implement provider for client

ethcore/src/client/client.rs

@@ -68,6 +68,7 @@ use factory::Factories;
 use rlp::{decode, View, UntrustedRlp};
 use state_db::StateDB;
 use rand::OsRng;
+use light::{self, request};
 
 // re-export
 pub use types::blockchain_info::BlockChainInfo;
@@ -1317,32 +1318,155 @@ impl MayPanic for Client {
 	}
 }
 
+// Implementation of a light client data provider for a client.
+impl light::Provider for Client {
+	fn chain_info(&self) -> BlockChainInfo {
+		BlockChainClient::chain_info(self)
+	}
 
-#[test]
-fn should_not_cache_details_before_commit() {
-	use tests::helpers::*;
-	use std::thread;
-	use std::time::Duration;
-	use std::sync::atomic::{AtomicBool, Ordering};
+	fn reorg_depth(&self, a: &H256, b: &H256) -> Option<u64> {
+		self.tree_route(a, b).map(|route| route.index as u64)
+	}
 
-	let client = generate_dummy_client(0);
-	let genesis = client.chain_info().best_block_hash;
-	let (new_hash, new_block) = get_good_dummy_block_hash();
+	fn earliest_state(&self) -> Option<u64> {
+		Some(self.pruning_info().earliest_state)
+	}
 
-	let go = {
-		// Separate thread uncommited transaction
-		let go = Arc::new(AtomicBool::new(false));
-		let go_thread = go.clone();
-		let another_client = client.reference().clone();
-		thread::spawn(move || {
-			let mut batch = DBTransaction::new(&*another_client.chain.read().db().clone());
-			another_client.chain.read().insert_block(&mut batch, &new_block, Vec::new());
-			go_thread.store(true, Ordering::SeqCst);
-		});
-		go
-	};
+	fn block_headers(&self, req: request::Headers) -> Vec<Bytes> {
+		let best_num = self.chain.read().best_block_number();
+		let start_num = req.block_num;
 
-	while !go.load(Ordering::SeqCst) { thread::park_timeout(Duration::from_millis(5)); }
+		match self.block_hash(BlockID::Number(req.block_num)) {
+			Some(hash) if hash == req.block_hash => {}
+			_=> {
+				trace!(target: "les_provider", "unknown/non-canonical start block in header request: {:?}", (req.block_num, req.block_hash));
+				return vec![]
+			}
+		}
 
-	assert!(client.tree_route(&genesis, &new_hash).is_none());
+		(0u64..req.max as u64)
+			.map(|x: u64| x.saturating_mul(req.skip))
+			.take_while(|x| if req.reverse { x < &start_num } else { best_num - start_num < *x })
+			.map(|x| if req.reverse { start_num - x } else { start_num + x })
+			.map(|x| self.block_header(BlockID::Number(x)))
+			.flat_map(|x| x)
+			.fuse() // collect no more beyond the first `None`
+			.collect()
+	}
+
+	fn block_bodies(&self, req: request::Bodies) -> Vec<Bytes> {
+		use ids::BlockID;
+
+		req.block_hashes.into_iter()
+			.map(|hash| self.block_body(BlockID::Hash(hash)))
+			.map(|body| body.unwrap_or_else(|| ::rlp::EMPTY_LIST_RLP.to_vec()))
+			.collect()
+	}
+
+	fn receipts(&self, req: request::Receipts) -> Vec<Bytes> {
+		req.block_hashes.into_iter()
+			.map(|hash| self.block_receipts(&hash))
+			.map(|receipts| receipts.unwrap_or_else(|| ::rlp::EMPTY_LIST_RLP.to_vec()))
+			.collect()
+	}
+
+	fn proofs(&self, req: request::StateProofs) -> Vec<Bytes> {
+		use rlp::{EMPTY_LIST_RLP, RlpStream, Stream};
+
+		let mut results = Vec::with_capacity(req.requests.len());
+
+		for request in req.requests {
+			let state = match self.state_at(BlockID::Hash(request.block)) {
+				Some(state) => state,
+				None => {
+					trace!(target: "light_provider", "state for {} not available", request.block);
+					results.push(EMPTY_LIST_RLP.to_vec());
+					continue;
+				}
+			};
+
+			let res = match request.key2 {
+				Some(storage_key) => state.prove_storage(request.key1, storage_key, request.from_level),
+				None => state.prove_account(request.key1, request.from_level),
+			};
+
+			match res {
+				Ok(records) => {
+					let mut stream = RlpStream::new_list(records.len());
+					for record in records {
+						stream.append_raw(&record, 1);
+					}
+					results.push(stream.out())
+				}
+				Err(e) => {
+					debug!(target: "light_provider", "encountered error {} while forming proof of state at {}", e, request.block);
+					results.push(EMPTY_LIST_RLP.to_vec());
+				}
+			}
+		}
+
+		results
+	}
+
+	fn contract_code(&self, req: request::ContractCodes) -> Vec<Bytes> {
+		req.code_requests.into_iter()
+			.map(|req| {
+				self.state_at(BlockID::Hash(req.block_hash))
+					.map(|state| {
+						match state.code_by_address_hash(req.account_key) {
+							Ok(code) => code.unwrap_or_else(Vec::new),
+							Err(e) => {
+								debug!(target: "light_provider", "encountered error {} while fetching code.", e);
+								Vec::new()
+							}
+						}
+					}).unwrap_or_else(Vec::new)
+			})
+			.collect()
+	}
+
+	fn header_proofs(&self, req: request::HeaderProofs) -> Vec<Bytes> {
+		req.requests.into_iter().map(|_| ::rlp::EMPTY_LIST_RLP.to_vec()).collect()
+	}
+
+	fn pending_transactions(&self) -> Vec<SignedTransaction> {
+		BlockChainClient::pending_transactions(self)
+	}
 }
+
+#[cfg(test)]
+mod tests {
+
+	#[test]
+	fn should_not_cache_details_before_commit() {
+		use client::BlockChainClient;
+		use tests::helpers::*;
+
+		use std::thread;
+		use std::time::Duration;
+		use std::sync::Arc;
+		use std::sync::atomic::{AtomicBool, Ordering};
+		use util::kvdb::DBTransaction;
+
+		let client = generate_dummy_client(0);
+		let genesis = client.chain_info().best_block_hash;
+		let (new_hash, new_block) = get_good_dummy_block_hash();
+
+		let go = {
+			// Separate thread uncommited transaction
+			let go = Arc::new(AtomicBool::new(false));
+			let go_thread = go.clone();
+			let another_client = client.reference().clone();
+			thread::spawn(move || {
+				let mut batch = DBTransaction::new(&*another_client.chain.read().db().clone());
+				another_client.chain.read().insert_block(&mut batch, &new_block, Vec::new());
+				go_thread.store(true, Ordering::SeqCst);
+			});
+			go
+		};
+
+		while !go.load(Ordering::SeqCst) { thread::park_timeout(Duration::from_millis(5)); }
+
+		assert!(client.tree_route(&genesis, &new_hash).is_none());
+	}
+}