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
206 lines
5.5 KiB
Go
206 lines
5.5 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 simple
|
|
|
|
import (
|
|
"container/heap"
|
|
"fmt"
|
|
|
|
"github.com/blevesearch/bleve/document"
|
|
"github.com/blevesearch/bleve/registry"
|
|
"github.com/blevesearch/bleve/search"
|
|
"github.com/blevesearch/bleve/search/highlight"
|
|
)
|
|
|
|
const Name = "simple"
|
|
const defaultSeparator = "…"
|
|
|
|
type SimpleHighlighter struct {
|
|
fragmenter highlight.Fragmenter
|
|
formatter highlight.FragmentFormatter
|
|
sep string
|
|
}
|
|
|
|
func NewSimpleHighlighter(fragmenter highlight.Fragmenter, formatter highlight.FragmentFormatter, separator string) *SimpleHighlighter {
|
|
return &SimpleHighlighter{
|
|
fragmenter: fragmenter,
|
|
formatter: formatter,
|
|
sep: separator,
|
|
}
|
|
}
|
|
|
|
func (s *SimpleHighlighter) Fragmenter() highlight.Fragmenter {
|
|
return s.fragmenter
|
|
}
|
|
|
|
func (s *SimpleHighlighter) SetFragmenter(f highlight.Fragmenter) {
|
|
s.fragmenter = f
|
|
}
|
|
|
|
func (s *SimpleHighlighter) FragmentFormatter() highlight.FragmentFormatter {
|
|
return s.formatter
|
|
}
|
|
|
|
func (s *SimpleHighlighter) SetFragmentFormatter(f highlight.FragmentFormatter) {
|
|
s.formatter = f
|
|
}
|
|
|
|
func (s *SimpleHighlighter) Separator() string {
|
|
return s.sep
|
|
}
|
|
|
|
func (s *SimpleHighlighter) SetSeparator(sep string) {
|
|
s.sep = sep
|
|
}
|
|
|
|
func (s *SimpleHighlighter) BestFragmentInField(dm *search.DocumentMatch, doc *document.Document, field string) string {
|
|
fragments := s.BestFragmentsInField(dm, doc, field, 1)
|
|
if len(fragments) > 0 {
|
|
return fragments[0]
|
|
}
|
|
return ""
|
|
}
|
|
|
|
func (s *SimpleHighlighter) BestFragmentsInField(dm *search.DocumentMatch, doc *document.Document, field string, num int) []string {
|
|
tlm := dm.Locations[field]
|
|
orderedTermLocations := highlight.OrderTermLocations(tlm)
|
|
scorer := NewSimpleFragmentScorer(dm.Locations[field])
|
|
|
|
// score the fragments and put them into a priority queue ordered by score
|
|
fq := make(FragmentQueue, 0)
|
|
heap.Init(&fq)
|
|
for _, f := range doc.Fields {
|
|
if f.Name() == field {
|
|
_, ok := f.(*document.TextField)
|
|
if ok {
|
|
fieldData := f.Value()
|
|
fragments := s.fragmenter.Fragment(fieldData, orderedTermLocations)
|
|
for _, fragment := range fragments {
|
|
scorer.Score(fragment)
|
|
heap.Push(&fq, fragment)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// now find the N best non-overlapping fragments
|
|
bestFragments := make([]*highlight.Fragment, 0)
|
|
if len(fq) > 0 {
|
|
candidate := heap.Pop(&fq)
|
|
OUTER:
|
|
for candidate != nil && len(bestFragments) < num {
|
|
// see if this overlaps with any of the best already identified
|
|
if len(bestFragments) > 0 {
|
|
for _, frag := range bestFragments {
|
|
if candidate.(*highlight.Fragment).Overlaps(frag) {
|
|
if len(fq) < 1 {
|
|
break OUTER
|
|
}
|
|
candidate = heap.Pop(&fq)
|
|
continue OUTER
|
|
}
|
|
}
|
|
bestFragments = append(bestFragments, candidate.(*highlight.Fragment))
|
|
} else {
|
|
bestFragments = append(bestFragments, candidate.(*highlight.Fragment))
|
|
}
|
|
|
|
if len(fq) < 1 {
|
|
break
|
|
}
|
|
candidate = heap.Pop(&fq)
|
|
}
|
|
}
|
|
|
|
// now that we have the best fragments, we can format them
|
|
formattedFragments := make([]string, len(bestFragments))
|
|
for i, fragment := range bestFragments {
|
|
formattedFragments[i] = ""
|
|
if fragment.Start != 0 {
|
|
formattedFragments[i] += s.sep
|
|
}
|
|
formattedFragments[i] += s.formatter.Format(fragment, dm.Locations[field])
|
|
if fragment.End != len(fragment.Orig) {
|
|
formattedFragments[i] += s.sep
|
|
}
|
|
}
|
|
|
|
if dm.Fragments == nil {
|
|
dm.Fragments = make(search.FieldFragmentMap, 0)
|
|
}
|
|
dm.Fragments[field] = formattedFragments
|
|
|
|
return formattedFragments
|
|
}
|
|
|
|
// A PriorityQueue implements heap.Interface and holds Items.
|
|
type FragmentQueue []*highlight.Fragment
|
|
|
|
func (fq FragmentQueue) Len() int { return len(fq) }
|
|
|
|
func (fq FragmentQueue) Less(i, j int) bool {
|
|
// We want Pop to give us the highest, not lowest, priority so we use greater than here.
|
|
return fq[i].Score > fq[j].Score
|
|
}
|
|
|
|
func (fq FragmentQueue) Swap(i, j int) {
|
|
fq[i], fq[j] = fq[j], fq[i]
|
|
fq[i].Index = i
|
|
fq[j].Index = j
|
|
}
|
|
|
|
func (fq *FragmentQueue) Push(x interface{}) {
|
|
n := len(*fq)
|
|
item := x.(*highlight.Fragment)
|
|
item.Index = n
|
|
*fq = append(*fq, item)
|
|
}
|
|
|
|
func (fq *FragmentQueue) Pop() interface{} {
|
|
old := *fq
|
|
n := len(old)
|
|
item := old[n-1]
|
|
item.Index = -1 // for safety
|
|
*fq = old[0 : n-1]
|
|
return item
|
|
}
|
|
|
|
func Constructor(config map[string]interface{}, cache *registry.Cache) (highlight.Highlighter, error) {
|
|
separator := defaultSeparator
|
|
separatorVal, ok := config["separator"].(string)
|
|
if ok {
|
|
separator = separatorVal
|
|
}
|
|
|
|
fragmenterName, ok := config["fragmenter"].(string)
|
|
if !ok {
|
|
return nil, fmt.Errorf("must specify fragmenter")
|
|
}
|
|
fragmenter, err := cache.FragmenterNamed(fragmenterName)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("error building fragmenter: %v", err)
|
|
}
|
|
|
|
formatterName, ok := config["formatter"].(string)
|
|
if !ok {
|
|
return nil, fmt.Errorf("must specify formatter")
|
|
}
|
|
formatter, err := cache.FragmentFormatterNamed(formatterName)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("error building fragment formatter: %v", err)
|
|
}
|
|
|
|
return NewSimpleHighlighter(fragmenter, formatter, separator), nil
|
|
}
|
|
|
|
func init() {
|
|
registry.RegisterHighlighter(Name, Constructor)
|
|
}
|