1 files changed, 170 insertions, 0 deletions
diff --git a/vendor/github.com/dexon-foundation/dexon-consensus/core/agreement-state.go b/vendor/github.com/dexon-foundation/dexon-consensus/core/agreement-state.go
new file mode 100644
index 000000000..77569d549
--- /dev/null
+++ b/vendor/github.com/dexon-foundation/dexon-consensus/core/agreement-state.go
@@ -0,0 +1,170 @@
+// 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 core
+
+import (
+	"fmt"
+
+	"github.com/dexon-foundation/dexon-consensus/common"
+	"github.com/dexon-foundation/dexon-consensus/core/types"
+)
+
+// Errors for agreement state module.
+var (
+	ErrNoEnoughVoteInPrepareState = fmt.Errorf("no enough vote in prepare state")
+	ErrNoEnoughVoteInAckState     = fmt.Errorf("no enough vote in ack state")
+)
+
+// agreementStateType is the state of agreement
+type agreementStateType int
+
+// agreementStateType enum.
+const (
+	stateInitial agreementStateType = iota
+	statePreCommit
+	stateCommit
+	stateForward
+	statePullVote
+)
+
+var nullBlockHash = common.Hash{}
+var skipBlockHash common.Hash
+
+func init() {
+	for idx := range skipBlockHash {
+		skipBlockHash[idx] = 0xff
+	}
+}
+
+type agreementState interface {
+	state() agreementStateType
+	nextState() (agreementState, error)
+	clocks() int
+}
+
+//----- InitialState -----
+type initialState struct {
+	a *agreementData
+}
+
+func newInitialState(a *agreementData) *initialState {
+	return &initialState{a: a}
+}
+
+func (s *initialState) state() agreementStateType { return stateInitial }
+func (s *initialState) clocks() int               { return 0 }
+func (s *initialState) nextState() (agreementState, error) {
+	hash := s.a.recv.ProposeBlock()
+	s.a.lock.Lock()
+	defer s.a.lock.Unlock()
+	s.a.recv.ProposeVote(&types.Vote{
+		Type:      types.VoteInit,
+		BlockHash: hash,
+		Period:    s.a.period,
+	})
+	return newPreCommitState(s.a), nil
+}
+
+//----- PreCommitState -----
+type preCommitState struct {
+	a *agreementData
+}
+
+func newPreCommitState(a *agreementData) *preCommitState {
+	return &preCommitState{a: a}
+}
+
+func (s *preCommitState) state() agreementStateType { return statePreCommit }
+func (s *preCommitState) clocks() int               { return 2 }
+func (s *preCommitState) nextState() (agreementState, error) {
+	s.a.lock.RLock()
+	defer s.a.lock.RUnlock()
+	hash := s.a.lockValue
+	if hash == nullBlockHash {
+		hash = s.a.leader.leaderBlockHash()
+	}
+	s.a.recv.ProposeVote(&types.Vote{
+		Type:      types.VotePreCom,
+		BlockHash: hash,
+		Period:    s.a.period,
+	})
+	return newCommitState(s.a), nil
+}
+
+//----- CommitState -----
+type commitState struct {
+	a *agreementData
+}
+
+func newCommitState(a *agreementData) *commitState {
+	return &commitState{a: a}
+}
+
+func (s *commitState) state() agreementStateType { return stateCommit }
+func (s *commitState) clocks() int               { return 2 }
+func (s *commitState) nextState() (agreementState, error) {
+	hash, ok := s.a.countVote(s.a.period, types.VotePreCom)
+	s.a.lock.Lock()
+	defer s.a.lock.Unlock()
+	if ok && hash != skipBlockHash {
+		s.a.lockValue = hash
+		s.a.lockRound = s.a.period
+	} else {
+		hash = skipBlockHash
+	}
+	s.a.recv.ProposeVote(&types.Vote{
+		Type:      types.VoteCom,
+		BlockHash: hash,
+		Period:    s.a.period,
+	})
+	return newForwardState(s.a), nil
+}
+
+// ----- ForwardState -----
+type forwardState struct {
+	a *agreementData
+}
+
+func newForwardState(a *agreementData) *forwardState {
+	return &forwardState{a: a}
+}
+
+func (s *forwardState) state() agreementStateType { return stateForward }
+func (s *forwardState) clocks() int               { return 4 }
+
+func (s *forwardState) nextState() (agreementState, error) {
+	return newPullVoteState(s.a), nil
+}
+
+// ----- PullVoteState -----
+// pullVoteState is a special state to ensure the assumption in the consensus
+// algorithm that every vote will eventually arrive for all nodes.
+type pullVoteState struct {
+	a *agreementData
+}
+
+func newPullVoteState(a *agreementData) *pullVoteState {
+	return &pullVoteState{a: a}
+}
+
+func (s *pullVoteState) state() agreementStateType { return statePullVote }
+func (s *pullVoteState) clocks() int               { return 4 }
+
+func (s *pullVoteState) nextState() (agreementState, error) {
+	return s, nil
+}