1 files changed, 111 insertions, 0 deletions
diff --git a/objects/object_snapshot.go b/objects/object_snapshot.go
new file mode 100644
index 0000000..a161f27
--- /dev/null
+++ b/objects/object_snapshot.go
@@ -0,0 +1,111 @@
+package objects
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+	"time"
+)
+
+type Snapshot struct {
+	Tree      ObjectId
+	Date      time.Time
+	Container string
+	Comment   string
+}
+
+func (s Snapshot) Type() ObjectType {
+	return OTSnapshot
+}
+
+func appendKVPair(b []byte, k, v string) []byte {
+	b = append(b, []byte(k)...)
+	b = append(b, ' ')
+	b = append(b, []byte(v)...)
+	b = append(b, '\n')
+	return b
+}
+
+func (s Snapshot) Payload() (out []byte) {
+	out = appendKVPair(out, "container", s.Container)
+	out = appendKVPair(out, "date", s.Date.Format(time.RFC3339))
+	out = appendKVPair(out, "tree", s.Tree.String())
+
+	if s.Comment != "" {
+		out = append(out, '\n')
+		out = append(out, []byte(s.Comment)...)
+	}
+
+	return out
+}
+
+func (s *Snapshot) FromPayload(payload []byte) error {
+	r := bytes.NewBuffer(payload)
+
+	seenContainer := false
+	seenDate := false
+	seenTree := false
+
+	for {
+		line, err := r.ReadString('\n')
+		if err != nil && err != io.EOF {
+			return err
+		}
+		line = strings.TrimSpace(line)
+
+		if line == "" {
+			break // Header read successfully
+		}
+
+		parts := strings.SplitN(line, " ", 2)
+		if len(parts) != 2 {
+			return fmt.Errorf("Invalid header: %s", line)
+		}
+
+		headerval := strings.TrimSpace(parts[1])
+		switch parts[0] {
+		case "container":
+			s.Container = headerval
+			seenContainer = true
+		case "date":
+			d, err := time.Parse(time.RFC3339, headerval)
+			if err != nil {
+				return err
+			}
+			s.Date = d
+			seenDate = true
+		case "tree":
+			oid, err := ParseObjectId(headerval)
+			if err != nil {
+				return err
+			}
+			s.Tree = oid
+			seenTree = true
+		}
+
+		if err == io.EOF {
+			break
+		}
+	}
+
+	if !seenContainer || !seenDate || !seenTree {
+		return errors.New("Missing container, date or tree header")
+	}
+
+	b := new(bytes.Buffer)
+	if _, err := io.Copy(b, r); err != nil {
+		return err
+	}
+
+	s.Comment = strings.TrimSpace(string(b.Bytes()))
+	return nil
+}
+
+func (a Snapshot) Equals(b Snapshot) bool {
+	return a.Tree.Equals(b.Tree) &&
+		a.Container == b.Container &&
+		a.Date.Equal(b.Date) &&
+		a.Comment == b.Comment
+}