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- // Copyright (c) 2017 Couchbase, Inc.
- //
- // Licensed under the Apache License, Version 2.0 (the "License");
- // you may not use this file except in compliance with the License.
- // You may obtain a copy of the License at
- //
- // http://www.apache.org/licenses/LICENSE-2.0
- //
- // Unless required by applicable law or agreed to in writing, software
- // distributed under the License is distributed on an "AS IS" BASIS,
- // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- // See the License for the specific language governing permissions and
- // limitations under the License.
-
- package zap
-
- import (
- "bytes"
- "encoding/binary"
- "fmt"
- "math"
- "reflect"
- "sort"
-
- index "github.com/blevesearch/bleve_index_api"
- segment "github.com/blevesearch/scorch_segment_api/v2"
- "github.com/golang/snappy"
- )
-
- var reflectStaticSizedocValueReader int
-
- func init() {
- var dvi docValueReader
- reflectStaticSizedocValueReader = int(reflect.TypeOf(dvi).Size())
- }
-
- type docNumTermsVisitor func(docNum uint64, terms []byte) error
-
- type docVisitState struct {
- dvrs map[uint16]*docValueReader
- segment *SegmentBase
- }
-
- type docValueReader struct {
- field string
- curChunkNum uint64
- chunkOffsets []uint64
- dvDataLoc uint64
- curChunkHeader []MetaData
- curChunkData []byte // compressed data cache
- uncompressed []byte // temp buf for snappy decompression
- }
-
- func (di *docValueReader) size() int {
- return reflectStaticSizedocValueReader + SizeOfPtr +
- len(di.field) +
- len(di.chunkOffsets)*SizeOfUint64 +
- len(di.curChunkHeader)*reflectStaticSizeMetaData +
- len(di.curChunkData)
- }
-
- func (di *docValueReader) cloneInto(rv *docValueReader) *docValueReader {
- if rv == nil {
- rv = &docValueReader{}
- }
-
- rv.field = di.field
- rv.curChunkNum = math.MaxUint64
- rv.chunkOffsets = di.chunkOffsets // immutable, so it's sharable
- rv.dvDataLoc = di.dvDataLoc
- rv.curChunkHeader = rv.curChunkHeader[:0]
- rv.curChunkData = nil
- rv.uncompressed = rv.uncompressed[:0]
-
- return rv
- }
-
- func (di *docValueReader) curChunkNumber() uint64 {
- return di.curChunkNum
- }
-
- func (s *SegmentBase) loadFieldDocValueReader(field string,
- fieldDvLocStart, fieldDvLocEnd uint64) (*docValueReader, error) {
- // get the docValue offset for the given fields
- if fieldDvLocStart == fieldNotUninverted {
- // no docValues found, nothing to do
- return nil, nil
- }
-
- // read the number of chunks, and chunk offsets position
- var numChunks, chunkOffsetsPosition uint64
-
- if fieldDvLocEnd-fieldDvLocStart > 16 {
- numChunks = binary.BigEndian.Uint64(s.mem[fieldDvLocEnd-8 : fieldDvLocEnd])
- // read the length of chunk offsets
- chunkOffsetsLen := binary.BigEndian.Uint64(s.mem[fieldDvLocEnd-16 : fieldDvLocEnd-8])
- // acquire position of chunk offsets
- chunkOffsetsPosition = (fieldDvLocEnd - 16) - chunkOffsetsLen
- } else {
- return nil, fmt.Errorf("loadFieldDocValueReader: fieldDvLoc too small: %d-%d", fieldDvLocEnd, fieldDvLocStart)
- }
-
- fdvIter := &docValueReader{
- curChunkNum: math.MaxUint64,
- field: field,
- chunkOffsets: make([]uint64, int(numChunks)),
- }
-
- // read the chunk offsets
- var offset uint64
- for i := 0; i < int(numChunks); i++ {
- loc, read := binary.Uvarint(s.mem[chunkOffsetsPosition+offset : chunkOffsetsPosition+offset+binary.MaxVarintLen64])
- if read <= 0 {
- return nil, fmt.Errorf("corrupted chunk offset during segment load")
- }
- fdvIter.chunkOffsets[i] = loc
- offset += uint64(read)
- }
-
- // set the data offset
- fdvIter.dvDataLoc = fieldDvLocStart
-
- return fdvIter, nil
- }
-
- func (di *docValueReader) loadDvChunk(chunkNumber uint64, s *SegmentBase) error {
- // advance to the chunk where the docValues
- // reside for the given docNum
- destChunkDataLoc, curChunkEnd := di.dvDataLoc, di.dvDataLoc
- start, end := readChunkBoundary(int(chunkNumber), di.chunkOffsets)
- if start >= end {
- di.curChunkHeader = di.curChunkHeader[:0]
- di.curChunkData = nil
- di.curChunkNum = chunkNumber
- di.uncompressed = di.uncompressed[:0]
- return nil
- }
-
- destChunkDataLoc += start
- curChunkEnd += end
-
- // read the number of docs reside in the chunk
- numDocs, read := binary.Uvarint(s.mem[destChunkDataLoc : destChunkDataLoc+binary.MaxVarintLen64])
- if read <= 0 {
- return fmt.Errorf("failed to read the chunk")
- }
- chunkMetaLoc := destChunkDataLoc + uint64(read)
-
- offset := uint64(0)
- if cap(di.curChunkHeader) < int(numDocs) {
- di.curChunkHeader = make([]MetaData, int(numDocs))
- } else {
- di.curChunkHeader = di.curChunkHeader[:int(numDocs)]
- }
- for i := 0; i < int(numDocs); i++ {
- di.curChunkHeader[i].DocNum, read = binary.Uvarint(s.mem[chunkMetaLoc+offset : chunkMetaLoc+offset+binary.MaxVarintLen64])
- offset += uint64(read)
- di.curChunkHeader[i].DocDvOffset, read = binary.Uvarint(s.mem[chunkMetaLoc+offset : chunkMetaLoc+offset+binary.MaxVarintLen64])
- offset += uint64(read)
- }
-
- compressedDataLoc := chunkMetaLoc + offset
- dataLength := curChunkEnd - compressedDataLoc
- di.curChunkData = s.mem[compressedDataLoc : compressedDataLoc+dataLength]
- di.curChunkNum = chunkNumber
- di.uncompressed = di.uncompressed[:0]
- return nil
- }
-
- func (di *docValueReader) iterateAllDocValues(s *SegmentBase, visitor docNumTermsVisitor) error {
- for i := 0; i < len(di.chunkOffsets); i++ {
- err := di.loadDvChunk(uint64(i), s)
- if err != nil {
- return err
- }
- if di.curChunkData == nil || len(di.curChunkHeader) == 0 {
- continue
- }
-
- // uncompress the already loaded data
- uncompressed, err := snappy.Decode(di.uncompressed[:cap(di.uncompressed)], di.curChunkData)
- if err != nil {
- return err
- }
- di.uncompressed = uncompressed
-
- start := uint64(0)
- for _, entry := range di.curChunkHeader {
- err = visitor(entry.DocNum, uncompressed[start:entry.DocDvOffset])
- if err != nil {
- return err
- }
-
- start = entry.DocDvOffset
- }
- }
-
- return nil
- }
-
- func (di *docValueReader) visitDocValues(docNum uint64,
- visitor index.DocValueVisitor) error {
- // binary search the term locations for the docNum
- start, end := di.getDocValueLocs(docNum)
- if start == math.MaxUint64 || end == math.MaxUint64 || start == end {
- return nil
- }
-
- var uncompressed []byte
- var err error
- // use the uncompressed copy if available
- if len(di.uncompressed) > 0 {
- uncompressed = di.uncompressed
- } else {
- // uncompress the already loaded data
- uncompressed, err = snappy.Decode(di.uncompressed[:cap(di.uncompressed)], di.curChunkData)
- if err != nil {
- return err
- }
- di.uncompressed = uncompressed
- }
-
- // pick the terms for the given docNum
- uncompressed = uncompressed[start:end]
- for {
- i := bytes.Index(uncompressed, termSeparatorSplitSlice)
- if i < 0 {
- break
- }
-
- visitor(di.field, uncompressed[0:i])
- uncompressed = uncompressed[i+1:]
- }
-
- return nil
- }
-
- func (di *docValueReader) getDocValueLocs(docNum uint64) (uint64, uint64) {
- i := sort.Search(len(di.curChunkHeader), func(i int) bool {
- return di.curChunkHeader[i].DocNum >= docNum
- })
- if i < len(di.curChunkHeader) && di.curChunkHeader[i].DocNum == docNum {
- return ReadDocValueBoundary(i, di.curChunkHeader)
- }
- return math.MaxUint64, math.MaxUint64
- }
-
- // VisitDocValues is an implementation of the
- // DocValueVisitable interface
- func (s *SegmentBase) VisitDocValues(localDocNum uint64, fields []string,
- visitor index.DocValueVisitor, dvsIn segment.DocVisitState) (
- segment.DocVisitState, error) {
- dvs, ok := dvsIn.(*docVisitState)
- if !ok || dvs == nil {
- dvs = &docVisitState{}
- } else {
- if dvs.segment != s {
- dvs.segment = s
- dvs.dvrs = nil
- }
- }
-
- var fieldIDPlus1 uint16
- if dvs.dvrs == nil {
- dvs.dvrs = make(map[uint16]*docValueReader, len(fields))
- for _, field := range fields {
- if fieldIDPlus1, ok = s.fieldsMap[field]; !ok {
- continue
- }
- fieldID := fieldIDPlus1 - 1
- if dvIter, exists := s.fieldDvReaders[fieldID]; exists &&
- dvIter != nil {
- dvs.dvrs[fieldID] = dvIter.cloneInto(dvs.dvrs[fieldID])
- }
- }
- }
-
- // find the chunkNumber where the docValues are stored
- docInChunk := localDocNum / uint64(s.chunkFactor)
- var dvr *docValueReader
- for _, field := range fields {
- if fieldIDPlus1, ok = s.fieldsMap[field]; !ok {
- continue
- }
- fieldID := fieldIDPlus1 - 1
- if dvr, ok = dvs.dvrs[fieldID]; ok && dvr != nil {
- // check if the chunk is already loaded
- if docInChunk != dvr.curChunkNumber() {
- err := dvr.loadDvChunk(docInChunk, s)
- if err != nil {
- return dvs, err
- }
- }
-
- _ = dvr.visitDocValues(localDocNum, visitor)
- }
- }
- return dvs, nil
- }
-
- // VisitableDocValueFields returns the list of fields with
- // persisted doc value terms ready to be visitable using the
- // VisitDocumentFieldTerms method.
- func (s *SegmentBase) VisitableDocValueFields() ([]string, error) {
- return s.fieldDvNames, nil
- }
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