diff options
Diffstat (limited to 'vendor/github.com/syndtr/goleveldb/leveldb/batch.go')
-rw-r--r-- | vendor/github.com/syndtr/goleveldb/leveldb/batch.go | 349 |
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 000000000..225920002 --- /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 +} |