Chris@0: <?php
Chris@0: namespace GuzzleHttp\Psr7;
Chris@0: 
Chris@0: use Psr\Http\Message\StreamInterface;
Chris@0: 
Chris@0: /**
Chris@0:  * Reads from multiple streams, one after the other.
Chris@0:  *
Chris@0:  * This is a read-only stream decorator.
Chris@0:  */
Chris@0: class AppendStream implements StreamInterface
Chris@0: {
Chris@0:     /** @var StreamInterface[] Streams being decorated */
Chris@0:     private $streams = [];
Chris@0: 
Chris@0:     private $seekable = true;
Chris@0:     private $current = 0;
Chris@0:     private $pos = 0;
Chris@0: 
Chris@0:     /**
Chris@0:      * @param StreamInterface[] $streams Streams to decorate. Each stream must
Chris@0:      *                                   be readable.
Chris@0:      */
Chris@0:     public function __construct(array $streams = [])
Chris@0:     {
Chris@0:         foreach ($streams as $stream) {
Chris@0:             $this->addStream($stream);
Chris@0:         }
Chris@0:     }
Chris@0: 
Chris@0:     public function __toString()
Chris@0:     {
Chris@0:         try {
Chris@0:             $this->rewind();
Chris@0:             return $this->getContents();
Chris@0:         } catch (\Exception $e) {
Chris@0:             return '';
Chris@0:         }
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Add a stream to the AppendStream
Chris@0:      *
Chris@0:      * @param StreamInterface $stream Stream to append. Must be readable.
Chris@0:      *
Chris@0:      * @throws \InvalidArgumentException if the stream is not readable
Chris@0:      */
Chris@0:     public function addStream(StreamInterface $stream)
Chris@0:     {
Chris@0:         if (!$stream->isReadable()) {
Chris@0:             throw new \InvalidArgumentException('Each stream must be readable');
Chris@0:         }
Chris@0: 
Chris@0:         // The stream is only seekable if all streams are seekable
Chris@0:         if (!$stream->isSeekable()) {
Chris@0:             $this->seekable = false;
Chris@0:         }
Chris@0: 
Chris@0:         $this->streams[] = $stream;
Chris@0:     }
Chris@0: 
Chris@0:     public function getContents()
Chris@0:     {
Chris@0:         return copy_to_string($this);
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Closes each attached stream.
Chris@0:      *
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function close()
Chris@0:     {
Chris@0:         $this->pos = $this->current = 0;
Chris@17:         $this->seekable = true;
Chris@0: 
Chris@0:         foreach ($this->streams as $stream) {
Chris@0:             $stream->close();
Chris@0:         }
Chris@0: 
Chris@0:         $this->streams = [];
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@17:      * Detaches each attached stream.
Chris@17:      *
Chris@17:      * Returns null as it's not clear which underlying stream resource to return.
Chris@0:      *
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function detach()
Chris@0:     {
Chris@17:         $this->pos = $this->current = 0;
Chris@17:         $this->seekable = true;
Chris@17: 
Chris@17:         foreach ($this->streams as $stream) {
Chris@17:             $stream->detach();
Chris@17:         }
Chris@17: 
Chris@17:         $this->streams = [];
Chris@0:     }
Chris@0: 
Chris@0:     public function tell()
Chris@0:     {
Chris@0:         return $this->pos;
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Tries to calculate the size by adding the size of each stream.
Chris@0:      *
Chris@0:      * If any of the streams do not return a valid number, then the size of the
Chris@0:      * append stream cannot be determined and null is returned.
Chris@0:      *
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function getSize()
Chris@0:     {
Chris@0:         $size = 0;
Chris@0: 
Chris@0:         foreach ($this->streams as $stream) {
Chris@0:             $s = $stream->getSize();
Chris@0:             if ($s === null) {
Chris@0:                 return null;
Chris@0:             }
Chris@0:             $size += $s;
Chris@0:         }
Chris@0: 
Chris@0:         return $size;
Chris@0:     }
Chris@0: 
Chris@0:     public function eof()
Chris@0:     {
Chris@0:         return !$this->streams ||
Chris@0:             ($this->current >= count($this->streams) - 1 &&
Chris@0:              $this->streams[$this->current]->eof());
Chris@0:     }
Chris@0: 
Chris@0:     public function rewind()
Chris@0:     {
Chris@0:         $this->seek(0);
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Attempts to seek to the given position. Only supports SEEK_SET.
Chris@0:      *
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function seek($offset, $whence = SEEK_SET)
Chris@0:     {
Chris@0:         if (!$this->seekable) {
Chris@0:             throw new \RuntimeException('This AppendStream is not seekable');
Chris@0:         } elseif ($whence !== SEEK_SET) {
Chris@0:             throw new \RuntimeException('The AppendStream can only seek with SEEK_SET');
Chris@0:         }
Chris@0: 
Chris@0:         $this->pos = $this->current = 0;
Chris@0: 
Chris@0:         // Rewind each stream
Chris@0:         foreach ($this->streams as $i => $stream) {
Chris@0:             try {
Chris@0:                 $stream->rewind();
Chris@0:             } catch (\Exception $e) {
Chris@0:                 throw new \RuntimeException('Unable to seek stream '
Chris@0:                     . $i . ' of the AppendStream', 0, $e);
Chris@0:             }
Chris@0:         }
Chris@0: 
Chris@0:         // Seek to the actual position by reading from each stream
Chris@0:         while ($this->pos < $offset && !$this->eof()) {
Chris@0:             $result = $this->read(min(8096, $offset - $this->pos));
Chris@0:             if ($result === '') {
Chris@0:                 break;
Chris@0:             }
Chris@0:         }
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Reads from all of the appended streams until the length is met or EOF.
Chris@0:      *
Chris@0:      * {@inheritdoc}
Chris@0:      */
Chris@0:     public function read($length)
Chris@0:     {
Chris@0:         $buffer = '';
Chris@0:         $total = count($this->streams) - 1;
Chris@0:         $remaining = $length;
Chris@0:         $progressToNext = false;
Chris@0: 
Chris@0:         while ($remaining > 0) {
Chris@0: 
Chris@0:             // Progress to the next stream if needed.
Chris@0:             if ($progressToNext || $this->streams[$this->current]->eof()) {
Chris@0:                 $progressToNext = false;
Chris@0:                 if ($this->current === $total) {
Chris@0:                     break;
Chris@0:                 }
Chris@0:                 $this->current++;
Chris@0:             }
Chris@0: 
Chris@0:             $result = $this->streams[$this->current]->read($remaining);
Chris@0: 
Chris@0:             // Using a loose comparison here to match on '', false, and null
Chris@0:             if ($result == null) {
Chris@0:                 $progressToNext = true;
Chris@0:                 continue;
Chris@0:             }
Chris@0: 
Chris@0:             $buffer .= $result;
Chris@0:             $remaining = $length - strlen($buffer);
Chris@0:         }
Chris@0: 
Chris@0:         $this->pos += strlen($buffer);
Chris@0: 
Chris@0:         return $buffer;
Chris@0:     }
Chris@0: 
Chris@0:     public function isReadable()
Chris@0:     {
Chris@0:         return true;
Chris@0:     }
Chris@0: 
Chris@0:     public function isWritable()
Chris@0:     {
Chris@0:         return false;
Chris@0:     }
Chris@0: 
Chris@0:     public function isSeekable()
Chris@0:     {
Chris@0:         return $this->seekable;
Chris@0:     }
Chris@0: 
Chris@0:     public function write($string)
Chris@0:     {
Chris@0:         throw new \RuntimeException('Cannot write to an AppendStream');
Chris@0:     }
Chris@0: 
Chris@0:     public function getMetadata($key = null)
Chris@0:     {
Chris@0:         return $key ? null : [];
Chris@0:     }
Chris@0: }