Method expandOut

query/shortest.go:141–273

(ctx context.Context,
	adjacencyMap map[uint64]map[uint64]mapItem, next chan bool, rch chan error)

}

func (sg *SubGraph) expandOut(ctx context.Context,
	adjacencyMap map[uint64]map[uint64]mapItem, next chan bool, rch chan error) {

	var numEdges uint64
	var exec []*SubGraph
	var err error
	in := []uint64{sg.Params.From}
	sg.SrcUIDs = &pb.List{Uids: in}
	sg.uidMatrix = []*pb.List{{Uids: in}}
	sg.DestUIDs = sg.SrcUIDs

	for _, child := range sg.Children {
		child.SrcUIDs = sg.DestUIDs
		exec = append(exec, child)
	}
	dummy := &SubGraph{}
	for {
		isNext := <-next
		if !isNext {
			return
		}
		rrch := make(chan error, len(exec))
		for _, subgraph := range exec {
			go ProcessGraph(ctx, subgraph, dummy, rrch)
		}

		for range exec {
			select {
			case err = <-rrch:
				if err != nil {
					rch <- err
					return
				}
			case <-ctx.Done():
				rch <- ctx.Err()
				return
			}
		}

		for _, subgraph := range exec {
			select {
			case <-ctx.Done():
				rch <- ctx.Err()
				return
			default:
				if subgraph.UnknownAttr {
					continue
				}

				// Call updateUidMatrix to ensure that entries in the uidMatrix are updated after
				// intersecting with DestUIDs. This should ideally be called during query
				// processing but doesn't seem to be called for shortest path queries. So we call
				// it explicitly here to ensure the results are correct.
				subgraph.updateUidMatrix()
				// Send the destuids in res chan.
				for mIdx, fromUID := range subgraph.SrcUIDs.Uids {
					// This can happen when trying to go traverse a predicate of type password
					// for example.