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|
use std::{
hash::{DefaultHasher, Hash, Hasher},
ops::Deref,
};
use serde::{Deserialize, Serialize};
use crate::{ZERO_PREFIX_AMOUNT, transaction::Transaction};
#[derive(Deserialize, Serialize, Clone, Copy, PartialEq)]
pub struct Block {
pub prev_hash: u64,
pub trans: Transaction,
pub pow: Option<u64>,
}
impl Block {
fn new(prev_hash: Option<u64>, trans: Transaction) -> Self {
Self {
prev_hash: prev_hash.unwrap_or(0), // special blocks
trans,
pow: None,
}
}
fn calc_pow(&self) -> u64 {
for i in 0.. {
// reset every loop
let mut hasher = DefaultHasher::new();
(&self.prev_hash, &self.trans, i).hash(&mut hasher);
let hashed = hasher.finish();
if hashed
.to_string()
.starts_with(
&"0".repeat(ZERO_PREFIX_AMOUNT)
.to_string(),
)
{
return hashed;
}
}
unreachable!()
}
pub fn verify_pow(&mut self) -> bool {
let mut hasher = DefaultHasher::new();
self.hash(&mut hasher);
hasher
.finish()
.to_string()
.to_string()
.starts_with(
&"0".repeat(ZERO_PREFIX_AMOUNT)
.to_string(),
)
}
pub fn calc_set_pow(&mut self) {
self.pow = Some(self.calc_pow());
}
}
impl Hash for Block {
fn hash<H: Hasher>(&self, state: &mut H) {
self.prev_hash
.hash(state);
self.trans
.hash(state);
self.pow
.expect("Cannot hash whole block with no PoW")
.hash(state);
}
}
#[derive(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, trans: Transaction) -> Block {
let mut hasher = DefaultHasher::new();
Block::new(
self.blocks
.last()
.map(|b| {
b.hash(&mut hasher);
hasher.finish()
}),
trans,
)
}
pub fn store(&mut self, block: Block) {
// TODO: verify blocks
self.blocks
.push(block)
}
}
impl Deref for BlockChain {
type Target = Vec<Block>;
fn deref(&self) -> &Self::Target {
&self.blocks
}
}
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