1 files changed, 349 insertions, 0 deletions
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/batch.go b/vendor/github.com/syndtr/goleveldb/leveldb/batch.go
new file mode 100644
index 0000000..2259200
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/batch.go
@@ -0,0 +1,349 @@
+// 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"
+	"io"
+
+	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/memdb"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+)
+
+// ErrBatchCorrupted records reason of batch corruption. This error will be
+// wrapped with errors.ErrCorrupted.
+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 (
+	batchHeaderLen = 8 + 4
+	batchGrowRec   = 3000
+	batchBufioSize = 16
+)
+
+// BatchReplay wraps basic batch operations.
+type BatchReplay interface {
+	Put(key, value []byte)
+	Delete(key []byte)
+}
+
+type batchIndex struct {
+	keyType            keyType
+	keyPos, keyLen     int
+	valuePos, valueLen int
+}
+
+func (index batchIndex) k(data []byte) []byte {
+	return data[index.keyPos : index.keyPos+index.keyLen]
+}
+
+func (index batchIndex) v(data []byte) []byte {
+	if index.valueLen != 0 {
+		return data[index.valuePos : index.valuePos+index.valueLen]
+	}
+	return nil
+}
+
+func (index batchIndex) kv(data []byte) (key, value []byte) {
+	return index.k(data), index.v(data)
+}
+
+// Batch is a write batch.
+type Batch struct {
+	data  []byte
+	index []batchIndex
+
+	// internalLen is sums of key/value pair length plus 8-bytes internal key.
+	internalLen int
+}
+
+func (b *Batch) grow(n int) {
+	o := len(b.data)
+	if cap(b.data)-o < n {
+		div := 1
+		if len(b.index) > batchGrowRec {
+			div = len(b.index) / batchGrowRec
+		}
+		ndata := make([]byte, o, o+n+o/div)
+		copy(ndata, b.data)
+		b.data = ndata
+	}
+}
+
+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)
+	index := batchIndex{keyType: kt}
+	o := len(b.data)
+	data := b.data[:o+n]
+	data[o] = byte(kt)
+	o++
+	o += binary.PutUvarint(data[o:], uint64(len(key)))
+	index.keyPos = o
+	index.keyLen = len(key)
+	o += copy(data[o:], key)
+	if kt == keyTypeVal {
+		o += binary.PutUvarint(data[o:], uint64(len(value)))
+		index.valuePos = o
+		index.valueLen = len(value)
+		o += copy(data[o:], value)
+	}
+	b.data = data[:o]
+	b.index = append(b.index, index)
+	b.internalLen += index.keyLen + index.valueLen + 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 but not
+// before.
+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 but
+// not before.
+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.data
+}
+
+// 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(data, -1)
+}
+
+// Replay replays batch contents.
+func (b *Batch) Replay(r BatchReplay) error {
+	for _, index := range b.index {
+		switch index.keyType {
+		case keyTypeVal:
+			r.Put(index.k(b.data), index.v(b.data))
+		case keyTypeDel:
+			r.Delete(index.k(b.data))
+		}
+	}
+	return nil
+}
+
+// Len returns number of records in the batch.
+func (b *Batch) Len() int {
+	return len(b.index)
+}
+
+// Reset resets the batch.
+func (b *Batch) Reset() {
+	b.data = b.data[:0]
+	b.index = b.index[:0]
+	b.internalLen = 0
+}
+
+func (b *Batch) replayInternal(fn func(i int, kt keyType, k, v []byte) error) error {
+	for i, index := range b.index {
+		if err := fn(i, index.keyType, index.k(b.data), index.v(b.data)); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (b *Batch) append(p *Batch) {
+	ob := len(b.data)
+	oi := len(b.index)
+	b.data = append(b.data, p.data...)
+	b.index = append(b.index, p.index...)
+	b.internalLen += p.internalLen
+
+	// Updating index offset.
+	if ob != 0 {
+		for ; oi < len(b.index); oi++ {
+			index := &b.index[oi]
+			index.keyPos += ob
+			if index.valueLen != 0 {
+				index.valuePos += ob
+			}
+		}
+	}
+}
+
+func (b *Batch) decode(data []byte, expectedLen int) error {
+	b.data = data
+	b.index = b.index[:0]
+	b.internalLen = 0
+	err := decodeBatch(data, func(i int, index batchIndex) error {
+		b.index = append(b.index, index)
+		b.internalLen += index.keyLen + index.valueLen + 8
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+	if expectedLen >= 0 && len(b.index) != expectedLen {
+		return newErrBatchCorrupted(fmt.Sprintf("invalid records length: %d vs %d", expectedLen, len(b.index)))
+	}
+	return nil
+}
+
+func (b *Batch) putMem(seq uint64, mdb *memdb.DB) error {
+	var ik []byte
+	for i, index := range b.index {
+		ik = makeInternalKey(ik, index.k(b.data), seq+uint64(i), index.keyType)
+		if err := mdb.Put(ik, index.v(b.data)); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (b *Batch) revertMem(seq uint64, mdb *memdb.DB) error {
+	var ik []byte
+	for i, index := range b.index {
+		ik = makeInternalKey(ik, index.k(b.data), seq+uint64(i), index.keyType)
+		if err := mdb.Delete(ik); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func newBatch() interface{} {
+	return &Batch{}
+}
+
+func decodeBatch(data []byte, fn func(i int, index batchIndex) error) error {
+	var index batchIndex
+	for i, o := 0, 0; o < len(data); i++ {
+		// Key type.
+		index.keyType = keyType(data[o])
+		if index.keyType > keyTypeVal {
+			return newErrBatchCorrupted(fmt.Sprintf("bad record: invalid type %#x", uint(index.keyType)))
+		}
+		o++
+
+		// Key.
+		x, n := binary.Uvarint(data[o:])
+		o += n
+		if n <= 0 || o+int(x) > len(data) {
+			return newErrBatchCorrupted("bad record: invalid key length")
+		}
+		index.keyPos = o
+		index.keyLen = int(x)
+		o += index.keyLen
+
+		// Value.
+		if index.keyType == keyTypeVal {
+			x, n = binary.Uvarint(data[o:])
+			o += n
+			if n <= 0 || o+int(x) > len(data) {
+				return newErrBatchCorrupted("bad record: invalid value length")
+			}
+			index.valuePos = o
+			index.valueLen = int(x)
+			o += index.valueLen
+		} else {
+			index.valuePos = 0
+			index.valueLen = 0
+		}
+
+		if err := fn(i, index); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func decodeBatchToMem(data []byte, expectSeq uint64, mdb *memdb.DB) (seq uint64, batchLen int, err error) {
+	seq, batchLen, err = decodeBatchHeader(data)
+	if err != nil {
+		return 0, 0, err
+	}
+	if seq < expectSeq {
+		return 0, 0, newErrBatchCorrupted("invalid sequence number")
+	}
+	data = data[batchHeaderLen:]
+	var ik []byte
+	var decodedLen int
+	err = decodeBatch(data, func(i int, index batchIndex) error {
+		if i >= batchLen {
+			return newErrBatchCorrupted("invalid records length")
+		}
+		ik = makeInternalKey(ik, index.k(data), seq+uint64(i), index.keyType)
+		if err := mdb.Put(ik, index.v(data)); err != nil {
+			return err
+		}
+		decodedLen++
+		return nil
+	})
+	if err == nil && decodedLen != batchLen {
+		err = newErrBatchCorrupted(fmt.Sprintf("invalid records length: %d vs %d", batchLen, decodedLen))
+	}
+	return
+}
+
+func encodeBatchHeader(dst []byte, seq uint64, batchLen int) []byte {
+	dst = ensureBuffer(dst, batchHeaderLen)
+	binary.LittleEndian.PutUint64(dst, seq)
+	binary.LittleEndian.PutUint32(dst[8:], uint32(batchLen))
+	return dst
+}
+
+func decodeBatchHeader(data []byte) (seq uint64, batchLen int, err error) {
+	if len(data) < batchHeaderLen {
+		return 0, 0, newErrBatchCorrupted("too short")
+	}
+
+	seq = binary.LittleEndian.Uint64(data)
+	batchLen = int(binary.LittleEndian.Uint32(data[8:]))
+	if batchLen < 0 {
+		return 0, 0, newErrBatchCorrupted("invalid records length")
+	}
+	return
+}
+
+func batchesLen(batches []*Batch) int {
+	batchLen := 0
+	for _, batch := range batches {
+		batchLen += batch.Len()
+	}
+	return batchLen
+}
+
+func writeBatchesWithHeader(wr io.Writer, batches []*Batch, seq uint64) error {
+	if _, err := wr.Write(encodeBatchHeader(nil, seq, batchesLen(batches))); err != nil {
+		return err
+	}
+	for _, batch := range batches {
+		if _, err := wr.Write(batch.data); err != nil {
+			return err
+		}
+	}
+	return nil
+}