Search bar for issues/pulls (#530)

vendor/github.com/blevesearch/bleve/index_alias_impl.go

@@ -0,0 +1,605 @@
+//  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 bleve
+
+import (
+	"sort"
+	"sync"
+	"time"
+
+	"golang.org/x/net/context"
+
+	"github.com/blevesearch/bleve/document"
+	"github.com/blevesearch/bleve/index"
+	"github.com/blevesearch/bleve/index/store"
+	"github.com/blevesearch/bleve/mapping"
+	"github.com/blevesearch/bleve/search"
+)
+
+type indexAliasImpl struct {
+	name    string
+	indexes []Index
+	mutex   sync.RWMutex
+	open    bool
+}
+
+// NewIndexAlias creates a new IndexAlias over the provided
+// Index objects.
+func NewIndexAlias(indexes ...Index) *indexAliasImpl {
+	return &indexAliasImpl{
+		name:    "alias",
+		indexes: indexes,
+		open:    true,
+	}
+}
+
+func (i *indexAliasImpl) isAliasToSingleIndex() error {
+	if len(i.indexes) < 1 {
+		return ErrorAliasEmpty
+	} else if len(i.indexes) > 1 {
+		return ErrorAliasMulti
+	}
+	return nil
+}
+
+func (i *indexAliasImpl) Index(id string, data interface{}) error {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	if !i.open {
+		return ErrorIndexClosed
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		return err
+	}
+
+	return i.indexes[0].Index(id, data)
+}
+
+func (i *indexAliasImpl) Delete(id string) error {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	if !i.open {
+		return ErrorIndexClosed
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		return err
+	}
+
+	return i.indexes[0].Delete(id)
+}
+
+func (i *indexAliasImpl) Batch(b *Batch) error {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	if !i.open {
+		return ErrorIndexClosed
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		return err
+	}
+
+	return i.indexes[0].Batch(b)
+}
+
+func (i *indexAliasImpl) Document(id string) (*document.Document, error) {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	if !i.open {
+		return nil, ErrorIndexClosed
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		return nil, err
+	}
+
+	return i.indexes[0].Document(id)
+}
+
+func (i *indexAliasImpl) DocCount() (uint64, error) {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	rv := uint64(0)
+
+	if !i.open {
+		return 0, ErrorIndexClosed
+	}
+
+	for _, index := range i.indexes {
+		otherCount, err := index.DocCount()
+		if err == nil {
+			rv += otherCount
+		}
+		// tolerate errors to produce partial counts
+	}
+
+	return rv, nil
+}
+
+func (i *indexAliasImpl) Search(req *SearchRequest) (*SearchResult, error) {
+	return i.SearchInContext(context.Background(), req)
+}
+
+func (i *indexAliasImpl) SearchInContext(ctx context.Context, req *SearchRequest) (*SearchResult, error) {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	if !i.open {
+		return nil, ErrorIndexClosed
+	}
+
+	if len(i.indexes) < 1 {
+		return nil, ErrorAliasEmpty
+	}
+
+	// short circuit the simple case
+	if len(i.indexes) == 1 {
+		return i.indexes[0].SearchInContext(ctx, req)
+	}
+
+	return MultiSearch(ctx, req, i.indexes...)
+}
+
+func (i *indexAliasImpl) Fields() ([]string, error) {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	if !i.open {
+		return nil, ErrorIndexClosed
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		return nil, err
+	}
+
+	return i.indexes[0].Fields()
+}
+
+func (i *indexAliasImpl) FieldDict(field string) (index.FieldDict, error) {
+	i.mutex.RLock()
+
+	if !i.open {
+		i.mutex.RUnlock()
+		return nil, ErrorIndexClosed
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		i.mutex.RUnlock()
+		return nil, err
+	}
+
+	fieldDict, err := i.indexes[0].FieldDict(field)
+	if err != nil {
+		i.mutex.RUnlock()
+		return nil, err
+	}
+
+	return &indexAliasImplFieldDict{
+		index:     i,
+		fieldDict: fieldDict,
+	}, nil
+}
+
+func (i *indexAliasImpl) FieldDictRange(field string, startTerm []byte, endTerm []byte) (index.FieldDict, error) {
+	i.mutex.RLock()
+
+	if !i.open {
+		i.mutex.RUnlock()
+		return nil, ErrorIndexClosed
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		i.mutex.RUnlock()
+		return nil, err
+	}
+
+	fieldDict, err := i.indexes[0].FieldDictRange(field, startTerm, endTerm)
+	if err != nil {
+		i.mutex.RUnlock()
+		return nil, err
+	}
+
+	return &indexAliasImplFieldDict{
+		index:     i,
+		fieldDict: fieldDict,
+	}, nil
+}
+
+func (i *indexAliasImpl) FieldDictPrefix(field string, termPrefix []byte) (index.FieldDict, error) {
+	i.mutex.RLock()
+
+	if !i.open {
+		i.mutex.RUnlock()
+		return nil, ErrorIndexClosed
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		i.mutex.RUnlock()
+		return nil, err
+	}
+
+	fieldDict, err := i.indexes[0].FieldDictPrefix(field, termPrefix)
+	if err != nil {
+		i.mutex.RUnlock()
+		return nil, err
+	}
+
+	return &indexAliasImplFieldDict{
+		index:     i,
+		fieldDict: fieldDict,
+	}, nil
+}
+
+func (i *indexAliasImpl) Close() error {
+	i.mutex.Lock()
+	defer i.mutex.Unlock()
+
+	i.open = false
+	return nil
+}
+
+func (i *indexAliasImpl) Mapping() mapping.IndexMapping {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	if !i.open {
+		return nil
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		return nil
+	}
+
+	return i.indexes[0].Mapping()
+}
+
+func (i *indexAliasImpl) Stats() *IndexStat {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	if !i.open {
+		return nil
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		return nil
+	}
+
+	return i.indexes[0].Stats()
+}
+
+func (i *indexAliasImpl) StatsMap() map[string]interface{} {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	if !i.open {
+		return nil
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		return nil
+	}
+
+	return i.indexes[0].StatsMap()
+}
+
+func (i *indexAliasImpl) GetInternal(key []byte) ([]byte, error) {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	if !i.open {
+		return nil, ErrorIndexClosed
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		return nil, err
+	}
+
+	return i.indexes[0].GetInternal(key)
+}
+
+func (i *indexAliasImpl) SetInternal(key, val []byte) error {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	if !i.open {
+		return ErrorIndexClosed
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		return err
+	}
+
+	return i.indexes[0].SetInternal(key, val)
+}
+
+func (i *indexAliasImpl) DeleteInternal(key []byte) error {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	if !i.open {
+		return ErrorIndexClosed
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		return err
+	}
+
+	return i.indexes[0].DeleteInternal(key)
+}
+
+func (i *indexAliasImpl) Advanced() (index.Index, store.KVStore, error) {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	if !i.open {
+		return nil, nil, ErrorIndexClosed
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return i.indexes[0].Advanced()
+}
+
+func (i *indexAliasImpl) Add(indexes ...Index) {
+	i.mutex.Lock()
+	defer i.mutex.Unlock()
+
+	i.indexes = append(i.indexes, indexes...)
+}
+
+func (i *indexAliasImpl) removeSingle(index Index) {
+	for pos, in := range i.indexes {
+		if in == index {
+			i.indexes = append(i.indexes[:pos], i.indexes[pos+1:]...)
+			break
+		}
+	}
+}
+
+func (i *indexAliasImpl) Remove(indexes ...Index) {
+	i.mutex.Lock()
+	defer i.mutex.Unlock()
+
+	for _, in := range indexes {
+		i.removeSingle(in)
+	}
+}
+
+func (i *indexAliasImpl) Swap(in, out []Index) {
+	i.mutex.Lock()
+	defer i.mutex.Unlock()
+
+	// add
+	i.indexes = append(i.indexes, in...)
+
+	// delete
+	for _, ind := range out {
+		i.removeSingle(ind)
+	}
+}
+
+// createChildSearchRequest creates a separate
+// request from the original
+// For now, avoid data race on req structure.
+// TODO disable highlight/field load on child
+// requests, and add code to do this only on
+// the actual final results.
+// Perhaps that part needs to be optional,
+// could be slower in remote usages.
+func createChildSearchRequest(req *SearchRequest) *SearchRequest {
+	rv := SearchRequest{
+		Query:     req.Query,
+		Size:      req.Size + req.From,
+		From:      0,
+		Highlight: req.Highlight,
+		Fields:    req.Fields,
+		Facets:    req.Facets,
+		Explain:   req.Explain,
+		Sort:      req.Sort,
+	}
+	return &rv
+}
+
+type asyncSearchResult struct {
+	Name   string
+	Result *SearchResult
+	Err    error
+}
+
+// MultiSearch executes a SearchRequest across multiple Index objects,
+// then merges the results.  The indexes must honor any ctx deadline.
+func MultiSearch(ctx context.Context, req *SearchRequest, indexes ...Index) (*SearchResult, error) {
+
+	searchStart := time.Now()
+	asyncResults := make(chan *asyncSearchResult, len(indexes))
+
+	// run search on each index in separate go routine
+	var waitGroup sync.WaitGroup
+
+	var searchChildIndex = func(in Index, childReq *SearchRequest) {
+		rv := asyncSearchResult{Name: in.Name()}
+		rv.Result, rv.Err = in.SearchInContext(ctx, childReq)
+		asyncResults <- &rv
+		waitGroup.Done()
+	}
+
+	waitGroup.Add(len(indexes))
+	for _, in := range indexes {
+		go searchChildIndex(in, createChildSearchRequest(req))
+	}
+
+	// on another go routine, close after finished
+	go func() {
+		waitGroup.Wait()
+		close(asyncResults)
+	}()
+
+	var sr *SearchResult
+	indexErrors := make(map[string]error)
+
+	for asr := range asyncResults {
+		if asr.Err == nil {
+			if sr == nil {
+				// first result
+				sr = asr.Result
+			} else {
+				// merge with previous
+				sr.Merge(asr.Result)
+			}
+		} else {
+			indexErrors[asr.Name] = asr.Err
+		}
+	}
+
+	// merge just concatenated all the hits
+	// now lets clean it up
+
+	// handle case where no results were successful
+	if sr == nil {
+		sr = &SearchResult{
+			Status: &SearchStatus{
+				Errors: make(map[string]error),
+			},
+		}
+	}
+
+	// sort all hits with the requested order
+	if len(req.Sort) > 0 {
+		sorter := newMultiSearchHitSorter(req.Sort, sr.Hits)
+		sort.Sort(sorter)
+	}
+
+	// now skip over the correct From
+	if req.From > 0 && len(sr.Hits) > req.From {
+		sr.Hits = sr.Hits[req.From:]
+	} else if req.From > 0 {
+		sr.Hits = search.DocumentMatchCollection{}
+	}
+
+	// now trim to the correct size
+	if req.Size > 0 && len(sr.Hits) > req.Size {
+		sr.Hits = sr.Hits[0:req.Size]
+	}
+
+	// fix up facets
+	for name, fr := range req.Facets {
+		sr.Facets.Fixup(name, fr.Size)
+	}
+
+	// fix up original request
+	sr.Request = req
+	searchDuration := time.Since(searchStart)
+	sr.Took = searchDuration
+
+	// fix up errors
+	if len(indexErrors) > 0 {
+		if sr.Status.Errors == nil {
+			sr.Status.Errors = make(map[string]error)
+		}
+		for indexName, indexErr := range indexErrors {
+			sr.Status.Errors[indexName] = indexErr
+			sr.Status.Total++
+			sr.Status.Failed++
+		}
+	}
+
+	return sr, nil
+}
+
+func (i *indexAliasImpl) NewBatch() *Batch {
+	i.mutex.RLock()
+	defer i.mutex.RUnlock()
+
+	if !i.open {
+		return nil
+	}
+
+	err := i.isAliasToSingleIndex()
+	if err != nil {
+		return nil
+	}
+
+	return i.indexes[0].NewBatch()
+}
+
+func (i *indexAliasImpl) Name() string {
+	return i.name
+}
+
+func (i *indexAliasImpl) SetName(name string) {
+	i.name = name
+}
+
+type indexAliasImplFieldDict struct {
+	index     *indexAliasImpl
+	fieldDict index.FieldDict
+}
+
+func (f *indexAliasImplFieldDict) Next() (*index.DictEntry, error) {
+	return f.fieldDict.Next()
+}
+
+func (f *indexAliasImplFieldDict) Close() error {
+	defer f.index.mutex.RUnlock()
+	return f.fieldDict.Close()
+}
+
+type multiSearchHitSorter struct {
+	hits          search.DocumentMatchCollection
+	sort          search.SortOrder
+	cachedScoring []bool
+	cachedDesc    []bool
+}
+
+func newMultiSearchHitSorter(sort search.SortOrder, hits search.DocumentMatchCollection) *multiSearchHitSorter {
+	return &multiSearchHitSorter{
+		sort:          sort,
+		hits:          hits,
+		cachedScoring: sort.CacheIsScore(),
+		cachedDesc:    sort.CacheDescending(),
+	}
+}
+
+func (m *multiSearchHitSorter) Len() int      { return len(m.hits) }
+func (m *multiSearchHitSorter) Swap(i, j int) { m.hits[i], m.hits[j] = m.hits[j], m.hits[i] }
+func (m *multiSearchHitSorter) Less(i, j int) bool {
+	c := m.sort.Compare(m.cachedScoring, m.cachedDesc, m.hits[i], m.hits[j])
+	return c < 0
+}