big refactor of executive in progress

src/evm/evm.rs

@@ -4,15 +4,26 @@ use util::uint::U256;
 use util::bytes::Bytes;
 use evm::{EvmParams, Ext};
 
-#[derive(Debug, Eq, PartialEq)]
+/// Evm errors.
-pub enum EvmResult {
+pub enum EvmError {
-	Stop { gas_left: U256 },
+	/// Returned when transaction execution run out of gas.
-	Return(Bytes),
+	/// The state should be reverted to the state from before the
-	Suicide,
+	/// transaction execution. But it does not mean that transaction
+	/// was invalid. Balance still should be transfered and nonce
+	/// should be increased.
 	OutOfGas,
-	InternalError
+	/// Returned on evm internal error. Should never be ignored during development.
+	/// Likely to cause consensus issues.
+	Internal,
 }
 
+/// Evm result.
+/// 
+/// Returns gas_left if execution is successfull, otherwise error.
+pub type EvmResult = Result<U256, EvmError>;
+
+/// Evm interface.
 pub trait Evm {
+	/// This function should be used to execute transaction.
 	fn exec(&self, params: &EvmParams, ext: &mut Ext) -> EvmResult;
 }

src/evm/executive.rs

@@ -1,5 +1,6 @@
 use std::collections::HashSet;
 use std::cmp;
+use std::ptr;
 use util::hash::*;
 use util::uint::*;
 use util::rlp::*;
@@ -7,9 +8,10 @@ use util::sha3::*;
 use util::bytes::*;
 use state::*;
 use env_info::*;
+use evm_schedule::*;
 use engine::*;
 use transaction::*;
-use evm::{VmFactory, Ext, LogEntry, EvmParams, EvmResult};
+use evm::{VmFactory, Ext, LogEntry, EvmParams, EvmResult, EvmError};
 
 /// Returns new address created from address and given nonce.
 pub fn contract_address(address: &Address, nonce: &U256) -> Address {
@@ -40,6 +42,7 @@ impl Substate {
 		}
 	}
 
+	// TODO: remove
 	pub fn logs(&self) -> &[LogEntry] {
 		&self.logs
 	}
@@ -52,17 +55,59 @@ impl Substate {
 	}
 }
 
+/// Transaction execution result.
+pub struct Executed {
+	/// Gas paid up front for execution of transaction.
+	pub gas: U256,
+	/// Gas used during execution of transaction.
+	pub gas_used: U256,
+	/// Gas refunded after the execution of transaction. 
+	/// To get gas that was required up front, add `refunded` and `gas_used`.
+	pub refunded: U256,
+	/// Cumulative gas used in current block so far.
+	/// 
+	/// cumulative_gas_used = gas_used(t0) + gas_used(t1) + ... gas_used(tn)
+	///
+	/// where `tn` is current transaction.
+	pub cumulative_gas_used: U256,
+	/// Transaction output.
+	pub output: Bytes,
+	/// Vector of logs generated by transaction.
+	pub logs: Vec<LogEntry>
+}
+
+impl Executed {
+	fn new() -> Executed {
+		Executed {
+			gas: U256::zero(),
+			gas_used: U256::zero(),
+			refunded: U256::zero(),
+			cumulative_gas_used: U256::zero(),
+			output: vec![],
+			logs: vec![]
+		}
+	}
+}
+
 /// Result of executing the transaction.
 #[derive(PartialEq, Debug)]
-pub enum ExecutiveResult {
+pub enum ExecutionError {
-	Ok,
+	/// Returned when block (gas_used + gas) > gas_limit.
+	/// 
+	/// If gas =< gas_limit, upstream may try to execute the transaction
+	/// in next block.
 	BlockGasLimitReached { gas_limit: U256, gas_used: U256, gas: U256 },
+	/// Returned when transaction nonce does not match state nonce.
 	InvalidNonce { expected: U256, is: U256 },
+	/// Returned when cost of transaction (value + gas_price * gas) exceeds 
+	/// current sender balance.
 	NotEnoughCash { required: U256, is: U256 },
-	OutOfGas,
+	/// Returned when internal evm error occurs.
-	InternalError
+	Internal
 }
 
+pub type ExecutionResult = Result<Executed, ExecutionError>;
+
 /// Message-call/contract-creation executor; useful for executing transactions.
 pub struct Executive<'a> {
 	state: &'a mut State,
@@ -94,22 +139,24 @@ impl<'a> Executive<'a> {
 	}
 
 	/// This funtion should be used to execute transaction.
-	pub fn transact(e: &mut Executive<'a>, t: &Transaction) -> ExecutiveResult {
+	pub fn transact(e: &mut Executive<'a>, t: &Transaction) -> ExecutionResult {
-		// validate if transaction fits into given block
+		// TODO: validate transaction signature ?/ sender
-		if e.info.gas_used + t.gas > e.info.gas_limit {
-			return ExecutiveResult::BlockGasLimitReached { 
-				gas_limit: e.info.gas_limit, 
-				gas_used: e.info.gas_used, 
-				gas: t.gas 
-			};
-		}
 
 		let sender = t.sender();
 		let nonce = e.state.nonce(&sender);
 
 		// validate transaction nonce
 		if t.nonce != nonce {
-			return ExecutiveResult::InvalidNonce { expected: nonce, is: t.nonce };
+			return Err(ExecutionError::InvalidNonce { expected: nonce, is: t.nonce });
+		}
+		
+		// validate if transaction fits into given block
+		if e.info.gas_used + t.gas > e.info.gas_limit {
+			return Err(ExecutionError::BlockGasLimitReached { 
+				gas_limit: e.info.gas_limit, 
+				gas_used: e.info.gas_used, 
+				gas: t.gas 
+			});
 		}
 
 		// TODO: we might need bigints here, or at least check overflows.
@@ -119,9 +166,10 @@ impl<'a> Executive<'a> {
 
 		// avoid unaffordable transactions
 		if balance < total_cost {
-			return ExecutiveResult::NotEnoughCash { required: total_cost, is: balance };
+			return Err(ExecutionError::NotEnoughCash { required: total_cost, is: balance });
 		}
 
+		// NOTE: there can be no invalid transactions from this point.
 		e.state.inc_nonce(&sender);
 		let mut substate = Substate::new();
 
@@ -137,7 +185,7 @@ impl<'a> Executive<'a> {
 					code: t.data.clone(),
 					data: vec![],
 				};
-				Executive::call(e, &params, &mut substate)
+				Executive::call(e, &params, &mut substate, &mut [])
 			},
 			TransactionKind::MessageCall => {
 				let params = EvmParams {
@@ -156,78 +204,51 @@ impl<'a> Executive<'a> {
 
 		// finalize here!
 		e.finalize(substate, &sender, U256::zero(), U256::zero(), t.gas_price);
-		res
+		//res
+		Ok(Executed::new())
 	}
 
 	/// Calls contract function with given contract params.
-	/// *Note. It does not finalize the transaction (doesn't do refunds, nor suicides).
+	/// NOTE. It does not finalize the transaction (doesn't do refunds, nor suicides).
-	fn call(e: &mut Executive<'a>, params: &EvmParams, substate: &mut Substate) -> ExecutiveResult {
+	/// Modifies the substate and the output.
+	/// Returns either gas_left or `EvmError`.
+	fn call(e: &mut Executive<'a>, params: &EvmParams, substate: &mut Substate, output: &mut [u8]) -> EvmResult {
 		// at first, transfer value to destination
 		e.state.transfer_balance(&params.sender, &params.address, &params.value);
 
-		// if destination is builtin, try to execute it, or quickly return
 		if e.engine.is_builtin(&params.address) {
-			return match e.engine.cost_of_builtin(&params.address, &params.data) > params.gas {
+			// if destination is builtin, try to execute it
-				true => ExecutiveResult::OutOfGas,
+			let cost = e.engine.cost_of_builtin(&params.address, &params.data);
-				false => {
+			match cost <= params.gas {
-					// TODO: substract gas for execution
+				true => {
-					let mut out = vec![];
+					e.engine.execute_builtin(&params.address, &params.data, output);
-					e.engine.execute_builtin(&params.address, &params.data, &mut out);
+					Ok(params.gas - cost)
-					ExecutiveResult::Ok
-				}
-			}
-		}
-
-		// otherwise do `normal` execution if destination is a contract
-		// TODO: is executing contract with no code different from not executing contract at all?
-		// if yes, there is a logic issue here. mk
-		if params.code.len() > 0 {
-			return match {
-				let mut ext = Externalities::new(e.state, e.info, e.engine, e.depth, params, substate);
-				let evm = VmFactory::create();
-				evm.exec(&params, &mut ext)
-			} {
-				EvmResult::Stop { gas_left } => ExecutiveResult::Ok,
-				EvmResult::Return(_) => ExecutiveResult::Ok,
-				EvmResult::Suicide => {
-					substate.suicides.insert(params.address.clone());
-					ExecutiveResult::Ok
 				},
-				EvmResult::OutOfGas => ExecutiveResult::OutOfGas,
+				false => Err(EvmError::OutOfGas)
-				_err => ExecutiveResult::InternalError
 			}
+		} else if params.code.len() > 0 {
+			// if destination is a contract, do normal message call
+			let mut ext = Externalities::new(e.state, e.info, e.engine, e.depth, params, substate, OutputPolicy::Return(output));
+			let evm = VmFactory::create();
+			evm.exec(&params, &mut ext)
+		} else {
+			// otherwise, nothing
+			Ok(params.gas)
 		}
-		
-		ExecutiveResult::Ok
 	}
 	
 	/// Creates contract with given contract params.
-	/// *Note. It does not finalize the transaction (doesn't do refunds, nor suicides).
+	/// NOTE. It does not finalize the transaction (doesn't do refunds, nor suicides).
-	fn create(e: &mut Executive<'a>, params: &EvmParams, substate: &mut Substate) -> ExecutiveResult {
+	/// Modifies the substate.
+	fn create(e: &mut Executive<'a>, params: &EvmParams, substate: &mut Substate) -> EvmResult {
 		// at first create new contract
 		e.state.new_contract(&params.address);
 		// then transfer value to it
 		e.state.transfer_balance(&params.sender, &params.address, &params.value);
 
-		match {
+		let mut ext = Externalities::new(e.state, e.info, e.engine, e.depth, params, substate, OutputPolicy::InitContract);
-			let mut ext = Externalities::new(e.state, e.info, e.engine, e.depth, params, substate);
+		let evm = VmFactory::create();
-			let evm = VmFactory::create();
+		evm.exec(&params, &mut ext)
-			evm.exec(&params, &mut ext)
-		} {
-			EvmResult::Stop { gas_left } => {
-				ExecutiveResult::Ok
-			},
-			EvmResult::Return(output) => {
-				e.state.init_code(&params.address, output);
-				ExecutiveResult::Ok
-			},
-			EvmResult::Suicide => {
-				substate.suicides.insert(params.address.clone());
-				ExecutiveResult::Ok
-			},
-			EvmResult::OutOfGas => ExecutiveResult::OutOfGas,
-			_err => ExecutiveResult::InternalError
-		}
 	}
 
 	/// Finalizes the transaction (does refunds and suicides).
@@ -256,6 +277,19 @@ impl<'a> Executive<'a> {
 	}
 }
 
+pub enum ExtMode {
+	Call,
+	Create
+}
+
+/// Wrapper structure for evm return data to avoid unnecessary copying.
+pub enum OutputPolicy<'a> {
+	/// Reference to fixed sized output of a message call.
+	Return(&'a mut [u8]),
+	/// Use it, if you want return code to initialize contract.
+	InitContract
+}
+
 /// Implementation of evm Externalities.
 pub struct Externalities<'a> {
 	state: &'a mut State,
@@ -263,19 +297,29 @@ pub struct Externalities<'a> {
 	engine: &'a Engine,
 	depth: usize,
 	params: &'a EvmParams,
-	substate: &'a mut Substate
+	substate: &'a mut Substate,
+	schedule: EvmSchedule,
+	output: OutputPolicy<'a>
 }
 
 impl<'a> Externalities<'a> {
 	/// Basic `Externalities` constructor.
-	pub fn new(state: &'a mut State, info: &'a EnvInfo, engine: &'a Engine, depth: usize, params: &'a EvmParams, substate: &'a mut Substate) -> Self {
+	pub fn new(state: &'a mut State, 
+			   info: &'a EnvInfo, 
+			   engine: &'a Engine, 
+			   depth: usize, 
+			   params: &'a EvmParams, 
+			   substate: &'a mut Substate, 
+			   output: OutputPolicy<'a>) -> Self {
 		Externalities {
 			state: state,
 			info: info,
 			engine: engine,
 			depth: depth,
 			params: params,
-			substate: substate
+			substate: substate,
+			schedule: engine.evm_schedule(info),
+			output: output
 		}
 	}
 }
@@ -345,19 +389,18 @@ impl<'a> Ext for Externalities<'a> {
 		println!("gas: {:?}", gas);
 		println!("call_gas: {:?}", call_gas);
 
-		let schedule = self.engine.evm_schedule(self.info);
 		let mut gas_cost = call_gas;
 		let mut call_gas = call_gas;
 
 		let is_call = receive_address == code_address;
 		if is_call && self.state.code(&code_address).is_none() {
-			gas_cost = gas_cost + schedule.call_new_account_gas as u64;
+			gas_cost = gas_cost + self.schedule.call_new_account_gas as u64;
 		}
 
 		if *value > U256::zero() {
-			assert!(schedule.call_value_transfer_gas > schedule.call_stipend, "overflow possible");
+			assert!(self.schedule.call_value_transfer_gas > self.schedule.call_stipend, "overflow possible");
-			gas_cost = gas_cost + schedule.call_value_transfer_gas as u64;
+			gas_cost = gas_cost + self.schedule.call_value_transfer_gas as u64;
-			call_gas = call_gas + schedule.call_stipend as u64;
+			call_gas = call_gas + self.schedule.call_stipend as u64;
 		}
 
 		if gas_cost > gas {
@@ -387,9 +430,11 @@ impl<'a> Ext for Externalities<'a> {
 		let mut substate = Substate::new();
 		{
 			let mut ex = Executive::from_parent(self);
-			Executive::call(&mut ex, &params, &mut substate);
+			// TODO: take output into account
+			Executive::call(&mut ex, &params, &mut substate, &mut []);
 		}
 
+		self.substate.accrue(substate);
 		// TODO: replace call_gas with what's actually left
 		Some((vec![], gas - gas_cost + call_gas))
 	}
@@ -398,10 +443,44 @@ impl<'a> Ext for Externalities<'a> {
 		self.state.code(address).unwrap_or(vec![])
 	}
 
+	fn ret(&mut self, gas: u64, data: &[u8]) -> Option<u64> {
+		match &mut self.output {
+			&mut OutputPolicy::Return(ref mut slice) => unsafe {
+				let len = cmp::min(slice.len(), data.len());
+				ptr::copy(data.as_ptr(), slice.as_mut_ptr(), len);
+				Some(gas)
+			},
+			&mut OutputPolicy::InitContract => {
+				let return_cost = data.len() as u64 * self.schedule.create_data_gas as u64;
+				if return_cost > gas {
+					return None;
+				}
+				let mut code = vec![];
+				code.reserve(data.len());
+				unsafe {
+					ptr::copy(data.as_ptr(), code.as_mut_ptr(), data.len());
+					code.set_len(data.len());
+				}
+				let address = &self.params.address;
+				self.state.init_code(address, code);
+				Some(gas - return_cost)
+			}
+		}
+	}
+
 	fn log(&mut self, topics: Vec<H256>, data: Bytes) {
 		let address = self.params.address.clone();
 		self.substate.logs.push(LogEntry::new(address, topics, data));
 	}
+
+	fn suicide(&mut self) {
+		let address = self.params.address.clone();
+		self.substate.suicides.insert(address);
+	}
+
+	fn schedule(&self) -> &EvmSchedule {
+		&self.schedule
+	}
 }
 
 #[cfg(test)]
@@ -462,7 +541,7 @@ mod tests {
 
 		{
 			let mut ex = Executive::new(&mut state, &info, &engine);
-			assert_eq!(Executive::create(&mut ex, &params, &mut substate), ExecutiveResult::Ok);
+			assert_eq!(Executive::create(&mut ex, &params, &mut substate), ExecutionResult::Ok);
 		}
 
 		assert_eq!(state.storage_at(&address, &H256::new()), H256::from(&U256::from(0xf9u64)));
@@ -489,7 +568,7 @@ mod tests {
 
 		{
 			let mut ex = Executive::new(&mut state, &info, &engine);
-			assert_eq!(Executive::create(&mut ex, &params, &mut substate), ExecutiveResult::Ok);
+			assert_eq!(Executive::create(&mut ex, &params, &mut substate), ExecutionResult::Ok);
 		}
 		
 		assert_eq!(state.storage_at(&address, &H256::new()), H256::from(next_address.clone()));
@@ -537,7 +616,7 @@ mod tests {
 
 		{
 			let mut ex = Executive::new(&mut state, &info, engine.deref());
-			assert_eq!(Executive::call(&mut ex, &params, &mut substate), ExecutiveResult::Ok);
+			assert_eq!(Executive::call(&mut ex, &params, &mut substate), ExecutionResult::Ok);
 		}
 
 		assert!(false);

src/evm/ext.rs

@@ -3,6 +3,7 @@
 use util::hash::*;
 use util::uint::*;
 use util::bytes::*;
+use evm_schedule::*;
 
 pub trait Ext {
 	/// Returns a value for given key.
@@ -33,4 +34,14 @@ pub trait Ext {
 
 	/// Creates log entry with given topics and data
 	fn log(&mut self, topics: Vec<H256>, data: Bytes);
+
+	/// Should be called when transaction calls `RETURN` opcode.
+	/// Returns gas_left if cost of returning the data is not too high.
+	fn ret(&mut self, gas: u64, data: &[u8]) -> Option<u64>;
+
+	/// Should be called when contract commits suicide.
+	fn suicide(&mut self);
+
+	/// Returns schedule.
+	fn schedule(&self) -> &EvmSchedule;
 }

src/evm/jit.rs

@@ -316,11 +316,21 @@ impl evm::Evm for JitEvm {
 		
 		let mut context = unsafe { evmjit::ContextHandle::new(data.into_jit(), &mut ext_handle) };
 		match context.exec() {
-			evmjit::ReturnCode::Stop => evm::EvmResult::Stop { gas_left: U256::from(context.gas_left()) },
+			evmjit::ReturnCode::Stop => Ok(evm::EvmOutput::new(U256::from(context.gas_left()), None)),
-			evmjit::ReturnCode::Return => evm::EvmResult::Return(context.output_data().to_vec()),
+			evmjit::ReturnCode::Return => {
-			evmjit::ReturnCode::Suicide => evm::EvmResult::Suicide,
+				if context.output_data().len() as u64 * ext.schedule().create_data_gas as u64 > context.gas_left() {
-			evmjit::ReturnCode::OutOfGas => evm::EvmResult::OutOfGas,
+					return Err(evm::EvmError::OutOfGas);
-			_ => evm::EvmResult::InternalError
+				}
+
+				Ok(evm::EvmOutput::new(U256::from(context.gas_left()), Some(context.output_data().to_vec())))
+			},
+			evmjit::ReturnCode::Suicide => { 
+				// what if there is a suicide and we run out of gas just after?
+				ext.suicide();
+				Ok(evm::EvmOutput::new(U256::from(context.gas_left()), None))
+			},
+			evmjit::ReturnCode::OutOfGas => Err(evm::EvmError::OutOfGas),
+			_err => Err(evm::EvmError::Internal)
 		}
 	}
 }

src/evm/mod.rs

@@ -9,9 +9,9 @@ pub mod params;
 #[cfg(feature = "jit" )]
 mod jit;
 
-pub use self::evm::{Evm, EvmResult};
+pub use self::evm::{Evm, EvmError, EvmResult};
 pub use self::ext::{Ext};
 pub use self::logentry::LogEntry;
 pub use self::vmfactory::VmFactory;
-pub use self::executive::{Executive, ExecutiveResult, Externalities, Substate};
+pub use self::executive::{Executive, ExecutionResult, Externalities, Substate};
 pub use self::params::EvmParams;