Find snapshot by source.

debian/snapshot.go

@@ -207,6 +207,18 @@ func (collection *SnapshotCollection) ByRemoteRepoSource(repo *RemoteRepo) []*Sn
 	return result
 }
 
+// BySnapshotSource looks up snapshots that have specified snapshot as a source
+func (collection *SnapshotCollection) BySnapshotSource(snapshot *Snapshot) []*Snapshot {
+	result := make([]*Snapshot, 0)
+
+	for _, s := range collection.list {
+		if s.SourceKind == "snapshot" && utils.StrSliceHasItem(s.SourceIDs, snapshot.UUID) {
+			result = append(result, s)
+		}
+	}
+	return result
+}
+
 // ForEach runs method for each snapshot
 func (collection *SnapshotCollection) ForEach(handler func(*Snapshot) error) error {
 	var err error

debian/snapshot_test.go

@@ -171,6 +171,22 @@ func (s *SnapshotCollectionSuite) TestFindByRemoteRepoSource(c *C) {
 	c.Check(s.collection.ByRemoteRepoSource(repo3), DeepEquals, []*Snapshot{})
 }
 
+func (s *SnapshotCollectionSuite) TestFindSnapshotSource(c *C) {
+	snapshot3 := NewSnapshotFromRefList("snap3", []*Snapshot{s.snapshot1, s.snapshot2}, s.reflist, "desc1")
+	snapshot4 := NewSnapshotFromRefList("snap4", []*Snapshot{s.snapshot1}, s.reflist, "desc2")
+	snapshot5 := NewSnapshotFromRefList("snap5", []*Snapshot{snapshot3}, s.reflist, "desc3")
+
+	c.Assert(s.collection.Add(s.snapshot1), IsNil)
+	c.Assert(s.collection.Add(s.snapshot2), IsNil)
+	c.Assert(s.collection.Add(snapshot3), IsNil)
+	c.Assert(s.collection.Add(snapshot4), IsNil)
+	c.Assert(s.collection.Add(snapshot5), IsNil)
+
+	c.Check(s.collection.BySnapshotSource(s.snapshot1), DeepEquals, []*Snapshot{snapshot3, snapshot4})
+	c.Check(s.collection.BySnapshotSource(s.snapshot2), DeepEquals, []*Snapshot{snapshot3})
+	c.Check(s.collection.BySnapshotSource(snapshot5), DeepEquals, []*Snapshot{})
+}
+
 func (s *SnapshotCollectionSuite) TestDrop(c *C) {
 	s.collection.Add(s.snapshot1)
 	s.collection.Add(s.snapshot2)