From 99483e85b92e07078291442bf1cd4c0db22a262d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A9ter=20Szil=C3=A1gyi?= <peterke@gmail.com>
Date: Mon, 11 Jun 2018 13:15:59 +0300
Subject: [PATCH] rpc: support returning nil pointer big.Ints (null)

---
 internal/ethapi/api.go | 14 +++++++-------
 rpc/json.go            |  8 --------
 rpc/server.go          |  1 -
 rpc/utils.go           | 15 ---------------
 4 files changed, 7 insertions(+), 31 deletions(-)

diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index 7a736bb76d..f95388d658 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -62,8 +62,9 @@ func NewPublicEthereumAPI(b Backend) *PublicEthereumAPI {
 }
 
 // GasPrice returns a suggestion for a gas price.
-func (s *PublicEthereumAPI) GasPrice(ctx context.Context) (*big.Int, error) {
-	return s.b.SuggestPrice(ctx)
+func (s *PublicEthereumAPI) GasPrice(ctx context.Context) (*hexutil.Big, error) {
+	price, err := s.b.SuggestPrice(ctx)
+	return (*hexutil.Big)(price), err
 }
 
 // ProtocolVersion returns the current Ethereum protocol version this node supports
@@ -487,21 +488,20 @@ func NewPublicBlockChainAPI(b Backend) *PublicBlockChainAPI {
 }
 
 // BlockNumber returns the block number of the chain head.
-func (s *PublicBlockChainAPI) BlockNumber() *big.Int {
+func (s *PublicBlockChainAPI) BlockNumber() hexutil.Uint64 {
 	header, _ := s.b.HeaderByNumber(context.Background(), rpc.LatestBlockNumber) // latest header should always be available
-	return header.Number
+	return hexutil.Uint64(header.Number.Uint64())
 }
 
 // GetBalance returns the amount of wei for the given address in the state of the
 // given block number. The rpc.LatestBlockNumber and rpc.PendingBlockNumber meta
 // block numbers are also allowed.
-func (s *PublicBlockChainAPI) GetBalance(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (*big.Int, error) {
+func (s *PublicBlockChainAPI) GetBalance(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (*hexutil.Big, error) {
 	state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
 	if state == nil || err != nil {
 		return nil, err
 	}
-	b := state.GetBalance(address)
-	return b, state.Error()
+	return (*hexutil.Big)(state.GetBalance(address)), state.Error()
 }
 
 // GetBlockByNumber returns the requested block. When blockNr is -1 the chain head is returned. When fullTx is true all
diff --git a/rpc/json.go b/rpc/json.go
index 837011f51b..a523eeb8ef 100644
--- a/rpc/json.go
+++ b/rpc/json.go
@@ -320,9 +320,6 @@ func parsePositionalArguments(rawArgs json.RawMessage, types []reflect.Type) ([]
 
 // CreateResponse will create a JSON-RPC success response with the given id and reply as result.
 func (c *jsonCodec) CreateResponse(id interface{}, reply interface{}) interface{} {
-	if isHexNum(reflect.TypeOf(reply)) {
-		return &jsonSuccessResponse{Version: jsonrpcVersion, Id: id, Result: fmt.Sprintf(`%#x`, reply)}
-	}
 	return &jsonSuccessResponse{Version: jsonrpcVersion, Id: id, Result: reply}
 }
 
@@ -340,11 +337,6 @@ func (c *jsonCodec) CreateErrorResponseWithInfo(id interface{}, err Error, info
 
 // CreateNotification will create a JSON-RPC notification with the given subscription id and event as params.
 func (c *jsonCodec) CreateNotification(subid, namespace string, event interface{}) interface{} {
-	if isHexNum(reflect.TypeOf(event)) {
-		return &jsonNotification{Version: jsonrpcVersion, Method: namespace + notificationMethodSuffix,
-			Params: jsonSubscription{Subscription: subid, Result: fmt.Sprintf(`%#x`, event)}}
-	}
-
 	return &jsonNotification{Version: jsonrpcVersion, Method: namespace + notificationMethodSuffix,
 		Params: jsonSubscription{Subscription: subid, Result: event}}
 }
diff --git a/rpc/server.go b/rpc/server.go
index 2b7393dd20..8925419fe0 100644
--- a/rpc/server.go
+++ b/rpc/server.go
@@ -313,7 +313,6 @@ func (s *Server) handle(ctx context.Context, codec ServerCodec, req *serverReque
 	if len(reply) == 0 {
 		return codec.CreateResponse(req.id, nil), nil
 	}
-
 	if req.callb.errPos >= 0 { // test if method returned an error
 		if !reply[req.callb.errPos].IsNil() {
 			e := reply[req.callb.errPos].Interface().(error)
diff --git a/rpc/utils.go b/rpc/utils.go
index 9315cab591..7f7ac4520b 100644
--- a/rpc/utils.go
+++ b/rpc/utils.go
@@ -22,7 +22,6 @@ import (
 	crand "crypto/rand"
 	"encoding/binary"
 	"encoding/hex"
-	"math/big"
 	"math/rand"
 	"reflect"
 	"strings"
@@ -105,20 +104,6 @@ func formatName(name string) string {
 	return string(ret)
 }
 
-var bigIntType = reflect.TypeOf((*big.Int)(nil)).Elem()
-
-// Indication if this type should be serialized in hex
-func isHexNum(t reflect.Type) bool {
-	if t == nil {
-		return false
-	}
-	for t.Kind() == reflect.Ptr {
-		t = t.Elem()
-	}
-
-	return t == bigIntType
-}
-
 // suitableCallbacks iterates over the methods of the given type. It will determine if a method satisfies the criteria
 // for a RPC callback or a subscription callback and adds it to the collection of callbacks or subscriptions. See server
 // documentation for a summary of these criteria.