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

198 lines
4.6 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 (
"math"
"github.com/blevesearch/bleve/index"
"github.com/blevesearch/bleve/search"
)
type PhraseSearcher struct {
indexReader index.IndexReader
mustSearcher *ConjunctionSearcher
queryNorm float64
currMust *search.DocumentMatch
slop int
terms []string
initialized bool
}
func NewPhraseSearcher(indexReader index.IndexReader, mustSearcher *ConjunctionSearcher, terms []string) (*PhraseSearcher, error) {
// build our searcher
rv := PhraseSearcher{
indexReader: indexReader,
mustSearcher: mustSearcher,
terms: terms,
}
rv.computeQueryNorm()
return &rv, nil
}
func (s *PhraseSearcher) computeQueryNorm() {
// first calculate sum of squared weights
sumOfSquaredWeights := 0.0
if s.mustSearcher != nil {
sumOfSquaredWeights += s.mustSearcher.Weight()
}
// now compute query norm from this
s.queryNorm = 1.0 / math.Sqrt(sumOfSquaredWeights)
// finally tell all the downstream searchers the norm
if s.mustSearcher != nil {
s.mustSearcher.SetQueryNorm(s.queryNorm)
}
}
func (s *PhraseSearcher) initSearchers(ctx *search.SearchContext) error {
err := s.advanceNextMust(ctx)
if err != nil {
return err
}
s.initialized = true
return nil
}
func (s *PhraseSearcher) advanceNextMust(ctx *search.SearchContext) error {
var err error
if s.mustSearcher != nil {
s.currMust, err = s.mustSearcher.Next(ctx)
if err != nil {
return err
}
}
return nil
}
func (s *PhraseSearcher) Weight() float64 {
return s.mustSearcher.Weight()
}
func (s *PhraseSearcher) SetQueryNorm(qnorm float64) {
s.mustSearcher.SetQueryNorm(qnorm)
}
func (s *PhraseSearcher) Next(ctx *search.SearchContext) (*search.DocumentMatch, error) {
if !s.initialized {
err := s.initSearchers(ctx)
if err != nil {
return nil, err
}
}
var rv *search.DocumentMatch
for s.currMust != nil {
rvftlm := make(search.FieldTermLocationMap, 0)
freq := 0
firstTerm := s.terms[0]
for field, termLocMap := range s.currMust.Locations {
rvtlm := make(search.TermLocationMap, 0)
locations, ok := termLocMap[firstTerm]
if ok {
OUTER:
for _, location := range locations {
crvtlm := make(search.TermLocationMap, 0)
INNER:
for i := 0; i < len(s.terms); i++ {
nextTerm := s.terms[i]
if nextTerm != "" {
// look through all these term locations
// to try and find the correct offsets
nextLocations, ok := termLocMap[nextTerm]
if ok {
for _, nextLocation := range nextLocations {
if nextLocation.Pos == location.Pos+float64(i) && nextLocation.SameArrayElement(location) {
// found a location match for this term
crvtlm.AddLocation(nextTerm, nextLocation)
continue INNER
}
}
// if we got here we didn't find a location match for this term
continue OUTER
} else {
continue OUTER
}
}
}
// if we got here all the terms matched
freq++
search.MergeTermLocationMaps(rvtlm, crvtlm)
rvftlm[field] = rvtlm
}
}
}
if freq > 0 {
// return match
rv = s.currMust
rv.Locations = rvftlm
err := s.advanceNextMust(ctx)
if err != nil {
return nil, err
}
return rv, nil
}
err := s.advanceNextMust(ctx)
if err != nil {
return nil, err
}
}
return nil, nil
}
func (s *PhraseSearcher) Advance(ctx *search.SearchContext, ID index.IndexInternalID) (*search.DocumentMatch, error) {
if !s.initialized {
err := s.initSearchers(ctx)
if err != nil {
return nil, err
}
}
var err error
s.currMust, err = s.mustSearcher.Advance(ctx, ID)
if err != nil {
return nil, err
}
return s.Next(ctx)
}
func (s *PhraseSearcher) Count() uint64 {
// for now return a worst case
return s.mustSearcher.Count()
}
func (s *PhraseSearcher) Close() error {
if s.mustSearcher != nil {
err := s.mustSearcher.Close()
if err != nil {
return err
}
}
return nil
}
func (s *PhraseSearcher) Min() int {
return 0
}
func (s *PhraseSearcher) DocumentMatchPoolSize() int {
return s.mustSearcher.DocumentMatchPoolSize() + 1
}