core: transition db now also returns the required gas amount

Exposes some core methods to transition and compute new state
information and adds an additional return value to the transition db
method to fetch required gas for that particular message (excluding gas
refunds from any SSTORE[X] = 0 and SUICIDE.

Fixes #2395

1 files changed, 3 insertions, 3 deletions

diff --git a/eth/api.go b/eth/api.go
index 06c10daa9..af03c096d 100644
--- a/eth/api.go
+++ b/eth/api.go
@@ -674,11 +674,11 @@ func (s *PublicBlockChainAPI) doCall(args CallArgs, blockNr rpc.BlockNumber) (st
 	vmenv := core.NewEnv(stateDb, s.config, s.bc, msg, block.Header(), s.config.VmConfig)
 	gp := new(core.GasPool).AddGas(common.MaxBig)
 
-	res, gas, err := core.ApplyMessage(vmenv, msg, gp)
+	res, requiredGas, _, err := core.NewStateTransition(vmenv, msg, gp).TransitionDb()
 	if len(res) == 0 { // backwards compatibility
-		return "0x", gas, err
+		return "0x", requiredGas, err
 	}
-	return common.ToHex(res), gas, err
+	return common.ToHex(res), requiredGas, err
 }
 
 // Call executes the given transaction on the state for the given block number.