| 1 |  |  | <?php | 
            
                                                                                                            
                            
            
                                    
            
            
                | 2 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 3 |  |  | namespace Yiisoft\Cache; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 4 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 5 |  |  | use DateInterval; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 6 |  |  | use DateTime; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 7 |  |  | use Exception; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 8 |  |  | use Psr\SimpleCache\CacheInterface; | 
                            
                    |  |  |  | 
                                                                                        
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                | 9 |  |  | use Yiisoft\Cache\Exception\InvalidConfigException; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 10 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 11 |  |  | /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 12 |  |  |  * Memcached implements a cache application component based on [memcached](http://pecl.php.net/package/memcached) PECL | 
            
                                                                                                            
                            
            
                                    
            
            
                | 13 |  |  |  * extension. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 14 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 15 |  |  |  * Memcached can be configured with a list of memcached servers passed to the constructor. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 16 |  |  |  * By default, Memcached assumes there is a memcached server running on localhost at port 11211. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 17 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 18 |  |  |  * See {@see \Psr\SimpleCache\CacheInterface} for common cache operations that MemCached supports. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 19 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 20 |  |  |  * Note, there is no security measure to protected data in memcached. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 21 |  |  |  * All data in memcached can be accessed by any process running in the system. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 22 |  |  |  */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 23 |  |  | final class Memcached implements CacheInterface | 
            
                                                                                                            
                            
            
                                    
            
            
                | 24 |  |  | { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 25 |  |  |     public const EXPIRATION_INFINITY = 0; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 26 |  |  |     public const DEFAULT_SERVER_HOST = '127.0.0.1'; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 27 |  |  |     public const DEFAULT_SERVER_PORT = 11211; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 28 |  |  |     public const DEFAULT_SERVER_WEIGHT = 1; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 29 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 30 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 31 |  |  |      * @var \Memcached the Memcached instance | 
            
                                                                                                            
                            
            
                                    
            
            
                | 32 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 33 |  |  |     private $cache; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 34 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 35 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 36 |  |  |      * @var string an ID that identifies a Memcached instance. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 37 |  |  |      * By default the Memcached instances are destroyed at the end of the request. To create an instance that | 
            
                                                                                                            
                            
            
                                    
            
            
                | 38 |  |  |      * persists between requests, you may specify a unique ID for the instance. All instances created with the | 
            
                                                                                                            
                            
            
                                    
            
            
                | 39 |  |  |      * same ID will share the same connection. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 40 |  |  |      * @see https://www.php.net/manual/en/memcached.construct.php | 
            
                                                                                                            
                            
            
                                    
            
            
                | 41 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 42 |  |  |     private $persistentId; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 43 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 44 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 45 |  |  |      * @param string $persistentId By default the Memcached instances are destroyed at the end of the request. To create an | 
            
                                                                                                            
                            
            
                                    
            
            
                | 46 |  |  |      * instance that persists between requests, use persistent_id to specify a unique ID for the instance. All instances | 
            
                                                                                                            
                            
            
                                    
            
            
                | 47 |  |  |      * created with the same persistent_id will share the same connection. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 48 |  |  |      * @param array $servers list of memcached servers that will be added to the server pool | 
            
                                                                                                            
                            
            
                                    
            
            
                | 49 |  |  |      * @see https://www.php.net/manual/en/memcached.construct.php | 
            
                                                                                                            
                            
            
                                    
            
            
                | 50 |  |  |      * @see https://www.php.net/manual/en/memcached.addservers.php | 
            
                                                                                                            
                            
            
                                    
            
            
                | 51 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 52 |  |  |     public function __construct($persistentId = '', array $servers = []) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 53 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 54 |  |  |         $this->persistentId = $persistentId; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 55 |  |  |         $this->initCache(); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 56 |  |  |         $this->initServers($servers); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 57 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 58 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 59 |  |  |     public function get($key, $default = null) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 60 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 61 |  |  |         $value = $this->cache->get($key); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 62 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 63 |  |  |         if ($this->cache->getResultCode() === \Memcached::RES_SUCCESS) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 64 |  |  |             return $value; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 65 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 66 | 17 |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 67 |  |  |         return $default; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 68 | 17 |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 69 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 70 | 17 |  |     public function set($key, $value, $ttl = null): bool | 
            
                                                                                                            
                            
            
                                    
            
            
                | 71 | 17 |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 72 |  |  |         $expiration = $this->ttlToExpiration($ttl); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 73 |  |  |         if ($expiration < 0) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 74 | 17 |  |             return $this->delete($key); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 75 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 76 | 17 |  |         return $this->cache->set($key, $value, $expiration); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 77 |  |  |     } | 
            
                                                                                                            
                                                                
            
                                    
            
            
                | 78 |  |  |  | 
            
                                                                        
                            
            
                                    
            
            
                | 79 |  |  |     public function delete($key): bool | 
            
                                                                        
                            
            
                                    
            
            
                | 80 |  |  |     { | 
            
                                                                        
                            
            
                                    
            
            
                | 81 |  |  |         return $this->cache->delete($key); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 82 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 83 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 84 |  |  |     public function clear(): bool | 
            
                                                                                                            
                            
            
                                    
            
            
                | 85 | 17 |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 86 |  |  |         return $this->cache->flush(); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 87 | 17 |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 88 | 17 |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 89 |  |  |     public function getMultiple($keys, $default = null) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 90 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 91 |  |  |         $values = $this->cache->getMulti($this->iterableToArray($keys)); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 92 |  |  |         return array_merge(array_fill_keys($this->iterableToArray($keys), $default), $values); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 93 | 17 |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 94 | 17 |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 95 | 17 |  |     public function setMultiple($values, $ttl = null): bool | 
            
                                                                                                            
                            
            
                                    
            
            
                | 96 | 17 |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 97 |  |  |         $expiration = $this->ttlToExpiration($ttl); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 98 |  |  |         return $this->cache->setMulti($this->iterableToArray($values), $expiration); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 99 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 100 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 101 |  |  |     public function deleteMultiple($keys): bool | 
            
                                                                                                            
                            
            
                                    
            
            
                | 102 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 103 |  |  |         foreach ($this->cache->deleteMulti($this->iterableToArray($keys)) as $result) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 104 |  |  |             if ($result === false) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 105 |  |  |                 return false; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 106 | 17 |  |             } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 107 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 108 | 17 |  |         return true; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 109 | 17 |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 110 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 111 |  |  |     public function has($key): bool | 
            
                                                                                                            
                            
            
                                    
            
            
                | 112 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 113 | 17 |  |         $this->cache->get($key); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 114 | 17 |  |         return $this->cache->getResultCode() === \Memcached::RES_SUCCESS; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 115 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 116 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 117 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 118 | 17 |  |      * Returns underlying \Memcached instance | 
            
                                                                                                            
                            
            
                                    
            
            
                | 119 |  |  |      * @return \Memcached | 
            
                                                                                                            
                            
            
                                    
            
            
                | 120 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 121 |  |  |     public function getCache(): \Memcached | 
            
                                                                                                            
                            
            
                                    
            
            
                | 122 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 123 | 17 |  |         return $this->cache; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 124 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 125 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 126 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 127 |  |  |      * Inits Memcached instance | 
            
                                                                                                            
                            
            
                                    
            
            
                | 128 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 129 |  |  |     private function initCache(): void | 
            
                                                                                                            
                            
            
                                    
            
            
                | 130 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 131 |  |  |         $this->cache = new \Memcached($this->persistentId); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 132 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 133 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 134 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 135 |  |  |      * Converts TTL to expiration | 
            
                                                                                                            
                            
            
                                    
            
            
                | 136 |  |  |      * @param $ttl | 
            
                                                                                                            
                            
            
                                    
            
            
                | 137 |  |  |      * @return int | 
            
                                                                                                            
                            
            
                                    
            
            
                | 138 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 139 |  |  |     private function ttlToExpiration($ttl): int | 
            
                                                                                                            
                            
            
                                    
            
            
                | 140 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 141 |  |  |         $ttl = $this->normalizeTtl($ttl); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 142 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 143 |  |  |         if ($ttl === null) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 144 |  |  |             $expiration = static::EXPIRATION_INFINITY; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 145 |  |  |         } elseif ($ttl <= 0) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 146 |  |  |             $expiration = -1; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 147 |  |  |         } else { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 148 |  |  |             $expiration = $ttl + time(); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 149 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 150 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 151 |  |  |         return $expiration; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 152 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 153 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 154 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 155 |  |  |      * Normalizes cache TTL handling `null` value and {@see DateInterval} objects. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 156 |  |  |      * @param int|DateInterval|null $ttl raw TTL. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 157 |  |  |      * @return int|null TTL value as UNIX timestamp or null meaning infinity | 
            
                                                                                                            
                            
            
                                    
            
            
                | 158 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 159 |  |  |     private function normalizeTtl($ttl): ?int | 
            
                                                                                                            
                            
            
                                    
            
            
                | 160 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 161 |  |  |         if ($ttl instanceof DateInterval) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 162 |  |  |             try { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 163 |  |  |                 return (new DateTime('@0'))->add($ttl)->getTimestamp(); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 164 |  |  |             } catch (Exception $e) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 165 |  |  |                 return null; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 166 |  |  |             } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 167 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 168 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 169 |  |  |         return $ttl; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 170 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 171 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 172 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 173 |  |  |      * Converts iterable to array | 
            
                                                                                                            
                            
            
                                    
            
            
                | 174 |  |  |      * @param iterable $iterable | 
            
                                                                                                            
                            
            
                                    
            
            
                | 175 |  |  |      * @return array | 
            
                                                                                                            
                            
            
                                    
            
            
                | 176 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 177 |  |  |     private function iterableToArray(iterable $iterable): array | 
            
                                                                                                            
                            
            
                                    
            
            
                | 178 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 179 |  |  |         return $iterable instanceof \Traversable ? iterator_to_array($iterable) : (array)$iterable; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 180 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 181 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 182 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 183 |  |  |      * @param array $servers | 
            
                                                                                                            
                            
            
                                    
            
            
                | 184 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 185 |  |  |     private function initServers(array $servers): void | 
            
                                                                                                            
                            
            
                                    
            
            
                | 186 | 15 |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 187 |  |  |         if (empty($servers)) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 188 | 15 |  |             $servers = [ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 189 |  |  |                 [self::DEFAULT_SERVER_HOST, self::DEFAULT_SERVER_PORT, self::DEFAULT_SERVER_WEIGHT], | 
            
                                                                                                            
                            
            
                                    
            
            
                | 190 | 15 |  |             ]; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 191 | 13 |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 192 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 193 |  |  |         if ($this->persistentId !== '') { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 194 | 9 |  |             $servers = $this->getNewServers($servers); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 195 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 196 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 197 | 3 |  |         $success = $this->cache->addServers($servers); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 198 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 199 | 3 |  |         if (!$success) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 200 |  |  |             throw new InvalidConfigException('An error occurred while adding servers to the server pool.'); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 201 | 3 |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 202 | 3 |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 203 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 204 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 205 | 1 |  |      * Returns the list of the servers that are not in the pool. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 206 |  |  |      * @param array $servers | 
            
                                                                                                            
                            
            
                                    
            
            
                | 207 |  |  |      * @return array | 
            
                                                                                                            
                            
            
                                    
            
            
                | 208 | 13 |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 209 |  |  |     private function getNewServers(array $servers): array | 
            
                                                                                                            
                            
            
                                    
            
            
                | 210 | 13 |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 211 | 13 |  |         $existingServers = []; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 212 |  |  |         foreach ($this->cache->getServerList() as $existingServer) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 213 |  |  |             $existingServers[$existingServer['host'] . ':' . $existingServer['port']] = true; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 214 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 215 | 13 |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 216 |  |  |         $newServers = []; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 217 |  |  |         foreach ($servers as $server) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 218 | 5 |  |             $serverAddress = $server[0] . ':' . $server[1]; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 219 |  |  |             if (!array_key_exists($serverAddress, $existingServers)) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 220 | 5 |  |                 $newServers[] = $server; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 221 | 4 |  |             } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 222 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 223 | 1 |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 224 |  |  |         return $newServers; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 225 | 5 |  |     } | 
            
                                                                                                            
                                                                
            
                                    
            
            
                | 226 |  |  | } | 
            
                                                        
            
                                    
            
            
                | 227 |  |  |  | 
            
                        
Let?s assume that you have a directory layout like this:
. |-- OtherDir | |-- Bar.php | `-- Foo.php `-- SomeDir `-- Foo.phpand let?s assume the following content of
Bar.php:If both files
OtherDir/Foo.phpandSomeDir/Foo.phpare loaded in the same runtime, you will see a PHP error such as the following:PHP Fatal error: Cannot use SomeDir\Foo as Foo because the name is already in use in OtherDir/Foo.phpHowever, as
OtherDir/Foo.phpdoes not necessarily have to be loaded and the error is only triggered if it is loaded beforeOtherDir/Bar.php, this problem might go unnoticed for a while. In order to prevent this error from surfacing, you must import the namespace with a different alias: