Merge pull request #17 from keep-starknet-strange/mk/state-draft

Cleaner ChainState

.tool-versions

@@ -1 +1 @@
-scarb 2.6.3
+scarb 2.7.0

Scarb.toml

@@ -4,4 +4,3 @@ version = "0.1.0"
 edition = "2023_11"
 
 [dependencies]
-starknet = "2.6.3"

src/lib.cairo

@@ -1,3 +1,3 @@
-pub mod engine;
-
+mod state;
+mod validation;
 mod main;

src/main.cairo

@@ -1,36 +1,3 @@
-use raito::engine::BlockHeaderEngineTrait;
-use raito::engine::BlockHeaderEngineImpl;
-use raito::engine::BlockHeaderValidationContextTrait;
-use raito::engine::BlockHeaderValidationContextImpl;
-use raito::engine::BlockHeaderTrait;
-use raito::engine::BlockHeaderImpl;
-use raito::engine::ChainStateTrait;
-use raito::engine::ChainStateImpl;
-use raito::engine::ChainState;
-
 fn main() {
     println!("Running Raito Bitcoin ZK client");
-    let block_header = BlockHeaderImpl::new(0, "", "", 0, 0, 0);
-
-    // The Times 03/Jan/2009 Chancellor on brink of second bailout for banks
-    let GENESIS = "000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f";
-
-    let chain_state = ChainState {
-        block_height: 0,
-        total_work: 0,
-        best_block_hash: GENESIS,
-        current_target: 0,
-        epoch_start_time: 0,
-        prev_timestamps: ArrayTrait::new()
-    };
-
-    let mut context = BlockHeaderValidationContextImpl::new(block_header, "", 0, chain_state, 0);
-    let mut engine = BlockHeaderEngineImpl::new(context);
-
-    let res = engine.validate_and_apply_block_header();
-    if res.is_ok() {
-        println!("Execution successful");
-    } else {
-        println!("Execution failed");
-    }
 }

src/state.cairo

@@ -0,0 +1,86 @@
+/// Represents the state of the blockchain.
+#[derive(Drop, Copy)]
+pub struct ChainState {
+    /// Height of the current block.
+    pub block_height: u32, // not u256?
+    /// Total work done.
+    pub total_work: u256,
+    /// Best block.
+    pub best_block_hash: u256,
+    /// Current block.
+    pub current_target: u32,
+    /// Start of the current epoch.
+    pub epoch_start_time: u32,
+    /// Previous timestamps.
+    pub prev_timestamps: Span<u32>,
+    // TODO: utreexo_roots?
+}
+
+/// Represents a block in the blockchain.
+///
+#[derive(Drop, Copy)]
+pub struct Block {
+    /// block header
+    pub header: Header,
+    // TODO: how to handle coinbase transactions?
+
+    /// Transactions
+    pub txs: Span<Transaction>,
+}
+
+/// Block header
+/// https://developer.bitcoin.org/reference/block_chain.html#block-headers
+#[derive(Drop, Copy)]
+struct Header {
+    /// The version of the block.
+    pub version: u32,
+    /// The hash of the previous block in the blockchain.
+    pub prev_block_hash: u256,
+    /// The Merkle root hash of the transactions in the block.
+    pub merkle_root_hash: u256,
+    /// The timestamp of the block.
+    pub time: u32,
+    /// The difficulty target for mining the block.
+    pub bits: u32,
+    /// The nonce used in mining the block.
+    pub nonce: u32,
+}
+
+/// Transaction
+/// https://developer.bitcoin.org/reference/transactions.html#raw-transaction-format
+#[derive(Drop, Copy)]
+pub struct Transaction {
+    /// The version of the transaction.
+    pub version: i32,
+    /// The inputs of the transaction.
+    pub inputs: Span<TxIn>,
+    /// The outputs of the transaction.
+    pub outputs: Span<TxOut>,
+    /// The lock time of the transaction.
+    pub lock_time: u32,
+}
+
+/// Output of a transaction.
+/// https://developer.bitcoin.org/reference/transactions.html#txout-a-transaction-output
+#[derive(Drop, Copy)]
+pub struct TxOut {
+    /// The value of the output.
+    value: i64,
+    /// The public key script of the output.
+    pk_script: @ByteArray,
+}
+
+/// Input of a transaction.
+/// https://developer.bitcoin.org/reference/transactions.html#txin-a-transaction-input-non-coinbase
+#[derive(Drop, Copy)]
+pub struct TxIn {
+    /// The transaction ID of the input.
+    txid: u256,
+    /// The index of the input.
+    index: u32,
+    /// The script of the input.
+    script: @ByteArray,
+    /// The sequence of the input.
+    sequence: u32,
+}
+

src/validation.cairo

@@ -0,0 +1,60 @@
+use super::state::{Block, ChainState};
+
+#[generate_trait]
+impl BlockValidatorImpl of BlockValidator {
+    fn validate_and_apply(self: ChainState, block: Block) -> Result<ChainState, ByteArray> {
+        validate_prev_block_hash(@self, @block)?;
+        validate_proof_of_work(@self, @block)?;
+        validate_target(@self, @block)?;
+        validate_timestamp(@self, @block)?;
+
+        // validate_merkle_root
+        // validate_and_apply_transactions
+
+        let prev_timestamps = next_prev_timestamps(@self, @block);
+        let total_work = compute_total_work(@self, @block);
+        let (current_target, epoch_start_time) = adjust_difficulty(@self, @block);
+
+        Result::Ok(
+            ChainState { total_work, current_target, epoch_start_time, prev_timestamps, ..self, }
+        )
+    }
+}
+
+fn validate_prev_block_hash(self: @ChainState, block: @Block) -> Result<(), ByteArray> {
+    if self.best_block_hash == block.header.prev_block_hash {
+        Result::Ok(())
+    } else {
+        Result::Err("Invalid `prev_block_hash`. This block does not extend the current chain.")
+    }
+}
+
+fn validate_proof_of_work(self: @ChainState, block: @Block) -> Result<(), ByteArray> {
+    // TODO: implement
+    Result::Ok(())
+}
+
+fn validate_target(self: @ChainState, block: @Block) -> Result<(), ByteArray> {
+    // TODO: implement
+    Result::Ok(())
+}
+
+fn validate_timestamp(self: @ChainState, block: @Block) -> Result<(), ByteArray> {
+    // TODO: implement
+    Result::Ok(())
+}
+
+fn next_prev_timestamps(self: @ChainState, block: @Block) -> Span<u32> {
+    // TODO: implement
+    *self.prev_timestamps
+}
+
+fn compute_total_work(self: @ChainState, block: @Block) -> u256 {
+    // TODO: implement
+    *self.total_work
+}
+
+fn adjust_difficulty(self: @ChainState, block: @Block) -> (u32, u32) {
+    // TODO: implement
+    (*self.current_target, *self.epoch_start_time)
+}