Implement PIP messages, request builder, and handlers (#4945)

* return errors on database corruption

* fix tests, json tests

* fix remainder of build

* buffer flow -> request credits

* proving state backend

* generate transaction proofs from provider

* network messages for transaction proof

* transaction proof test

* test for transaction proof message

* fix call bug

* request transaction proofs from on_demand

* most of proved_execution rpc

* proved execution future

* initial request definitions

* RLP encoding and decoding for requests

* proofs of non-existance in ProvingBlockChainClient

* new requests in provider.

* encode and decode responses

* complete initial request changes

* handle request packet in LightProtocol

* handle response packets

* implement requesting from

* re-do cost table

* get tests compiling

* fix cost table RLP encoding

* roundtrip tests for request types

* request builder tests

* move request_builder -> request::builder

* get network tests working

* return only complete headers responses

* request builder improvements

* New version of jsonrpc.

* split request filling into fill,complete

* Better invalid encoding messages

* Fixing deprecated methods of tokio_core

* use PIP messages in on_demand, old API

* migrate oneshot::complete to send in on_demand

* get on_demand tests to compile

* port ethsync to PIP messages

* adjust to minor on_demand API changes in RPC

* Using dedicated branch for jsonrpc

* Bump

sync/src/light_sync/response.rs

@@ -18,10 +18,11 @@
 
 use std::fmt;
 
+use ethcore::encoded;
 use ethcore::header::Header;
-use light::request::{HashOrNumber, Headers as HeadersRequest};
-use rlp::{DecoderError, UntrustedRlp};
-use util::{Bytes, H256};
+use light::request::{HashOrNumber, CompleteHeadersRequest as HeadersRequest};
+use rlp::DecoderError;
+use util::H256;
 
 /// Errors found when decoding headers and verifying with basic constraints.
 #[derive(Debug, PartialEq)]
@@ -71,13 +72,13 @@ pub trait Constraint {
 	fn verify(&self, headers: &[Header], reverse: bool) -> Result<(), Self::Error>;
 }
 
-/// Decode a response and do basic verification against a request.
-pub fn decode_and_verify(headers: &[Bytes], request: &HeadersRequest) -> Result<Vec<Header>, BasicError> {
-	let headers: Vec<_> = try!(headers.iter().map(|x| UntrustedRlp::new(&x).as_val()).collect());
+/// Do basic verification of provided headers against a request.
+pub fn verify(headers: &[encoded::Header], request: &HeadersRequest) -> Result<Vec<Header>, BasicError> {
+	let headers: Vec<_> = headers.iter().map(|h| h.decode()).collect();
 
 	let reverse = request.reverse;
 
-	try!(Max(request.max).verify(&headers, reverse));
+	try!(Max(request.max as usize).verify(&headers, reverse));
 	match request.start {
 		HashOrNumber::Number(ref num) => try!(StartsAtNumber(*num).verify(&headers, reverse)),
 		HashOrNumber::Hash(ref hash) => try!(StartsAtHash(*hash).verify(&headers, reverse)),
@@ -150,8 +151,9 @@ impl Constraint for Max {
 
 #[cfg(test)]
 mod tests {
+	use ethcore::encoded;
 	use ethcore::header::Header;
-	use light::request::Headers as HeadersRequest;
+	use light::request::CompleteHeadersRequest as HeadersRequest;
 
 	use super::*;
 
@@ -175,10 +177,10 @@ mod tests {
 
 			parent_hash = Some(header.hash());
 
-			::rlp::encode(&header).to_vec()
+			encoded::Header::new(::rlp::encode(&header).to_vec())
 		}).collect();
 
-		assert!(decode_and_verify(&headers, &request).is_ok());
+		assert!(verify(&headers, &request).is_ok());
 	}
 
 	#[test]
@@ -201,10 +203,10 @@ mod tests {
 
 			parent_hash = Some(header.hash());
 
-			::rlp::encode(&header).to_vec()
+			encoded::Header::new(::rlp::encode(&header).to_vec())
 		}).collect();
 
-		assert!(decode_and_verify(&headers, &request).is_ok());
+		assert!(verify(&headers, &request).is_ok());
 	}
 
 	#[test]
@@ -227,10 +229,10 @@ mod tests {
 
 			parent_hash = Some(header.hash());
 
-			::rlp::encode(&header).to_vec()
+			encoded::Header::new(::rlp::encode(&header).to_vec())
 		}).collect();
 
-		assert_eq!(decode_and_verify(&headers, &request), Err(BasicError::TooManyHeaders(20, 25)));
+		assert_eq!(verify(&headers, &request), Err(BasicError::TooManyHeaders(20, 25)));
 	}
 
 	#[test]
@@ -246,9 +248,9 @@ mod tests {
 			let mut header = Header::default();
 			header.set_number(x);
 
-			::rlp::encode(&header).to_vec()
+			encoded::Header::new(::rlp::encode(&header).to_vec())
 		}).collect();
 
-		assert_eq!(decode_and_verify(&headers, &request), Err(BasicError::WrongSkip(5, Some(2))));
+		assert_eq!(verify(&headers, &request), Err(BasicError::WrongSkip(5, Some(2))));
 	}
 }