State diffing, exposed through JSONRPC.

ethcore/src/client/client.rs

@@ -37,7 +37,7 @@ use filter::Filter;
 use log_entry::LocalizedLogEntry;
 use block_queue::{BlockQueue, BlockQueueInfo};
 use blockchain::{BlockChain, BlockProvider, TreeRoute, ImportRoute};
-use client::{BlockID, TransactionID, UncleID, TraceId, ClientConfig, BlockChainClient, TraceFilter};
+use client::{BlockID, TransactionID, UncleID, TraceId, ClientConfig, BlockChainClient, TraceFilter, CallAnalytics};
 use client::Error as ClientError;
 use env_info::EnvInfo;
 use executive::{Executive, Executed, TransactOptions, contract_address};
@@ -414,14 +414,14 @@ impl<V> Client<V> where V: Verifier {
 			TransactionID::Hash(ref hash) => self.chain.transaction_address(hash),
 			TransactionID::Location(id, index) => Self::block_hash(&self.chain, id).map(|hash| TransactionAddress {
 				block_hash: hash,
-				index: index
+				index: index,
 			})
 		}
 	}
 }
 
 impl<V> BlockChainClient for Client<V> where V: Verifier {
-	fn call(&self, t: &SignedTransaction, vm_tracing: bool) -> Result<Executed, ExecutionError> {
+	fn call(&self, t: &SignedTransaction, analytics: CallAnalytics) -> Result<Executed, ExecutionError> {
 		let header = self.block_header(BlockID::Latest).unwrap();
 		let view = HeaderView::new(&header);
 		let last_hashes = self.build_last_hashes(view.hash());
@@ -441,11 +441,20 @@ impl<V> BlockChainClient for Client<V> where V: Verifier {
 			ExecutionError::TransactionMalformed(message)
 		}));
 		let balance = state.balance(&sender);
-		// give the sender a decent balance
-		state.sub_balance(&sender, &balance);
-		state.add_balance(&sender, &(U256::from(1) << 200));
-		let options = TransactOptions { tracing: false, vm_tracing: vm_tracing, check_nonce: false };
-		Executive::new(&mut state, &env_info, self.engine.deref().deref(), &self.vm_factory).transact(t, options)
+		let needed_balance = t.value + t.gas * t.gas_price;
+		if balance < needed_balance {
+			// give the sender a sufficient balance
+			state.add_balance(&sender, &(needed_balance - balance));
+		}
+		let options = TransactOptions { tracing: false, vm_tracing: analytics.vm_tracing, check_nonce: false };
+		let mut ret = Executive::new(&mut state, &env_info, self.engine.deref().deref(), &self.vm_factory).transact(t, options);
+		// TODO gav move this into Executive.
+		if analytics.diffing {
+			if let Ok(ref mut x) = ret {
+				x.diff = Some(state.diff_from(self.state()));
+			}
+		}
+		ret
 	}
 
 	// TODO [todr] Should be moved to miner crate eventually.
@@ -561,7 +570,6 @@ impl<V> BlockChainClient for Client<V> where V: Verifier {
 		self.state_at(id).map(|s| s.nonce(address))
 	}
 
-
 	fn block_hash(&self, id: BlockID) -> Option<H256> {
 		Self::block_hash(&self.chain, id)
 	}

ethcore/src/client/mod.rs

@@ -47,6 +47,15 @@ use receipt::LocalizedReceipt;
 use trace::LocalizedTrace;
 use evm::Factory as EvmFactory;
 
+/// Options concerning what analytics we run on the call.
+#[derive(Eq, PartialEq, Default, Clone, Copy, Debug)]
+pub struct CallAnalytics {
+	/// Make a VM trace.
+	pub vm_tracing: bool,
+	/// Make a diff.
+	pub diffing: bool,
+}
+
 /// Blockchain database client. Owns and manages a blockchain and a block queue.
 pub trait BlockChainClient : Sync + Send {
 	/// Get raw block header data by block id.
@@ -165,7 +174,7 @@ pub trait BlockChainClient : Sync + Send {
 
 	/// Makes a non-persistent transaction call.
 	// TODO: should be able to accept blockchain location for call.
-	fn call(&self, t: &SignedTransaction, vm_tracing: bool) -> Result<Executed, ExecutionError>;
+	fn call(&self, t: &SignedTransaction, analytics: CallAnalytics) -> Result<Executed, ExecutionError>;
 
 	/// Returns EvmFactory.
 	fn vm_factory(&self) -> &EvmFactory;

ethcore/src/client/test_client.rs

@@ -20,7 +20,7 @@ use std::sync::atomic::{AtomicUsize, Ordering as AtomicOrder};
 use util::*;
 use transaction::{Transaction, LocalizedTransaction, SignedTransaction, Action};
 use blockchain::TreeRoute;
-use client::{BlockChainClient, BlockChainInfo, BlockStatus, BlockID, TransactionID, UncleID, TraceId, TraceFilter, LastHashes};
+use client::{BlockChainClient, BlockChainInfo, BlockStatus, BlockID, TransactionID, UncleID, TraceId, TraceFilter, LastHashes, CallAnalytics};
 use header::{Header as BlockHeader, BlockNumber};
 use filter::Filter;
 use log_entry::LocalizedLogEntry;
@@ -233,7 +233,7 @@ impl TestBlockChainClient {
 }
 
 impl BlockChainClient for TestBlockChainClient {
-	fn call(&self, _t: &SignedTransaction, _vm_tracing: bool) -> Result<Executed, ExecutionError> {
+	fn call(&self, _t: &SignedTransaction, _analytics: CallAnalytics) -> Result<Executed, ExecutionError> {
 		Ok(self.execution_result.read().unwrap().clone().unwrap())
 	}