rdf: add DescribeW method for serialization using Encoder

knakk · May 17, 2017 · bd91c78 · bd91c78
1 parent cb2980a
commit bd91c78
Show file tree

Hide file tree

Showing 3 changed files with 62 additions and 0 deletions.
diff --git a/rdf/disk/graph.go b/rdf/disk/graph.go
@@ -123,6 +123,33 @@ func (g *Graph) Describe(nodes ...rdf.NamedNode) (rdf.Graph, error) {
 	return res, err
 }
 
+func (g *Graph) DescribeW(enc *rdf.Encoder, nodes ...rdf.NamedNode) error {
+	return g.kv.View(func(tx *bolt.Tx) error {
+		cache := make(map[uint32]rdf.Node)
+		for _, node := range nodes {
+			sID, err := g.getID(tx, node)
+			if err == ErrNotFound {
+				return nil
+			}
+			if err != nil {
+				return err
+			}
+
+			cache[sID] = node
+			trs, err := g.describe(tx, sID, cache)
+			if err != nil {
+				return err
+			}
+			for _, tr := range trs {
+				if err := enc.Encode(tr); err != nil {
+					return err
+				}
+			}
+		}
+		return nil
+	})
+}
+
 func (g *Graph) describe(tx *bolt.Tx, nodeID uint32, cache map[uint32]rdf.Node) ([]rdf.Triple, error) {
 	// nodeID must represent either a Named Node or Blank Node.
 	var trs []rdf.Triple

diff --git a/rdf/graph.go b/rdf/graph.go
@@ -15,6 +15,8 @@ type Graph interface {
 	// as well all triples of blank nodes which are outgoing relation of the node.
 	Describe(...NamedNode) (Graph, error)
 
+	DescribeW(*Encoder, ...NamedNode) error
+
 	// Update performs an update query which inserts and/or deletes triples
 	// from the Graph.
 	//

diff --git a/rdf/memory/graph.go b/rdf/memory/graph.go
@@ -125,6 +125,39 @@ func (g *Graph) Describe(nodes ...rdf.NamedNode) (rdf.Graph, error) {
 	return res, nil
 }
 
+func (g *Graph) DescribeW(enc *rdf.Encoder, nodes ...rdf.NamedNode) error {
+	for _, node := range nodes {
+		if s, found := g.node2id[node]; found {
+			for p, objs := range g.spo[s] {
+				for _, o := range objs {
+					if err := enc.Encode(rdf.Triple{
+						Subject:   node,
+						Predicate: g.id2node[p].(rdf.NamedNode),
+						Object:    g.id2node[o],
+					}); err != nil {
+						return err
+					}
+					if _, ok := g.id2node[o].(rdf.BlankNode); ok {
+						for p, objs := range g.spo[o] {
+							for _, bo := range objs {
+								if err := enc.Encode(rdf.Triple{
+									Subject:   g.id2node[o].(rdf.SubjectNode),
+									Predicate: g.id2node[p].(rdf.NamedNode),
+									Object:    g.id2node[bo],
+								}); err != nil {
+									return err
+								}
+							}
+						}
+					}
+				}
+			}
+		}
+
+	}
+	return nil
+}
+
 func (g *Graph) Update(del []rdf.TriplePattern, ins []rdf.TriplePattern, where []rdf.TriplePattern) (delN, insN int, err error) {
 	if where != nil {
 		// Encode patterns