Complex classes like Run often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Run, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 16 | class Run  | 
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| 17 | { | 
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| 18 | const EXCEPTION_HANDLER = "handleException";  | 
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| 19 | const ERROR_HANDLER = "handleError";  | 
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| 20 | const SHUTDOWN_HANDLER = "handleShutdown";  | 
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| 21 | |||
| 22 | protected $isRegistered;  | 
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| 23 | protected $allowQuit = true;  | 
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| 24 | protected $sendOutput = true;  | 
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| 25 | |||
| 26 | /**  | 
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| 27 | * @var integer|false  | 
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| 28 | */  | 
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| 29 | protected $sendHttpCode = 500;  | 
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| 30 | |||
| 31 | /**  | 
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| 32 | * @var HandlerInterface[]  | 
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| 33 | */  | 
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| 34 | protected $handlerStack = array();  | 
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| 35 | |||
| 36 | protected $silencedPatterns = array();  | 
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| 37 | |||
| 38 | /**  | 
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| 39 | * Pushes a handler to the end of the stack  | 
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| 40 | *  | 
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| 41 | * @throws InvalidArgumentException If argument is not callable or instance of HandlerInterface  | 
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| 42 | * @param Callable|HandlerInterface $handler  | 
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| 43 | * @return Run  | 
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| 44 | */  | 
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| 45 | 9 | public function pushHandler($handler)  | 
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| 61 | |||
| 62 | /**  | 
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| 63 | * Removes the last handler in the stack and returns it.  | 
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| 64 | * Returns null if there"s nothing else to pop.  | 
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| 65 | * @return null|HandlerInterface  | 
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| 66 | */  | 
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| 67 | 1 | public function popHandler()  | 
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| 71 | |||
| 72 | /**  | 
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| 73 | * Returns an array with all handlers, in the  | 
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| 74 | * order they were added to the stack.  | 
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| 75 | * @return array  | 
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| 76 | */  | 
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| 77 | 2 | public function getHandlers()  | 
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| 81 | |||
| 82 | /**  | 
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| 83 | * Clears all handlers in the handlerStack, including  | 
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| 84 | * the default PrettyPage handler.  | 
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| 85 | * @return Run  | 
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| 86 | */  | 
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| 87 | 1 | public function clearHandlers()  | 
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| 92 | |||
| 93 | /**  | 
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| 94 | * @param mixed $exception  | 
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| 95 | * @return Inspector  | 
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| 96 | */  | 
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| 97 | 2 | protected function getInspector($exception)  | 
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| 101 | |||
| 102 | /**  | 
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| 103 | * Registers this instance as an error handler.  | 
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| 104 | * @return Run  | 
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| 105 | */  | 
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| 106 | 5 | public function register()  | 
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| 125 | |||
| 126 | /**  | 
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| 127 | * Unregisters all handlers registered by this Whoops\Run instance  | 
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| 128 | * @return Run  | 
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| 129 | */  | 
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| 130 | 1 | public function unregister()  | 
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| 141 | |||
| 142 | /**  | 
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| 143 | * Should Whoops allow Handlers to force the script to quit?  | 
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| 144 | * @param bool|int $exit  | 
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| 145 | * @return bool  | 
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| 146 | */  | 
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| 147 | 5 | public function allowQuit($exit = null)  | 
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| 155 | |||
| 156 | /**  | 
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| 157 | * Silence particular errors in particular files  | 
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| 158 | * @param array|string $patterns List or a single regex pattern to match  | 
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| 159 | * @param int $levels Defaults to E_STRICT | E_DEPRECATED  | 
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| 160 | * @return \Whoops\Run  | 
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| 161 | */  | 
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| 162 | 1 | public function silenceErrorsInPaths($patterns, $levels = 10240)  | 
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| 178 | |||
| 179 | /*  | 
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| 180 | * Should Whoops send HTTP error code to the browser if possible?  | 
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| 181 | * Whoops will by default send HTTP code 500, but you may wish to  | 
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| 182 | * use 502, 503, or another 5xx family code.  | 
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| 183 | *  | 
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| 184 | * @param bool|int $code  | 
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| 185 | * @return int|false  | 
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| 186 | */  | 
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| 187 | 4 | public function sendHttpCode($code = null)  | 
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| 209 | |||
| 210 | /**  | 
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| 211 | * Should Whoops push output directly to the client?  | 
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| 212 | * If this is false, output will be returned by handleException  | 
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| 213 | * @param bool|int $send  | 
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| 214 | * @return bool  | 
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| 215 | */  | 
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| 216 | 4 | public function writeToOutput($send = null)  | 
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| 224 | |||
| 225 | /**  | 
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| 226 | * Handles an exception, ultimately generating a Whoops error  | 
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| 227 | * page.  | 
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| 228 | *  | 
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| 229 | * @param mixed $exception  | 
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| 230 | * @return string Output generated by handlers  | 
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| 231 | */  | 
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| 232 | 6 | public function handleException($exception)  | 
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| 293 | |||
| 294 | /**  | 
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| 295 | * Converts generic PHP errors to \ErrorException  | 
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| 296 | * instances, before passing them off to be handled.  | 
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| 297 | *  | 
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| 298 | * This method MUST be compatible with set_error_handler.  | 
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| 299 | *  | 
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| 300 | * @param int $level  | 
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| 301 | * @param string $message  | 
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| 302 | * @param string $file  | 
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| 303 | * @param int $line  | 
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| 304 | *  | 
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| 305 | * @return bool  | 
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| 306 | * @throws ErrorException  | 
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| 307 | */  | 
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| 308 | 5 | public function handleError($level, $message, $file = null, $line = null)  | 
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| 336 | |||
| 337 | /**  | 
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| 338 | * Special case to deal with Fatal errors and the like.  | 
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| 339 | */  | 
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| 340 | public function handleShutdown()  | 
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| 359 | |||
| 360 | /**  | 
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| 361 | * In certain scenarios, like in shutdown handler, we can not throw exceptions  | 
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| 362 | * @var bool  | 
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| 363 | */  | 
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| 364 | private $canThrowExceptions = true;  | 
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| 365 | |||
| 366 | /**  | 
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| 367 | * Echo something to the browser  | 
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| 368 | * @param string $output  | 
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| 369 | * @return $this  | 
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| 370 | */  | 
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| 371 | 2 | private function writeToOutputNow($output)  | 
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| 396 | |||
| 397 | private static function isLevelFatal($level)  | 
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| 407 | }  | 
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| 408 | 
This check marks implicit conversions of arrays to boolean values in a comparison. While in PHP an empty array is considered to be equal (but not identical) to false, this is not always apparent.
Consider making the comparison explicit by using
empty(..)or! empty(...)instead.