[#266] pilorama: Allow to get current tree height

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

pkg/local_object_storage/engine/tree.go

@@ -213,6 +213,14 @@ func (e *StorageEngine) TreeExists(cid cidSDK.ID, treeID string) (bool, error) {
 	return err == nil, err
 }
 
+func (e *StorageEngine) TreeHeight(cid cidSDK.ID, treeID string) (uint64, error) {
+	index, lst, err := e.getTreeShard(cid, treeID)
+	if err != nil {
+		return 0, nil
+	}
+	return lst[index].TreeHeight(cid, treeID)
+}
+
 // TreeUpdateLastSyncHeight implements the pilorama.Forest interface.
 func (e *StorageEngine) TreeUpdateLastSyncHeight(cid cidSDK.ID, treeID string, height uint64) error {
 	index, lst, err := e.getTreeShard(cid, treeID)

pkg/local_object_storage/pilorama/boltdb.go

@@ -174,6 +174,32 @@ func (t *boltForest) TreeMove(d CIDDescriptor, treeID string, m *Move) (*Move, e
 	})
 }
 
+func (t *boltForest) TreeHeight(cid cidSDK.ID, treeID string) (uint64, error) {
+	t.modeMtx.RLock()
+	defer t.modeMtx.RUnlock()
+
+	if t.mode.NoMetabase() {
+		return 0, ErrDegradedMode
+	}
+
+	var height uint64
+	var retErr error
+	err := t.db.View(func(tx *bbolt.Tx) error {
+		treeRoot := tx.Bucket(bucketName(cid, treeID))
+		if treeRoot != nil {
+			k, _ := treeRoot.Bucket(logBucket).Cursor().Last()
+			height = binary.BigEndian.Uint64(k)
+		} else {
+			retErr = ErrTreeNotFound
+		}
+		return nil
+	})
+	if err == nil {
+		err = retErr
+	}
+	return height, err
+}
+
 // TreeExists implements the Forest interface.
 func (t *boltForest) TreeExists(cid cidSDK.ID, treeID string) (bool, error) {
 	t.modeMtx.RLock()

pkg/local_object_storage/pilorama/forest.go

@@ -216,6 +216,15 @@ func (f *memoryForest) TreeList(cid cid.ID) ([]string, error) {
 	return res, nil
 }
 
+func (f *memoryForest) TreeHeight(cid cid.ID, treeID string) (uint64, error) {
+	fullID := cid.EncodeToString() + "/" + treeID
+	tree, ok := f.treeMap[fullID]
+	if !ok {
+		return 0, ErrTreeNotFound
+	}
+	return tree.operations[len(tree.operations)-1].Time, nil
+}
+
 // TreeExists implements the pilorama.Forest interface.
 func (f *memoryForest) TreeExists(cid cid.ID, treeID string) (bool, error) {
 	fullID := cid.EncodeToString() + "/" + treeID

pkg/local_object_storage/pilorama/forest_test.go

@@ -527,9 +527,18 @@ func testForestTreeExists(t *testing.T, constructor func(t testing.TB, opts ...O
 		checkExists(t, false, cid, treeID)
 	})
 
-	require.NoError(t, s.TreeApply(cid, treeID, &Move{Parent: 0, Child: 1}, false))
+	require.NoError(t, s.TreeApply(cid, treeID, &Move{Meta: Meta{Time: 11}, Parent: 0, Child: 1}, false))
 	checkExists(t, true, cid, treeID)
+
+	height, err := s.TreeHeight(cid, treeID)
+	require.NoError(t, err)
+	require.EqualValues(t, 11, height)
+
 	checkExists(t, false, cidtest.ID(), treeID) // different CID, same tree
+
+	_, err = s.TreeHeight(cidtest.ID(), treeID)
+	require.ErrorIs(t, err, ErrTreeNotFound)
+
 	checkExists(t, false, cid, "another tree") // same CID, different tree
 
 	t.Run("can be removed", func(t *testing.T) {

pkg/local_object_storage/pilorama/interface.go

@@ -48,6 +48,8 @@ type Forest interface {
 	TreeUpdateLastSyncHeight(cid cidSDK.ID, treeID string, height uint64) error
 	// TreeLastSyncHeight returns last log height synchronized with _all_ container nodes.
 	TreeLastSyncHeight(cid cidSDK.ID, treeID string) (uint64, error)
+	// TreeHeight returns current tree height.
+	TreeHeight(cid cidSDK.ID, treeID string) (uint64, error)
 }
 
 type ForestStorage interface {

pkg/local_object_storage/shard/tree.go

@@ -155,6 +155,13 @@ func (s *Shard) TreeList(cid cidSDK.ID) ([]string, error) {
 	return s.pilorama.TreeList(cid)
 }
 
+func (s *Shard) TreeHeight(cid cidSDK.ID, treeID string) (uint64, error) {
+	if s.pilorama == nil {
+		return 0, ErrPiloramaDisabled
+	}
+	return s.pilorama.TreeHeight(cid, treeID)
+}
+
 // TreeExists implements the pilorama.Forest interface.
 func (s *Shard) TreeExists(cid cidSDK.ID, treeID string) (bool, error) {
 	if s.pilorama == nil {