Struct akd::tree_node::TreeNodeWithPreviousValue

pub struct TreeNodeWithPreviousValue {
    pub label: NodeLabel,
    pub latest_node: TreeNode,
    pub previous_node: Option<TreeNode>,
}

Represents a TreeNode with its current state and potential future state. Depending on the epoch which the Directory believes is the “most current” version, we may need to load a slightly older version of the tree node. This is because we can’t guarantee that a “publish” operation is globally atomic at the storage layer, however we do assume record-level atomicity. This means that some records may be updated to “future” values, and therefore we might need to temporarily read their previous values.

The Directory publishes the AZKS after all other records are successfully written. This single record is where the “current” epoch is determined, so any instances with read-only access (example: Directory instances service proof generation, but not publishing) will be notified that a new epoch is available, flush their caches, and retrieve data from storage directly again.

This structure holds the label along with the current value & epoch - 1

Fields

label: NodeLabel

The label of the node

latest_node: TreeNode

The “latest” node, either future or current

previous_node: Option<TreeNode>

The “previous” node, either current or past

Trait Implementations

impl Clone for TreeNodeWithPreviousValue

fn clone(&self) -> TreeNodeWithPreviousValue

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for TreeNodeWithPreviousValue

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

Formats the value using the given formatter.

impl Hash for TreeNodeWithPreviousValue

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl PartialEq<TreeNodeWithPreviousValue> for TreeNodeWithPreviousValue

fn eq(&self, other: &TreeNodeWithPreviousValue) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Storable for TreeNodeWithPreviousValue

type StorageKey = NodeKey

This particular storage will have a key type

fn data_type() -> StorageType

Must return a valid storage type

fn get_id(&self) -> NodeKey

Retrieve an instance of the id of this storable. The combination of the storable’s StorageType and this id are globally unique

fn get_full_binary_key_id(key: &NodeKey) -> Vec<u8>

Retrieve the full binary version of a key (for comparisons)

fn key_from_full_binary(bin: &[u8]) -> Result<NodeKey, String>

Reformat a key from the full-binary specification

fn get_full_binary_id(&self) -> Vec<u8>

Retrieve the full binary version of a key (for comparisons)

impl Eq for TreeNodeWithPreviousValue

impl StructuralEq for TreeNodeWithPreviousValue

impl StructuralPartialEq for TreeNodeWithPreviousValue