From 7f3e718851166eb75ff8c4f99d302f041844340e Mon Sep 17 00:00:00 2001
From: Robert Habermeier <rphmeier@gmail.com>
Date: Tue, 22 Aug 2017 21:02:40 +0800
Subject: [PATCH] EngineClient implementation for light client

---
 ethcore/light/src/client/mod.rs     | 51 ++++++++++++++++++++++++-----
 ethcore/light/src/client/service.rs |  3 ++
 2 files changed, 46 insertions(+), 8 deletions(-)

diff --git a/ethcore/light/src/client/mod.rs b/ethcore/light/src/client/mod.rs
index c13d6ba91..e880ef3ba 100644
--- a/ethcore/light/src/client/mod.rs
+++ b/ethcore/light/src/client/mod.rs
@@ -19,11 +19,11 @@
 use std::sync::{Weak, Arc};
 
 use ethcore::block_status::BlockStatus;
-use ethcore::client::{ClientReport, EnvInfo};
-use ethcore::engines::{epoch, Engine, EpochChange, Proof, Unsure};
-use ethcore::error::BlockImportError;
+use ethcore::client::{TransactionImportResult, ClientReport, EnvInfo};
+use ethcore::engines::{epoch, Engine, EpochChange, EpochTransition, Proof, Unsure};
+use ethcore::error::{TransactionError, BlockImportError, Error as EthcoreError};
 use ethcore::ids::BlockId;
-use ethcore::header::Header;
+use ethcore::header::{BlockNumber, Header};
 use ethcore::verification::queue::{self, HeaderQueue};
 use ethcore::blockchain_info::BlockChainInfo;
 use ethcore::spec::Spec;
@@ -33,7 +33,7 @@ use io::IoChannel;
 
 use futures::{IntoFuture, Future};
 
-use util::{H256, U256, Mutex, RwLock};
+use util::{Address, H256, U256, Mutex, RwLock};
 use util::kvdb::{KeyValueDB, CompactionProfile};
 
 use self::fetch::ChainDataFetcher;
@@ -131,7 +131,7 @@ pub trait LightChainClient: Send + Sync {
 	fn cht_root(&self, i: usize) -> Option<H256>;
 
 	/// Get the EIP-86 transition block number.
-	fn eip86_transition(&self) -> u64;
+	fn eip86_transition(&self) -> BlockNumber;
 
 	/// Get a report of import activity since the last call.
 	fn report(&self) -> ClientReport;
@@ -555,7 +555,7 @@ impl<T: ChainDataFetcher> LightChainClient for Client<T> {
 		Box::new(Client::ancestry_iter(self, start))
 	}
 
-	fn signing_network_id(&self) -> Option<u64> {
+	fn signing_network_id(&self) -> Option<BlockNumber> {
 		Client::signing_network_id(self)
 	}
 
@@ -587,7 +587,7 @@ impl<T: ChainDataFetcher> LightChainClient for Client<T> {
 		Client::cht_root(self, i)
 	}
 
-	fn eip86_transition(&self) -> u64 {
+	fn eip86_transition(&self) -> BlockNumber {
 		self.engine().params().eip86_transition
 	}
 
@@ -595,3 +595,38 @@ impl<T: ChainDataFetcher> LightChainClient for Client<T> {
 		Client::report(self)
 	}
 }
+
+impl<T: ChainDataFetcher> ::ethcore::client::EngineClient for Client<T> {
+	fn update_sealing(&self) { }
+	fn submit_seal(&self, _block_hash: H256, _seal: Vec<Vec<u8>>) { }
+	fn broadcast_consensus_message(&self, _message: Vec<u8>) { }
+
+	fn epoch_transition_for(&self, parent_hash: H256) -> Option<EpochTransition> {
+		self.chain.epoch_transition_for(parent_hash).map(|(hdr, proof)| EpochTransition {
+			block_hash: hdr.hash(),
+			block_number: hdr.number(),
+			proof: proof,
+		})
+	}
+
+	fn chain_info(&self) -> BlockChainInfo {
+		Client::chain_info(self)
+	}
+
+	fn call_contract(&self, _id: BlockId, _address: Address, _data: Vec<u8>) -> Result<Vec<u8>, String> {
+		Err("Contract calling not supported by light client".into())
+	}
+
+	fn transact_contract(&self, _address: Address, _data: Vec<u8>)
+		-> Result<TransactionImportResult, EthcoreError>
+	{
+		// TODO: these are only really used for misbehavior reporting.
+		// no relevant clients will be running light clients, but maybe
+		// they could be at some point?
+		Err(TransactionError::LimitReached.into())
+	}
+
+	fn block_number(&self, id: BlockId) -> Option<BlockNumber> {
+		self.block_header(id).map(|hdr| hdr.number())
+	}
+}
diff --git a/ethcore/light/src/client/service.rs b/ethcore/light/src/client/service.rs
index 59a5d28c6..458db85c8 100644
--- a/ethcore/light/src/client/service.rs
+++ b/ethcore/light/src/client/service.rs
@@ -85,7 +85,10 @@ impl<T: ChainDataFetcher> Service<T> {
 			io_service.channel(),
 			cache,
 		).map_err(Error::Database)?);
+
 		io_service.register_handler(Arc::new(ImportBlocks(client.clone()))).map_err(Error::Io)?;
+		spec.engine.register_client(Arc::downgrade(&client) as _);
+
 		Ok(Service {
 			client: client,
 			io_service: io_service,