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/**
* Standalone signaling server for the Nextcloud Spreed app.
* Copyright (C) 2021 struktur AG
*
* @author Joachim Bauch <bauch@struktur.de>
*
* @license GNU AGPL version 3 or any later version
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package signaling
import (
"context"
"sync"
)
type Waiter struct {
key string
ctx context.Context
cancel context.CancelFunc
}
func (w *Waiter) Wait(ctx context.Context) error {
select {
case <-w.ctx.Done():
return nil
case <-ctx.Done():
return ctx.Err()
}
}
type Notifier struct {
sync.Mutex
waiters map[string]*Waiter
waiterMap map[string]map[*Waiter]bool
}
func (n *Notifier) NewWaiter(key string) *Waiter {
n.Lock()
defer n.Unlock()
waiter, found := n.waiters[key]
if found {
w := &Waiter{
key: key,
ctx: waiter.ctx,
cancel: waiter.cancel,
}
n.waiterMap[key][w] = true
return w
}
ctx, cancel := context.WithCancel(context.Background())
waiter = &Waiter{
key: key,
ctx: ctx,
cancel: cancel,
}
if n.waiters == nil {
n.waiters = make(map[string]*Waiter)
}
if n.waiterMap == nil {
n.waiterMap = make(map[string]map[*Waiter]bool)
}
n.waiters[key] = waiter
if _, found := n.waiterMap[key]; !found {
n.waiterMap[key] = make(map[*Waiter]bool)
}
n.waiterMap[key][waiter] = true
return waiter
}
func (n *Notifier) Reset() {
n.Lock()
defer n.Unlock()
for _, w := range n.waiters {
w.cancel()
}
n.waiters = nil
n.waiterMap = nil
}
func (n *Notifier) Release(w *Waiter) {
n.Lock()
defer n.Unlock()
if waiters, found := n.waiterMap[w.key]; found {
if _, found := waiters[w]; found {
delete(waiters, w)
if len(waiters) == 0 {
delete(n.waiters, w.key)
w.cancel()
}
}
}
}
func (n *Notifier) Notify(key string) {
n.Lock()
defer n.Unlock()
if w, found := n.waiters[key]; found {
w.cancel()
delete(n.waiters, w.key)
delete(n.waiterMap, w.key)
}
}