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/*
* Increase-unblocking capped semaphores
*
* Copyright (C) 2024 Runxi Yu <https://runxiyu.org>
* SPDX-License-Identifier: AGPL-3.0-or-later
*
* 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 <https://www.gnu.org/licenses/>.
*/
package main
/*
* usemT is basically a semaphore capped at 1. Adding is always non-blocking;
* adding it multiple times without a read in between is equivalent to setting
* it once. Reading blocks after the first read after the last set.
*/
type usemT struct {
ch (chan struct{})
}
func (s *usemT) init() {
s.ch = make(chan struct{}, 1)
}
func (s *usemT) set() {
select {
case s.ch <- struct{}{}:
default:
}
}
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