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set.go
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set.go
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// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// Package set contains set types.
package set
// Set is a set of T.
type Set[T comparable] map[T]struct{}
// Add adds e to the set.
func (s Set[T]) Add(e T) { s[e] = struct{}{} }
// Delete removes e from the set.
func (s Set[T]) Delete(e T) { delete(s, e) }
// Contains reports whether s contains e.
func (s Set[T]) Contains(e T) bool {
_, ok := s[e]
return ok
}
// Len reports the number of items in s.
func (s Set[T]) Len() int { return len(s) }
// HandleSet is a set of T.
//
// It is not safe for concurrent use.
type HandleSet[T any] map[Handle]T
// Handle is a opaque comparable value that's used as the map key
// in a HandleSet. The only way to get one is to call HandleSet.Add.
type Handle struct {
v *byte
}
// Add adds the element (map value) e to the set.
//
// It returns the handle (map key) with which e can be removed, using a map
// delete.
func (s *HandleSet[T]) Add(e T) Handle {
h := Handle{new(byte)}
if *s == nil {
*s = make(HandleSet[T])
}
(*s)[h] = e
return h
}