lua对象池管理工具剖析

一个高效的对象池实现，通过对象复用来减少内存分配和垃圾回收压力，特别适合频繁创建销毁对象的场景

源码

-- object pool, from: https://github.com/treamology/pool.lualocal type, pairs, table, setmetatable = type, pairs, table, setmetatable 
local pool = {}
local poolmt = {__index = pool}function pool.create(newObject, poolSize, maxPoolSize)if type(newObject) ~= "function" thenreturn nilendpoolSize = poolSize or 16maxPoolSize = (maxPoolSize and maxPoolSize >= poolSize) and maxPoolSize or 2 * poolSizelocal freeObjects = {}for _ = 1, poolSize dotable.insert(freeObjects, newObject())endreturn setmetatable({freeObjects = freeObjects,newObject = newObject,maxPoolSize = maxPoolSize},poolmt)
endfunction pool:obtain()return #self.freeObjects == 0 and self.newObject() or table.remove(self.freeObjects)
endfunction pool:free(obj, ...)if not obj thenreturn falseendif #self.freeObjects < self.maxPoolSize thentable.insert(self.freeObjects, obj)endif obj.reset then obj.reset(obj, ...) endreturn true
endfunction pool:clear()for k in pairs(self.freeObjects) doself.freeObjects[k] = nilend
endreturn pool

对象池创建函数

function pool.create(newObject, poolSize, maxPoolSize)-- 参数验证：必须提供对象构造函数if type(newObject) ~= "function" thenreturn nilend-- 参数默认值设置poolSize = poolSize or 16maxPoolSize = (maxPoolSize and maxPoolSize >= poolSize) and maxPoolSize or 2 * poolSize-- 预分配对象池local freeObjects = {}for _ = 1, poolSize dotable.insert(freeObjects, newObject())end-- 返回池实例return setmetatable({freeObjects = freeObjects,newObject = newObject,maxPoolSize = maxPoolSize},poolmt)
end

对象获取机制

function pool:obtain()return #self.freeObjects == 0 and self.newObject() or table.remove(self.freeObjects)
end

执行逻辑：

对象回收机制

function pool:free(obj, ...)if not obj thenreturn falseend-- 检查池容量，避免无限增长if #self.freeObjects < self.maxPoolSize thentable.insert(self.freeObjects, obj)end-- 调用对象的reset方法进行清理if obj.reset then obj.reset(obj, ...) endreturn true
end

池清理功能

function pool:clear()for k in pairs(self.freeObjects) doself.freeObjects[k] = nilend
end

设计模式分析

1. 对象池模式

-- 使用示例
local function createConnection()return { id = math.random(1000),connected = false,reset = function(self)self.connected = falseend}
endlocal connectionPool = pool.create(createConnection, 10, 50)

2. 享元模式

通过对象复用，减少相似对象的创建开销

内存管理策略

策略	实现方式	优势
预分配	初始化时创建固定数量对象	减少运行时分配
动态扩展	池空时自动创建新对象	避免阻塞
容量限制	maxPoolSize控制内存上限	防止内存泄漏

垃圾回收优化

-- 传统方式：频繁创建销毁
for i = 1, 1000 dolocal obj = createObject()  -- 触发GCuse(obj)-- obj被销毁，GC压力大
end-- 对象池方式：复用对象
for i = 1, 1000 dolocal obj = pool:obtain()   -- 从池中获取use(obj)pool:free(obj)              -- 放回池中，无GC压力
end

使用场景分析

1. 网络连接管理

local socketPool = pool.create(function()return {fd = nil,status = "closed",reset = function(self)if self.fd thenself:close()endself.status = "closed"end,connect = function(self, host, port)-- 连接逻辑end}
end, 20, 100)

2. 游戏对象管理

local bulletPool = pool.create(function()return {x = 0, y = 0, velocity = 100,active = false,reset = function(self)self.x, self.y = 0, 0self.active = falseend}
end, 50, 200)

3. 数据库连接池

local dbPool = pool.create(function()local conn = mysql.connect(config)return {conn = conn,reset = function(self)-- 重置连接状态self.conn:ping()  -- 保持连接活跃end}
end, 5, 20)

与直接创建方案的对比

方面	对象池	直接创建
内存分配	预分配+复用	每次新建
GC压力	极小	频繁触发
初始化成本	一次性	每次都有
灵活性	需要reset逻辑	无需特殊处理