将可能可执行的内容转换成is_callable可识别的callable

开发 · 2017-10-10 · 更新于 2020-06-26

```
<?php

function func()
{}

$callables = [
    function () {},
    'func',
    'C1',
    C1::class,
    'C2',
    new C2,
    C2::class,
    'SC1::sc11',
    [SC1::class, 'sc11'],
    [new C2, '__invoke'],
    ['cla' => new C2, 'me' => '__invoke'],
];

class C1
{}

class C2
{
    public function __invoke()
    {}

public function aaa()
    {}
}

class SC1
{
    public static function sc11()
    {}
}

foreach ($callables as $callable) {
    var_dump(resolveCallable($callable));
    echo "\n";
}

/**
 * 将可能可执行的内容转换成is_callable可识别的callable
 * 可识别内容: 
 * 任何is_callable()===true的callable
 * 任意存在且含有__invoke方法的AnyClass::class
 * 
 * @param string $callable 可能可执行的内容
 * @param bool $return_false 当发生无法转换时，是否返回false，默认返回一个空匿名函数
 * @return callable | false
 */
function resolveCallable($callable, $return_false = false)
{
    if (is_callable($callable)) {
        return $callable;
    } elseif (is_string($callable) && class_exists($callable)) {
        return resolveCallable(new $callable, $return_false);
    } elseif (is_array($callable) && @$callable[1] === '__invoke') {
        return resolveCallable(@$callable[0], $return_false);
    } else {
        return $return_false ? false : function () {};
    }
}
```