Add filter, add READMES

backend_go/selection_queries/helpers.go

@@ -0,0 +1,102 @@
+package selection_queries
+
+import (
+	"encoding/json"
+	"fmt"
+	"sort"
+	"strings"
+)
+
+func nodeKey(termType, iri string) string {
+	return termType + "\x00" + iri
+}
+
+func valuesTerm(n NodeRef) string {
+	if n.TermType == "uri" {
+		if n.IRI == "" {
+			return ""
+		}
+		return "<" + n.IRI + ">"
+	}
+	if n.TermType == "bnode" {
+		if n.IRI == "" {
+			return ""
+		}
+		if strings.HasPrefix(n.IRI, "_:") {
+			return n.IRI
+		}
+		return "_:" + n.IRI
+	}
+	return ""
+}
+
+func termKeyFromSparqlTerm(term sparqlTerm, includeBNodes bool) (string, bool) {
+	if term.Type == "" || term.Value == "" {
+		return "", false
+	}
+	if term.Type == "literal" {
+		return "", false
+	}
+	if term.Type == "bnode" {
+		if !includeBNodes {
+			return "", false
+		}
+		return nodeKey("bnode", "_:"+term.Value), true
+	}
+	if term.Type == "uri" {
+		return nodeKey("uri", term.Value), true
+	}
+	return "", false
+}
+
+func selectedNodesFromIDs(idx Index, selectedIDs []int, includeBNodes bool) ([]NodeRef, map[int]struct{}) {
+	out := make([]NodeRef, 0, len(selectedIDs))
+	set := make(map[int]struct{}, len(selectedIDs))
+	for _, nid := range selectedIDs {
+		n, ok := idx.IDToNode[nid]
+		if !ok {
+			continue
+		}
+		if n.TermType == "bnode" && !includeBNodes {
+			continue
+		}
+		out = append(out, n)
+		set[nid] = struct{}{}
+	}
+	return out, set
+}
+
+func idsFromBindings(raw []byte, varName string, idx Index, selectedSet map[int]struct{}, includeBNodes bool) ([]int, error) {
+	var res sparqlResponse
+	if err := json.Unmarshal(raw, &res); err != nil {
+		return nil, fmt.Errorf("failed to parse SPARQL JSON: %w", err)
+	}
+
+	neighborSet := make(map[int]struct{})
+	for _, b := range res.Results.Bindings {
+		term, ok := b[varName]
+		if !ok {
+			continue
+		}
+		key, ok := termKeyFromSparqlTerm(term, includeBNodes)
+		if !ok {
+			continue
+		}
+		nid, ok := idx.KeyToID[key]
+		if !ok {
+			continue
+		}
+		if _, sel := selectedSet[nid]; sel {
+			continue
+		}
+		neighborSet[nid] = struct{}{}
+	}
+
+	ids := make([]int, 0, len(neighborSet))
+	for nid := range neighborSet {
+		ids = append(ids, nid)
+	}
+	sort.Ints(ids)
+	return ids, nil
+}
+