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Copy pathgpool.go
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184 lines (165 loc) · 4.44 KB
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// Copyright 2018 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,
// You can obtain one at https://github.com/gogf/gf.
// Package gpool provides object-reusable concurrent-safe pool.
package gpool
import (
"errors"
"time"
"github.com/gogf/gf/container/glist"
"github.com/gogf/gf/container/gtype"
"github.com/gogf/gf/os/gtime"
"github.com/gogf/gf/os/gtimer"
)
// 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)
// ExpireFunc is the for expired items destruction.
// This function needs to be defined when the pool items
// need to perform additional destruction operations.
// Eg: net.Conn, os.File, etc.
ExpireFunc func(interface{})
}
// Pool item.
type poolItem struct {
expire int64 // Expire timestamp in milliseconds.
value interface{} // Item value.
}
// Creation function for object.
type NewFunc func() (interface{}, error)
// Destruction function for object.
type ExpireFunc func(interface{})
// New creates and returns a new object pool.
// To ensure execution efficiency, the expiration time cannot be modified once it is set.
//
// Note the expiration logic:
// ttl = 0 : not expired;
// ttl < 0 : immediate expired after use;
// ttl > 0 : timeout expired;
func New(ttl time.Duration, newFunc NewFunc, expireFunc ...ExpireFunc) *Pool {
r := &Pool{
list: glist.New(true),
closed: gtype.NewBool(),
TTL: ttl,
NewFunc: newFunc,
}
if len(expireFunc) > 0 {
r.ExpireFunc = expireFunc[0]
}
gtimer.AddSingleton(time.Second, r.checkExpireItems)
return r
}
// Put puts an item to pool.
func (p *Pool) Put(value interface{}) error {
if p.closed.Val() {
return errors.New("pool is closed")
}
item := &poolItem{
value: value,
}
if p.TTL == 0 {
item.expire = 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
}
p.list.PushBack(item)
return nil
}
// Clear clears pool, which means it will remove all items from pool.
func (p *Pool) Clear() {
if p.ExpireFunc != nil {
for {
if r := p.list.PopFront(); r != nil {
p.ExpireFunc(r.(*poolItem).value)
} else {
break
}
}
} else {
p.list.RemoveAll()
}
}
// Get picks and returns an item from pool. If the pool is empty and NewFunc is defined,
// it creates and returns one from NewFunc.
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() {
return f.value, nil
}
} else {
break
}
}
if p.NewFunc != nil {
return p.NewFunc()
}
return nil, errors.New("pool is empty")
}
// Size returns the count of available items of pool.
func (p *Pool) Size() int {
return p.list.Len()
}
// Close closes the pool. If <p> has ExpireFunc,
// then it automatically closes all items using this function before it's closed.
// Commonly you do not need call this function manually.
func (p *Pool) Close() {
p.closed.Set(true)
}
// checkExpire removes expired items from pool in every second.
func (p *Pool) checkExpireItems() {
if p.closed.Val() {
// If p has ExpireFunc,
// then it must close all items using this function.
if p.ExpireFunc != nil {
for {
if r := p.list.PopFront(); r != nil {
p.ExpireFunc(r.(*poolItem).value)
} else {
break
}
}
}
gtimer.Exit()
}
// All items do not expire.
if p.TTL == 0 {
return
}
// The latest item expire timestamp in milliseconds.
var latestExpire int64 = -1
// Retrieve the current timestamp in milliseconds, it expires the items
// by comparing with this timestamp. It is not accurate comparison for
// every items expired, but high performance.
var timestampMilli = gtime.TimestampMilli()
for {
if latestExpire > timestampMilli {
break
}
if r := p.list.PopFront(); r != nil {
item := r.(*poolItem)
latestExpire = item.expire
if item.expire > timestampMilli {
p.list.PushFront(item)
break
}
if p.ExpireFunc != nil {
p.ExpireFunc(item.value)
}
} else {
break
}
}
}