/
ClassExistenceResource.php
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/
ClassExistenceResource.php
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<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Symfony\Component\Config\Resource;
/**
* ClassExistenceResource represents a class existence.
* Freshness is only evaluated against resource existence.
*
* The resource must be a fully-qualified class name.
*
* @author Fabien Potencier <fabien@symfony.com>
*/
class ClassExistenceResource implements SelfCheckingResourceInterface, \Serializable
{
private $resource;
private $exists;
private static $autoloadLevel = 0;
private static $autoloadedClass;
private static $existsCache = [];
/**
* @param string $resource The fully-qualified class name
* @param bool|null $exists Boolean when the existency check has already been done
*/
public function __construct($resource, $exists = null)
{
$this->resource = $resource;
if (null !== $exists) {
$this->exists = (bool) $exists;
}
}
/**
* {@inheritdoc}
*/
public function __toString()
{
return $this->resource;
}
/**
* @return string The file path to the resource
*/
public function getResource()
{
return $this->resource;
}
/**
* {@inheritdoc}
*
* @throws \ReflectionException when a parent class/interface/trait is not found
*/
public function isFresh($timestamp)
{
$loaded = class_exists($this->resource, false) || interface_exists($this->resource, false) || trait_exists($this->resource, false);
if (null !== $exists = &self::$existsCache[(int) (0 >= $timestamp)][$this->resource]) {
$exists = $exists || $loaded;
} elseif (!$exists = $loaded) {
if (!self::$autoloadLevel++) {
spl_autoload_register(__CLASS__.'::throwOnRequiredClass');
}
$autoloadedClass = self::$autoloadedClass;
self::$autoloadedClass = $this->resource;
try {
$exists = class_exists($this->resource) || interface_exists($this->resource, false) || trait_exists($this->resource, false);
} catch (\Exception $e) {
try {
self::throwOnRequiredClass($this->resource, $e);
} catch (\ReflectionException $e) {
if (0 >= $timestamp) {
unset(self::$existsCache[1][$this->resource]);
throw $e;
}
}
} finally {
self::$autoloadedClass = $autoloadedClass;
if (!--self::$autoloadLevel) {
spl_autoload_unregister(__CLASS__.'::throwOnRequiredClass');
}
}
}
if (null === $this->exists) {
$this->exists = $exists;
}
return $this->exists xor !$exists;
}
/**
* @internal
*/
public function serialize()
{
if (null === $this->exists) {
$this->isFresh(0);
}
return serialize([$this->resource, $this->exists]);
}
/**
* @internal
*/
public function unserialize($serialized)
{
list($this->resource, $this->exists) = unserialize($serialized);
}
/**
* Throws a reflection exception when the passed class does not exist but is required.
*
* A class is considered "not required" when it's loaded as part of a "class_exists" or similar check.
*
* This function can be used as an autoload function to throw a reflection
* exception if the class was not found by previous autoload functions.
*
* A previous exception can be passed. In this case, the class is considered as being
* required totally, so if it doesn't exist, a reflection exception is always thrown.
* If it exists, the previous exception is rethrown.
*
* @throws \ReflectionException
*
* @internal
*/
public static function throwOnRequiredClass($class, \Exception $previous = null)
{
// If the passed class is the resource being checked, we shouldn't throw.
if (null === $previous && self::$autoloadedClass === $class) {
return;
}
if (class_exists($class, false) || interface_exists($class, false) || trait_exists($class, false)) {
if (null !== $previous) {
throw $previous;
}
return;
}
if ($previous instanceof \ReflectionException) {
throw $previous;
}
$e = new \ReflectionException(sprintf('Class "%s" not found while loading "%s".', $class, self::$autoloadedClass), 0, $previous);
if (null !== $previous) {
throw $e;
}
$trace = $e->getTrace();
$autoloadFrame = [
'function' => 'spl_autoload_call',
'args' => [$class],
];
if (false === $i = array_search($autoloadFrame, $trace, true)) {
throw $e;
}
if (isset($trace[++$i]['function']) && !isset($trace[$i]['class'])) {
switch ($trace[$i]['function']) {
case 'get_class_methods':
case 'get_class_vars':
case 'get_parent_class':
case 'is_a':
case 'is_subclass_of':
case 'class_exists':
case 'class_implements':
case 'class_parents':
case 'trait_exists':
case 'defined':
case 'interface_exists':
case 'method_exists':
case 'property_exists':
case 'is_callable':
return;
}
$props = [
'file' => $trace[$i]['file'],
'line' => $trace[$i]['line'],
'trace' => \array_slice($trace, 1 + $i),
];
foreach ($props as $p => $v) {
$r = new \ReflectionProperty('Exception', $p);
$r->setAccessible(true);
$r->setValue($e, $v);
}
}
throw $e;
}
}