github.com/cloudwego/hertz@v0.9.3/pkg/common/timer/timer.go (about)

     1  /*
     2   * Copyright 2022 CloudWeGo Authors
     3   *
     4   * Licensed under the Apache License, Version 2.0 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   *     http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   *
    16   * The MIT License (MIT)
    17   *
    18   * Copyright (c) 2015-present Aliaksandr Valialkin, VertaMedia, Kirill Danshin, Erik Dubbelboer, FastHTTP Authors
    19   *
    20   * Permission is hereby granted, free of charge, to any person obtaining a copy
    21   * of this software and associated documentation files (the "Software"), to deal
    22   * in the Software without restriction, including without limitation the rights
    23   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    24   * copies of the Software, and to permit persons to whom the Software is
    25   * furnished to do so, subject to the following conditions:
    26   *
    27   * The above copyright notice and this permission notice shall be included in
    28   * all copies or substantial portions of the Software.
    29   *
    30   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    31   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    32   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    33   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    34   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    35   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    36   * THE SOFTWARE.
    37   *
    38   * This file may have been modified by CloudWeGo authors. All CloudWeGo
    39   * Modifications are Copyright 2022 CloudWeGo Authors.
    40   */
    41  
    42  package timer
    43  
    44  import (
    45  	"sync"
    46  	"time"
    47  )
    48  
    49  func initTimer(t *time.Timer, timeout time.Duration) *time.Timer {
    50  	if t == nil {
    51  		return time.NewTimer(timeout)
    52  	}
    53  	if t.Reset(timeout) {
    54  		panic("BUG: active timer trapped into initTimer()")
    55  	}
    56  	return t
    57  }
    58  
    59  func stopTimer(t *time.Timer) {
    60  	if !t.Stop() {
    61  		// Collect possibly added time from the channel
    62  		// if timer has been stopped and nobody collected its value.
    63  		select {
    64  		case <-t.C:
    65  		default:
    66  		}
    67  	}
    68  }
    69  
    70  // AcquireTimer returns a time.Timer from the pool and updates it to
    71  // send the current time on its channel after at least timeout.
    72  //
    73  // The returned Timer may be returned to the pool with ReleaseTimer
    74  // when no longer needed. This allows reducing GC load.
    75  func AcquireTimer(timeout time.Duration) *time.Timer {
    76  	v := timerPool.Get()
    77  	if v == nil {
    78  		return time.NewTimer(timeout)
    79  	}
    80  	t := v.(*time.Timer)
    81  	initTimer(t, timeout)
    82  	return t
    83  }
    84  
    85  // ReleaseTimer returns the time.Timer acquired via AcquireTimer to the pool
    86  // and prevents the Timer from firing.
    87  //
    88  // Do not access the released time.Timer or read from its channel otherwise
    89  // data races may occur.
    90  func ReleaseTimer(t *time.Timer) {
    91  	stopTimer(t)
    92  	timerPool.Put(t)
    93  }
    94  
    95  var timerPool sync.Pool