xeth, rpc: implement eth_estimateGas. Closes #930

1 files changed, 4 insertions, 2 deletions

diff --git a/xeth/xeth.go b/xeth/xeth.go
index bf5844770..1ddd4c6e4 100644
--- a/xeth/xeth.go
+++ b/xeth/xeth.go
@@ -773,7 +773,7 @@ func (self *XEth) PushTx(encodedTx string) (string, error) {
 	return tx.Hash().Hex(), nil
 }
 
-func (self *XEth) Call(fromStr, toStr, valueStr, gasStr, gasPriceStr, dataStr string) (string, error) {
+func (self *XEth) Call(fromStr, toStr, valueStr, gasStr, gasPriceStr, dataStr string) (string, string, error) {
 	statedb := self.State().State() //self.eth.ChainManager().TransState()
 	var from *state.StateObject
 	if len(fromStr) == 0 {
@@ -807,8 +807,10 @@ func (self *XEth) Call(fromStr, toStr, valueStr, gasStr, gasPriceStr, dataStr st
 	block := self.CurrentBlock()
 	vmenv := core.NewEnv(statedb, self.backend.ChainManager(), msg, block)
 
+	initialGas := new(big.Int).Set(msg.gas)
 	res, err := vmenv.Call(msg.from, msg.to, msg.data, msg.gas, msg.gasPrice, msg.value)
-	return common.ToHex(res), err
+
+	return common.ToHex(res), initialGas.Sub(initialGas, msg.gas).String(), err
 }
 
 func (self *XEth) ConfirmTransaction(tx string) bool {