Trait ChainStore

pub trait ChainStore {
    type Error: DatabaseError;

    // Required methods
    fn save_roots_for_block(
        &mut self,
        roots: Vec<u8>,
        height: u32,
    ) -> Result<(), Self::Error>;
    fn load_roots_for_block(
        &mut self,
        height: u32,
    ) -> Result<Option<Vec<u8>>, Self::Error>;
    fn load_height(&self) -> Result<Option<BestChain>, Self::Error>;
    fn save_height(&mut self, height: &BestChain) -> Result<(), Self::Error>;
    fn get_header(
        &self,
        block_hash: &BlockHash,
    ) -> Result<Option<DiskBlockHeader>, Self::Error>;
    fn get_header_by_height(
        &self,
        height: u32,
    ) -> Result<Option<DiskBlockHeader>, Self::Error>;
    fn save_header(
        &mut self,
        header: &DiskBlockHeader,
    ) -> Result<(), Self::Error>;
    fn get_block_hash(
        &self,
        height: u32,
    ) -> Result<Option<BlockHash>, Self::Error>;
    fn flush(&mut self) -> Result<(), Self::Error>;
    fn update_block_index(
        &mut self,
        height: u32,
        hash: BlockHash,
    ) -> Result<(), Self::Error>;
    fn check_integrity(&self) -> Result<(), Self::Error>;
}

This trait is defining how we interact with our chain database. This definitions will be used by the ChainState to save and retrieve data about the blockchain, likely on disk. Right now, you can use the KvChainStore in your code, it implements this trait and uses a key-value store to save data. The DatabaseError is a simple trait that can be implemented by any error type that implements std::error::Error and std::fmt::Display. This is useful to abstract the database implementation from the blockchain. See the documentation of DatabaseError for more info.

Required Associated Types

type Error: DatabaseError

Required Methods

fn save_roots_for_block( &mut self, roots: Vec<u8>, height: u32, ) -> Result<(), Self::Error>

Saves the accumulator state for a given block height.

fn load_roots_for_block( &mut self, height: u32, ) -> Result<Option<Vec<u8>>, Self::Error>

Loads the state of our accumulator for a given block height.

This is the state of the resulting accumulator after we process the block at height. If you need the accumulator used to validate a block at height n, you should get the accumulator from block n - 1.

fn load_height(&self) -> Result<Option<BestChain>, Self::Error>

Loads the blockchain height

fn save_height(&mut self, height: &BestChain) -> Result<(), Self::Error>

Saves the blockchain height.

fn get_header( &self, block_hash: &BlockHash, ) -> Result<Option<DiskBlockHeader>, Self::Error>

Get a block header from our database. See DiskBlockHeader for more info about the data we save.

fn get_header_by_height( &self, height: u32, ) -> Result<Option<DiskBlockHeader>, Self::Error>

Get a block header by its height in our database.

fn save_header(&mut self, header: &DiskBlockHeader) -> Result<(), Self::Error>

Saves a block header to our database. See DiskBlockHeader for more info about the data we save.

fn get_block_hash(&self, height: u32) -> Result<Option<BlockHash>, Self::Error>

Returns the block hash for a given height.

fn flush(&mut self) -> Result<(), Self::Error>

Flushes write buffers to disk, this is called periodically by the ChainState, so in case of a crash, we don’t lose too much data. If the database doesn’t support write buffers, this method can be a no-op.

fn update_block_index( &mut self, height: u32, hash: BlockHash, ) -> Result<(), Self::Error>

Associates a block hash with a given height, so we can retrieve it later.

fn check_integrity(&self) -> Result<(), Self::Error>

Checks if our database didn’t get corrupted, and if it has, it returns an error.

If you’re using a database that already checks for integrity by itself, this can safely be a no-op.

Implementors

impl ChainStore for FlatChainStore

Available on crate feature flat-chainstore only.

type Error = FlatChainstoreError

impl ChainStore for KvChainStore<'_>

Available on crate feature kv-chainstore only.

type Error = Error