core, core/vm: implemented a generic environment (#3348)

Environment is now a struct (not an interface). This
reduces a lot of tech-debt throughout the codebase where a virtual
machine environment had to be implemented in order to test or run it.

The new environment is suitable to be used en the json tests, core
consensus and light client.

1 files changed, 5 insertions, 8 deletions

diff --git a/core/vm/contract.go b/core/vm/contract.go
index 70455a4c2..dfa93ab18 100644
--- a/core/vm/contract.go
+++ b/core/vm/contract.go
@@ -24,7 +24,7 @@ import (
 
 // ContractRef is a reference to the contract's backing object
 type ContractRef interface {
-	ReturnGas(*big.Int, *big.Int)
+	ReturnGas(*big.Int)
 	Address() common.Address
 	Value() *big.Int
 	SetCode(common.Hash, []byte)
@@ -48,7 +48,7 @@ type Contract struct {
 	CodeAddr *common.Address
 	Input    []byte
 
-	value, Gas, UsedGas, Price *big.Int
+	value, Gas, UsedGas *big.Int
 
 	Args []byte
 
@@ -56,7 +56,7 @@ type Contract struct {
 }
 
 // NewContract returns a new contract environment for the execution of EVM.
-func NewContract(caller ContractRef, object ContractRef, value, gas, price *big.Int) *Contract {
+func NewContract(caller ContractRef, object ContractRef, value, gas *big.Int) *Contract {
 	c := &Contract{CallerAddress: caller.Address(), caller: caller, self: object, Args: nil}
 
 	if parent, ok := caller.(*Contract); ok {
@@ -70,9 +70,6 @@ func NewContract(caller ContractRef, object ContractRef, value, gas, price *big.
 	// This pointer will be off the state transition
 	c.Gas = gas //new(big.Int).Set(gas)
 	c.value = new(big.Int).Set(value)
-	// In most cases price and value are pointers to transaction objects
-	// and we don't want the transaction's values to change.
-	c.Price = new(big.Int).Set(price)
 	c.UsedGas = new(big.Int)
 
 	return c
@@ -114,7 +111,7 @@ func (c *Contract) Caller() common.Address {
 // caller.
 func (c *Contract) Finalise() {
 	// Return the remaining gas to the caller
-	c.caller.ReturnGas(c.Gas, c.Price)
+	c.caller.ReturnGas(c.Gas)
 }
 
 // UseGas attempts the use gas and subtracts it and returns true on success
@@ -127,7 +124,7 @@ func (c *Contract) UseGas(gas *big.Int) (ok bool) {
 }
 
 // ReturnGas adds the given gas back to itself.
-func (c *Contract) ReturnGas(gas, price *big.Int) {
+func (c *Contract) ReturnGas(gas *big.Int) {
 	// Return the gas to the context
 	c.Gas.Add(c.Gas, gas)
 	c.UsedGas.Sub(c.UsedGas, gas)