func (self *Server) SignUp(user string) error {
if len(user) > trib.MaxUsernameLen {
return fmt.Errorf("username %q too long", user)
}
if !trib.IsValidUsername(user) {
return fmt.Errorf("invalid username %q", user)
}
self.lock.Lock()
defer self.lock.Unlock()
_, found := self.users[user]
if found {
return fmt.Errorf("user %q already exists", user)
}
self.users[user] = newUser()
return nil
}
func (self *FrontServer) SignUp(user string) error {
if len(user) > trib.MaxUsernameLen {
return fmt.Errorf("username %q too long", user)
}
if !trib.IsValidUsername(user) {
return fmt.Errorf("invalid username %q", user)
}
self.lock.Lock()
defer self.lock.Unlock()
client := self.storageClient.Bin(user)
// make sure the global buffer is not a user
anotherClient := self.storageClient.Bin("GlobalUsersCache")
value := ""
succ := false
if e := anotherClient.Get("Existence", &value); e != nil {
return e
}
if value != "True" {
succ = false
if e := anotherClient.Set(&trib.KeyValue{"Existence", "True"}, &succ); e != nil {
return e
}
}
// check existence:
value = ""
if e := client.Get("Existence", &value); e != nil {
return e
}
if value == "True" {
return fmt.Errorf("user %q already exists", user)
}
// simulate a lock using key-value store
succ = false
if e := self.Lock("SignupLock", client, &succ); e != nil {
return e
}
// try signup
succ = false
if e := client.Set(&trib.KeyValue{"Existence", "True"}, &succ); e != nil {
return e
}
// try unlock
unlock, e := self.Unlock("SignupLock", client)
if e != nil {
return e
}
if unlock == true {
// add to global cache
if len(self.usersCache) < trib.MinListUser {
self.usersCache = append(self.usersCache, user)
succ = false
if e := anotherClient.ListAppend(&trib.KeyValue{"Usernames", user}, &succ); e != nil {
return e
}
}
return nil
} else {
return fmt.Errorf("user %q already signed up by others..", user)
}
}