Validating minimal required gas for a transaction (#2937)

* Validating minimal required gas for a transaction

* Adding RPC case and note

* Fixing whitespace [ci skip]

ethcore/src/client/client.rs

@@ -60,7 +60,7 @@ use receipt::LocalizedReceipt;
 use trace::{TraceDB, ImportRequest as TraceImportRequest, LocalizedTrace, Database as TraceDatabase};
 use trace;
 use trace::FlatTransactionTraces;
-use evm::Factory as EvmFactory;
+use evm::{Factory as EvmFactory, Schedule};
 use miner::{Miner, MinerService};
 use snapshot::{self, io as snapshot_io};
 use factory::Factories;
@@ -1156,6 +1156,23 @@ impl BlockChainClient for Client {
 }
 
 impl MiningBlockChainClient for Client {
+
+	fn latest_schedule(&self) -> Schedule {
+		let header_data = self.best_block_header();
+		let view = HeaderView::new(&header_data);
+
+		let env_info = EnvInfo {
+			number: view.number(),
+			author: view.author(),
+			timestamp: view.timestamp(),
+			difficulty: view.difficulty(),
+			last_hashes: self.build_last_hashes(view.hash()),
+			gas_used: U256::default(),
+			gas_limit: view.gas_limit(),
+		};
+		self.engine.schedule(&env_info)
+	}
+
 	fn prepare_open_block(&self, author: Address, gas_range_target: (U256, U256), extra_data: Bytes) -> OpenBlock {
 		let engine = &*self.engine;
 		let chain = self.chain.read();

ethcore/src/client/test_client.rs

@@ -34,7 +34,7 @@ use log_entry::LocalizedLogEntry;
 use receipt::{Receipt, LocalizedReceipt};
 use blockchain::extras::BlockReceipts;
 use error::{ImportResult};
-use evm::{Factory as EvmFactory, VMType};
+use evm::{Factory as EvmFactory, VMType, Schedule};
 use miner::{Miner, MinerService, TransactionImportResult};
 use spec::Spec;
 
@@ -137,7 +137,7 @@ impl TestBlockChainClient {
 		client.genesis_hash = client.last_hash.read().clone();
 		client
 	}
-	
+
 	/// Set the transaction receipt result
 	pub fn set_transaction_receipt(&self, id: TransactionID, receipt: LocalizedReceipt) {
 		self.receipts.write().insert(id, receipt);
@@ -306,6 +306,10 @@ pub fn get_temp_state_db() -> GuardedTempResult<StateDB> {
 }
 
 impl MiningBlockChainClient for TestBlockChainClient {
+	fn latest_schedule(&self) -> Schedule {
+		Schedule::new_homestead_gas_fix()
+	}
+
 	fn prepare_open_block(&self, author: Address, gas_range_target: (U256, U256), extra_data: Bytes) -> OpenBlock {
 		let engine = &*self.spec.engine;
 		let genesis_header = self.spec.genesis_header();

ethcore/src/client/traits.rs

@@ -27,7 +27,7 @@ use views::{BlockView};
 use error::{ImportResult, CallError};
 use receipt::LocalizedReceipt;
 use trace::LocalizedTrace;
-use evm::Factory as EvmFactory;
+use evm::{Factory as EvmFactory, Schedule};
 use types::ids::*;
 use types::trace_filter::Filter as TraceFilter;
 use executive::Executed;
@@ -236,6 +236,9 @@ pub trait MiningBlockChainClient : BlockChainClient {
 
 	/// Import sealed block. Skips all verifications.
 	fn import_sealed_block(&self, block: SealedBlock) -> ImportResult;
+
+	/// Returns latest schedule.
+	fn latest_schedule(&self) -> Schedule;
 }
 
 impl IpcConfig for BlockChainClient { }