Chris@0: <?php
Chris@0: /**
Chris@0:  * Zend Framework (http://framework.zend.com/)
Chris@0:  *
Chris@0:  * @see       http://github.com/zendframework/zend-diactoros for the canonical source repository
Chris@0:  * @copyright Copyright (c) 2015-2016 Zend Technologies USA Inc. (http://www.zend.com)
Chris@0:  * @license   https://github.com/zendframework/zend-diactoros/blob/master/LICENSE.md New BSD License
Chris@0:  */
Chris@0: 
Chris@0: namespace Zend\Diactoros;
Chris@0: 
Chris@0: use InvalidArgumentException;
Chris@16: use Psr\Http\Message\StreamInterface;
Chris@0: use RuntimeException;
Chris@16: 
Chris@16: use function array_key_exists;
Chris@16: 
Chris@16: use const SEEK_SET;
Chris@0: 
Chris@0: /**
Chris@0:  * Implementation of PSR HTTP streams
Chris@0:  */
Chris@0: class CallbackStream implements StreamInterface
Chris@0: {
Chris@0:     /**
Chris@0:      * @var callable|null
Chris@0:      */
Chris@0:     protected $callback;
Chris@0: 
Chris@0:     /**
Chris@0:      * @param callable $callback
Chris@0:      * @throws InvalidArgumentException
Chris@0:      */
Chris@0:     public function __construct(callable $callback)
Chris@0:     {
Chris@0:         $this->attach($callback);
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function __toString()
Chris@0:     {
Chris@0:         return $this->getContents();
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function close()
Chris@0:     {
Chris@0:         $this->callback = null;
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function detach()
Chris@0:     {
Chris@0:         $callback = $this->callback;
Chris@0:         $this->callback = null;
Chris@0:         return $callback;
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Attach a new callback to the instance.
Chris@0:      *
Chris@0:      * @param callable $callback
Chris@0:      * @throws InvalidArgumentException for callable callback
Chris@0:      */
Chris@0:     public function attach(callable $callback)
Chris@0:     {
Chris@0:         $this->callback = $callback;
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function getSize()
Chris@0:     {
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function tell()
Chris@0:     {
Chris@0:         throw new RuntimeException('Callback streams cannot tell position');
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function eof()
Chris@0:     {
Chris@0:         return empty($this->callback);
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function isSeekable()
Chris@0:     {
Chris@0:         return false;
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function seek($offset, $whence = SEEK_SET)
Chris@0:     {
Chris@0:         throw new RuntimeException('Callback streams cannot seek position');
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function rewind()
Chris@0:     {
Chris@0:         throw new RuntimeException('Callback streams cannot rewind position');
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function isWritable()
Chris@0:     {
Chris@0:         return false;
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function write($string)
Chris@0:     {
Chris@0:         throw new RuntimeException('Callback streams cannot write');
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function isReadable()
Chris@0:     {
Chris@0:         return false;
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function read($length)
Chris@0:     {
Chris@0:         throw new RuntimeException('Callback streams cannot read');
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function getContents()
Chris@0:     {
Chris@0:         $callback = $this->detach();
Chris@0:         return $callback ? $callback() : '';
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function getMetadata($key = null)
Chris@0:     {
Chris@0:         $metadata = [
Chris@0:             'eof' => $this->eof(),
Chris@0:             'stream_type' => 'callback',
Chris@0:             'seekable' => false
Chris@0:         ];
Chris@0: 
Chris@0:         if (null === $key) {
Chris@0:             return $metadata;
Chris@0:         }
Chris@0: 
Chris@0:         if (! array_key_exists($key, $metadata)) {
Chris@0:             return null;
Chris@0:         }
Chris@0: 
Chris@0:         return $metadata[$key];
Chris@0:     }
Chris@0: }