// Copyright 2021 Liuxiangchao iwind.liu@gmail.com. All rights reserved.
//go:build script
// +build script

package js

type ContextPool struct {
	ch      chan *Context
	maxSize int
}

func NewContextPool(maxSize int) *ContextPool {
	if maxSize <= 0 {
		maxSize = 128
	}
	return &ContextPool{
		ch:      make(chan *Context, maxSize),
		maxSize: maxSize,
	}
}

func (this *ContextPool) MaxSize() int {
	return this.maxSize
}

func (this *ContextPool) Size() int {
	return len(this.ch)
}

func (this *ContextPool) Get() *Context {
	// 不需要default语句，我们要确保整个Pool中只有固定的元素，防止内存溢出
	select {
	case ctx := <-this.ch:
		return ctx
	}
}

func (this *ContextPool) Put(ctx *Context) {
	ctx.Cleanup()
	select {
	case this.ch <- ctx:
	default:
		ctx.Close()
	}
}

func (this *ContextPool) IsUsing() bool {
	return len(this.ch) != this.maxSize
}

func (this *ContextPool) Close() {
Loop:
	for {
		select {
		case ctx := <-this.ch:
			ctx.Close()
		default:
			break Loop
		}
	}
}