2ee7289bc8
this started initially to relocate highlighting into a self contained package, which would then also use the registry however, it turned into a much larger refactor in order to avoid cyclic imports now facets, searchers, scorers and collectors are also broken out into subpackages of search
100 lines
2.9 KiB
Go
100 lines
2.9 KiB
Go
// Copyright (c) 2014 Couchbase, Inc.
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
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// except in compliance with the License. You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software distributed under the
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// License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
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// either express or implied. See the License for the specific language governing permissions
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// and limitations under the License.
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package simple
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import (
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"github.com/blevesearch/bleve/registry"
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"github.com/blevesearch/bleve/search/highlight"
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)
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const Name = "simple"
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const defaultFragmentSize = 200
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type SimpleFragmenter struct {
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fragmentSize int
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}
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func NewSimpleFragmenter(fragmentSize int) *SimpleFragmenter {
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return &SimpleFragmenter{
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fragmentSize: fragmentSize,
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}
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}
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func (s *SimpleFragmenter) Fragment(orig []byte, ot highlight.TermLocations) []*highlight.Fragment {
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rv := make([]*highlight.Fragment, 0)
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maxbegin := 0
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for currTermIndex, termLocation := range ot {
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// start with with this
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// it should be the highest scoring fragment with this term first
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start := termLocation.Start
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end := start + s.fragmentSize
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if end > len(orig) {
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end = len(orig)
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// we hit end, so push back as far as we can without crossing maxbegin
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extra := s.fragmentSize - (end - start)
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if start-extra >= maxbegin {
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start -= extra
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} else {
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start = maxbegin
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}
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}
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// however, we'd rather have the tokens centered more in the frag
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// lets try to do that as best we can, without affecting the score
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// find the end of the last term in this fragment
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minend := end
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for _, innerTermLocation := range ot[currTermIndex:] {
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if innerTermLocation.End > end {
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break
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}
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minend = innerTermLocation.End
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}
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// find the smaller of the two rooms to move
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roomToMove := end - minend
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if start-maxbegin < roomToMove {
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roomToMove = start - maxbegin
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}
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offset := roomToMove / 2
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rv = append(rv, &highlight.Fragment{Orig: orig, Start: start - offset, End: end - offset})
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// set maxbegin to the end of the current term location
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// so that next one won't back up to include it
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maxbegin = termLocation.End
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}
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if len(ot) == 0 {
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// if there were no terms to highlight
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// produce a single fragment from the beginning
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start := 0
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end := start + s.fragmentSize
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if end > len(orig) {
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end = len(orig)
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}
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rv = append(rv, &highlight.Fragment{Orig: orig, Start: start, End: end})
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}
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return rv
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}
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func Constructor(config map[string]interface{}, cache *registry.Cache) (highlight.Fragmenter, error) {
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size := defaultFragmentSize
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sizeVal, ok := config["size"].(float64)
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if ok {
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size = int(sizeVal)
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}
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return NewSimpleFragmenter(size), nil
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}
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func init() {
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registry.RegisterFragmenter(Name, Constructor)
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}
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