snapshot of https://github.com/blevesearch/bleve.git (master, 2026-09-15; blobs > 131072B omitted)

search/collector/nested.go

@@ -0,0 +1,103 @@
+//  Copyright (c) 2026 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 collector
+
+import (
+	"github.com/blevesearch/bleve/v2/search"
+	index "github.com/blevesearch/bleve_index_api"
+)
+
+type collectStoreNested struct {
+	// descAdder is used to customize how descendants are merged into their parent
+	descAdder search.DescendantAdderCallbackFn
+	// nested reader to retrieve ancestor information
+	nr index.NestedReader
+	// the current root document match being built
+	currRoot *search.DocumentMatch
+	// the ancestor ID of the current root document being built
+	currRootAncestorID index.AncestorID
+	// prealloc slice for ancestor IDs
+	ancestors []index.AncestorID
+}
+
+func newStoreNested(nr index.NestedReader, descAdder search.DescendantAdderCallbackFn) *collectStoreNested {
+	rv := &collectStoreNested{
+		descAdder: descAdder,
+		nr:        nr,
+	}
+	return rv
+}
+
+// ProcessNestedDocument adds a document to the nested store, merging it into its root document
+// as needed. If the returned DocumentMatch is nil, the incoming doc has been merged
+// into its parent and should not be processed further. If the returned DocumentMatch
+// is non-nil, it represents a complete root document that should be processed further.
+// NOTE: This implementation assumes that documents are added in increasing order of their internal IDs
+// which is guaranteed by all searchers in bleve.
+func (c *collectStoreNested) ProcessNestedDocument(ctx *search.SearchContext, doc *search.DocumentMatch) (*search.DocumentMatch, error) {
+	// find ancestors for the doc
+	var err error
+	c.ancestors, err = c.nr.Ancestors(doc.IndexInternalID, c.ancestors[:0])
+	if err != nil {
+		return nil, err
+	}
+	if len(c.ancestors) == 0 {
+		// should not happen, every doc should have at least itself as ancestor
+		return nil, nil
+	}
+	// root docID is the last ancestor
+	rootID := c.ancestors[len(c.ancestors)-1]
+	// check if there is an interim root already and if the incoming doc belongs to it
+	if c.currRoot != nil && c.currRootAncestorID.Equals(rootID) {
+		// there is an interim root already, and the incoming doc belongs to it
+		if err := c.descAdder(c.currRoot, doc); err != nil {
+			return nil, err
+		}
+		// recycle the child document now that it's merged into the interim root
+		ctx.DocumentMatchPool.Put(doc)
+		return nil, nil
+	}
+	// completedRoot is the root document match to return, if any
+	var completedRoot *search.DocumentMatch
+	if c.currRoot != nil {
+		// we have an existing interim root, return it for processing
+		completedRoot = c.currRoot
+	}
+	// no interim root for now so either we have a root document incoming
+	// or we have a child doc and need to create an interim root
+	if len(c.ancestors) == 1 {
+		// incoming doc is the root itself
+		c.currRoot = doc
+		c.currRootAncestorID = rootID
+		return completedRoot, nil
+	}
+	// this is a child doc, create interim root
+	newDM := ctx.DocumentMatchPool.Get()
+	newDM.IndexInternalID = rootID.ToIndexInternalID(newDM.IndexInternalID)
+	// merge the incoming doc into the new interim root
+	c.currRoot = newDM
+	c.currRootAncestorID = rootID
+	if err := c.descAdder(c.currRoot, doc); err != nil {
+		return nil, err
+	}
+	// recycle the child document now that it's merged into the interim root
+	ctx.DocumentMatchPool.Put(doc)
+	return completedRoot, nil
+}
+
+// Current returns the current interim root document match being built, if any
+func (c *collectStoreNested) Current() *search.DocumentMatch {
+	return c.currRoot
+}