// Copyright 2021 ByteDance Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//go:build race
// +build race

package syncx

import (
	"sync"
)

type Pool struct {
	p    sync.Pool
	once sync.Once
	// New optionally specifies a function to generate
	// a value when Get would otherwise return nil.
	// It may not be changed concurrently with calls to Get.
	New func() interface{}
	// NoGC any objects in this Pool.
	NoGC bool
}

func (p *Pool) init() {
	p.once.Do(func() {
		p.p = sync.Pool{
			New: p.New,
		}
	})
}

// Put adds x to the pool.
func (p *Pool) Put(x interface{}) {
	p.init()
	p.p.Put(x)
}

// Get selects an arbitrary item from the Pool, removes it from the
// Pool, and returns it to the caller.
// Get may choose to ignore the pool and treat it as empty.
// Callers should not assume any relation between values passed to Put and
// the values returned by Get.
//
// If Get would otherwise return nil and p.New is non-nil, Get returns
// the result of calling p.New.
func (p *Pool) Get() (x interface{}) {
	p.init()
	return p.p.Get()
}