kiwikefei
5/23/2012 - 3:50 AM
closurize(): Converts any valid PHP callable into a Closure. Requires PHP 5.4.0+.
closurize(): Converts any valid PHP callable into a Closure. Requires PHP 5.4.0+.
<?php
/**
* Converts any valid PHP callable into a Closure. Requires PHP 5.4.0+.
*
* The ramifications of this are many, but basically it means that any function
* or method can be converted into a Closure, bound to another scope, and
* executed easily. Works properly even with private methods.
*
* - On success, returns a Closure corresponding to the provided callable.
* - If the parameter is not callable, issues an E_USER_WARNING and returns a
* Closure which only returns null.
* - In the event of a strange or unrecoverable situation (e.g. providing a
* non-static method without an object), an UnexpectedValueException is
* thrown.
*
* @author Matthew Lanigan <rintaun@gmail.com>
* @copyright (c) 2012, Matthew Lanigan
* @license http://www.opensource.org/licenses/mit-license.php MIT License
* @link https://gist.github.com/2773168 Official closurize() gist
* @param callable $callable
* @return \Closure
* @throws \UnexpectedValueException
*/
function closurize($callable) {
if ($callable instanceof \Closure) {
return $callable;
}
$is_callable = function($callable) {
return \is_callable($callable);
};
$error = function() {
$debug = \debug_backtrace(\DEBUG_BACKTRACE_PROVIDE_OBJECT, 2);
$fmt = 'Parameter 1 for closurize() must be callable ' .
'in %s on line %d (issued at %s on line %d)';
$error = \sprintf($fmt, $debug[1]['file'], $debug[1]['line'],
$debug[0]['file'], $debug[0]['line']);
\trigger_error($error, \E_USER_WARNING);
return function() {
return null;
};
};
$object = null;
$class = null;
$debug = \debug_backtrace(\DEBUG_BACKTRACE_PROVIDE_OBJECT, 2);
if (isset($debug[1]['object']) && \is_object($debug[1]['object'])) {
$object = $debug[1]['object'];
$class = $debug[1]['class'];
$is_callable = $is_callable->bindTo($object, $object);
}
if (!$is_callable($callable)) {
if (isset($callable[0]) && is_object($callable[0])) {
$is_callable = $is_callable->bindTo($callable[0], $callable[0]);
} else if (isset($callable[0]) && \class_exists($callable[0])) {
$is_callable = $is_callable->bindTo(null, $callable[0]);
}
if (!$is_callable($callable)) {
return $error();
}
}
if (\is_string($callable) && (\strpos($callable, '::') === false)) {
$ref = new \ReflectionFunction($callable);
return $ref->getClosure();
} else if (\is_string($callable)) {
$callable = \explode('::', $callable);
}
if (!\is_array($callable)) {
throw new \UnexpectedValueException('Callable is not string, array, '.
'or Closure');
}
if (\is_object($callable[0])) {
$ref = new \ReflectionMethod($callable[0], $callable[1]);
return $ref->getClosure($callable[0]);
}
if (!\is_string($callable[0])) {
throw new \UnexpectedValueException('Callable class is not string ' .
'or object');
}
switch ($callable[0]) {
case 'self':
if (!\is_object($object) && \is_null($class)) {
return $error();
}
$self = function() {
return \get_class();
};
$self = $self->bindTo($object, $class);
$ref = new \ReflectionMethod($self(), $callable[1]);
$callable[0] = $object;
break;
case 'static':
if (!\is_object($object)) {
return $error();
}
$static = function() {
return \get_called_class();
};
$static = $static->bindTo($object, $class);
$ref = new \ReflectionMethod($static(), $callable[1]);
$callable[0] = $object;
break;
case 'parent':
if (!\is_object($object)) {
return $error();
}
$parent = function() {
return \get_parent_class();
};
$parent = $parent->bindTo($object, $class);
$ref = new \ReflectionMethod($parent(), $callable[1]);
$callable[0] = $object;
break;
default:
$ref = new \ReflectionMethod($callable[0], $callable[1]);
break;
}
if (!$ref->isStatic() && \is_object($callable[0])) {
return $ref->getClosure($callable[0]);
} else if (!$ref->isStatic()) {
throw new \UnexpectedValueException('Callable method is not static, ' .
'but no calling object available');
}
return $ref->getClosure();
}