Merge pull request #787 from ethcore/eth_estimateGas

eth_estimateGas

ethcore/src/client/client.rs

@@ -37,6 +37,8 @@ use log_entry::LocalizedLogEntry;
 use block_queue::{BlockQueue, BlockQueueInfo};
 use blockchain::{BlockChain, BlockProvider, TreeRoute, ImportRoute};
 use client::{BlockId, TransactionId, ClientConfig, BlockChainClient};
+use env_info::EnvInfo;
+use executive::{Executive, Executed};
 pub use blockchain::CacheSize as BlockChainCacheSize;
 
 /// General block status
@@ -385,6 +387,29 @@ impl<V> Client<V> where V: Verifier {
 }
 
 impl<V> BlockChainClient for Client<V> where V: Verifier {
+	fn call(&self, t: &SignedTransaction) -> Result<Executed, Error> {
+		let header = self.block_header(BlockId::Latest).unwrap();
+		let view = HeaderView::new(&header);
+		let last_hashes = self.build_last_hashes(view.hash());
+		let env_info = EnvInfo {
+			number: view.number(),
+			author: view.author(),
+			timestamp: view.timestamp(),
+			difficulty: view.difficulty(),
+			last_hashes: last_hashes,
+			gas_used: U256::zero(),
+			gas_limit: U256::max_value(),
+		};
+		// that's just a copy of the state.
+		let mut state = self.state();
+		let sender = try!(t.sender());
+		let balance = state.balance(&sender);
+		// give the sender max balance
+		state.sub_balance(&sender, &balance);
+		state.add_balance(&sender, &U256::max_value());
+		Executive::new(&mut state, &env_info, self.engine.deref().deref()).transact(t, false)
+	}
+
 	// TODO [todr] Should be moved to miner crate eventually.
 	fn try_seal(&self, block: ClosedBlock, seal: Vec<Bytes>) -> Result<SealedBlock, ClosedBlock> {
 		block.try_seal(self.engine.deref().deref(), seal)

ethcore/src/client/mod.rs

@@ -25,6 +25,7 @@ pub use self::client::*;
 pub use self::config::{ClientConfig, BlockQueueConfig, BlockChainConfig};
 pub use self::ids::{BlockId, TransactionId};
 pub use self::test_client::{TestBlockChainClient, EachBlockWith};
+pub use executive::Executed;
 
 use std::collections::HashSet;
 use util::bytes::Bytes;
@@ -37,7 +38,7 @@ use header::BlockNumber;
 use transaction::{LocalizedTransaction, SignedTransaction};
 use log_entry::LocalizedLogEntry;
 use filter::Filter;
-use error::{ImportResult};
+use error::{ImportResult, Error};
 
 /// Blockchain database client. Owns and manages a blockchain and a block queue.
 pub trait BlockChainClient : Sync + Send {
@@ -118,5 +119,7 @@ pub trait BlockChainClient : Sync + Send {
 	/// Attempts to seal given block. Returns `SealedBlock` on success and the same block in case of error.
 	fn try_seal(&self, block: ClosedBlock, seal: Vec<Bytes>) -> Result<SealedBlock, ClosedBlock>;
 
+	/// Makes a non-persistent transaction call.
+	fn call(&self, t: &SignedTransaction) -> Result<Executed, Error>;
 }
 

ethcore/src/client/test_client.rs

@@ -29,6 +29,8 @@ use error::{ImportResult};
 
 use block_queue::BlockQueueInfo;
 use block::{SealedBlock, ClosedBlock};
+use executive::Executed;
+use error::Error;
 
 /// Test client.
 pub struct TestBlockChainClient {
@@ -48,6 +50,8 @@ pub struct TestBlockChainClient {
 	pub storage: RwLock<HashMap<(Address, H256), H256>>,
 	/// Code.
 	pub code: RwLock<HashMap<Address, Bytes>>,
+	/// Execution result.
+	pub execution_result: RwLock<Option<Executed>>,
 }
 
 #[derive(Clone)]
@@ -82,12 +86,18 @@ impl TestBlockChainClient {
 			balances: RwLock::new(HashMap::new()),
 			storage: RwLock::new(HashMap::new()),
 			code: RwLock::new(HashMap::new()),
+			execution_result: RwLock::new(None),
 		};
 		client.add_blocks(1, EachBlockWith::Nothing); // add genesis block
 		client.genesis_hash = client.last_hash.read().unwrap().clone();
 		client
 	}
 
+	/// Set the execution result.
+	pub fn set_execution_result(&self, result: Executed) {
+		*self.execution_result.write().unwrap() = Some(result);
+	}
+
 	/// Set the balance of account `address` to `balance`.
 	pub fn set_balance(&self, address: Address, balance: U256) {
 		self.balances.write().unwrap().insert(address, balance);
@@ -182,6 +192,10 @@ impl TestBlockChainClient {
 }
 
 impl BlockChainClient for TestBlockChainClient {
+	fn call(&self, _t: &SignedTransaction) -> Result<Executed, Error> {
+		Ok(self.execution_result.read().unwrap().clone().unwrap())
+	}
+
 	fn block_total_difficulty(&self, _id: BlockId) -> Option<U256> {
 		Some(U256::zero())
 	}

ethcore/src/executive.rs

@@ -37,7 +37,7 @@ pub fn contract_address(address: &Address, nonce: &U256) -> Address {
 }
 
 /// Transaction execution receipt.
-#[derive(Debug)]
+#[derive(Debug, PartialEq, Clone)]
 pub struct Executed {
 	/// Gas paid up front for execution of transaction.
 	pub gas: U256,

ethcore/src/views.rs

@@ -256,6 +256,9 @@ impl<'a> HeaderView<'a> {
 		}
 	}
 
+	/// Returns header hash.
+	pub fn hash(&self) -> H256 { self.sha3() }
+
 	/// Returns raw rlp.
 	pub fn rlp(&self) -> &Rlp<'a> { &self.rlp }