forgejo-federation/vendor/github.com/syndtr/goleveldb/leveldb/batch.go

262 lines
6 KiB
Go
Raw Normal View History

// 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"
)
// ErrBatchCorrupted records reason of batch corruption.
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
)
// BatchReplay wraps basic batch operations.
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 keyType, key, value []byte) {
n := 1 + binary.MaxVarintLen32 + len(key)
if kt == keyTypeVal {
n += binary.MaxVarintLen32 + len(value)
}
b.grow(n)
off := len(b.data)
data := b.data[:off+n]
data[off] = byte(kt)
off++
off += binary.PutUvarint(data[off:], uint64(len(key)))
copy(data[off:], key)
off += len(key)
if kt == keyTypeVal {
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(keyTypeVal, 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(keyTypeDel, 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 keyType, key, value []byte) error {
switch kt {
case keyTypeVal:
r.Put(key, value)
case keyTypeDel:
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 keyType, 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 := keyType(b.data[off])
if kt > keyTypeVal {
panic(kt)
return newErrBatchCorrupted("bad record: invalid type")
}
off++
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 == keyTypeVal {
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 keyType, key, value []byte) error {
ikScratch = makeInternalKey(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 keyType, key, value []byte) error {
ikScratch := makeInternalKey(ikScratch, key, b.seq+uint64(i), kt)
return to.Delete(ikScratch)
})
}