util/sets.go: Use generics Sets

server/auth.go

@@ -25,7 +25,7 @@ func (service *simpleAuthenticator) CheckUserPassword(userID, password string) e
 	// FIXME: al momento quando la password è giusta creiamo tutti gli account necessari
 	err := service.database.CreateUser(&db.User{
 		ID:          userID,
-		Permissions: make(util.StringSet),
+		Permissions: make(util.Set[string]),
 	})
 	if err != nil {
 		log.Printf(`got "%v" while trying to log as @%s`, err, userID)

server/db/database.go

@@ -32,8 +32,8 @@ const (
 
 // User represents a user in the database.
 type User struct {
-	ID          string         `json:"id"`
-	Permissions util.StringSet `json:"permissions"`
+	ID          string           `json:"id"`
+	Permissions util.Set[string] `json:"permissions"`
 
 	// passwordSaltHash string
 }
@@ -122,7 +122,7 @@ type Database interface {
 	GetRoomOccupiedSeats(roomID string) ([]string, error)
 	GetRoomFreeSeats(roomID string) ([]string, error)
 
-	GetUserSeats(userID string) (util.StringSet, error)
+	GetUserSeats(userID string) (util.Set[string], error)
 
 	OccupySeat(seatID, userID string) error
 	FreeSeat(seatID string) error
@@ -161,12 +161,12 @@ func NewInMemoryStore() Database {
 
 	db.users["aziis98"] = &User{
 		ID:          "aziis98",
-		Permissions: util.NewStringSet(PermissionAdmin),
+		Permissions: util.NewSet[string](PermissionAdmin),
 	}
 
 	db.users["bachoseven"] = &User{
 		ID:          "bachoseven",
-		Permissions: util.NewStringSet(PermissionAdmin),
+		Permissions: util.NewSet[string](PermissionAdmin),
 	}
 
 	return db

server/db/inmemory.go

@@ -146,14 +146,14 @@ func (db *memDB) GetRoomFreeSeats(roomID string) ([]string, error) {
 	return seats, nil
 }
 
-func (db *memDB) GetUserSeats(userID string) (util.StringSet, error) {
+func (db *memDB) GetUserSeats(userID string) (util.Set[string], error) {
 	for _, seat := range db.seats {
 		if len(seat.OccupiedBy) > 0 && seat.OccupiedBy[0] == userID {
-			return util.NewStringSet(seat.ID), nil
+			return util.NewSet[string](seat.ID), nil
 		}
 	}
 
-	return util.NewStringSet(), nil
+	return util.NewSet[string](), nil
 }
 
 func (db *memDB) OccupySeat(seatID, userID string) error {

server/util/sets.go

@@ -4,12 +4,10 @@ import "encoding/json"
 
 type present struct{}
 
-// Waiting for Go 18...
-// type Set[T comparable] map[T]present
-type StringSet map[string]present
+type Set[T comparable] map[T]present
 
-func NewStringSet(elements ...string) StringSet {
-	set := StringSet{}
+func NewSet[T comparable](elements ...T) Set[T] {
+	set := Set[T]{}
 
 	for _, elem := range elements {
 		set.Add(elem)
@@ -18,12 +16,12 @@ func NewStringSet(elements ...string) StringSet {
 	return set
 }
 
-func (set StringSet) Has(value string) bool {
+func (set Set[T]) Has(value T) bool {
 	_, present := set[value]
 	return present
 }
 
-func (set StringSet) HasAny(values ...string) bool {
+func (set Set[T]) HasAny(values ...T) bool {
 	for _, value := range values {
 		if _, present := set[value]; present {
 			return true
@@ -32,7 +30,7 @@ func (set StringSet) HasAny(values ...string) bool {
 	return false
 }
 
-func (set StringSet) Contains(other StringSet) bool {
+func (set Set[T]) Contains(other Set[T]) bool {
 	for v := range other {
 		if !set.Has(v) {
 			return false
@@ -41,16 +39,16 @@ func (set StringSet) Contains(other StringSet) bool {
 	return true
 }
 
-func (set StringSet) Add(value string) {
+func (set Set[T]) Add(value T) {
 	set[value] = present{}
 }
 
-func (set StringSet) Remove(value string) {
+func (set Set[T]) Remove(value T) {
 	delete(set, value)
 }
 
-func (set StringSet) Elements() []string {
-	elements := []string{}
+func (set Set[T]) Elements() []T {
+	elements := []T{}
 
 	for elem := range set {
 		elements = append(elements, elem)
@@ -59,12 +57,12 @@ func (set StringSet) Elements() []string {
 	return elements
 }
 
-func (set StringSet) MarshalJSON() ([]byte, error) {
+func (set Set[T]) MarshalJSON() ([]byte, error) {
 	return json.Marshal(set.Elements())
 }
 
-func (set StringSet) UnmarshalJSON(data []byte) error {
-	elements := []string{}
+func (set Set[T]) UnmarshalJSON(data []byte) error {
+	elements := []T{}
 	if err := json.Unmarshal(data, &elements); err != nil {
 		return err
 	}