Lib.rs

This library package contains implementations of the various indexes (lookup tables) of information related to Arweave block validation.

BlockIndex

The first index is the BlockIndex which stores a list of BlockIndexItems indexed by block height.

pub struct BlockIndexItem {
    pub block_hash: H384, // 48 bytes
    pub weave_size: u128, // 16 bytes
    pub tx_root: H256,    // 32 bytes
}

These BlockIndexItems enable the validator to look up the tx_root for any chunk provided for the poa or poa2 proof in the block header. This is critical for proving weather the chunk belongs to a transaction in the block or not.

BlockIndexScraper

In order to initialize the BlockIndex this package includes a scraper module that connects to an Arweave peer and queries the block index. Arweave peers provide a specialized endpoint specifically for this task.

/block_index/{start_block_height}/{end_block_height}

At startup the BlockIndex will attempt to connect to the network and update its local cache with updated block index data. The local cache is persisted to disk at ./data/index.dat and will be appended to over time. This removes the need to require the entire index every time the BlockIndex is used.