eth_call

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

@@ -37,7 +37,8 @@ use header::BlockNumber;
 use transaction::{LocalizedTransaction, SignedTransaction};
 use log_entry::LocalizedLogEntry;
 use filter::Filter;
-use error::{ImportResult};
+use error::{ImportResult, Error};
+use executive::Executed;
 
 /// 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 {
@@ -182,6 +184,10 @@ impl TestBlockChainClient {
 }
 
 impl BlockChainClient for TestBlockChainClient {
+	fn call(&self, _t: &SignedTransaction) -> Result<Executed, Error> {
+		unimplemented!()
+	}
+
 	fn block_total_difficulty(&self, _id: BlockId) -> Option<U256> {
 		Some(U256::zero())
 	}

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 }
 

rpc/src/v1/impls/eth.rs

@@ -398,6 +398,28 @@ impl<C, S, A, M, EM> Eth for EthClient<C, S, A, M, EM>
 				}
 		})
 	}
+
+	fn call(&self, params: Params) -> Result<Value, Error> {
+		from_params::<(TransactionRequest, BlockNumber)>(params)
+			.and_then(|(transaction_request, _block_number)| {
+				let accounts = take_weak!(self.accounts);
+				match accounts.account_secret(&transaction_request.from) {
+					Ok(secret) => {
+						let client = take_weak!(self.client);
+
+						let transaction: EthTransaction = transaction_request.into();
+						let signed_transaction = transaction.sign(&secret);
+
+						let output = client.call(&signed_transaction)
+							.map(|e| Bytes::new(e.output))
+							.unwrap_or(Bytes::default());
+
+						to_value(&output)
+					},
+					Err(_) => { to_value(&Bytes::default()) }
+				}
+			})
+	}
 }
 
 /// Eth filter rpc implementation.

util/bigint/src/uint.rs

@@ -490,6 +490,8 @@ pub trait Uint: Sized + Default + FromStr + From<u64> + fmt::Debug + fmt::Displa
 	fn zero() -> Self;
 	/// Returns new instance equalling one.
 	fn one() -> Self;
+	/// Returns the largest value that can be represented by this integer type.
+	fn max_value() -> Self;
 
 	/// Error type for converting from a decimal string.
 	type FromDecStrErr;
@@ -647,6 +649,15 @@ macro_rules! construct_uint {
 				From::from(1u64)
 			}
 
+			#[inline]
+			fn max_value() -> Self {
+				let mut result = [0; $n_words];
+				for i in 0..$n_words {
+					result[i] = u64::max_value();
+				}
+				$name(result)
+			}
+
 			/// Fast exponentation by squaring
 			/// https://en.wikipedia.org/wiki/Exponentiation_by_squaring
 			fn pow(self, expon: Self) -> Self {