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

rpc/src/v1/helpers/errors.rs

@@ -20,6 +20,7 @@ use std::fmt;
 
 use ethcore::account_provider::{SignError as AccountError};
 use ethcore::error::{Error as EthcoreError, ErrorKind, CallError};
+use ethcore::client::BlockId;
 use jsonrpc_core::{futures, Error, ErrorCode, Value};
 use rlp::DecoderError;
 use transaction::Error as TransactionError;
@@ -422,6 +423,19 @@ pub fn filter_not_found() -> Error {
 	}
 }
 
+pub fn filter_block_not_found(id: BlockId) -> Error {
+	Error {
+		code: ErrorCode::ServerError(codes::UNSUPPORTED_REQUEST), // Specified in EIP-234.
+		message: "One of the blocks specified in filter (fromBlock, toBlock or blockHash) cannot be found".into(),
+		data: Some(Value::String(match id {
+			BlockId::Hash(hash) => format!("0x{:x}", hash),
+			BlockId::Number(number) => format!("0x{:x}", number),
+			BlockId::Earliest => "earliest".to_string(),
+			BlockId::Latest => "latest".to_string(),
+		})),
+	}
+}
+
 // on-demand sender cancelled.
 pub fn on_demand_cancel(_cancel: futures::sync::oneshot::Canceled) -> Error {
 	internal("on-demand sender cancelled", "")