github.com/pawelgaczynski/gain@v0.4.0-alpha.0.20230821120126-41f1e60a18da/key_pool.go (about)

     1  // Copyright (c) 2023 Paweł Gaczyński
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package gain
    16  
    17  import (
    18  	"sync/atomic"
    19  
    20  	"github.com/pawelgaczynski/gain/pkg/stack"
    21  )
    22  
    23  const firstFreeKey = 2
    24  
    25  type keyPool struct {
    26  	stack   stack.LockFreeStack[uint64]
    27  	nextKey uint64
    28  }
    29  
    30  func (p *keyPool) get() uint64 {
    31  	key := p.stack.Pop()
    32  	if key == 0 {
    33  		value := atomic.AddUint64(&p.nextKey, 1) - 1
    34  
    35  		return value
    36  	}
    37  
    38  	return key
    39  }
    40  
    41  func (p *keyPool) put(key uint64) {
    42  	p.stack.Push(key)
    43  }
    44  
    45  func newKeyPool() *keyPool {
    46  	return &keyPool{
    47  		stack: stack.NewLockFreeStack[uint64](),
    48  		// 0 is invalid key, 1 is reserved for main socket
    49  		nextKey: firstFreeKey,
    50  	}
    51  }