-
Notifications
You must be signed in to change notification settings - Fork 2
/
storage.go
165 lines (145 loc) · 3.01 KB
/
storage.go
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
package storage
import (
"fmt"
"strings"
)
// suppose Visible()==true
func compareNode(a *DBRecord, b *DBRecord, machineID string) int {
if a == nil && b == nil {
return 0
}
if a == nil {
return -1
}
if b == nil {
return 1
}
if a.Changes(machineID) > b.Changes(machineID) {
return 1
} else if a.Changes(machineID) < b.Changes(machineID) {
return -1
}
if a.Seq > b.Seq {
return 1
} else if a.Seq < b.Seq {
return -1
}
if a.MachineID > b.MachineID {
return 1
} else if a.MachineID < b.MachineID {
return -1
} else {
// should not be
return 0
}
}
func findMain(a []*DBRecord, machineID string) *DBRecord {
var maxRecord *DBRecord
for _, record := range a {
if compareNode(record, maxRecord, machineID) > 0 {
maxRecord = record
}
}
return maxRecord
}
type ValueVersion struct {
key string
value string
machineID string
gid string
seq int
}
func (v *ValueVersion) String() string {
return fmt.Sprintf("%v\t%v\t%v\t%v", v.key, v.value, v.machineID, v.seq)
}
type Value struct {
versions []*ValueVersion
}
func (v *Value) setMain(key string, value string) {
main := ValueVersion{key: key, value: value, seq: 0}
if len(v.versions) > 0 {
v.versions[0] = &main
} else {
v.versions = append(v.versions, &main)
}
}
func (v *Value) from(leaves []*DBRecord, machineID string) error {
main := findMain(leaves, machineID)
if main == nil {
return fmt.Errorf("cannot find main node")
}
v.versions = append(v.versions,
&ValueVersion{key: main.Key, value: main.Value,
gid: main.CurrentLogGid, machineID: main.MachineID,
seq: 0})
seq := 1
for _, e := range leaves {
if e == nil {
continue
}
if e.CurrentLogGid == main.CurrentLogGid {
continue
}
v.versions = append(v.versions,
&ValueVersion{key: e.Key, value: e.Value,
machineID: e.MachineID, gid: e.CurrentLogGid,
seq: seq})
seq++
}
return nil
}
func (v *Value) ValidSeq(seq int) bool {
return seq < len(v.versions)
}
func (v *Value) Versions() []*ValueVersion {
return v.versions
}
func (v *Value) Branches() []*ValueVersion {
return v.versions[1:]
}
func (v *Value) Main() *ValueVersion {
return v.versions[0]
}
func (v *Value) String() string {
sb := strings.Builder{}
sb.WriteString(v.Main().key)
sb.WriteString(": ")
sb.WriteString(v.Main().value)
nonEmpty := false
for _, b := range v.Branches() {
if b != nil {
nonEmpty = true
break
}
}
if nonEmpty {
sb.WriteString("(*)")
}
for _, b := range v.Branches() {
if b == nil {
continue
}
sb.WriteString(" ")
sb.WriteString(b.value)
}
return sb.String()
}
func valuesToArray(v []*Value) [][2]string {
results := [][2]string{}
for _, vv := range v {
if vv == nil {
continue
}
results = append(results, [2]string{vv.Main().key, vv.Main().value})
}
return results
}
// Storage ...
type Storage interface {
Save(key string, value string) error
Del(key string) error
Has(key string) (bool, error)
Load(key string) (val *Value, err error)
All() ([]*Value, error)
Accept(v *Value, seq int) error
}