-
Notifications
You must be signed in to change notification settings - Fork 0
/
buckets.go
154 lines (124 loc) · 3.31 KB
/
buckets.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
package bclient
import (
"fmt"
"go.etcd.io/bbolt"
)
// Bucket holds the name of a bucket in a BoltDB database.
type Bucket struct {
Name string `json:"name,omitempty"`
Nested map[string]*Bucket `json:"children,omitempty"`
Parent *Bucket
}
// NewBucket returns a Bucket with the specified name.
func NewBucket(name string) *Bucket {
return &Bucket{
Name: name,
Nested: make(map[string]*Bucket),
}
}
func (b *Bucket) SetNestedBucket(c *Bucket) {
b.Nested[c.Name] = c
c.Parent = b
}
// write writes a bucket to the database.
func (b Bucket) write() *boltTxn {
return createIfNotExists(&b)
}
// validate validates whether a bucket exists or not.
func (b Bucket) exists() *boltTxn {
return exists(b.Name)
}
// delete deletes the bucket.
func (b Bucket) delete() *boltTxn {
var btxn boltTxn
btxn.txn = func(tx *bbolt.Tx) error {
if err := tx.DeleteBucket([]byte(b.Name)); err != nil {
return fmt.Errorf("error deleting bucket")
}
return nil
}
return &btxn
}
// read fetches all KV pairs in a bucket and returns the values in
// the return value of a boltTxn.
func (b Bucket) read() *boltTxn {
var kvs KVs
var btxn boltTxn
btxn.txn = func(tx *bbolt.Tx) error {
bucket := getBucket(tx, &b)
if bucket == nil {
return fmt.Errorf("bucket not found")
}
cursor := bucket.Cursor()
for k, v := cursor.First(); k != nil; k, v = cursor.Next() {
kv := &KV{
Key: string(k),
Value: string(v),
}
kvs = append(kvs, kv)
}
// since the function is returned and then run, the value needs to be set in the returnValue
// field of the boltTxn struct. This way the value(s) can be persisted after a db.View()
btxn.returnValue = kvs
return nil
}
return &btxn
}
// createifNotExists creates a new bucket in the database with the specified name
func createIfNotExists(b *Bucket) *boltTxn {
var btxn boltTxn
btxn.txn = func(tx *bbolt.Tx) error {
return createNestedBuckets(tx, b, nil)
}
return &btxn
}
func createNestedBuckets(tx *bbolt.Tx, bucket *Bucket, bbucket *bbolt.Bucket) error {
var nested *bbolt.Bucket
var err error
if bbucket == nil {
nested, err = tx.CreateBucketIfNotExists([]byte(bucket.Name))
} else {
nested, err = bbucket.CreateBucketIfNotExists([]byte(bucket.Name))
}
if err != nil {
return err
}
for _, v := range bucket.Nested {
if v.Nested != nil {
createNestedBuckets(tx, v, nested)
}
}
return nil
}
// exists returns false if the bucket does not exist
func exists(name string) *boltTxn {
var btxn boltTxn
btxn.returnValue = false
btxn.txn = func(tx *bbolt.Tx) error {
b := tx.Bucket([]byte(name))
if b != nil {
btxn.returnValue = true
}
return nil
}
return &btxn
}
// getBucket takes a bbolt Transaction and a bucket. It traverses up the links of buckets to find the top level parent. Then
// traverses down the buckets to get the actual bucket. This is needed since the nested buckets are called by chaining together
// instead of just calling the bucket name directly.
func getBucket(tx *bbolt.Tx, b *Bucket) *bbolt.Bucket {
buckets := []*Bucket{}
head := b
for head.Parent != nil {
buckets = append(buckets, head)
head = head.Parent
}
bucket := tx.Bucket([]byte(head.Name))
for i := len(buckets) - 1; i >= 0; i-- {
tmp := bucket.Bucket([]byte(buckets[i].Name))
if tmp != nil {
bucket = tmp
}
}
return bucket
}