Ranges cache: add ownership check (#6004)

* add ownership check. if the value isn't owned, copy it

* stop copying value's bytes since the byte buffer is owned by the calling function

pkg/graveler/committed/value.go

@@ -74,8 +74,7 @@ func getBytes(b *[]byte) ([]byte, error) {
 	if l < 0 {
 		return nil, fmt.Errorf("impossible negative length %d: %w", l, ErrBadValueBytes)
 	}
-	ret := make([]byte, l)
-	copy(ret, (*b)[:l])
+	ret := (*b)[:l]
 	*b = (*b)[l:]
 	return ret, nil
 }

pkg/graveler/sstable/range_manager.go

@@ -92,7 +92,13 @@ func (m *RangeManager) GetValueGE(ctx context.Context, ns committed.Namespace, i
 		}
 		return nil, ErrKeyNotFound
 	}
-	vBytes, _, err := value.Value(nil)
+	vBytes, owned, err := value.Value(nil)
+	if !owned {
+		b := vBytes
+		vBytes = make([]byte, len(b))
+		copy(vBytes, b)
+	}
+
 	if err != nil {
 		return nil, fmt.Errorf("extract value from sstable id %s (key %s): %w", id, key, err)
 	}
@@ -132,7 +138,13 @@ func (m *RangeManager) GetValue(ctx context.Context, ns committed.Namespace, id
 		// lookup path in range but key not found
 		return nil, ErrKeyNotFound
 	}
-	vBytes, _, err := value.Value(nil)
+	vBytes, owned, err := value.Value(nil)
+	if !owned {
+		b := vBytes
+		vBytes = make([]byte, len(b))
+		copy(vBytes, b)
+	}
+
 	if err != nil {
 		return nil, fmt.Errorf("extract value from sstable id %s (key %s): %w", id, key, err)
 	}