package backend

// IDSet is a set of IDs.
type IDSet map[ID]struct{}

// NewIDSet returns a new IDSet, populated with ids.
func NewIDSet(ids ...ID) IDSet {
	m := make(IDSet)
	for _, id := range ids {
		m[id] = struct{}{}
	}

	return m
}

// Has returns true iff id is contained in the set.
func (s IDSet) Has(id ID) bool {
	_, ok := s[id]
	return ok
}

// Insert adds id to the set.
func (s IDSet) Insert(id ID) {
	s[id] = struct{}{}
}

// Delete removes id from the set.
func (s IDSet) Delete(id ID) {
	delete(s, id)
}