From 0aa82ad02075b646f3d92e0bbc577b6cbf08e861 Mon Sep 17 00:00:00 2001
From: John Guo <john@johng.cn>
Date: Mon, 7 Dec 2020 18:57:40 +0800
Subject: [PATCH] improve package gpool

---
 container/gpool/gpool.go | 33 +++++++++++++--------------------
 1 file changed, 13 insertions(+), 20 deletions(-)

diff --git a/container/gpool/gpool.go b/container/gpool/gpool.go
index 6d411982f..e7a59905d 100644
--- a/container/gpool/gpool.go
+++ b/container/gpool/gpool.go
@@ -1,4 +1,4 @@
-// Copyright 2018 gf Author(https://github.com/gogf/gf). All Rights Reserved.
+// Copyright GoFrame gf Author(https://github.com/gogf/gf). All Rights Reserved.
 //
 // This Source Code Form is subject to the terms of the MIT License.
 // If a copy of the MIT was not distributed with this file,
@@ -19,18 +19,10 @@ import (
 
 // Pool is an Object-Reusable Pool.
 type Pool struct {
-	// Available/idle items list.
-	list *glist.List
-
-	// Whether the pool is closed.
-	closed *gtype.Bool
-
-	// Time To Live for pool items.
-	TTL time.Duration
-
-	// Callback function to create pool item.
-	NewFunc func() (interface{}, error)
-
+	list    *glist.List                 // Available/idle items list.
+	closed  *gtype.Bool                 // Whether the pool is closed.
+	TTL     time.Duration               // Time To Live for pool items.
+	NewFunc func() (interface{}, error) // Callback function to create pool item.
 	// ExpireFunc is the for expired items destruction.
 	// This function needs to be defined when the pool items
 	// need to perform additional destruction operations.
@@ -40,8 +32,8 @@ type Pool struct {
 
 // Pool item.
 type poolItem struct {
-	expire int64       // Expire timestamp in milliseconds.
-	value  interface{} // Item value.
+	value    interface{} // Item value.
+	expireAt int64       // Expire timestamp in milliseconds.
 }
 
 // Creation function for object.
@@ -80,11 +72,11 @@ func (p *Pool) Put(value interface{}) error {
 		value: value,
 	}
 	if p.TTL == 0 {
-		item.expire = 0
+		item.expireAt = 0
 	} else {
 		// As for Golang version < 1.13, there's no method Milliseconds for time.Duration.
 		// So we need calculate the milliseconds using its nanoseconds value.
-		item.expire = gtime.TimestampMilli() + p.TTL.Nanoseconds()/1000000
+		item.expireAt = gtime.TimestampMilli() + p.TTL.Nanoseconds()/1000000
 	}
 	p.list.PushBack(item)
 	return nil
@@ -112,9 +104,10 @@ func (p *Pool) Get() (interface{}, error) {
 	for !p.closed.Val() {
 		if r := p.list.PopFront(); r != nil {
 			f := r.(*poolItem)
-			if f.expire == 0 || f.expire > gtime.TimestampMilli() {
+			if f.expireAt == 0 || f.expireAt > gtime.TimestampMilli() {
 				return f.value, nil
 			} else if p.ExpireFunc != nil {
+				// TODO: move expire function calling asynchronously from `Get` operation.
 				p.ExpireFunc(f.value)
 			}
 		} else {
@@ -171,9 +164,9 @@ func (p *Pool) checkExpireItems() {
 		}
 		if r := p.list.PopFront(); r != nil {
 			item := r.(*poolItem)
-			latestExpire = item.expire
+			latestExpire = item.expireAt
 			// TODO improve the auto-expiration mechanism of the pool.
-			if item.expire > timestampMilli {
+			if item.expireAt > timestampMilli {
 				p.list.PushFront(item)
 				break
 			}