Add agreement.Signal

1 files changed, 86 insertions, 0 deletions

diff --git a/core/agreement/signal.go b/core/agreement/signal.go
new file mode 100644
index 0000000..5fc96e8
--- /dev/null
+++ b/core/agreement/signal.go
@@ -0,0 +1,86 @@
+// Copyright 2018 The dexon-consensus Authors
+// This file is part of the dexon-consensus library.
+//
+// The dexon-consensus library is free software: you can redistribute it
+// and/or modify it under the terms of the GNU Lesser General Public License as
+// published by the Free Software Foundation, either version 3 of the License,
+// or (at your option) any later version.
+//
+// The dexon-consensus library is distributed in the hope that it will be
+// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+// General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the dexon-consensus library. If not, see
+// <http://www.gnu.org/licenses/>.
+
+package agreement
+
+import (
+	"fmt"
+
+	"github.com/dexon-foundation/dexon-consensus/core/types"
+	"github.com/ethereum/go-ethereum/common"
+)
+
+// SignalType is the type of agreemnt signal.
+type SignalType byte
+
+const (
+	// SignalInvalid is just a type guard, not intend to be used.
+	SignalInvalid SignalType = iota
+	// SignalLock is triggered when receiving more than 2t+1 pre-commit votes
+	// for one value.
+	SignalLock
+	// SignalForward is triggered when receiving more than 2t+1 commit votes for
+	// different values.
+	SignalForward
+	// SignalDecide is triggered when receiving more than 2t+1 commit
+	// votes for one value.
+	SignalDecide
+	// SignalFork is triggered when detecting a fork vote.
+	SignalFork
+)
+
+func (t SignalType) String() string {
+	switch t {
+	case SignalLock:
+		return "Lock"
+	case SignalForward:
+		return "Forward"
+	case SignalDecide:
+		return "Decide"
+	case SignalFork:
+		return "Fork"
+	}
+	panic(fmt.Errorf("attempting to dump unknown agreement signal type: %d", t))
+}
+
+// Signal represents an agreement signal, ex. fast forward, decide,
+// fork, ..., which would trigger state change of agreement module.
+type Signal struct {
+	Position  types.Position
+	Period    uint64
+	Votes     []types.Vote
+	Type      SignalType
+	VType     types.VoteType
+	BlockHash common.Hash
+}
+
+func (s *Signal) String() string {
+	return fmt.Sprintf(
+		"AgreementSignal{Type:%s,vType:%s,Pos:%s,Period:%d,Hash:%s",
+		s.Type, s.VType, &s.Position, s.Period, s.BlockHash.String()[:6])
+}
+
+// NewSignal constructs an Signal instance.
+func NewSignal(t SignalType, votes []types.Vote) *Signal {
+	return &Signal{
+		Position: votes[0].Position,
+		Period:   votes[0].Period,
+		Type:     t,
+		VType:    votes[0].Type,
+		Votes:    votes,
+	}
+}