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gitea/vendor/github.com/blevesearch/bleve/search/searcher/search_disjunction.go
2017-01-25 10:43:02 +08:00

259 lines
6.1 KiB
Go

// Copyright (c) 2014 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 searcher
import (
"fmt"
"math"
"sort"
"github.com/blevesearch/bleve/index"
"github.com/blevesearch/bleve/search"
"github.com/blevesearch/bleve/search/scorer"
)
// DisjunctionMaxClauseCount is a compile time setting that applications can
// adjust to non-zero value to cause the DisjunctionSearcher to return an
// error instead of exeucting searches when the size exceeds this value.
var DisjunctionMaxClauseCount = 0
type DisjunctionSearcher struct {
indexReader index.IndexReader
searchers OrderedSearcherList
numSearchers int
queryNorm float64
currs []*search.DocumentMatch
scorer *scorer.DisjunctionQueryScorer
min int
matching []*search.DocumentMatch
matchingIdxs []int
initialized bool
}
func tooManyClauses(count int) bool {
if DisjunctionMaxClauseCount != 0 && count > DisjunctionMaxClauseCount {
return true
}
return false
}
func tooManyClausesErr() error {
return fmt.Errorf("TooManyClauses[maxClauseCount is set to %d]", DisjunctionMaxClauseCount)
}
func NewDisjunctionSearcher(indexReader index.IndexReader, qsearchers []search.Searcher, min float64, explain bool) (*DisjunctionSearcher, error) {
if tooManyClauses(len(qsearchers)) {
return nil, tooManyClausesErr()
}
// build the downstream searchers
searchers := make(OrderedSearcherList, len(qsearchers))
for i, searcher := range qsearchers {
searchers[i] = searcher
}
// sort the searchers
sort.Sort(sort.Reverse(searchers))
// build our searcher
rv := DisjunctionSearcher{
indexReader: indexReader,
searchers: searchers,
numSearchers: len(searchers),
currs: make([]*search.DocumentMatch, len(searchers)),
scorer: scorer.NewDisjunctionQueryScorer(explain),
min: int(min),
matching: make([]*search.DocumentMatch, len(searchers)),
matchingIdxs: make([]int, len(searchers)),
}
rv.computeQueryNorm()
return &rv, nil
}
func (s *DisjunctionSearcher) computeQueryNorm() {
// first calculate sum of squared weights
sumOfSquaredWeights := 0.0
for _, termSearcher := range s.searchers {
sumOfSquaredWeights += termSearcher.Weight()
}
// now compute query norm from this
s.queryNorm = 1.0 / math.Sqrt(sumOfSquaredWeights)
// finally tell all the downstream searchers the norm
for _, termSearcher := range s.searchers {
termSearcher.SetQueryNorm(s.queryNorm)
}
}
func (s *DisjunctionSearcher) initSearchers(ctx *search.SearchContext) error {
var err error
// get all searchers pointing at their first match
for i, termSearcher := range s.searchers {
if s.currs[i] != nil {
ctx.DocumentMatchPool.Put(s.currs[i])
}
s.currs[i], err = termSearcher.Next(ctx)
if err != nil {
return err
}
}
err = s.updateMatches()
if err != nil {
return err
}
s.initialized = true
return nil
}
func (s *DisjunctionSearcher) updateMatches() error {
matching := s.matching[:0]
matchingIdxs := s.matchingIdxs[:0]
for i := 0; i < len(s.currs); i++ {
curr := s.currs[i]
if curr == nil {
continue
}
if len(matching) > 0 {
cmp := curr.IndexInternalID.Compare(matching[0].IndexInternalID)
if cmp > 0 {
continue
}
if cmp < 0 {
matching = matching[:0]
matchingIdxs = matchingIdxs[:0]
}
}
matching = append(matching, curr)
matchingIdxs = append(matchingIdxs, i)
}
s.matching = matching
s.matchingIdxs = matchingIdxs
return nil
}
func (s *DisjunctionSearcher) Weight() float64 {
var rv float64
for _, searcher := range s.searchers {
rv += searcher.Weight()
}
return rv
}
func (s *DisjunctionSearcher) SetQueryNorm(qnorm float64) {
for _, searcher := range s.searchers {
searcher.SetQueryNorm(qnorm)
}
}
func (s *DisjunctionSearcher) Next(ctx *search.SearchContext) (*search.DocumentMatch, error) {
if !s.initialized {
err := s.initSearchers(ctx)
if err != nil {
return nil, err
}
}
var err error
var rv *search.DocumentMatch
found := false
for !found && len(s.matching) > 0 {
if len(s.matching) >= s.min {
found = true
// score this match
rv = s.scorer.Score(ctx, s.matching, len(s.matching), s.numSearchers)
}
// invoke next on all the matching searchers
for _, i := range s.matchingIdxs {
searcher := s.searchers[i]
if s.currs[i] != rv {
ctx.DocumentMatchPool.Put(s.currs[i])
}
s.currs[i], err = searcher.Next(ctx)
if err != nil {
return nil, err
}
}
err = s.updateMatches()
if err != nil {
return nil, err
}
}
return rv, nil
}
func (s *DisjunctionSearcher) Advance(ctx *search.SearchContext, ID index.IndexInternalID) (*search.DocumentMatch, error) {
if !s.initialized {
err := s.initSearchers(ctx)
if err != nil {
return nil, err
}
}
// get all searchers pointing at their first match
var err error
for i, termSearcher := range s.searchers {
if s.currs[i] != nil {
ctx.DocumentMatchPool.Put(s.currs[i])
}
s.currs[i], err = termSearcher.Advance(ctx, ID)
if err != nil {
return nil, err
}
}
err = s.updateMatches()
if err != nil {
return nil, err
}
return s.Next(ctx)
}
func (s *DisjunctionSearcher) Count() uint64 {
// for now return a worst case
var sum uint64
for _, searcher := range s.searchers {
sum += searcher.Count()
}
return sum
}
func (s *DisjunctionSearcher) Close() (rv error) {
for _, searcher := range s.searchers {
err := searcher.Close()
if err != nil && rv == nil {
rv = err
}
}
return rv
}
func (s *DisjunctionSearcher) Min() int {
return s.min
}
func (s *DisjunctionSearcher) DocumentMatchPoolSize() int {
rv := len(s.currs)
for _, s := range s.searchers {
rv += s.DocumentMatchPoolSize()
}
return rv
}