Implement EIP234 block_hash for eth_getLogs (#9256)

* Implement EIP234

* Make filter conversion returns error if both blockHash and from/toBlock is found

This also changes PollFilter to store the EthFilter type, instead of the jsonrpc one, saving repeated conversion.

* Return error if block filtering target is not found in eth_getLogs

Use the old behavior (unwrap_or_default) for anywhere else.

* fix test: secret_store

* Fix weird indentation

* Make client log filter return error in case a block cannot be found

* Return blockId error in rpc

* test_client: allow return error on logs

* Add a mocked test for eth_getLogs error

* fix: should return error if from_block/to_block greater than best block number

* Add notes on pending

* Add comment for UNSUPPORTED_REQUEST

* Address grumbles

* Return err if from > to

ethcore/src/client/test_client.rs

@@ -94,6 +94,8 @@ pub struct TestBlockChainClient {
 	pub receipts: RwLock<HashMap<TransactionId, LocalizedReceipt>>,
 	/// Logs
 	pub logs: RwLock<Vec<LocalizedLogEntry>>,
+	/// Should return errors on logs.
+	pub error_on_logs: RwLock<Option<BlockId>>,
 	/// Block queue size.
 	pub queue_size: AtomicUsize,
 	/// Miner
@@ -178,6 +180,7 @@ impl TestBlockChainClient {
 			traces: RwLock::new(None),
 			history: RwLock::new(None),
 			disabled: AtomicBool::new(false),
+			error_on_logs: RwLock::new(None),
 		};
 
 		// insert genesis hash.
@@ -233,6 +236,11 @@ impl TestBlockChainClient {
 		*self.logs.write() = logs;
 	}
 
+	/// Set return errors on logs.
+	pub fn set_error_on_logs(&self, val: Option<BlockId>) {
+		*self.error_on_logs.write() = val;
+	}
+
 	/// Add blocks to test client.
 	pub fn add_blocks(&self, count: usize, with: EachBlockWith) {
 		let len = self.numbers.read().len();
@@ -665,13 +673,18 @@ impl BlockChainClient for TestBlockChainClient {
 		self.receipts.read().get(&id).cloned()
 	}
 
-	fn logs(&self, filter: Filter) -> Vec<LocalizedLogEntry> {
+	fn logs(&self, filter: Filter) -> Result<Vec<LocalizedLogEntry>, BlockId> {
+		match self.error_on_logs.read().as_ref() {
+			Some(id) => return Err(id.clone()),
+			None => (),
+		}
+
 		let mut logs = self.logs.read().clone();
 		let len = logs.len();
-		match filter.limit {
+		Ok(match filter.limit {
 			Some(limit) if limit <= len => logs.split_off(len - limit),
 			_ => logs,
-		}
+		})
 	}
 
 	fn last_hashes(&self) -> LastHashes {