Exposing engine extra info in block RPC (#3169)

* Exposing extra info in RPC

* Proper serialization and client trait API

ethcore/src/client/client.rs

@@ -65,7 +65,7 @@ use evm::{Factory as EvmFactory, Schedule};
 use miner::{Miner, MinerService};
 use snapshot::{self, io as snapshot_io};
 use factory::Factories;
-use rlp::{View, UntrustedRlp};
+use rlp::{decode, View, UntrustedRlp};
 use state_db::StateDB;
 use rand::OsRng;
 
@@ -1189,6 +1189,18 @@ impl BlockChainClient for Client {
 	fn signing_network_id(&self) -> Option<u8> {
 		self.engine.signing_network_id(&self.latest_env_info())
 	}
+
+	fn block_extra_info(&self, id: BlockID) -> Option<BTreeMap<String, String>> {
+		self.block_header(id)
+			.map(|block| decode(&block))
+			.map(|header| self.engine.extra_info(&header))
+	}
+
+	fn uncle_extra_info(&self, id: UncleID) -> Option<BTreeMap<String, String>> {
+		self.uncle(id)
+			.map(|block| BlockView::new(&block).header())
+			.map(|header| self.engine.extra_info(&header))
+	}
 }
 
 impl MiningBlockChainClient for Client {

ethcore/src/client/test_client.rs

@@ -38,6 +38,7 @@ use evm::{Factory as EvmFactory, VMType, Schedule};
 use miner::{Miner, MinerService, TransactionImportResult};
 use spec::Spec;
 use types::mode::Mode;
+use views::BlockView;
 
 use verification::queue::QueueInfo;
 use block::{OpenBlock, SealedBlock};
@@ -417,6 +418,10 @@ impl BlockChainClient for TestBlockChainClient {
 		None	// Simple default.
 	}
 
+	fn uncle_extra_info(&self, _id: UncleID) -> Option<BTreeMap<String, String>> {
+		None
+	}
+
 	fn transaction_receipt(&self, id: TransactionID) -> Option<LocalizedReceipt> {
 		self.receipts.read().get(&id).cloned()
 	}
@@ -459,6 +464,13 @@ impl BlockChainClient for TestBlockChainClient {
 		self.block_hash(id).and_then(|hash| self.blocks.read().get(&hash).cloned())
 	}
 
+	fn block_extra_info(&self, id: BlockID) -> Option<BTreeMap<String, String>> {
+		self.block(id)
+			.map(|block| BlockView::new(&block).header())
+			.map(|header| self.spec.engine.extra_info(&header))
+	}
+
+
 	fn block_status(&self, id: BlockID) -> BlockStatus {
 		match id {
 			BlockID::Number(number) if (number as usize) < self.blocks.read().len() => BlockStatus::InChain,

ethcore/src/client/traits.rs

@@ -29,13 +29,13 @@ use error::{ImportResult, CallError};
 use receipt::LocalizedReceipt;
 use trace::LocalizedTrace;
 use evm::{Factory as EvmFactory, Schedule};
-use types::ids::*;
-use types::trace_filter::Filter as TraceFilter;
 use executive::Executed;
 use env_info::LastHashes;
-use types::call_analytics::CallAnalytics;
 use block_import_error::BlockImportError;
 use ipc::IpcConfig;
+use types::ids::*;
+use types::trace_filter::Filter as TraceFilter;
+use types::call_analytics::CallAnalytics;
 use types::blockchain_info::BlockChainInfo;
 use types::block_status::BlockStatus;
 use types::mode::Mode;
@@ -235,6 +235,12 @@ pub trait BlockChainClient : Sync + Send {
 
 	/// Set the mode.
 	fn set_mode(&self, mode: Mode);
+
+	/// Returns engine-related extra info for `BlockID`.
+	fn block_extra_info(&self, id: BlockID) -> Option<BTreeMap<String, String>>;
+
+	/// Returns engine-related extra info for `UncleID`.
+	fn uncle_extra_info(&self, id: UncleID) -> Option<BTreeMap<String, String>>;
 }
 
 /// Extended client interface used for mining