/
boltpersistentstate.go
239 lines (215 loc) · 5.34 KB
/
boltpersistentstate.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
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
package chezmoi
import (
"errors"
"fmt"
"io/fs"
"os"
"slices"
"syscall"
"time"
"go.etcd.io/bbolt"
)
// A BoltPersistentStateMode is a mode for opening a PersistentState.
type BoltPersistentStateMode int
// Persistent state modes.
const (
BoltPersistentStateReadOnly BoltPersistentStateMode = iota
BoltPersistentStateReadWrite
)
// A BoltPersistentState is a state persisted with bolt.
type BoltPersistentState struct {
system System
empty bool
path AbsPath
options bbolt.Options
db *bbolt.DB
}
// NewBoltPersistentState returns a new BoltPersistentState.
func NewBoltPersistentState(system System, path AbsPath, mode BoltPersistentStateMode) (*BoltPersistentState, error) {
empty := false
switch _, err := system.Stat(path); {
case errors.Is(err, fs.ErrNotExist):
// We need to simulate an empty persistent state because Bolt's
// read-only mode is only supported for databases that already exist.
//
// If the database does not already exist, then Bolt will open it with
// O_RDONLY and then attempt to initialize it, which leads to EBADF
// errors on Linux. See also https://github.com/etcd-io/bbolt/issues/98.
empty = true
case err != nil:
return nil, err
}
options := bbolt.Options{
OpenFile: func(name string, flag int, perm fs.FileMode) (*os.File, error) {
rawPath, err := system.RawPath(NewAbsPath(name))
if err != nil {
return nil, err
}
return os.OpenFile(rawPath.String(), flag, perm)
},
ReadOnly: mode == BoltPersistentStateReadOnly,
Timeout: time.Second,
}
return &BoltPersistentState{
system: system,
empty: empty,
path: path,
options: options,
}, nil
}
// Close closes b.
func (b *BoltPersistentState) Close() error {
if b.db != nil {
if err := b.db.Close(); err != nil {
return err
}
b.db = nil
}
return nil
}
// CopyTo copies b to p.
func (b *BoltPersistentState) CopyTo(p PersistentState) error {
if b.empty {
return nil
}
if err := b.open(); err != nil {
return err
}
return b.db.View(func(tx *bbolt.Tx) error {
return tx.ForEach(func(bucket []byte, b *bbolt.Bucket) error {
return b.ForEach(func(key, value []byte) error {
return p.Set(slices.Clone(bucket), slices.Clone(key), slices.Clone(value))
})
})
})
}
// Delete deletes the value associate with key in bucket. If bucket or key does
// not exist then Delete does nothing.
func (b *BoltPersistentState) Delete(bucket, key []byte) error {
if b.empty {
return nil
}
if err := b.open(); err != nil {
return err
}
return b.db.Update(func(tx *bbolt.Tx) error {
b := tx.Bucket(bucket)
if b == nil {
return nil
}
return b.Delete(key)
})
}
// DeleteBucket deletes the bucket.
func (b *BoltPersistentState) DeleteBucket(bucket []byte) error {
if b.empty {
return nil
}
if err := b.open(); err != nil {
return err
}
return b.db.Update(func(tx *bbolt.Tx) error {
return tx.DeleteBucket(bucket)
})
}
// Data returns all the data in b.
func (b *BoltPersistentState) Data() (any, error) {
if b.empty {
return nil, nil
}
if err := b.open(); err != nil {
return nil, err
}
data := make(map[string]map[string]string)
err := b.db.View(func(tx *bbolt.Tx) error {
return tx.ForEach(func(name []byte, b *bbolt.Bucket) error {
bucketName := string(name)
bucket, ok := data[bucketName]
if !ok {
bucket = make(map[string]string)
data[bucketName] = bucket
}
return b.ForEach(func(k, v []byte) error {
bucket[string(k)] = string(v)
return nil
})
})
})
if err != nil {
return nil, err
}
return data, nil
}
// ForEach calls fn for each key, value pair in bucket.
func (b *BoltPersistentState) ForEach(bucket []byte, fn func(k, v []byte) error) error {
if b.empty {
return nil
}
if err := b.open(); err != nil {
return err
}
return b.db.View(func(tx *bbolt.Tx) error {
b := tx.Bucket(bucket)
if b == nil {
return nil
}
return b.ForEach(func(k, v []byte) error {
return fn(slices.Clone(k), slices.Clone(v))
})
})
}
// Get returns the value associated with key in bucket.
func (b *BoltPersistentState) Get(bucket, key []byte) ([]byte, error) {
if b.empty {
return nil, nil
}
if err := b.open(); err != nil {
return nil, err
}
var value []byte
if err := b.db.View(func(tx *bbolt.Tx) error {
b := tx.Bucket(bucket)
if b == nil {
return nil
}
value = slices.Clone(b.Get(key))
return nil
}); err != nil {
return nil, err
}
return value, nil
}
// Set sets the value associated with key in bucket. bucket will be created if
// it does not already exist.
func (b *BoltPersistentState) Set(bucket, key, value []byte) error {
if err := b.open(); err != nil {
return err
}
return b.db.Update(func(tx *bbolt.Tx) error {
b, err := tx.CreateBucketIfNotExists(bucket)
if err != nil {
return err
}
return b.Put(key, value)
})
}
// open opens b's database if it is not already open, creating it if needed.
func (b *BoltPersistentState) open() error {
if b.db != nil {
return nil
}
if err := MkdirAll(b.system, b.path.Dir(), fs.ModePerm); err != nil {
return err
}
switch db, err := bbolt.Open(b.path.String(), 0o600, &b.options); {
case errors.Is(err, syscall.EINVAL):
// Assume that any EINVAL error is because flock(2) failed.
return fmt.Errorf("open %s: failed to acquire lock: %w", b.path, err)
case err != nil:
return fmt.Errorf("open %s: %w", b.path, err)
default:
b.empty = false
b.db = db
return nil
}
}