77 lines
1.8 KiB
Go
77 lines
1.8 KiB
Go
/**
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* Standalone signaling server for the Nextcloud Spreed app.
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* Copyright (C) 2022 struktur AG
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*
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* @author Joachim Bauch <bauch@struktur.de>
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*
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* @license GNU AGPL version 3 or any later version
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package signaling
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import (
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"context"
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"fmt"
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"time"
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)
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type Backoff interface {
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Reset()
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NextWait() time.Duration
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Wait(context.Context)
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}
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type exponentialBackoff struct {
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initial time.Duration
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maxWait time.Duration
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nextWait time.Duration
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}
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func NewExponentialBackoff(initial time.Duration, maxWait time.Duration) (Backoff, error) {
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if initial <= 0 {
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return nil, fmt.Errorf("initial must be larger than 0")
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}
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if maxWait < initial {
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return nil, fmt.Errorf("maxWait must be larger or equal to initial")
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}
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return &exponentialBackoff{
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initial: initial,
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maxWait: maxWait,
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nextWait: initial,
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}, nil
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}
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func (b *exponentialBackoff) Reset() {
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b.nextWait = b.initial
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}
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func (b *exponentialBackoff) NextWait() time.Duration {
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return b.nextWait
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}
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func (b *exponentialBackoff) Wait(ctx context.Context) {
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waiter, cancel := context.WithTimeout(ctx, b.nextWait)
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defer cancel()
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b.nextWait = b.nextWait * 2
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if b.nextWait > b.maxWait {
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b.nextWait = b.maxWait
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}
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<-waiter.Done()
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}
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