frame as a permanent anchor (never evicted, always a keyframe once stored).

pub fn remove_anchor(&mut self, frame: u64)

Remove an anchor registration (frame 0 stays anchored regardless).

pub fn is_anchor(&self, frame: u64) -> bool

true if frame is a permanent anchor.

pub fn clear_non_default_anchors(&mut self)

Drop every anchor except frame 0 (used when the marker set is rebuilt wholesale — a branch load or project load).

pub fn clear(&mut self)

Drop all cached states (anchor registrations are kept).

pub const fn len(&self) -> usize

Number of cached frames.

pub const fn is_empty(&self) -> bool

true if no states are cached.

pub const fn used_bytes(&self) -> usize

Total compressed bytes currently held.

pub const fn budget_bytes(&self) -> usize

The compressed byte budget eviction targets.

pub fn cached_frames(&self) -> impl Iterator<Item = u64> + '_

The set of frames a state is cached for (ascending). Used to colour greenzone-resident rows.

Trait Implementations

impl Debug for ZwinderStateManager

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

Formats the value using the given formatter.

impl Default for ZwinderStateManager

fn default() -> Self

Returns the “default value” for a type.