Adding upstream version 2.5.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

search/query/query.go

@@ -0,0 +1,783 @@
+//  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 query
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"strings"
+
+	"github.com/blevesearch/bleve/v2/analysis"
+	"github.com/blevesearch/bleve/v2/mapping"
+	"github.com/blevesearch/bleve/v2/search"
+	"github.com/blevesearch/bleve/v2/search/searcher"
+	"github.com/blevesearch/bleve/v2/util"
+	index "github.com/blevesearch/bleve_index_api"
+)
+
+var logger = log.New(io.Discard, "bleve mapping ", log.LstdFlags)
+
+// SetLog sets the logger used for logging
+// by default log messages are sent to io.Discard
+func SetLog(l *log.Logger) {
+	logger = l
+}
+
+// A Query represents a description of the type
+// and parameters for a query into the index.
+type Query interface {
+	Searcher(ctx context.Context, i index.IndexReader, m mapping.IndexMapping,
+		options search.SearcherOptions) (search.Searcher, error)
+}
+
+// A BoostableQuery represents a Query which can be boosted
+// relative to other queries.
+type BoostableQuery interface {
+	Query
+	SetBoost(b float64)
+	Boost() float64
+}
+
+// A FieldableQuery represents a Query which can be restricted
+// to a single field.
+type FieldableQuery interface {
+	Query
+	SetField(f string)
+	Field() string
+}
+
+// A ValidatableQuery represents a Query which can be validated
+// prior to execution.
+type ValidatableQuery interface {
+	Query
+	Validate() error
+}
+
+// ParsePreSearchData deserializes a JSON representation of
+// a PreSearchData object.
+func ParsePreSearchData(input []byte) (map[string]interface{}, error) {
+	var rv map[string]interface{}
+
+	var tmp map[string]json.RawMessage
+	err := util.UnmarshalJSON(input, &tmp)
+	if err != nil {
+		return nil, err
+	}
+
+	for k, v := range tmp {
+		switch k {
+		case search.KnnPreSearchDataKey:
+			var value []*search.DocumentMatch
+			if v != nil {
+				err := util.UnmarshalJSON(v, &value)
+				if err != nil {
+					return nil, err
+				}
+			}
+			if rv == nil {
+				rv = make(map[string]interface{})
+			}
+			rv[search.KnnPreSearchDataKey] = value
+		case search.SynonymPreSearchDataKey:
+			var value search.FieldTermSynonymMap
+			if v != nil {
+				err := util.UnmarshalJSON(v, &value)
+				if err != nil {
+					return nil, err
+				}
+			}
+			if rv == nil {
+				rv = make(map[string]interface{})
+			}
+			rv[search.SynonymPreSearchDataKey] = value
+		case search.BM25PreSearchDataKey:
+			var value *search.BM25Stats
+			if v != nil {
+				err := util.UnmarshalJSON(v, &value)
+				if err != nil {
+					return nil, err
+				}
+			}
+			if rv == nil {
+				rv = make(map[string]interface{})
+			}
+			rv[search.BM25PreSearchDataKey] = value
+
+		}
+	}
+	return rv, nil
+}
+
+// ParseQuery deserializes a JSON representation of
+// a Query object.
+func ParseQuery(input []byte) (Query, error) {
+	if len(input) == 0 {
+		// interpret as a match_none query
+		return NewMatchNoneQuery(), nil
+	}
+
+	var tmp map[string]interface{}
+	err := util.UnmarshalJSON(input, &tmp)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(tmp) == 0 {
+		// interpret as a match_none query
+		return NewMatchNoneQuery(), nil
+	}
+
+	_, hasFuzziness := tmp["fuzziness"]
+	_, isMatchQuery := tmp["match"]
+	_, isMatchPhraseQuery := tmp["match_phrase"]
+	_, hasTerms := tmp["terms"]
+	if hasFuzziness && !isMatchQuery && !isMatchPhraseQuery && !hasTerms {
+		var rv FuzzyQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	if isMatchQuery {
+		var rv MatchQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	if isMatchPhraseQuery {
+		var rv MatchPhraseQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	if hasTerms {
+		var rv PhraseQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			// now try multi-phrase
+			var rv2 MultiPhraseQuery
+			err = util.UnmarshalJSON(input, &rv2)
+			if err != nil {
+				return nil, err
+			}
+			return &rv2, nil
+		}
+		return &rv, nil
+	}
+	_, isTermQuery := tmp["term"]
+	if isTermQuery {
+		var rv TermQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasMust := tmp["must"]
+	_, hasShould := tmp["should"]
+	_, hasMustNot := tmp["must_not"]
+	if hasMust || hasShould || hasMustNot {
+		var rv BooleanQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasConjuncts := tmp["conjuncts"]
+	if hasConjuncts {
+		var rv ConjunctionQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasDisjuncts := tmp["disjuncts"]
+	if hasDisjuncts {
+		var rv DisjunctionQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+
+	_, hasSyntaxQuery := tmp["query"]
+	if hasSyntaxQuery {
+		var rv QueryStringQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasMin := tmp["min"].(float64)
+	_, hasMax := tmp["max"].(float64)
+	if hasMin || hasMax {
+		var rv NumericRangeQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasMinStr := tmp["min"].(string)
+	_, hasMaxStr := tmp["max"].(string)
+	if hasMinStr || hasMaxStr {
+		var rv TermRangeQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasStart := tmp["start"]
+	_, hasEnd := tmp["end"]
+	if hasStart || hasEnd {
+		var rv DateRangeStringQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasPrefix := tmp["prefix"]
+	if hasPrefix {
+		var rv PrefixQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasRegexp := tmp["regexp"]
+	if hasRegexp {
+		var rv RegexpQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasWildcard := tmp["wildcard"]
+	if hasWildcard {
+		var rv WildcardQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasMatchAll := tmp["match_all"]
+	if hasMatchAll {
+		var rv MatchAllQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasMatchNone := tmp["match_none"]
+	if hasMatchNone {
+		var rv MatchNoneQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasDocIds := tmp["ids"]
+	if hasDocIds {
+		var rv DocIDQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasBool := tmp["bool"]
+	if hasBool {
+		var rv BoolFieldQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasTopLeft := tmp["top_left"]
+	_, hasBottomRight := tmp["bottom_right"]
+	if hasTopLeft && hasBottomRight {
+		var rv GeoBoundingBoxQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasDistance := tmp["distance"]
+	if hasDistance {
+		var rv GeoDistanceQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+	_, hasPoints := tmp["polygon_points"]
+	if hasPoints {
+		var rv GeoBoundingPolygonQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+
+	_, hasGeo := tmp["geometry"]
+	if hasGeo {
+		var rv GeoShapeQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+
+	_, hasCIDR := tmp["cidr"]
+	if hasCIDR {
+		var rv IPRangeQuery
+		err := util.UnmarshalJSON(input, &rv)
+		if err != nil {
+			return nil, err
+		}
+		return &rv, nil
+	}
+
+	return nil, fmt.Errorf("unknown query type")
+}
+
+// expandQuery traverses the input query tree and returns a new tree where
+// query string queries have been expanded into base queries. Returned tree may
+// reference queries from the input tree or new queries.
+func expandQuery(m mapping.IndexMapping, query Query) (Query, error) {
+	var expand func(query Query) (Query, error)
+	var expandSlice func(queries []Query) ([]Query, error) = func(queries []Query) ([]Query, error) {
+		expanded := []Query{}
+		for _, q := range queries {
+			exp, err := expand(q)
+			if err != nil {
+				return nil, err
+			}
+			expanded = append(expanded, exp)
+		}
+		return expanded, nil
+	}
+
+	expand = func(query Query) (Query, error) {
+		switch q := query.(type) {
+		case *QueryStringQuery:
+			parsed, err := parseQuerySyntax(q.Query)
+			if err != nil {
+				return nil, fmt.Errorf("could not parse '%s': %s", q.Query, err)
+			}
+			return expand(parsed)
+		case *ConjunctionQuery:
+			children, err := expandSlice(q.Conjuncts)
+			if err != nil {
+				return nil, err
+			}
+			q.Conjuncts = children
+			return q, nil
+		case *DisjunctionQuery:
+			children, err := expandSlice(q.Disjuncts)
+			if err != nil {
+				return nil, err
+			}
+			q.Disjuncts = children
+			return q, nil
+		case *BooleanQuery:
+			var err error
+			q.Must, err = expand(q.Must)
+			if err != nil {
+				return nil, err
+			}
+			q.Should, err = expand(q.Should)
+			if err != nil {
+				return nil, err
+			}
+			q.MustNot, err = expand(q.MustNot)
+			if err != nil {
+				return nil, err
+			}
+			return q, nil
+		default:
+			return query, nil
+		}
+	}
+	return expand(query)
+}
+
+// DumpQuery returns a string representation of the query tree, where query
+// string queries have been expanded into base queries. The output format is
+// meant for debugging purpose and may change in the future.
+func DumpQuery(m mapping.IndexMapping, query Query) (string, error) {
+	q, err := expandQuery(m, query)
+	if err != nil {
+		return "", err
+	}
+	data, err := json.MarshalIndent(q, "", "  ")
+	return string(data), err
+}
+
+// FieldSet represents a set of queried fields.
+type FieldSet map[string]struct{}
+
+// ExtractFields returns a set of fields referenced by the query.
+// The returned set may be nil if the query does not explicitly reference any field
+// and the DefaultSearchField is unset in the index mapping.
+func ExtractFields(q Query, m mapping.IndexMapping, fs FieldSet) (FieldSet, error) {
+	if q == nil || m == nil {
+		return fs, nil
+	}
+	var err error
+	switch q := q.(type) {
+	case FieldableQuery:
+		f := q.Field()
+		if f == "" {
+			f = m.DefaultSearchField()
+		}
+		if f != "" {
+			if fs == nil {
+				fs = make(FieldSet)
+			}
+			fs[f] = struct{}{}
+		}
+	case *QueryStringQuery:
+		var expandedQuery Query
+		expandedQuery, err = expandQuery(m, q)
+		if err == nil {
+			fs, err = ExtractFields(expandedQuery, m, fs)
+		}
+	case *BooleanQuery:
+		for _, subq := range []Query{q.Must, q.Should, q.MustNot} {
+			fs, err = ExtractFields(subq, m, fs)
+			if err != nil {
+				break
+			}
+		}
+	case *ConjunctionQuery:
+		for _, subq := range q.Conjuncts {
+			fs, err = ExtractFields(subq, m, fs)
+			if err != nil {
+				break
+			}
+		}
+	case *DisjunctionQuery:
+		for _, subq := range q.Disjuncts {
+			fs, err = ExtractFields(subq, m, fs)
+			if err != nil {
+				break
+			}
+		}
+	}
+	return fs, err
+}
+
+const (
+	FuzzyMatchType = iota
+	RegexpMatchType
+	PrefixMatchType
+)
+
+// ExtractSynonyms extracts synonyms from the query tree and returns a map of
+// field-term pairs to their synonyms. The input query tree is traversed and
+// for each term query, the synonyms are extracted from the synonym source
+// associated with the field. The synonyms are then added to the provided map.
+// The map is returned and may be nil if no synonyms were found.
+func ExtractSynonyms(ctx context.Context, m mapping.SynonymMapping, r index.ThesaurusReader,
+	query Query, rv search.FieldTermSynonymMap,
+) (search.FieldTermSynonymMap, error) {
+	if r == nil || m == nil || query == nil {
+		return rv, nil
+	}
+	var err error
+	resolveFieldAndSource := func(field string) (string, string) {
+		if field == "" {
+			field = m.DefaultSearchField()
+		}
+		return field, m.SynonymSourceForPath(field)
+	}
+	handleAnalyzer := func(analyzerName, field string) (analysis.Analyzer, error) {
+		if analyzerName == "" {
+			analyzerName = m.AnalyzerNameForPath(field)
+		}
+		analyzer := m.AnalyzerNamed(analyzerName)
+		if analyzer == nil {
+			return nil, fmt.Errorf("no analyzer named '%s' registered", analyzerName)
+		}
+		return analyzer, nil
+	}
+	switch q := query.(type) {
+	case *BooleanQuery:
+		rv, err = ExtractSynonyms(ctx, m, r, q.Must, rv)
+		if err != nil {
+			return nil, err
+		}
+		rv, err = ExtractSynonyms(ctx, m, r, q.Should, rv)
+		if err != nil {
+			return nil, err
+		}
+		rv, err = ExtractSynonyms(ctx, m, r, q.MustNot, rv)
+		if err != nil {
+			return nil, err
+		}
+	case *ConjunctionQuery:
+		for _, child := range q.Conjuncts {
+			rv, err = ExtractSynonyms(ctx, m, r, child, rv)
+			if err != nil {
+				return nil, err
+			}
+		}
+	case *DisjunctionQuery:
+		for _, child := range q.Disjuncts {
+			rv, err = ExtractSynonyms(ctx, m, r, child, rv)
+			if err != nil {
+				return nil, err
+			}
+		}
+	case *FuzzyQuery:
+		field, source := resolveFieldAndSource(q.FieldVal)
+		if source != "" {
+			fuzziness := q.Fuzziness
+			if q.autoFuzzy {
+				fuzziness = searcher.GetAutoFuzziness(q.Term)
+			}
+			rv, err = addSynonymsForTermWithMatchType(ctx, FuzzyMatchType, source, field, q.Term, fuzziness, q.Prefix, r, rv)
+			if err != nil {
+				return nil, err
+			}
+		}
+	case *MatchQuery, *MatchPhraseQuery:
+		var analyzerName, matchString, fieldVal string
+		var fuzziness, prefix int
+		var autoFuzzy bool
+		if mq, ok := q.(*MatchQuery); ok {
+			analyzerName, fieldVal, matchString, fuzziness, prefix, autoFuzzy = mq.Analyzer, mq.FieldVal, mq.Match, mq.Fuzziness, mq.Prefix, mq.autoFuzzy
+		} else if mpq, ok := q.(*MatchPhraseQuery); ok {
+			analyzerName, fieldVal, matchString, fuzziness, autoFuzzy = mpq.Analyzer, mpq.FieldVal, mpq.MatchPhrase, mpq.Fuzziness, mpq.autoFuzzy
+		}
+		field, source := resolveFieldAndSource(fieldVal)
+		if source != "" {
+			analyzer, err := handleAnalyzer(analyzerName, field)
+			if err != nil {
+				return nil, err
+			}
+			tokens := analyzer.Analyze([]byte(matchString))
+			for _, token := range tokens {
+				if autoFuzzy {
+					fuzziness = searcher.GetAutoFuzziness(string(token.Term))
+				}
+				rv, err = addSynonymsForTermWithMatchType(ctx, FuzzyMatchType, source, field, string(token.Term), fuzziness, prefix, r, rv)
+				if err != nil {
+					return nil, err
+				}
+			}
+		}
+	case *MultiPhraseQuery, *PhraseQuery:
+		var fieldVal string
+		var fuzziness int
+		var autoFuzzy bool
+		if mpq, ok := q.(*MultiPhraseQuery); ok {
+			fieldVal, fuzziness, autoFuzzy = mpq.FieldVal, mpq.Fuzziness, mpq.autoFuzzy
+		} else if pq, ok := q.(*PhraseQuery); ok {
+			fieldVal, fuzziness, autoFuzzy = pq.FieldVal, pq.Fuzziness, pq.autoFuzzy
+		}
+		field, source := resolveFieldAndSource(fieldVal)
+		if source != "" {
+			var terms []string
+			if mpq, ok := q.(*MultiPhraseQuery); ok {
+				for _, termGroup := range mpq.Terms {
+					terms = append(terms, termGroup...)
+				}
+			} else if pq, ok := q.(*PhraseQuery); ok {
+				terms = pq.Terms
+			}
+			for _, term := range terms {
+				if autoFuzzy {
+					fuzziness = searcher.GetAutoFuzziness(term)
+				}
+				rv, err = addSynonymsForTermWithMatchType(ctx, FuzzyMatchType, source, field, term, fuzziness, 0, r, rv)
+				if err != nil {
+					return nil, err
+				}
+			}
+		}
+	case *PrefixQuery:
+		field, source := resolveFieldAndSource(q.FieldVal)
+		if source != "" {
+			rv, err = addSynonymsForTermWithMatchType(ctx, PrefixMatchType, source, field, q.Prefix, 0, 0, r, rv)
+			if err != nil {
+				return nil, err
+			}
+		}
+	case *QueryStringQuery:
+		expanded, err := expandQuery(m, q)
+		if err != nil {
+			return nil, err
+		}
+		rv, err = ExtractSynonyms(ctx, m, r, expanded, rv)
+		if err != nil {
+			return nil, err
+		}
+	case *TermQuery:
+		field, source := resolveFieldAndSource(q.FieldVal)
+		if source != "" {
+			rv, err = addSynonymsForTerm(ctx, source, field, q.Term, r, rv)
+			if err != nil {
+				return nil, err
+			}
+		}
+	case *RegexpQuery:
+		field, source := resolveFieldAndSource(q.FieldVal)
+		if source != "" {
+			rv, err = addSynonymsForTermWithMatchType(ctx, RegexpMatchType, source, field, strings.TrimPrefix(q.Regexp, "^"), 0, 0, r, rv)
+			if err != nil {
+				return nil, err
+			}
+		}
+	case *WildcardQuery:
+		field, source := resolveFieldAndSource(q.FieldVal)
+		if source != "" {
+			rv, err = addSynonymsForTermWithMatchType(ctx, RegexpMatchType, source, field, wildcardRegexpReplacer.Replace(q.Wildcard), 0, 0, r, rv)
+			if err != nil {
+				return nil, err
+			}
+		}
+	}
+	return rv, nil
+}
+
+// addFuzzySynonymsForTerm finds all terms that match the given term with the
+// given fuzziness and adds their synonyms to the provided map.
+func addSynonymsForTermWithMatchType(ctx context.Context, matchType int, src, field, term string, fuzziness, prefix int,
+	r index.ThesaurusReader, rv search.FieldTermSynonymMap,
+) (search.FieldTermSynonymMap, error) {
+	// Determine the terms based on the match type (fuzzy, prefix, or regexp)
+	var thesKeys index.ThesaurusKeys
+	var err error
+	var terms []string
+	switch matchType {
+	case FuzzyMatchType:
+		// Ensure valid fuzziness
+		if fuzziness == 0 {
+			rv, err = addSynonymsForTerm(ctx, src, field, term, r, rv)
+			if err != nil {
+				return nil, err
+			}
+			return rv, nil
+		}
+		if fuzziness > searcher.MaxFuzziness {
+			return nil, fmt.Errorf("fuzziness exceeds max (%d)", searcher.MaxFuzziness)
+		}
+		if fuzziness < 0 {
+			return nil, fmt.Errorf("invalid fuzziness, negative")
+		}
+		// Handle fuzzy match
+		prefixTerm := ""
+		for i, r := range term {
+			if i < prefix {
+				prefixTerm += string(r)
+			} else {
+				break
+			}
+		}
+		thesKeys, err = r.ThesaurusKeysFuzzy(src, term, fuzziness, prefixTerm)
+	case RegexpMatchType:
+		// Handle regexp match
+		thesKeys, err = r.ThesaurusKeysRegexp(src, term)
+	case PrefixMatchType:
+		// Handle prefix match
+		thesKeys, err = r.ThesaurusKeysPrefix(src, []byte(term))
+	default:
+		return nil, fmt.Errorf("invalid match type: %d", matchType)
+	}
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		if cerr := thesKeys.Close(); cerr != nil && err == nil {
+			err = cerr
+		}
+	}()
+	// Collect the matching terms
+	terms = []string{}
+	tfd, err := thesKeys.Next()
+	for err == nil && tfd != nil {
+		terms = append(terms, tfd.Term)
+		tfd, err = thesKeys.Next()
+	}
+	if err != nil {
+		return nil, err
+	}
+	for _, synTerm := range terms {
+		rv, err = addSynonymsForTerm(ctx, src, field, synTerm, r, rv)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return rv, nil
+}
+
+func addSynonymsForTerm(ctx context.Context, src, field, term string,
+	r index.ThesaurusReader, rv search.FieldTermSynonymMap,
+) (search.FieldTermSynonymMap, error) {
+	termReader, err := r.ThesaurusTermReader(ctx, src, []byte(term))
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		if cerr := termReader.Close(); cerr != nil && err == nil {
+			err = cerr
+		}
+	}()
+	var synonyms []string
+	synonym, err := termReader.Next()
+	for err == nil && synonym != "" {
+		synonyms = append(synonyms, synonym)
+		synonym, err = termReader.Next()
+	}
+	if err != nil {
+		return nil, err
+	}
+	if len(synonyms) > 0 {
+		if rv == nil {
+			rv = make(search.FieldTermSynonymMap)
+		}
+		if _, exists := rv[field]; !exists {
+			rv[field] = make(map[string][]string)
+		}
+		rv[field][term] = synonyms
+	}
+	return rv, nil
+}