[#1419] pilorama: Create new nodes in path if needed

Consider a node `{FileName: "dir", Attribute: "xxx"}`. In case we add
a new node by path `["dir", "file.txt"]`, create a new intermediate node
with a single attribute.

`GetByPath` now also considers only nodes with a single attribute while building a path.

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>

pkg/local_object_storage/pilorama/boltdb.go

@@ -470,14 +470,10 @@ loop:
 				return 0, 0, err
 			}
 
-			for j := range m.Items {
-				if m.Items[j].Key == attr {
-					if string(m.Items[j].Value) == path[i] {
-						curNode = child
-						continue loop
-					}
-					break
-				}
+			// Internal nodes have exactly one attribute.
+			if len(m.Items) == 1 && m.Items[0].Key == attr && string(m.Items[0].Value) == path[i] {
+				curNode = child
+				continue loop
 			}
 			childKey, _ = c.Next()
 		}

pkg/local_object_storage/pilorama/forest.go

@@ -59,9 +59,12 @@ func (f *memoryForest) TreeAddByPath(cid cidSDK.ID, treeID string, attr string,
 		node = lm[j-i].Child
 		s.operations = append(s.operations, lm[j-i])
 	}
+
+	mCopy := make([]KeyValue, len(m))
+	copy(mCopy, m)
 	lm[len(lm)-1] = s.do(&Move{
 		Parent: node,
-		Meta:   Meta{Time: s.timestamp(), Items: m},
+		Meta:   Meta{Time: s.timestamp(), Items: mCopy},
 		Child:  s.findSpareID(),
 	})
 	return lm, nil

pkg/local_object_storage/pilorama/forest_test.go

@@ -242,6 +242,44 @@ func testForestTreeAddByPath(t *testing.T, s Forest) {
 	require.Equal(t, 2, len(lm))
 	testMeta(t, s, cid, treeID, lm[0].Child, lm[0].Parent, Meta{Time: lm[0].Time, Items: []KeyValue{{AttributeFilename, []byte("dir")}}})
 	testMeta(t, s, cid, treeID, lm[1].Child, lm[1].Parent, Meta{Time: lm[1].Time, Items: meta})
+
+	t.Run("create internal nodes", func(t *testing.T) {
+		meta[0].Value = []byte("SomeValue")
+		meta[1].Value = []byte("another")
+		lm, err = s.TreeAddByPath(cid, treeID, AttributeFilename, []string{"path"}, meta)
+		require.NoError(t, err)
+		require.Equal(t, 1, len(lm))
+
+		oldMove := lm[0]
+
+		meta[0].Value = []byte("Leaf")
+		meta[1].Value = []byte("file.txt")
+		lm, err = s.TreeAddByPath(cid, treeID, AttributeFilename, []string{"path", "another"}, meta)
+		require.NoError(t, err)
+		require.Equal(t, 2, len(lm))
+
+		testMeta(t, s, cid, treeID, lm[0].Child, lm[0].Parent,
+			Meta{Time: lm[0].Time, Items: []KeyValue{{AttributeFilename, []byte("another")}}})
+		testMeta(t, s, cid, treeID, lm[1].Child, lm[1].Parent, Meta{Time: lm[1].Time, Items: meta})
+
+		require.NotEqual(t, lm[0].Child, oldMove.Child)
+		testMeta(t, s, cid, treeID, oldMove.Child, oldMove.Parent,
+			Meta{Time: oldMove.Time, Items: []KeyValue{
+				{AttributeVersion, []byte("SomeValue")},
+				{AttributeFilename, []byte("another")}}})
+
+		t.Run("get by path", func(t *testing.T) {
+			nodes, err := s.TreeGetByPath(cid, treeID, AttributeFilename, []string{"path", "another"}, false)
+			require.NoError(t, err)
+			require.Equal(t, 2, len(nodes))
+			require.ElementsMatch(t, []Node{lm[0].Child, oldMove.Child}, nodes)
+
+			nodes, err = s.TreeGetByPath(cid, treeID, AttributeFilename, []string{"path", "another", "file.txt"}, false)
+			require.NoError(t, err)
+			require.Equal(t, 1, len(nodes))
+			require.Equal(t, lm[1].Child, nodes[0])
+		})
+	})
 }
 
 func TestForest_Apply(t *testing.T) {
@@ -475,15 +513,18 @@ func testTreeGetByPath(t *testing.T, s Forest) {
 }
 
 func testMove(t *testing.T, s Forest, ts int, node, parent Node, cid cidSDK.ID, treeID, filename, version string) {
+	items := make([]KeyValue, 1, 2)
+	items[0] = KeyValue{AttributeFilename, []byte(filename)}
+	if version != "" {
+		items = append(items, KeyValue{AttributeVersion, []byte(version)})
+	}
+
 	require.NoError(t, s.TreeApply(cid, treeID, &Move{
 		Parent: parent,
 		Child:  node,
 		Meta: Meta{
-			Time: uint64(ts),
-			Items: []KeyValue{
-				{AttributeFilename, []byte(filename)},
-				{AttributeVersion, []byte(version)},
-			},
+			Time:  uint64(ts),
+			Items: items,
 		},
 	}))
 }

pkg/local_object_storage/pilorama/inmemory.go

@@ -184,8 +184,9 @@ loop:
 	for i := range path {
 		children := t.childMap[curNode]
 		for j := range children {
-			f := t.infoMap[children[j]].Meta.GetAttr(attr)
-			if string(f) == path[i] {
+			meta := t.infoMap[children[j]].Meta
+			f := meta.GetAttr(attr)
+			if len(meta.Items) == 1 && string(f) == path[i] {
 				curNode = children[j]
 				continue loop
 			}

pkg/local_object_storage/pilorama/interface.go

@@ -10,6 +10,7 @@ type Forest interface {
 	TreeMove(cid cidSDK.ID, treeID string, m *Move) (*LogMove, error)
 	// TreeAddByPath adds new node in the tree using provided path.
 	// The path is constructed by descending from the root using the values of the attr in meta.
+	// Internal nodes in path should have exactly one attribute, otherwise a new node is created.
 	TreeAddByPath(cid cidSDK.ID, treeID string, attr string, path []string, meta []KeyValue) ([]LogMove, error)
 	// TreeApply applies replicated operation from another node.
 	TreeApply(cid cidSDK.ID, treeID string, m *Move) error