Snapshots and snapshot collection.

debian/snapshot.go

@@ -1,8 +1,12 @@
 package debian
 
 import (
+	"bytes"
 	"code.google.com/p/go-uuid/uuid"
 	"fmt"
+	"github.com/smira/aptly/database"
+	"github.com/ugorji/go/codec"
+	"log"
 	"time"
 )
 
@@ -41,6 +45,11 @@ func NewSnapshotFromRepository(name string, repo *RemoteRepo) *Snapshot {
 	}
 }
 
+// String returns string representation of snapshot
+func (s *Snapshot) String() string {
+	return fmt.Sprintf("[%s]: %s", s.Name, s.Description)
+}
+
 // NumPackages returns number of packages in snapshot
 func (s *Snapshot) NumPackages() int {
 	return s.packageRefs.Len()
@@ -50,3 +59,108 @@ func (s *Snapshot) NumPackages() int {
 func (s *Snapshot) Key() []byte {
 	return []byte("S" + s.UUID)
 }
+
+// RefKey is a unique id for package reference list
+func (s *Snapshot) RefKey() []byte {
+	return []byte("E" + s.UUID)
+}
+
+// Encode does msgpack encoding of Snapshot
+func (s *Snapshot) Encode() []byte {
+	var buf bytes.Buffer
+
+	encoder := codec.NewEncoder(&buf, &codec.MsgpackHandle{})
+	encoder.Encode(s)
+
+	return buf.Bytes()
+}
+
+// Decode decodes msgpack representation into Snapshot
+func (s *Snapshot) Decode(input []byte) error {
+	decoder := codec.NewDecoderBytes(input, &codec.MsgpackHandle{})
+	return decoder.Decode(s)
+}
+
+// SnapshotCollection does listing, updating/adding/deleting of Snapshots
+type SnapshotCollection struct {
+	db   database.Storage
+	list []*Snapshot
+}
+
+// NewSnapshotCollection loads Snapshots from DB and makes up collection
+func NewSnapshotCollection(db database.Storage) *SnapshotCollection {
+	result := &SnapshotCollection{
+		db: db,
+	}
+
+	blobs := db.FetchByPrefix([]byte("S"))
+	result.list = make([]*Snapshot, 0, len(blobs))
+
+	for _, blob := range blobs {
+		s := &Snapshot{}
+		if err := s.Decode(blob); err != nil {
+			log.Printf("Error decoding snapshot: %s\n", err)
+		} else {
+			result.list = append(result.list, s)
+		}
+	}
+
+	return result
+}
+
+// Add appends new repo to collection and saves it
+func (collection *SnapshotCollection) Add(snapshot *Snapshot) error {
+	for _, s := range collection.list {
+		if s.Name == snapshot.Name {
+			return fmt.Errorf("snapshot with name %s already exists", snapshot.Name)
+		}
+	}
+
+	err := collection.Update(snapshot)
+	if err != nil {
+		return err
+	}
+
+	collection.list = append(collection.list, snapshot)
+	return nil
+}
+
+// Update stores updated information about repo in DB
+func (collection *SnapshotCollection) Update(snapshot *Snapshot) error {
+	err := collection.db.Put(snapshot.Key(), snapshot.Encode())
+	if err != nil {
+		return err
+	}
+	return collection.db.Put(snapshot.RefKey(), snapshot.packageRefs.Encode())
+}
+
+// LoadComplete loads additional information about snapshot
+func (collection *SnapshotCollection) LoadComplete(snapshot *Snapshot) error {
+	encoded, err := collection.db.Get(snapshot.RefKey())
+	if err == database.ErrNotFound {
+		return nil
+	}
+	if err != nil {
+		return err
+	}
+
+	snapshot.packageRefs = &PackageRefList{}
+	return snapshot.packageRefs.Decode(encoded)
+}
+
+// ByName looks up snapshot by name
+func (collection *SnapshotCollection) ByName(name string) (*Snapshot, error) {
+	for _, s := range collection.list {
+		if s.Name == name {
+			return s, nil
+		}
+	}
+	return nil, fmt.Errorf("snapshot with name %s not found", name)
+}
+
+// ForEach runs method for each snapshot
+func (collection *SnapshotCollection) ForEach(handler func(*Snapshot)) {
+	for _, s := range collection.list {
+		handler(s)
+	}
+}