1 files changed, 92 insertions, 0 deletions
diff --git a/core/vm/utils.go b/core/vm/utils.go
new file mode 100644
index 000000000..0cc6343cc
--- /dev/null
+++ b/core/vm/utils.go
@@ -0,0 +1,92 @@
+package vm
+
+import (
+	"errors"
+	"math/big"
+
+	"github.com/tangerine-network/go-tangerine/common"
+	"github.com/tangerine-network/go-tangerine/core/state"
+	"github.com/tangerine-network/go-tangerine/crypto"
+	"github.com/tangerine-network/go-tangerine/log"
+	dexCore "github.com/tangerine-network/tangerine-consensus/core"
+)
+
+type GovUtilInterface interface {
+	GetHeadGovState() (*GovernanceState, error)
+	StateAt(height uint64) (*state.StateDB, error)
+}
+
+type GovUtil struct {
+	Intf GovUtilInterface
+}
+
+func (g GovUtil) GetRoundHeight(round uint64) uint64 {
+	gs, err := g.Intf.GetHeadGovState()
+	if err != nil {
+		return 0
+	}
+	return gs.RoundHeight(big.NewInt(int64(round))).Uint64()
+}
+
+func (g GovUtil) GetStateAtRound(round uint64) (*GovernanceState, error) {
+	height := g.GetRoundHeight(round)
+
+	if round != 0 && height == 0 {
+		log.Error("Governance state incorrect", "round", round, "got height", height)
+		return nil, errors.New("incorrect governance state")
+	}
+
+	s, err := g.Intf.StateAt(height)
+	if err != nil {
+		return nil, err
+	}
+	return &GovernanceState{StateDB: s}, nil
+}
+
+func (g GovUtil) GetConfigState(round uint64) (*GovernanceState, error) {
+	if round < dexCore.ConfigRoundShift {
+		round = 0
+	} else {
+		round -= dexCore.ConfigRoundShift
+	}
+	return g.GetStateAtRound(round)
+}
+
+func (g *GovUtil) CRSRound() uint64 {
+	gs, err := g.Intf.GetHeadGovState()
+	if err != nil {
+		return 0
+	}
+	return gs.CRSRound().Uint64()
+}
+
+func (g GovUtil) CRS(round uint64) common.Hash {
+	if round <= dexCore.DKGDelayRound {
+		s, err := g.GetStateAtRound(0)
+		if err != nil {
+			return common.Hash{}
+		}
+		crs := s.CRS()
+		for i := uint64(0); i < round; i++ {
+			crs = crypto.Keccak256Hash(crs[:])
+		}
+		return crs
+	}
+	if round > g.CRSRound() {
+		return common.Hash{}
+	}
+	var s *GovernanceState
+	var err error
+	if round == g.CRSRound() {
+		s, err = g.Intf.GetHeadGovState()
+		if err != nil {
+			return common.Hash{}
+		}
+	} else {
+		s, err = g.GetStateAtRound(round)
+		if err != nil {
+			return common.Hash{}
+		}
+	}
+	return s.CRS()
+}