Merge pull request #46 from gavofyork/state

Removed need for mutation in State.

src/account.rs

@@ -41,10 +41,10 @@ impl Account {
 	}
 
 	/// Create a new account with the given balance.
-	pub fn new_basic(balance: U256) -> Account {
+	pub fn new_basic(balance: U256, nonce: U256) -> Account {
 		Account {
 			balance: balance,
-			nonce: U256::from(0u8),
+			nonce: nonce,
 			storage_root: SHA3_NULL_RLP,
 			storage_overlay: RefCell::new(HashMap::new()),
 			code_hash: Some(SHA3_EMPTY),

src/engine.rs

@@ -0,0 +1,109 @@
+use util::uint::*;
+use util::hash::*;
+use util::bytes::*;
+use util::semantic_version::*;
+use header::Header;
+use std::collections::hash_map::*;
+use util::error::*;
+
+/// Definition of the cost schedule and other parameterisations for the EVM.
+pub struct EvmSchedule {
+	pub exceptional_failed_code_deposit: bool,
+	pub have_delegate_call: bool,
+	pub stack_limit: U256,
+	pub tier_step_gas: [U256; 8],
+	pub exp_gas: U256,
+	pub exp_byte_gas: U256,
+	pub sha3_gas: U256,
+	pub sha3_word_gas: U256,
+	pub sload_gas: U256,
+	pub sstore_set_gas: U256,
+	pub sstore_reset_gas: U256,
+	pub sstore_refund_gas: U256,
+	pub jumpdest_gas: U256,
+	pub log_gas: U256,
+	pub log_data_gas: U256,
+	pub log_topic_gas: U256,
+	pub create_gas: U256,
+	pub call_gas: U256,
+	pub call_stipend: U256,
+	pub call_value_transfer_gas: U256,
+	pub call_new_account_gas: U256,
+	pub suicide_refund_gas: U256,
+	pub memory_gas: U256,
+	pub quad_coeff_div: U256,
+	pub create_data_gas: U256,
+	pub tx_gas: U256,
+	pub tx_create_gas: U256,
+	pub tx_data_zero_gas: U256,
+	pub tx_data_non_zero_gas: U256,
+	pub copy_gas: U256,
+}
+
+/// Definition of a contract whose implementation is built-in. 
+pub struct Builtin {
+	/// The gas cost of running this built-in for the given size of input data.
+	pub cost: Box<Fn(usize) -> U256>,	// TODO: U256 should be bignum.
+	/// Run this built-in function with the input being the first argument and the output
+	/// being placed into the second.
+	pub execute: Box<Fn(&[u8], &mut [u8])>,
+}
+
+/// Parameters for a block chain; includes both those intrinsic to the design of the
+/// chain and those to be interpreted by the active chain engine.
+pub struct Params {
+	/*
+	TODO: std::unordered_map<Address, PrecompiledContract> precompiled;
+	*/
+	pub block_reward: U256,
+	pub maximum_extra_data_size: U256,
+	pub account_start_nonce: U256,
+	pub evm_schedule: EvmSchedule,
+	pub builtins: HashMap<Address, Builtin>,
+	pub misc: HashMap<String, String>,
+}
+
+/// A consensus mechanism for the chain. Generally either proof-of-work or proof-of-stake-based.
+/// Provides hooks into each of the major parts of block import.
+pub trait Engine {
+	/// The name of this engine.
+	fn name(&self) -> &str;
+	/// The version of this engine. Should be of the form 
+	fn version(&self) -> SemanticVersion { SemanticVersion::new(0, 0 ,0) }
+
+	/// The number of additional header fields required for this engine.
+	fn seal_fields(&self) -> u32 { 0 }
+	/// Default values of the additional fields RLP-encoded in a raw (non-list) harness.
+	fn seal_rlp(&self) -> Bytes { vec![] }
+
+	/// Additional engine-specific information for the user/developer concerning `header`.
+	fn extra_info(&self, _header: &Header) -> HashMap<String, String> { HashMap::new() }
+
+	/// Verify that `header` is valid.
+	/// `parent` (the parent header) and `block` (the header's full block) may be provided for additional
+	/// checks. Returns either a null `Ok` or a general error detailing the problem with import.
+	fn verify(&self, _header: &Header, _parent: Option<&Header>, _block: Option<&[u8]>) -> Result<(), EthcoreError> { Ok(()) }
+/*
+	virtual void verify(Strictness _s, BlockHeader const& _bi, BlockHeader const& _parent = BlockHeader(), bytesConstRef _block = bytesConstRef()) const;
+	/// Additional verification for transactions in blocks.
+	virtual void verifyTransaction(ImportRequirements::value _ir, TransactionBase const& _t, BlockHeader const& _bi) const;
+	/// Don't forget to call Super::populateFromParent when subclassing & overriding.
+	virtual void populateFromParent(BlockHeader& _bi, BlockHeader const& _parent) const;
+*/
+
+	/// Get the general parameters of the chain.
+	fn params(&self) -> &Params;
+	/// Set the general parameters of the chain.
+	fn set_params(&mut self, p: Params);
+}
+
+/// An engine which does not provide any consensus mechanism.
+pub struct NullEngine {
+	params: Params,
+}
+
+impl Engine for NullEngine {
+	fn name(&self) -> &str { "NullEngine" }
+	fn params(&self) -> &Params { &self.params }
+	fn set_params(&mut self, params: Params) { self.params = params; }
+}

src/env_info.rs

@@ -0,0 +1,24 @@
+use util::uint::*;
+use util::hash::*;
+
+/// Simple vector of hashes, should be at most 256 items large, can be smaller if being used
+/// for a block whose number is less than 257.
+pub type LastHashes = Vec<H256>;
+
+/// Information concerning the execution environment for a message-call/contract-creation.
+pub struct EnvInfo {
+	/// The block number.
+	pub number: U256,
+	/// The block author.
+	pub author: Address,
+	/// The block timestamp.
+	pub timestamp: U256,
+	/// The block difficulty.
+	pub difficulty: U256,
+	/// The block gas limit.
+	pub gas_limit: U256,
+	/// The last 256 block hashes.
+	pub last_hashes: LastHashes,
+	/// The gas used.
+	pub gas_used: U256,
+}

src/lib.rs

@@ -1,3 +1,5 @@
+#![feature(cell_extras)]
+
 //! Ethcore's ethereum implementation
 //! 
 //! ### Rust version
@@ -82,10 +84,13 @@ pub use util::hash::*;
 pub use util::uint::*;
 pub use util::bytes::*;
 
+pub mod env_info;
+pub mod engine;
 pub mod state;
 pub mod account;
-pub mod blockheader;
+pub mod header;
 pub mod transaction;
+pub mod receipt;
 pub mod networkparams;
 pub mod denominations;
 

src/receipt.rs

@@ -0,0 +1,6 @@
+use util::hash::*;
+
+pub struct Receipt {
+	// TODO
+	pub state_root: H256,
+}

src/state.rs

@@ -1,42 +1,29 @@
+use std::cell::*;
+use std::ops::*;
 use std::collections::HashMap;
 use util::hash::*;
 use util::hashdb::*;
 use util::overlaydb::*;
 use util::trie::*;
+use util::bytes::*;
 use util::rlp::*;
 use util::uint::*;
-//use std::cell::*;
-//use std::ops::*;
 use account::Account;
-/*
-enum ValueOrRef<'self, 'db: 'self> {
-	Value(OverlayDB),
-	Ref(&'db mut OverlayDB)
-}
+use transaction::Transaction;
+use receipt::Receipt;
+use env_info::EnvInfo;
+use engine::Engine;
 
-impl<'self, 'db> ValueOrRef<'self, 'db: 'self> {
-	pub fn get_mut(&mut self) -> &mut OverlayDB {
-		match self {
-			Value(ref mut x) => x,
-			Ref(x) => x,
-		}
-	}
-	pub fn get(&self) -> &OverlayDB {
-		match self {
-			Value(ref x) => x,
-			Ref(x) => x,
-		}
-	}
-}
-*/
+/// Information concerning the result of the `State::apply` operation.
+pub struct ApplyResult;	// TODO
 
 /// Representation of the entire state of all accounts in the system.
 pub struct State {
 	db: OverlayDB,
 	root: H256,
-	cache: HashMap<Address, Option<Account>>,
+	cache: RefCell<HashMap<Address, Option<Account>>>,
 
-	_account_start_nonce: U256,
+	account_start_nonce: U256,
 }
 
 impl State {
@@ -51,8 +38,8 @@ impl State {
 		State {
 			db: db,
 			root: root,
-			cache: HashMap::new(),
-			_account_start_nonce: account_start_nonce,
+			cache: RefCell::new(HashMap::new()),
+			account_start_nonce: account_start_nonce,
 		}
 	}
 
@@ -66,8 +53,8 @@ impl State {
 		State {
 			db: db,
 			root: root,
-			cache: HashMap::new(),
-			_account_start_nonce: account_start_nonce,
+			cache: RefCell::new(HashMap::new()),
+			account_start_nonce: account_start_nonce,
 		}
 	}
 
@@ -76,27 +63,41 @@ impl State {
 		Self::new(OverlayDB::new_temp(), U256::from(0u8))
 	}
 
-	/// Return reference to root
-	pub fn root(&self) -> &H256 {
-		&self.root
-	}
-
 	/// Destroy the current object and return root and database.
 	pub fn drop(self) -> (H256, OverlayDB) {
 		(self.root, self.db)
 	}
 
+	/// Return reference to root
+	pub fn root(&self) -> &H256 {
+		&self.root
+	}
+
 	/// Expose the underlying database; good to use for calling `state.db().commit()`.
 	pub fn db(&mut self) -> &mut OverlayDB {
 		&mut self.db
 	}
 
 	/// Get the balance of account `a`.
-	// TODO: make immutable
-	pub fn balance(&mut self, a: &Address) -> U256 {
+	pub fn balance(&self, a: &Address) -> U256 {
 		self.get(a, false).as_ref().map(|account| account.balance().clone()).unwrap_or(U256::from(0u8))
 	}
 
+	/// Get the nonce of account `a`.
+	pub fn nonce(&self, a: &Address) -> U256 {
+		self.get(a, false).as_ref().map(|account| account.nonce().clone()).unwrap_or(U256::from(0u8))
+	}
+
+	/// Mutate storage of account `a` so that it is `value` for `key`.
+	pub fn storage_at(&self, a: &Address, key: &H256) -> H256 {
+		self.get(a, false).as_ref().map(|a|a.storage_at(&self.db, key)).unwrap_or(H256::new())	
+	}
+
+	/// Mutate storage of account `a` so that it is `value` for `key`.
+	pub fn code(&self, a: &Address) -> Option<Vec<u8>> {
+		self.get(a, true).as_ref().map(|a|a.code().map(|x|x.to_vec())).unwrap_or(None)
+	}
+
 	/// Add `incr` to the balance of account `a`.
 	pub fn add_balance(&mut self, a: &Address, incr: &U256) {
 		self.require(a, false).add_balance(incr)
@@ -107,10 +108,10 @@ impl State {
 		self.require(a, false).sub_balance(decr)
 	}
 
-	/// Get the nonce of account `a`.
-	// TODO: make immutable
-	pub fn nonce(&mut self, a: &Address) -> U256 {
-		self.get(a, false).as_ref().map(|account| account.nonce().clone()).unwrap_or(U256::from(0u8))
+	/// Subtracts `by` from the balance of `from` and adds it to that of `to`.
+	pub fn transfer_balance(&mut self, from: &Address, to: &Address, by: &U256) {
+		self.sub_balance(from, by);
+		self.add_balance(to, by);
 	}
 
 	/// Increment the nonce of account `a` by 1.
@@ -118,23 +119,27 @@ impl State {
 		self.require(a, false).inc_nonce()
 	}
 
-	/// Mutate storage of account `a` so that it is `value` for `key`.
-	pub fn storage_at(&mut self, a: &Address, key: &H256) -> H256 {
-		self.ensure_cached(a, false);
-		self.try_get(a).map(|a|a.storage_at(&self.db, key)).unwrap_or(H256::new())	
-	}
-
-	/// Mutate storage of account `a` so that it is `value` for `key`.
-	pub fn code(&mut self, a: &Address) -> Option<&[u8]> {
-		self.ensure_cached(a, true);
-		self.try_get(a).map(|a|a.code()).unwrap_or(None)
-	}
-
 	/// Mutate storage of account `a` so that it is `value` for `key`.
 	pub fn set_storage(&mut self, a: &Address, key: H256, value: H256) {
 		self.require(a, false).set_storage(key, value);
 	}
 
+	/// Mutate storage of account `a` so that it is `value` for `key`.
+	pub fn set_code(&mut self, a: &Address, code: Bytes) {
+		self.require_or_from(a, true, || Account::new_contract(U256::from(0u8))).set_code(code);
+	}
+
+	/// Execute a given transaction.
+	/// This will change the state accordingly.
+	pub fn apply(_env_info: &EnvInfo, _engine: &Engine, _t: &Transaction, _is_permanent: bool) -> (ApplyResult, Receipt) {
+		unimplemented!();
+	}
+
+	/// Convert into a JSON representation.
+	pub fn as_json(&self) -> String {
+		unimplemented!();
+	}
+
 	/// Commit accounts to TrieDBMut. This is similar to cpp-ethereum's dev::eth::commit.
 	/// `accounts` is mutable because we may need to commit the code or storage and record that.
 	pub fn commit_into(db: &mut HashDB, mut root: H256, accounts: &mut HashMap<Address, Option<Account>>) -> H256 {
@@ -165,69 +170,49 @@ impl State {
 	/// Commits our cached account changes into the trie.
 	pub fn commit(&mut self) {
 		let r = self.root.clone();	// would prefer not to do this, really. 
-		self.root = Self::commit_into(&mut self.db, r, &mut self.cache);
+		self.root = Self::commit_into(&mut self.db, r, self.cache.borrow_mut().deref_mut());
+	}
+
+	/// Populate the state from `accounts`. Just uses `commit_into`.
+	pub fn populate_from(&mut self, _accounts: &mut HashMap<Address, Option<Account>>) {
+		unimplemented!();
 	}
 
 	/// Pull account `a` in our cache from the trie DB and return it.
 	/// `require_code` requires that the code be cached, too.
-	// TODO: make immutable through returning an Option<Ref<Account>>
-	fn get(&mut self, a: &Address, require_code: bool) -> Option<&Account> {
-		self.ensure_cached(a, require_code);
-		self.try_get(a)
-	}
-
-	/// Return account `a` from our cache, or None if it doesn't exist in the cache or
-	/// the account is empty.
-	/// Call `ensure_cached` before if you want to avoid the "it doesn't exist in the cache"
-	/// possibility.
-	fn try_get(&self, a: &Address) -> Option<&Account> {
-		self.cache.get(a).map(|x| x.as_ref()).unwrap_or(None)
-	}
-
-	/// Ensure account `a` exists in our cache.
-	/// `require_code` requires that the code be cached, too.
-	fn ensure_cached(&mut self, a: &Address, require_code: bool) {
-		if self.cache.get(a).is_none() {
-			// load from trie.
-			let act = TrieDB::new(&self.db, &self.root).get(&a).map(|rlp| Account::from_rlp(rlp));
-			println!("Loaded {:?} from trie: {:?}", a, act);
-			self.cache.insert(a.clone(), act);
-		}
-		let db = &self.db;
+	fn get(&self, a: &Address, require_code: bool) -> Ref<Option<Account>> {
+		self.cache.borrow_mut().entry(a.clone()).or_insert_with(||
+			TrieDB::new(&self.db, &self.root).get(&a).map(|rlp| Account::from_rlp(rlp)));
 		if require_code {
-			if let Some(ref mut account) = self.cache.get_mut(a).unwrap().as_mut() {
-				println!("Caching code");
-				account.cache_code(db);
-				println!("Now: {:?}", account);
+			if let Some(ref mut account) = self.cache.borrow_mut().get_mut(a).unwrap().as_mut() {
+				account.cache_code(&self.db);
 			}
 		}
+		Ref::map(self.cache.borrow(), |m| m.get(a).unwrap())
 	}
 
 	/// Pull account `a` in our cache from the trie DB. `require_code` requires that the code be cached, too.
 	/// `force_create` creates a new, empty basic account if there is not currently an active account.
-	fn require(&mut self, a: &Address, require_code: bool) -> &mut Account {
-		self.require_or_from(a, require_code, || Account::new_basic(U256::from(0u8)))
+	fn require(&self, a: &Address, require_code: bool) -> RefMut<Account> {
+		self.require_or_from(a, require_code, || Account::new_basic(U256::from(0u8), self.account_start_nonce))
 	}
 
 	/// Pull account `a` in our cache from the trie DB. `require_code` requires that the code be cached, too.
 	/// `force_create` creates a new, empty basic account if there is not currently an active account.
-	fn require_or_from<F: FnOnce() -> Account>(&mut self, a: &Address, require_code: bool, default: F) -> &mut Account {
-		if self.cache.get(a).is_none() {
-			// load from trie.
-			self.cache.insert(a.clone(), TrieDB::new(&self.db, &self.root).get(&a).map(|rlp| Account::from_rlp(rlp)));
+	fn require_or_from<F: FnOnce() -> Account>(&self, a: &Address, require_code: bool, default: F) -> RefMut<Account> {
+		self.cache.borrow_mut().entry(a.clone()).or_insert_with(||
+			TrieDB::new(&self.db, &self.root).get(&a).map(|rlp| Account::from_rlp(rlp)));
+		if self.cache.borrow().get(a).unwrap().is_none() {
+			self.cache.borrow_mut().insert(a.clone(), Some(default()));
 		}
 
-		if self.cache.get(a).unwrap().is_none() {
-			self.cache.insert(a.clone(), Some(default()));
-		}
-
-		let db = &self.db;
-		self.cache.get_mut(a).unwrap().as_mut().map(|account| {
+		let b = self.cache.borrow_mut();
+		RefMut::map(b, |m| m.get_mut(a).unwrap().as_mut().map(|account| {
 			if require_code {
-				account.cache_code(db);
+				account.cache_code(&self.db);
 			}
 			account
-		}).unwrap()
+		}).unwrap())
 	}
 }
 
@@ -247,15 +232,16 @@ fn code_from_database() {
 	let a = Address::from_str("0000000000000000000000000000000000000000").unwrap();
 	let (r, db) = {
 		let mut s = State::new_temp();
-		s.require_or_from(&a, false, ||Account::new_contract(U256::from(42u32))).set_code(vec![1, 2, 3]);
-		assert_eq!(s.code(&a), Some(&[1u8, 2, 3][..]));
+		s.require_or_from(&a, false, ||Account::new_contract(U256::from(42u32)));
+		s.set_code(&a, vec![1, 2, 3]);
+		assert_eq!(s.code(&a), Some([1u8, 2, 3].to_vec()));
 		s.commit();
-		assert_eq!(s.code(&a), Some(&[1u8, 2, 3][..]));
+		assert_eq!(s.code(&a), Some([1u8, 2, 3].to_vec()));
 		s.drop()
 	};
 
-	let mut s = State::new_existing(db, r, U256::from(0u8));
-	assert_eq!(s.code(&a), Some(&[1u8, 2, 3][..]));
+	let s = State::new_existing(db, r, U256::from(0u8));
+	assert_eq!(s.code(&a), Some([1u8, 2, 3].to_vec()));
 }
 
 #[test]
@@ -268,7 +254,7 @@ fn storage_at_from_database() {
 		s.drop()
 	};
 
-	let mut s = State::new_existing(db, r, U256::from(0u8));
+	let s = State::new_existing(db, r, U256::from(0u8));
 	assert_eq!(s.storage_at(&a, &H256::from(&U256::from(01u64))), H256::from(&U256::from(69u64)));
 }
 
@@ -284,7 +270,7 @@ fn get_from_database() {
 		s.drop()
 	};
 
-	let mut s = State::new_existing(db, r, U256::from(0u8));
+	let s = State::new_existing(db, r, U256::from(0u8));
 	assert_eq!(s.balance(&a), U256::from(69u64));
 	assert_eq!(s.nonce(&a), U256::from(1u64));
 }
@@ -293,6 +279,7 @@ fn get_from_database() {
 fn alter_balance() {
 	let mut s = State::new_temp();
 	let a = Address::from_str("0000000000000000000000000000000000000000").unwrap();
+	let b = Address::from_str("0000000000000000000000000000000000000001").unwrap();
 	s.add_balance(&a, &U256::from(69u64));
 	assert_eq!(s.balance(&a), U256::from(69u64));
 	s.commit();
@@ -301,6 +288,12 @@ fn alter_balance() {
 	assert_eq!(s.balance(&a), U256::from(27u64));
 	s.commit();
 	assert_eq!(s.balance(&a), U256::from(27u64));
+	s.transfer_balance(&a, &b, &U256::from(18u64));
+	assert_eq!(s.balance(&a), U256::from(9u64));
+	assert_eq!(s.balance(&b), U256::from(18u64));
+	s.commit();
+	assert_eq!(s.balance(&a), U256::from(9u64));
+	assert_eq!(s.balance(&b), U256::from(18u64));
 }
 
 #[test]

src/transaction.rs

@@ -3,20 +3,23 @@ use util::bytes::*;
 use util::uint::*;
 use util::rlp::*;
 
+/// A set of information describing an externally-originating message call
+/// or contract creation operation.
 pub struct Transaction {
 	nonce: U256,
 	gas_price: U256,
 	gas: U256,
-	receive_address: Option<Address>,
+	to: Option<Address>,
 	value: U256,
 	data: Bytes,
 }
 
 impl Transaction {
+	/// Is this transaction meant to create a contract?
 	pub fn is_contract_creation(&self) -> bool {
-		self.receive_address.is_none()
+		self.to.is_none()
 	}
-
+	/// Is this transaction meant to send a message?
 	pub fn is_message_call(&self) -> bool {
 		!self.is_contract_creation()
 	}
@@ -28,7 +31,7 @@ impl Encodable for Transaction {
 			self.nonce.encode(e);
 			self.gas_price.encode(e);
 			self.gas.encode(e);
-			self.receive_address.encode(e);
+			self.to.encode(e);
 			self.value.encode(e);
 			self.data.encode(e);
 		})
@@ -43,7 +46,7 @@ impl Decodable for Transaction {
 			nonce: try!(Decodable::decode(&d[0])),
 			gas_price: try!(Decodable::decode(&d[1])),
 			gas: try!(Decodable::decode(&d[2])),
-			receive_address: try!(Decodable::decode(&d[3])),
+			to: try!(Decodable::decode(&d[3])),
 			value: try!(Decodable::decode(&d[4])),
 			data: try!(Decodable::decode(&d[5])),
 		};