Viewing file:  ClassDiscovery.php (6.81 KB) -rw-r--r--
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<?php
namespace Http\Discovery;
use Http\Discovery\Exception\ClassInstantiationFailedException;
use Http\Discovery\Exception\DiscoveryFailedException;
use Http\Discovery\Exception\NoCandidateFoundException;
use Http\Discovery\Exception\StrategyUnavailableException;
use Http\Discovery\Strategy\DiscoveryStrategy;
/**
* Registry that based find results on class existence.
*
* @author David de Boer <david@ddeboer.nl>
* @author Márk Sági-Kazár <mark.sagikazar@gmail.com>
* @author Tobias Nyholm <tobias.nyholm@gmail.com>
*/
abstract class ClassDiscovery
{
/**
* A list of strategies to find classes.
*
* @var DiscoveryStrategy[]
*/
private static $strategies = [
Strategy\GeneratedDiscoveryStrategy::class,
Strategy\CommonClassesStrategy::class,
Strategy\CommonPsr17ClassesStrategy::class,
Strategy\PuliBetaStrategy::class,
];
private static $deprecatedStrategies = [
Strategy\PuliBetaStrategy::class => true,
];
/**
* Discovery cache to make the second time we use discovery faster.
*
* @var array
*/
private static $cache = [];
/**
* Finds a class.
*
* @param string $type
*
* @return string|\Closure
*
* @throws DiscoveryFailedException
*/
protected static function findOneByType($type)
{
// Look in the cache
if (null !== ($class = self::getFromCache($type))) {
return $class;
}
static $skipStrategy;
$skipStrategy ?? $skipStrategy = self::safeClassExists(Strategy\GeneratedDiscoveryStrategy::class) ? false : Strategy\GeneratedDiscoveryStrategy::class;
$exceptions = [];
foreach (self::$strategies as $strategy) {
if ($skipStrategy === $strategy) {
continue;
}
try {
$candidates = $strategy::getCandidates($type);
} catch (StrategyUnavailableException $e) {
if (!isset(self::$deprecatedStrategies[$strategy])) {
$exceptions[] = $e;
}
continue;
}
foreach ($candidates as $candidate) {
if (isset($candidate['condition'])) {
if (!self::evaluateCondition($candidate['condition'])) {
continue;
}
}
// save the result for later use
self::storeInCache($type, $candidate);
return $candidate['class'];
}
$exceptions[] = new NoCandidateFoundException($strategy, $candidates);
}
throw DiscoveryFailedException::create($exceptions);
}
/**
* Get a value from cache.
*
* @param string $type
*
* @return string|null
*/
private static function getFromCache($type)
{
if (!isset(self::$cache[$type])) {
return;
}
$candidate = self::$cache[$type];
if (isset($candidate['condition'])) {
if (!self::evaluateCondition($candidate['condition'])) {
return;
}
}
return $candidate['class'];
}
/**
* Store a value in cache.
*
* @param string $type
* @param string $class
*/
private static function storeInCache($type, $class)
{
self::$cache[$type] = $class;
}
/**
* Set new strategies and clear the cache.
*
* @param string[] $strategies list of fully qualified class names that implement DiscoveryStrategy
*/
public static function setStrategies(array $strategies)
{
self::$strategies = $strategies;
self::clearCache();
}
/**
* Returns the currently configured discovery strategies as fully qualified class names.
*
* @return string[]
*/
public static function getStrategies(): iterable
{
return self::$strategies;
}
/**
* Append a strategy at the end of the strategy queue.
*
* @param string $strategy Fully qualified class name of a DiscoveryStrategy
*/
public static function appendStrategy($strategy)
{
self::$strategies[] = $strategy;
self::clearCache();
}
/**
* Prepend a strategy at the beginning of the strategy queue.
*
* @param string $strategy Fully qualified class name to a DiscoveryStrategy
*/
public static function prependStrategy($strategy)
{
array_unshift(self::$strategies, $strategy);
self::clearCache();
}
public static function clearCache()
{
self::$cache = [];
}
/**
* Evaluates conditions to boolean.
*
* @return bool
*/
protected static function evaluateCondition($condition)
{
if (is_string($condition)) {
// Should be extended for functions, extensions???
return self::safeClassExists($condition);
}
if (is_callable($condition)) {
return (bool) $condition();
}
if (is_bool($condition)) {
return $condition;
}
if (is_array($condition)) {
foreach ($condition as $c) {
if (false === static::evaluateCondition($c)) {
// Immediately stop execution if the condition is false
return false;
}
}
return true;
}
return false;
}
/**
* Get an instance of the $class.
*
* @param string|\Closure $class a FQCN of a class or a closure that instantiate the class
*
* @return object
*
* @throws ClassInstantiationFailedException
*/
protected static function instantiateClass($class)
{
try {
if (is_string($class)) {
return new $class();
}
if (is_callable($class)) {
return $class();
}
} catch (\Exception $e) {
throw new ClassInstantiationFailedException('Unexpected exception when instantiating class.', 0, $e);
}
throw new ClassInstantiationFailedException('Could not instantiate class because parameter is neither a callable nor a string');
}
/**
* We need a "safe" version of PHP's "class_exists" because Magento has a bug
* (or they call it a "feature"). Magento is throwing an exception if you do class_exists()
* on a class that ends with "Factory" and if that file does not exits.
*
* This function catches all potential exceptions and makes sure to always return a boolean.
*
* @param string $class
*
* @return bool
*/
public static function safeClassExists($class)
{
try {
return class_exists($class) || interface_exists($class);
} catch (\Exception $e) {
return false;
}
}
}
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