1 files changed, 97 insertions, 0 deletions
diff --git a/core/vm/stateDB.go b/core/vm/stateDB.go
new file mode 100644
index 000000000..753b04247
--- /dev/null
+++ b/core/vm/stateDB.go
@@ -0,0 +1,97 @@
+package vm
+
+import (
+	"math/big"
+
+	"github.com/dexon-foundation/dexon/common"
+	"github.com/dexon-foundation/dexon/core/state"
+	"github.com/dexon-foundation/dexon/core/types"
+)
+
+type (
+	// CanTransferFunc is the signature of a transfer guard function
+	CanTransferFunc func(StateDB, common.Address, *big.Int) bool
+	// TransferFunc is the signature of a transfer function
+	TransferFunc func(StateDB, common.Address, common.Address, *big.Int)
+	// GetHashFunc returns the nth block hash in the blockchain
+	// and is used by the BLOCKHASH EVM op code.
+	GetHashFunc func(uint64) common.Hash
+	// StateAtFunc returns the statedb given a root hash.
+	StateAtNumberFunc func(uint64) (*state.StateDB, error)
+	// GetRoundHeightFunc returns the round height.
+	GetRoundHeightFunc func(uint64) (uint64, bool)
+)
+
+// Context provides the EVM with auxiliary information. Once provided
+// it shouldn't be modified.
+type Context struct {
+	// CanTransfer returns whether the account contains
+	// sufficient ether to transfer the value
+	CanTransfer CanTransferFunc
+	// Transfer transfers ether from one account to the other
+	Transfer TransferFunc
+	// GetHash returns the hash corresponding to n
+	GetHash GetHashFunc
+	// StateAtNumber returns the statedb given a root hash.
+	StateAtNumber StateAtNumberFunc
+	// GetRoundHeight returns the round height.
+	GetRoundHeight GetRoundHeightFunc
+
+	// Message information
+	Origin   common.Address // Provides information for ORIGIN
+	GasPrice *big.Int       // Provides information for GASPRICE
+
+	// Block information
+	Coinbase    common.Address // Provides information for COINBASE
+	GasLimit    uint64         // Provides information for GASLIMIT
+	BlockNumber *big.Int       // Provides information for NUMBER
+	Time        *big.Int       // Provides information for TIME
+	Randomness  []byte         // Provides information for RAND
+	Difficulty  *big.Int       // Provides information for DIFFICULTY
+	Round       *big.Int       // Current round number.
+
+	RandCallIndex uint64 // Number of times opRand is called
+}
+
+// StateDB is an EVM database for full state querying.
+type StateDB interface {
+	CreateAccount(common.Address)
+
+	SubBalance(common.Address, *big.Int)
+	AddBalance(common.Address, *big.Int)
+	GetBalance(common.Address) *big.Int
+
+	GetNonce(common.Address) uint64
+	SetNonce(common.Address, uint64)
+
+	GetCodeHash(common.Address) common.Hash
+	GetCode(common.Address) []byte
+	SetCode(common.Address, []byte)
+	GetCodeSize(common.Address) int
+
+	AddRefund(uint64)
+	SubRefund(uint64)
+	GetRefund() uint64
+
+	GetCommittedState(common.Address, common.Hash) common.Hash
+	GetState(common.Address, common.Hash) common.Hash
+	SetState(common.Address, common.Hash, common.Hash)
+
+	Suicide(common.Address) bool
+	HasSuicided(common.Address) bool
+
+	// Exist reports whether the given account exists in state.
+	// Notably this should also return true for suicided accounts.
+	Exist(common.Address) bool
+	// Empty returns whether the given account is empty. Empty
+	// is defined according to EIP161 (balance = nonce = code = 0).
+	Empty(common.Address) bool
+
+	RevertToSnapshot(int)
+	Snapshot() int
+
+	AddLog(*types.Log)
+	AddPreimage(common.Hash, []byte)
+
+	ForEachStorage(common.Address, func(common.Hash, common.Hash) bool)
+}