move genesis_epoch_data function to spec

ethcore/src/spec/spec.rs

@@ -481,6 +481,63 @@ impl Spec {
 			.and_then(|x| load_from(cache_dir, x).map_err(fmt))
 	}
 
+	/// initialize genesis epoch data, using in-memory database for
+	/// constructor.
+	pub fn genesis_epoch_data(&self) -> Result<Vec<u8>, String> {
+		use transaction::{Action, Transaction};
+		use util::{journaldb, kvdb};
+
+		let genesis = self.genesis_header();
+
+		let factories = Default::default();
+		let mut db = journaldb::new(
+			Arc::new(kvdb::in_memory(0)),
+			journaldb::Algorithm::Archive,
+			None,
+		);
+
+		self.ensure_db_good(BasicBackend(db.as_hashdb_mut()), &factories)
+			.map_err(|e| format!("Unable to initialize genesis state: {}", e))?;
+
+		let call = |a, d| {
+			let mut db = db.boxed_clone();
+			let env_info = ::evm::EnvInfo {
+				number: 0,
+				author: *genesis.author(),
+				timestamp: genesis.timestamp(),
+				difficulty: *genesis.difficulty(),
+				gas_limit: *genesis.gas_limit(),
+				last_hashes: Arc::new(Vec::new()),
+				gas_used: 0.into()
+			};
+
+			let from = Address::default();
+			let tx = Transaction {
+				nonce: self.engine.account_start_nonce(0),
+				action: Action::Call(a),
+				gas: U256::from(50_000_000), // TODO: share with client.
+				gas_price: U256::default(),
+				value: U256::default(),
+				data: d,
+			}.fake_sign(from);
+
+			let res = ::state::prove_transaction(
+				db.as_hashdb_mut(),
+				*genesis.state_root(),
+				&tx,
+				&*self.engine,
+				&env_info,
+				factories.clone(),
+				true,
+			);
+
+			res.map(|(out, proof)| (out, proof.into_iter().map(|x| x.into_vec()).collect()))
+				.ok_or_else(|| "Failed to prove call: insufficient state".into())
+		};
+
+		self.engine.genesis_epoch_data(&genesis, &call)
+	}
+
 	/// Create a new Spec which conforms to the Frontier-era Morden chain except that it's a NullEngine consensus.
 	pub fn new_test() -> Spec { load_bundled!("null_morden") }