set.go

package gossip

import "sync"

// Set is a generic and thread-safe
// set container
type Set struct {
	items map[interface{}]struct{}
	lock  *sync.RWMutex
}

// NewSet returns a new set
func NewSet() *Set {
	return &Set{lock: &sync.RWMutex{}, items: make(map[interface{}]struct{})}
}

// Add adds given item to the set
func (s *Set) Add(item interface{}) {
	s.lock.Lock()
	defer s.lock.Unlock()
	s.items[item] = struct{}{}
}

// Exists returns true whether given item is in the set
func (s *Set) Exists(item interface{}) bool {
	s.lock.RLock()
	defer s.lock.RUnlock()
	_, exists := s.items[item]
	return exists
}

// Size returns the size of the set
func (s *Set) Size() int {
	s.lock.RLock()
	defer s.lock.RUnlock()
	return len(s.items)
}

// ToArray returns a slice with items
// at the point in time the method was invoked
func (s *Set) ToArray() []interface{} {
	s.lock.RLock()
	defer s.lock.RUnlock()
	a := make([]interface{}, len(s.items))
	i := 0
	for item := range s.items {
		a[i] = item
		i++
	}
	return a
}

// Clear removes all elements from set
func (s *Set) Clear() {
	s.lock.Lock()
	defer s.lock.Unlock()
	s.items = make(map[interface{}]struct{})
}

// Remove removes a given item from the set
func (s *Set) Remove(item interface{}) {
	s.lock.Lock()
	defer s.lock.Unlock()
	delete(s.items, item)
}