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|
use bincode::Encode;
use sha2::{Digest, Sha256, digest::DynDigest};
use std::ops::Deref;
use serde::{Deserialize, Serialize};
use crate::{ZERO_PREFIX_AMOUNT, transaction::Transaction};
use std::sync::{
Arc,
atomic::{AtomicBool, Ordering},
};
use tokio::sync::mpsc;
use tokio::task;
pub trait CryptoDigest {
fn digest(&self, state: &mut impl DynDigest);
}
#[derive(Debug, Deserialize, Serialize, Clone, PartialEq, Encode)]
pub struct Block {
pub prev_hash: Vec<u8>,
pub tx: Transaction,
pub pow: Option<u64>,
}
impl Block {
fn new(prev_hash: Option<&[u8]>, tx: Transaction) -> Self {
Self {
prev_hash: prev_hash
.unwrap_or(&[])
.to_vec(), // special blocks
tx,
pow: None,
}
}
fn pref_zeros(hashed: &[u8]) -> Result<usize, usize> {
hashed
.iter()
.try_fold(0, |nonce, x| {
if nonce >= ZERO_PREFIX_AMOUNT {
Ok(nonce)
} else if *x == 0 {
Ok(nonce + 1)
} else {
Err(nonce)
}
})
}
pub async fn calc_pow(&self) -> u64 {
let threads = std::thread::available_parallelism()
.map(|n| n.get())
.unwrap_or(4);
let found = Arc::new(AtomicBool::new(false));
let (ptx, mut rx) = mpsc::unbounded_channel::<u64>();
let prev_hash = Arc::new(
self.prev_hash
.clone(),
);
let tx = self.tx;
let mut handles = Vec::with_capacity(threads);
for t in 0..threads {
let found = Arc::clone(&found);
let ptx = ptx.clone();
let prev_hash = Arc::clone(&prev_hash);
let start = t as u64;
handles.push(task::spawn_blocking(move || {
let mut i = start;
while !found.load(Ordering::Relaxed) {
let mut hasher = Sha256::new();
Digest::update(&mut hasher, bincode::encode_to_vec((&*prev_hash, &tx, i), bincode::config::standard()).unwrap());
let hashed = hasher.finalize();
if Block::pref_zeros(&hashed).is_ok() {
if !found.swap(true, Ordering::Relaxed) {
let _ = ptx.send(i);
}
break;
}
println!("{i}");
i = i.wrapping_add(threads as u64);
}
}));
}
drop(ptx);
let pow_nonce = rx
.recv()
.await
.expect("miner dropped without sending");
for h in handles {
_ = h.await;
}
pow_nonce
}
pub async fn calc_set_pow(&mut self) {
self.pow = Some(
self.calc_pow()
.await,
);
}
pub fn verify_pow(&self) -> bool {
if let Some(nonce) = self.pow {
let mut hasher = Sha256::new();
Digest::update(&mut hasher, bincode::encode_to_vec((&self.prev_hash, &self.tx, nonce), bincode::config::standard()).unwrap());
Self::pref_zeros(&hasher.finalize()).is_ok()
} else {
false
}
}
}
impl CryptoDigest for Block {
fn digest(&self, state: &mut impl DynDigest) {
state.update(&bincode::encode_to_vec((&self.prev_hash, &self.tx, &self.pow), bincode::config::standard()).unwrap());
}
}
#[derive(Debug, Default, Deserialize, Serialize, Clone, PartialEq)]
pub struct BlockChain {
pub blocks: Vec<Block>,
}
impl BlockChain {
pub fn new(blocks: Vec<Block>) -> Self {
Self {
blocks,
}
}
pub fn new_block(&self, tx: Transaction) -> Block {
let mut hasher = Sha256::new();
let prev = self
.blocks
.last();
let prev_hash = if let Some(b) = prev {
b.digest(&mut hasher);
Some(&*hasher.finalize())
} else {
None
};
Block::new(prev_hash, tx)
}
pub fn store(&mut self, block: Block) {
// TODO: check config
if block.verify_pow() {
self.blocks
.push(block)
} else {
eprint!("Err: Failed to store unverified block")
}
}
}
impl Deref for BlockChain {
type Target = Vec<Block>;
fn deref(&self) -> &Self::Target {
&self.blocks
}
}
|
