// EnsureReverseEdges checks if gs contains reverse edges. If it doesn't, it
// will scan gs for all forward edges, adding a reverse for each back into the
// GraphStore. This is necessary for a GraphStoreService to work properly.
func EnsureReverseEdges(ctx context.Context, gs graphstore.Service) error {
var edge *spb.Entry
if err := gs.Scan(ctx, &spb.ScanRequest{}, func(e *spb.Entry) error {
if graphstore.IsEdge(e) {
edge = e
return io.EOF
}
return nil
}); err != nil {
return err
}
if edge == nil {
log.Println("No edges found in GraphStore")
return nil
} else if schema.EdgeDirection(edge.EdgeKind) == schema.Reverse {
return nil
}
var foundReverse bool
if err := gs.Read(ctx, &spb.ReadRequest{
Source: edge.Target,
EdgeKind: schema.MirrorEdge(edge.EdgeKind),
}, func(entry *spb.Entry) error {
foundReverse = true
return nil
}); err != nil {
return fmt.Errorf("error checking for reverse edge: %v", err)
}
if foundReverse {
return nil
}
return addReverseEdges(ctx, gs)
}
func readEntries(ctx context.Context, gs graphstore.Service, entryFunc graphstore.EntryFunc, edgeKind string, tickets []string) error {
for _, ticket := range tickets {
src, err := kytheuri.ToVName(ticket)
if err != nil {
return fmt.Errorf("error parsing ticket %q: %v", ticket, err)
}
if err := gs.Read(ctx, &spb.ReadRequest{
Source: src,
EdgeKind: edgeKind,
}, entryFunc); err != nil {
return fmt.Errorf("GraphStore Read error for ticket %q: %v", ticket, err)
}
}
return nil
}
// getEdges returns edgeTargets with the given node as their source. Only edge
// entries that return true when applied to pred are returned.
func getEdges(ctx context.Context, gs graphstore.Service, node *spb.VName, pred func(*spb.Entry) bool) ([]*edgeTarget, error) {
var targets []*edgeTarget
if err := gs.Read(ctx, &spb.ReadRequest{
Source: node,
EdgeKind: "*",
}, func(entry *spb.Entry) error {
if graphstore.IsEdge(entry) && pred(entry) {
targets = append(targets, &edgeTarget{entry.EdgeKind, entry.Target})
}
return nil
}); err != nil {
return nil, fmt.Errorf("read error: %v", err)
}
return targets, nil
}
func getSourceText(ctx context.Context, gs graphstore.Service, fileVName *spb.VName) (text []byte, encoding string, err error) {
if err := gs.Read(ctx, &spb.ReadRequest{Source: fileVName}, func(entry *spb.Entry) error {
switch entry.FactName {
case schema.TextFact:
text = entry.FactValue
case schema.TextEncodingFact:
encoding = string(entry.FactValue)
default:
// skip other file facts
}
return nil
}); err != nil {
return nil, "", fmt.Errorf("read error: %v", err)
}
if text == nil {
err = fmt.Errorf("file not found: %+v", fileVName)
}
return
}