hotmint-mempool

Transaction mempool for the Hotmint BFT consensus framework.

A thread-safe, async transaction pool with FIFO ordering, Blake3-based deduplication, and configurable size limits. Provides length-prefixed payload encoding for block inclusion.

Features

FIFO ordering — transactions are proposed in the order they were received
Deduplication — duplicate transactions (by Blake3 hash) are silently rejected
Size limits — configurable max transaction count and per-transaction byte limit
Payload encoding — length-prefixed format for embedding transactions in blocks
Thread-safe — all operations are async and safe for concurrent access

Usage

use hotmint_mempool::Mempool;

// custom limits: max 10,000 txs, 1MB per tx
let mempool = Mempool::new(10_000, 1_048_576);

// or use defaults (10k txs, 1MB)
let mempool = Mempool::default();

Add transactions

// returns true if accepted, false if rejected (duplicate or full)
let accepted = mempool.add_tx(b"transfer alice bob 100".to_vec()).await;

Collect payload for block proposal

// drain up to 1MB of transactions for block inclusion
let payload = mempool.collect_payload(1_048_576).await;

Decode payload from a committed block

let txs: Vec<Vec<u8>> = Mempool::decode_payload(&block.payload);
for tx in &txs {
    // process each transaction
}

Integration with Application trait

use std::sync::Arc;
use hotmint_consensus::application::Application;
use hotmint_mempool::Mempool;

struct MyApp {
    mempool: Arc<Mempool>,
}

impl Application for MyApp {
    fn create_payload(&self, _ctx: &hotmint_types::context::BlockContext) -> Vec<u8> {
        let rt = tokio::runtime::Handle::current();
        rt.block_on(self.mempool.collect_payload(1_048_576))
    }
}

License

GPL-3.0-only

hotmint-mempool 0.6.0