1 files changed, 71 insertions, 0 deletions
diff --git a/storage/index.go b/storage/index.go
new file mode 100644
index 0000000..f34abab
--- /dev/null
+++ b/storage/index.go
@@ -0,0 +1,71 @@
+package storage
+
+import (
+	"bufio"
+	"code.laria.me/petrific/objects"
+	"fmt"
+	"io"
+	"strings"
+)
+
+type Index map[objects.ObjectType]map[string]struct{}
+
+func NewIndex() Index {
+	idx := make(Index)
+	idx.Init()
+	return idx
+}
+
+func (idx Index) Init() {
+	for _, t := range objects.AllObjectTypes {
+		idx[t] = make(map[string]struct{})
+	}
+}
+
+func (idx Index) Set(id objects.ObjectId, typ objects.ObjectType) {
+	idx[typ][id.String()] = struct{}{}
+}
+
+func (idx Index) List(typ objects.ObjectType) []objects.ObjectId {
+	ids := make([]objects.ObjectId, 0, len(idx[typ]))
+	for id := range idx[typ] {
+		ids = append(ids, objects.MustParseObjectId(id))
+	}
+
+	return ids
+}
+
+func (idx Index) Save(w io.Writer) error {
+	for t, objs := range idx {
+		for id := range objs {
+			if _, err := fmt.Fprintf(w, "%s %s\n", t, id); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func (idx Index) Load(r io.Reader) error {
+	scan := bufio.NewScanner(r)
+	for scan.Scan() {
+		line := scan.Text()
+
+		parts := strings.SplitN(strings.TrimSpace(line), " ", 2)
+		if len(parts) == 2 {
+			id, err := objects.ParseObjectId(parts[1])
+			if err != nil {
+				return err
+			}
+
+			typ := objects.ObjectType(parts[0])
+
+			if _, ok := idx[typ]; !ok {
+				return fmt.Errorf("Failed loading index: Unknown ObjectType %s", typ)
+			}
+
+			idx[typ][id.String()] = struct{}{}
+		}
+	}
+	return scan.Err()
+}