Adding upstream version 2.5.1.

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

index/scorch/snapshot_index_thes.go

@@ -0,0 +1,107 @@
+//  Copyright (c) 2024 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 scorch
+
+import (
+	"container/heap"
+
+	index "github.com/blevesearch/bleve_index_api"
+	segment "github.com/blevesearch/scorch_segment_api/v2"
+)
+
+type segmentThesCursor struct {
+	thes segment.Thesaurus
+	itr  segment.ThesaurusIterator
+	curr index.ThesaurusEntry
+}
+
+type IndexSnapshotThesaurusKeys struct {
+	snapshot *IndexSnapshot
+	cursors  []*segmentThesCursor
+	entry    index.ThesaurusEntry
+}
+
+func (i *IndexSnapshotThesaurusKeys) Len() int { return len(i.cursors) }
+func (i *IndexSnapshotThesaurusKeys) Less(a, b int) bool {
+	return i.cursors[a].curr.Term < i.cursors[b].curr.Term
+}
+func (i *IndexSnapshotThesaurusKeys) Swap(a, b int) {
+	i.cursors[a], i.cursors[b] = i.cursors[b], i.cursors[a]
+}
+
+func (i *IndexSnapshotThesaurusKeys) Push(x interface{}) {
+	i.cursors = append(i.cursors, x.(*segmentThesCursor))
+}
+
+func (i *IndexSnapshotThesaurusKeys) Pop() interface{} {
+	n := len(i.cursors)
+	x := i.cursors[n-1]
+	i.cursors = i.cursors[0 : n-1]
+	return x
+}
+
+func (i *IndexSnapshotThesaurusKeys) Next() (*index.ThesaurusEntry, error) {
+	if len(i.cursors) == 0 {
+		return nil, nil
+	}
+	i.entry = i.cursors[0].curr
+	next, err := i.cursors[0].itr.Next()
+	if err != nil {
+		return nil, err
+	}
+	if next == nil {
+		// at end of this cursor, remove it
+		heap.Pop(i)
+	} else {
+		// modified heap, fix it
+		i.cursors[0].curr = *next
+		heap.Fix(i, 0)
+	}
+	// look for any other entries with the exact same term
+	for len(i.cursors) > 0 && i.cursors[0].curr.Term == i.entry.Term {
+		next, err := i.cursors[0].itr.Next()
+		if err != nil {
+			return nil, err
+		}
+		if next == nil {
+			// at end of this cursor, remove it
+			heap.Pop(i)
+		} else {
+			// modified heap, fix it
+			i.cursors[0].curr = *next
+			heap.Fix(i, 0)
+		}
+	}
+
+	return &i.entry, nil
+}
+
+func (i *IndexSnapshotThesaurusKeys) Close() error {
+	return nil
+}
+
+func (i *IndexSnapshotThesaurusKeys) Contains(key []byte) (bool, error) {
+	if len(i.cursors) == 0 {
+		return false, nil
+	}
+
+	for _, cursor := range i.cursors {
+		if found, _ := cursor.thes.Contains(key); found {
+			return true, nil
+		}
+	}
+
+	return false, nil
+}