Struct bridgetree::Checkpoint

pub struct Checkpoint { /* private fields */ }

A data structure used to store the information necessary to “rewind” the state of a BridgeTree to a particular leaf position.

This is needed because the BridgeTree::marked_indices map is a cache of information that crosses MerkleBridge boundaries, and so it is not sufficient to just truncate the list of bridges; instead, we use Checkpoint values to be able to rapidly restore the cache to its previous state.

Implementations

impl Checkpoint

pub fn from_parts(
    bridges_len: usize,
    is_marked: bool,
    marked: BTreeSet<Position>,
    forgotten: BTreeMap<Position, usize>
) -> Self

Creates a new checkpoint from its constituent parts.

pub fn at_length(bridges_len: usize, is_marked: bool) -> Self

Creates a new empty checkpoint for the specified BridgeTree state.

Examples found in repository

src/lib.rs (line 1027)

    pub fn checkpoint(&mut self) {
        match self.current_bridge.take() {
            Some(cur_b) => {
                let is_marked = self.get_marked_leaf(cur_b.position()).is_some();

                // Do not create a duplicate bridge
                if self
                    .prior_bridges
                    .last()
                    .map_or(false, |pb| pb.position() == cur_b.position())
                {
                    self.current_bridge = Some(cur_b);
                } else {
                    self.current_bridge = Some(cur_b.successor(false));
                    self.prior_bridges.push(cur_b);
                }

                self.checkpoints
                    .push(Checkpoint::at_length(self.prior_bridges.len(), is_marked));
            }
            None => {
                self.checkpoints.push(Checkpoint::at_length(0, false));
            }
        }

        if self.checkpoints.len() > self.max_checkpoints {
            self.drop_oldest_checkpoint();
        }
    }

pub fn bridges_len(&self) -> usize

Returns the length of the BridgeTree::prior_bridges vector of the BridgeTree to which this checkpoint refers.

This is the number of bridges that will be retained in the event of a rewind to this checkpoint.

pub fn is_marked(&self) -> bool

Returns whether the current state of the tree had been marked at the point that this checkpoint was made.

In the event of a rewind, the rewind logic will ensure that mark information is properly reconstituted for the checkpointed tree state.

pub fn marked(&self) -> &BTreeSet<Position>

Returns a set of the positions that have been marked during the period that this checkpoint is the current checkpoint.

pub fn forgotten(&self) -> &BTreeMap<Position, usize>

Returns the set of previously-marked positions that have had their marks removed during the period that this checkpoint is the current checkpoint.

Trait Implementations

impl Clone for Checkpoint

fn clone(&self) -> Checkpoint

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Checkpoint

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Checkpoint

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>where
    __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq<Checkpoint> for Checkpoint

fn eq(&self, other: &Checkpoint) -> 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 Serialize for Checkpoint

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>where
    __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for Checkpoint

impl StructuralEq for Checkpoint

impl StructuralPartialEq for Checkpoint