Add randomness contract support to Authority Round.

Changes have been cherry-picked from poanetwork's aura-pos branch.
Most of the work has been done by @mbr.

ethcore/Cargo.toml

@@ -73,7 +73,6 @@ blooms-db = { path = "../util/blooms-db" }
 criterion = "0.3"
 engine = { path = "./engine", features = ["test-helpers"] }
 env_logger = "0.5"
-ethash = { path = "../ethash" }
 ethcore-accounts = { path = "../accounts" }
 ethcore-builtin = { path = "./builtin" }
 ethjson = { path = "../json", features = ["test-helpers"] }

ethcore/client-traits/src/lib.rs

@@ -41,7 +41,7 @@ use common_types::{
 	pruning_info::PruningInfo,
 	receipt::LocalizedReceipt,
 	trace_filter::Filter as TraceFilter,
-	transaction::{self, LocalizedTransaction, CallError, SignedTransaction, UnverifiedTransaction},
+	transaction::{self, Action, LocalizedTransaction, CallError, SignedTransaction, UnverifiedTransaction},
 	tree_route::TreeRoute,
 	verification::{VerificationQueueInfo, Unverified},
 };
@@ -380,7 +380,27 @@ pub trait BlockChainClient : Sync + Send + AccountData + BlockChain + CallContra
 	fn pruning_info(&self) -> PruningInfo;
 
 	/// Schedule state-altering transaction to be executed on the next pending block.
-	fn transact_contract(&self, address: Address, data: Bytes) -> Result<(), transaction::Error>;
+	fn transact_contract(&self, address: Address, data: Bytes) -> Result<(), transaction::Error> {
+		self.transact(Action::Call(address), data, None, None, None)
+	}
+
+	/// Returns a signed transaction. If gas limit, gas price, or nonce are not
+	/// specified, the defaults are used.
+	fn create_transaction(
+		&self,
+		action: Action,
+		data: Bytes,
+		gas: Option<U256>,
+		gas_price: Option<U256>,
+		nonce: Option<U256>
+	) -> Result<SignedTransaction, transaction::Error>;
+
+	/// Schedule state-altering transaction to be executed on the next pending
+	/// block with the given gas and nonce parameters.
+	///
+	/// If they are `None`, sensible values are selected automatically.
+	fn transact(&self, action: Action, data: Bytes, gas: Option<U256>, gas_price: Option<U256>, nonce: Option<U256>)
+		-> Result<(), transaction::Error>;
 
 	/// Get the address of the registry itself.
 	fn registrar_address(&self) -> Option<Address>;

ethcore/engine/src/engine.rs

@@ -32,7 +32,7 @@ use common_types::{
 	},
 	errors::{EthcoreError as Error, EngineError},
 	snapshot::Snapshotting,
-	transaction::{self, UnverifiedTransaction},
+	transaction::{self, SignedTransaction, UnverifiedTransaction},
 };
 use client_traits::EngineClient;
 
@@ -185,6 +185,12 @@ pub trait Engine: Sync + Send {
 	/// Allow mutating the header during seal generation. Currently only used by Clique.
 	fn on_seal_block(&self, _block: &mut ExecutedBlock) -> Result<(), Error> { Ok(()) }
 
+	/// Returns a list of transactions for a new block if we are the author.
+	///
+	/// This is called when the miner prepares a new block that this node will author and seal. It returns a list of
+	/// transactions that will be added to the block before any other transactions from the queue.
+	fn on_prepare_block(&self, _block: &ExecutedBlock) -> Result<Vec<SignedTransaction>, Error> { Ok(Vec::new()) }
+
 	/// Returns the engine's current sealing state.
 	fn sealing_state(&self) -> SealingState { SealingState::External }
 

ethcore/engine/src/signer.rs

@@ -18,6 +18,7 @@
 
 use ethereum_types::{H256, Address};
 use ethkey::{self, Signature};
+use ethkey::crypto::ecies;
 
 /// Everything that an Engine needs to sign messages.
 pub trait EngineSigner: Send + Sync {
@@ -26,6 +27,12 @@ pub trait EngineSigner: Send + Sync {
 
 	/// Signing address
 	fn address(&self) -> Address;
+
+	/// Decrypt a message that was encrypted to this signer's key.
+	fn decrypt(&self, auth_data: &[u8], cipher: &[u8]) -> Result<Vec<u8>, ethkey::crypto::Error>;
+
+	/// The signer's public key, if available.
+	fn public(&self) -> Option<ethkey::Public>;
 }
 
 /// Creates a new `EngineSigner` from given key pair.
@@ -40,7 +47,15 @@ impl EngineSigner for Signer {
 		ethkey::sign(self.0.secret(), &hash)
 	}
 
+	fn decrypt(&self, auth_data: &[u8], cipher: &[u8]) -> Result<Vec<u8>, ethkey::crypto::Error> {
+		ecies::decrypt(self.0.secret(), auth_data, cipher)
+	}
+
 	fn address(&self) -> Address {
 		self.0.address()
 	}
+
+	fn public(&self) -> Option<ethkey::Public> {
+		Some(*self.0.public())
+	}
 }

ethcore/engine/src/test_helpers.rs

@@ -43,7 +43,18 @@ impl EngineSigner for (Arc<AccountProvider>, Address, Password) {
 		}
 	}
 
+	fn decrypt(&self, auth_data: &[u8], cipher: &[u8]) -> Result<Vec<u8>, ethkey::crypto::Error> {
+		self.0.decrypt(self.1, None, auth_data, cipher).map_err(|e| {
+			warn!("Unable to decrypt message: {:?}", e);
+			ethkey::crypto::Error::InvalidMessage
+		})
+	}
+
 	fn address(&self) -> Address {
 		self.1
 	}
+
+	fn public(&self) -> Option<ethkey::Public> {
+		self.0.account_public(self.1, &self.2).ok()
+	}
 }

ethcore/engines/authority-round/Cargo.toml

@@ -10,6 +10,10 @@ license = "GPL-3.0"
 block-reward = { path = "../../block-reward" }
 client-traits = { path = "../../client-traits" }
 common-types = { path = "../../types" }
+derive_more = "0.15.0"
+ethabi = "8.0"
+ethabi-contract = "8.0"
+ethabi-derive = "8.0"
 ethereum-types = "0.6.0"
 ethjson = { path = "../../../json" }
 ethkey = { path = "../../../accounts/ethkey" }
@@ -22,6 +26,7 @@ log = "0.4"
 lru-cache = "0.1"
 machine = { path = "../../machine" }
 macros = { path = "../../../util/macros" }
+parity-bytes = "0.1"
 parking_lot = "0.8"
 rand = "0.6"
 rlp = "0.4.0"