Struct CheckPoint

pub struct CheckPoint(/* private fields */);

A checkpoint is a node of a reference-counted linked list of BlockIds.

Checkpoints are cheaply cloneable and are useful to find the agreement point between two sparse block chains.

Implementations

impl CheckPoint

pub fn new(block: BlockId) -> CheckPoint

Construct a new base block at the front of a linked list.

pub fn from_block_ids( block_ids: impl IntoIterator<Item = BlockId>, ) -> Result<CheckPoint, Option<CheckPoint>>

Construct a checkpoint from a list of BlockIds in ascending height order.

Errors

This method will error if any of the follow occurs:

• The blocks iterator is empty, in which case, the error will be None.
• The blocks iterator is not in ascending height order.
• The blocks iterator contains multiple BlockIds of the same height.

The error type is the last successful checkpoint constructed (if any).

pub fn from_header(header: &Header, height: u32) -> CheckPoint

Construct a checkpoint from the given header and block height.

If header is of the genesis block, the checkpoint won’t have a prev node. Otherwise, we return a checkpoint linked with the previous block.

pub fn push(self, block: BlockId) -> Result<CheckPoint, CheckPoint>

Puts another checkpoint onto the linked list representing the blockchain.

Returns an Err(self) if the block you are pushing on is not at a greater height that the one you are pushing on to.

pub fn extend( self, blocks: impl IntoIterator<Item = BlockId>, ) -> Result<CheckPoint, CheckPoint>

Extends the checkpoint linked list by a iterator of block ids.

Returns an Err(self) if there is block which does not have a greater height than the previous one.

pub fn block_id(&self) -> BlockId

Get the BlockId of the checkpoint.

pub fn height(&self) -> u32

Get the height of the checkpoint.

pub fn hash(&self) -> BlockHash

Get the block hash of the checkpoint.

pub fn prev(&self) -> Option<CheckPoint>

Get the previous checkpoint in the chain

pub fn iter(&self) -> CheckPointIter

Iterate from this checkpoint in descending height.

pub fn get(&self, height: u32) -> Option<CheckPoint>

Get checkpoint at height.

Returns None if checkpoint at height does not exist`.

pub fn range<R>(&self, range: R) -> impl Iterator<Item = CheckPoint>

where R: RangeBounds<u32>,

Iterate checkpoints over a height range.

Note that we always iterate checkpoints in reverse height order (iteration starts at tip height).

pub fn floor_at(&self, height: u32) -> Option<CheckPoint>

Returns the checkpoint at height if one exists, otherwise the nearest checkpoint at a lower height.

This is equivalent to taking the “floor” of height over this checkpoint chain.

Returns None if no checkpoint exists at or below the given height.

pub fn floor_below(&self, offset: u32) -> Option<CheckPoint>

Returns the checkpoint located a number of heights below this one.

This is a convenience wrapper for CheckPoint::floor_at, subtracting to_subtract from the current height.

• If a checkpoint exists exactly offset heights below, it is returned.
• Otherwise, the nearest checkpoint below that target height is returned.

Returns None if to_subtract is greater than the current height, or if there is no checkpoint at or below the target height.

pub fn insert(self, block_id: BlockId) -> CheckPoint

Inserts block_id at its height within the chain.

The effect of insert depends on whether a height already exists. If it doesn’t the block_id we inserted and all pre-existing blocks higher than it will be re-inserted after it. If the height already existed and has a conflicting block hash then it will be purged along with all block following it. The returned chain will have a tip of the block_id passed in. Of course, if the block_id was already present then this just returns self.

Panics

This panics if called with a genesis block that differs from that of self.

pub fn eq_ptr(&self, other: &CheckPoint) -> bool

This method tests for self and other to have equal internal pointers.

Trait Implementations

impl Clone for CheckPoint

fn clone(&self) -> CheckPoint

Returns a duplicate 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<(), Error>

Formats the value using the given formatter.

impl IntoIterator for CheckPoint

type Item = CheckPoint

The type of the elements being iterated over.

type IntoIter = CheckPointIter

Which kind of iterator are we turning this into?

fn into_iter(self) -> <CheckPoint as IntoIterator>::IntoIter

Creates an iterator from a value.

impl PartialEq for CheckPoint

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

Tests for self and other values to be equal, and is used by ==.

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

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