Struct StorageSnapshotManager 

pub struct StorageSnapshotManager { /* private fields */ }

Production-grade point-in-time snapshot manager with incremental deltas and chain-based restoration.

Implementations

impl StorageSnapshotManager

pub fn new(max_snapshots: usize) -> Self

Create a new, empty manager.

max_snapshots controls how many snapshots are retained before the oldest is evicted to make room for a new one.

pub fn put(&mut self, key: String, value: Vec<u8>, _now: u64)

Insert or update a key in the live state.

The entry’s version is set to self.next_version (then incremented).

pub fn delete(&mut self, key: &str) -> bool

Remove a key from the live state.

Returns false if the key was not present.

pub fn get(&self, key: &str) -> Option<&[u8]>

Look up the value bytes for a key in the live state.

pub fn take_snapshot(&mut self, label: Option<String>, now: u64) -> SnapshotId

Capture the current live state as a new snapshot.

• If this is the first snapshot, it is a full snapshot (delta is None).
• Otherwise, a delta relative to the preceding snapshot is computed.

If the queue is already at max_snapshots, the oldest snapshot is evicted before appending the new one.

pub fn restore_snapshot(&mut self, id: SnapshotId) -> Result<(), SnapshotError>

Restore the live state to the point captured by snapshot id.

The state stored inline in the snapshot is used directly (O(1) after locating the snapshot in the deque).

pub fn list_snapshots(&self) -> Vec<&SsmSnapshot>

Return all retained snapshots ordered oldest to newest.

pub fn get_snapshot(&self, id: SnapshotId) -> Option<&SsmSnapshot>

Look up a snapshot by id.

pub fn delete_snapshot(&mut self, id: SnapshotId) -> Result<(), SnapshotError>

Remove the oldest snapshot from the queue.

Returns CannotDeleteNonOldest if id does not refer to the oldest snapshot, and SnapshotNotFound if no snapshot with id exists.

pub fn diff_snapshots( &self, a: SnapshotId, b: SnapshotId, ) -> Result<SnapshotDelta, SnapshotError>

Compute the full state diff between two snapshots.

Reconstructs both states from the stored inline state, then compares.

pub fn snapshot_count(&self) -> usize

Number of snapshots currently retained.

pub fn live_entry_count(&self) -> usize

Number of entries in the current live state.

pub fn live_total_bytes(&self) -> u64

Sum of value byte sizes in the current live state.

pub fn stats(&self) -> SnapshotStats

Return aggregate statistics.