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
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
|
// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
// All rights reserved.
//
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package leveldb
import (
"encoding/binary"
"fmt"
"github.com/syndtr/goleveldb/leveldb/errors"
"github.com/syndtr/goleveldb/leveldb/memdb"
"github.com/syndtr/goleveldb/leveldb/storage"
)
type ErrBatchCorrupted struct {
Reason string
}
func (e *ErrBatchCorrupted) Error() string {
return fmt.Sprintf("leveldb: batch corrupted: %s", e.Reason)
}
func newErrBatchCorrupted(reason string) error {
return errors.NewErrCorrupted(storage.FileDesc{}, &ErrBatchCorrupted{reason})
}
const (
batchHdrLen = 8 + 4
batchGrowRec = 3000
)
type BatchReplay interface {
Put(key, value []byte)
Delete(key []byte)
}
// Batch is a write batch.
type Batch struct {
data []byte
rLen, bLen int
seq uint64
sync bool
}
func (b *Batch) grow(n int) {
off := len(b.data)
if off == 0 {
off = batchHdrLen
if b.data != nil {
b.data = b.data[:off]
}
}
if cap(b.data)-off < n {
if b.data == nil {
b.data = make([]byte, off, off+n)
} else {
odata := b.data
div := 1
if b.rLen > batchGrowRec {
div = b.rLen / batchGrowRec
}
b.data = make([]byte, off, off+n+(off-batchHdrLen)/div)
copy(b.data, odata)
}
}
}
func (b *Batch) appendRec(kt kType, key, value []byte) {
n := 1 + binary.MaxVarintLen32 + len(key)
if kt == ktVal {
n += binary.MaxVarintLen32 + len(value)
}
b.grow(n)
off := len(b.data)
data := b.data[:off+n]
data[off] = byte(kt)
off += 1
off += binary.PutUvarint(data[off:], uint64(len(key)))
copy(data[off:], key)
off += len(key)
if kt == ktVal {
off += binary.PutUvarint(data[off:], uint64(len(value)))
copy(data[off:], value)
off += len(value)
}
b.data = data[:off]
b.rLen++
// Include 8-byte ikey header
b.bLen += len(key) + len(value) + 8
}
// Put appends 'put operation' of the given key/value pair to the batch.
// It is safe to modify the contents of the argument after Put returns.
func (b *Batch) Put(key, value []byte) {
b.appendRec(ktVal, key, value)
}
// Delete appends 'delete operation' of the given key to the batch.
// It is safe to modify the contents of the argument after Delete returns.
func (b *Batch) Delete(key []byte) {
b.appendRec(ktDel, key, nil)
}
// Dump dumps batch contents. The returned slice can be loaded into the
// batch using Load method.
// The returned slice is not its own copy, so the contents should not be
// modified.
func (b *Batch) Dump() []byte {
return b.encode()
}
// Load loads given slice into the batch. Previous contents of the batch
// will be discarded.
// The given slice will not be copied and will be used as batch buffer, so
// it is not safe to modify the contents of the slice.
func (b *Batch) Load(data []byte) error {
return b.decode(0, data)
}
// Replay replays batch contents.
func (b *Batch) Replay(r BatchReplay) error {
return b.decodeRec(func(i int, kt kType, key, value []byte) error {
switch kt {
case ktVal:
r.Put(key, value)
case ktDel:
r.Delete(key)
}
return nil
})
}
// Len returns number of records in the batch.
func (b *Batch) Len() int {
return b.rLen
}
// Reset resets the batch.
func (b *Batch) Reset() {
b.data = b.data[:0]
b.seq = 0
b.rLen = 0
b.bLen = 0
b.sync = false
}
func (b *Batch) init(sync bool) {
b.sync = sync
}
func (b *Batch) append(p *Batch) {
if p.rLen > 0 {
b.grow(len(p.data) - batchHdrLen)
b.data = append(b.data, p.data[batchHdrLen:]...)
b.rLen += p.rLen
}
if p.sync {
b.sync = true
}
}
// size returns sums of key/value pair length plus 8-bytes ikey.
func (b *Batch) size() int {
return b.bLen
}
func (b *Batch) encode() []byte {
b.grow(0)
binary.LittleEndian.PutUint64(b.data, b.seq)
binary.LittleEndian.PutUint32(b.data[8:], uint32(b.rLen))
return b.data
}
func (b *Batch) decode(prevSeq uint64, data []byte) error {
if len(data) < batchHdrLen {
return newErrBatchCorrupted("too short")
}
b.seq = binary.LittleEndian.Uint64(data)
if b.seq < prevSeq {
return newErrBatchCorrupted("invalid sequence number")
}
b.rLen = int(binary.LittleEndian.Uint32(data[8:]))
if b.rLen < 0 {
return newErrBatchCorrupted("invalid records length")
}
// No need to be precise at this point, it won't be used anyway
b.bLen = len(data) - batchHdrLen
b.data = data
return nil
}
func (b *Batch) decodeRec(f func(i int, kt kType, key, value []byte) error) error {
off := batchHdrLen
for i := 0; i < b.rLen; i++ {
if off >= len(b.data) {
return newErrBatchCorrupted("invalid records length")
}
kt := kType(b.data[off])
if kt > ktVal {
return newErrBatchCorrupted("bad record: invalid type")
}
off += 1
x, n := binary.Uvarint(b.data[off:])
off += n
if n <= 0 || off+int(x) > len(b.data) {
return newErrBatchCorrupted("bad record: invalid key length")
}
key := b.data[off : off+int(x)]
off += int(x)
var value []byte
if kt == ktVal {
x, n := binary.Uvarint(b.data[off:])
off += n
if n <= 0 || off+int(x) > len(b.data) {
return newErrBatchCorrupted("bad record: invalid value length")
}
value = b.data[off : off+int(x)]
off += int(x)
}
if err := f(i, kt, key, value); err != nil {
return err
}
}
return nil
}
func (b *Batch) memReplay(to *memdb.DB) error {
var ikScratch []byte
return b.decodeRec(func(i int, kt kType, key, value []byte) error {
ikScratch = makeIkey(ikScratch, key, b.seq+uint64(i), kt)
return to.Put(ikScratch, value)
})
}
func (b *Batch) memDecodeAndReplay(prevSeq uint64, data []byte, to *memdb.DB) error {
if err := b.decode(prevSeq, data); err != nil {
return err
}
return b.memReplay(to)
}
func (b *Batch) revertMemReplay(to *memdb.DB) error {
var ikScratch []byte
return b.decodeRec(func(i int, kt kType, key, value []byte) error {
ikScratch := makeIkey(ikScratch, key, b.seq+uint64(i), kt)
return to.Delete(ikScratch)
})
}
|