gitea/vendor/github.com/blevesearch/zapx/v15/docvalues.go

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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"
"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
// NOTE: doc values continue to use legacy chunk mode
chunkFactor, err := getChunkSize(LegacyChunkMode, 0, 0)
if err != nil {
return nil, err
}
docInChunk := localDocNum / 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
}