522f9d5cc7
this introduces disk format v4 now the summary rows for a term are stored in their own "dictionary row" format, previously the same information was stored in special term frequency rows this now allows us to easily iterate all the terms for a field in sorted order (useful for many other fuzzy data structures) at the top-level of bleve you can now browse terms within a field using the following api on the Index interface: FieldDict(field string) (index.FieldDict, error) FieldDictRange(field string, startTerm []byte, endTerm []byte) (index.FieldDict, error) FieldDictPrefix(field string, termPrefix []byte) (index.FieldDict, error) fixes #127
110 lines
2.9 KiB
Go
110 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 searchers
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import (
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"github.com/blevesearch/bleve/index"
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"github.com/blevesearch/bleve/search"
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)
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type FuzzySearcher struct {
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indexReader index.IndexReader
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term string
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prefix int
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fuzziness int
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field string
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explain bool
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searcher *DisjunctionSearcher
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}
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func NewFuzzySearcher(indexReader index.IndexReader, term string, prefix, fuzziness int, field string, boost float64, explain bool) (*FuzzySearcher, error) {
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prefixTerm := ""
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for i, r := range term {
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if i < prefix {
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prefixTerm += string(r)
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}
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}
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// find the terms with this prefix
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var fieldDict index.FieldDict
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var err error
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if len(prefixTerm) > 0 {
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fieldDict, err = indexReader.FieldDictPrefix(field, []byte(prefixTerm))
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} else {
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fieldDict, err = indexReader.FieldDict(field)
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}
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// enumerate terms and check levenshtein distance
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candidateTerms := make([]string, 0)
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tfd, err := fieldDict.Next()
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for err == nil && tfd != nil {
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ld, exceeded := search.LevenshteinDistanceMax(&term, &tfd.Term, fuzziness)
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if !exceeded && ld <= fuzziness {
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candidateTerms = append(candidateTerms, tfd.Term)
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}
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tfd, err = fieldDict.Next()
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}
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// enumerate all the terms in the range
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qsearchers := make([]search.Searcher, 0, 25)
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for _, cterm := range candidateTerms {
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qsearcher, err := NewTermSearcher(indexReader, cterm, field, 1.0, explain)
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if err != nil {
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return nil, err
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}
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qsearchers = append(qsearchers, qsearcher)
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}
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// build disjunction searcher of these ranges
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searcher, err := NewDisjunctionSearcher(indexReader, qsearchers, 0, explain)
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if err != nil {
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return nil, err
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}
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return &FuzzySearcher{
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indexReader: indexReader,
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term: term,
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prefix: prefix,
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fuzziness: fuzziness,
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field: field,
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explain: explain,
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searcher: searcher,
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}, nil
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}
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func (s *FuzzySearcher) Count() uint64 {
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return s.searcher.Count()
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}
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func (s *FuzzySearcher) Weight() float64 {
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return s.searcher.Weight()
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}
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func (s *FuzzySearcher) SetQueryNorm(qnorm float64) {
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s.searcher.SetQueryNorm(qnorm)
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}
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func (s *FuzzySearcher) Next() (*search.DocumentMatch, error) {
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return s.searcher.Next()
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}
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func (s *FuzzySearcher) Advance(ID string) (*search.DocumentMatch, error) {
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return s.searcher.Next()
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}
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func (s *FuzzySearcher) Close() error {
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return s.searcher.Close()
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}
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func (s *FuzzySearcher) Min() int {
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return 0
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}
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