Method Update

stack.go:191–218

Update updates an item in the stack without changing its position.

(id uint64, newValue []byte)

// Update updates an item in the stack without changing its position.
func (s *Stack) Update(id uint64, newValue []byte) (*Item, error) {
	s.Lock()
	defer s.Unlock()

	// Check if stack is closed.
	if !s.isOpen {
		return nil, ErrDBClosed
	}

	// Check if item exists in stack.
	if id > s.head || id <= s.tail {
		return nil, ErrOutOfBounds
	}

	// Create new Item.
	item := &Item{
		ID:    id,
		Key:   idToKey(id),
		Value: newValue,
	}

	// Update this item in the stack.
	if err := s.db.Put(item.Key, item.Value, nil); err != nil {
		return nil, err
	}

	return item, nil
}

// UpdateString is a helper function for Update that accepts a value
// as a string rather than a byte slice.