1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
|
// 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
stateSleep
)
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.NewVote(types.VoteInit, hash, 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.NewVote(types.VotePreCom, hash, 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) {
s.a.lock.Lock()
defer s.a.lock.Unlock()
hash, ok := s.a.countVoteNoLock(s.a.period, types.VotePreCom)
if ok && hash != skipBlockHash {
s.a.lockValue = hash
s.a.lockRound = s.a.period
} else {
hash = skipBlockHash
}
s.a.recv.ProposeVote(types.NewVote(types.VoteCom, hash, 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
}
// ----- SleepState -----
// sleepState is a special state after BA has output and waits for restart.
type sleepState struct {
a *agreementData
}
func newSleepState(a *agreementData) *sleepState {
return &sleepState{a: a}
}
func (s *sleepState) state() agreementStateType { return stateSleep }
func (s *sleepState) clocks() int { return 65536 }
func (s *sleepState) nextState() (agreementState, error) {
return s, nil
}
|