# Coroutine::getContext [TOC] > v4.3.0后可用 获取当前协程的上下文对象 ~~~ function Coroutine::getContext() : Coroutine\Context ~~~ 接受一个可选参数cid, 默认返回当前协程的上下文对象 ## 代码 ~~~ function func(callable $fn, ...$args) { go(function () use ($fn, $args) { $fn(...$args); echo 'Coroutine#' . Co::getCid() . ' exit' . PHP_EOL; }); } /** * Compatibility for lower version * @param object|Resource $object * @return int */ function php_object_id($object) { static $id = 0; static $map = []; $hash = spl_object_hash($object); return $map[$hash] ?? ($map[$hash] = ++$id); } class Resource { public function __construct() { echo __CLASS__ . '#' . php_object_id((object)$this) . ' constructed' . PHP_EOL; } public function __destruct() { echo __CLASS__ . '#' . php_object_id((object)$this) . ' destructed' . PHP_EOL; } } $context = new Co\Context(); assert($context instanceof ArrayObject); assert(Co::getContext() === null); func(function () { $context = Co::getContext(); assert($context instanceof Co\Context); $context['resource1'] = new Resource; $context->resource2 = new Resource; func(function () { Co::getContext()['resource3'] = new Resource; Co::yield(); Co::getContext()['resource3']->resource4 = new Resource; Co::getContext()->resource5 = new Resource; }); }); Co::resume(2); ~~~ ## 输出 ~~~ Resource#1 constructed Resource#2 constructed Resource#3 constructed Coroutine#1 exit Resource#2 destructed Resource#1 destructed Resource#4 constructed Resource#5 constructed Coroutine#2 exit Resource#5 destructed Resource#3 destructed Resource#4 destructed ~~~ ## 作用 * 协程退出后上下文自动清理 (如无其它协程或全局变量引用) * 无defer注册和调用的开销 (无需注册清理方法, 无需调用函数清理) * 无PHP数组实现的上下文的哈希计算开销 (在协程数量巨大时有一定好处) * `Co\Context`使用ArrayObject, 满足各种存储需求 (既是对象, 也可以以数组方式操作) ## 实现 https://github.com/swoole/swoole-src/pull/2399