Chris@0: <?php
Chris@0: 
Chris@0: /*
Chris@0:  * This file is part of Psy Shell.
Chris@0:  *
Chris@0:  * (c) 2012-2017 Justin Hileman
Chris@0:  *
Chris@0:  * For the full copyright and license information, please view the LICENSE
Chris@0:  * file that was distributed with this source code.
Chris@0:  */
Chris@0: 
Chris@0: namespace Psy\Output;
Chris@0: 
Chris@0: use Symfony\Component\Console\Output\StreamOutput;
Chris@0: 
Chris@0: /**
Chris@0:  * ProcOutputPager class.
Chris@0:  *
Chris@0:  * A ProcOutputPager instance wraps a regular StreamOutput's stream. Rather
Chris@0:  * than writing directly to the stream, it shells out to a pager process and
Chris@0:  * gives that process the stream as stdout. This means regular *nix commands
Chris@0:  * like `less` and `more` can be used to page large amounts of output.
Chris@0:  */
Chris@0: class ProcOutputPager extends StreamOutput implements OutputPager
Chris@0: {
Chris@0:     private $proc;
Chris@0:     private $pipe;
Chris@0:     private $stream;
Chris@0:     private $cmd;
Chris@0: 
Chris@0:     /**
Chris@0:      * Constructor.
Chris@0:      *
Chris@0:      * @param StreamOutput $output
Chris@0:      * @param string       $cmd    Pager process command (default: 'less -R -S -F -X')
Chris@0:      */
Chris@0:     public function __construct(StreamOutput $output, $cmd = 'less -R -S -F -X')
Chris@0:     {
Chris@0:         $this->stream = $output->getStream();
Chris@0:         $this->cmd    = $cmd;
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Writes a message to the output.
Chris@0:      *
Chris@0:      * @param string $message A message to write to the output
Chris@0:      * @param bool   $newline Whether to add a newline or not
Chris@0:      *
Chris@0:      * @throws \RuntimeException When unable to write output (should never happen)
Chris@0:      */
Chris@0:     public function doWrite($message, $newline)
Chris@0:     {
Chris@0:         $pipe = $this->getPipe();
Chris@0:         if (false === @fwrite($pipe, $message . ($newline ? PHP_EOL : ''))) {
Chris@0:             // @codeCoverageIgnoreStart
Chris@0:             // should never happen
Chris@0:             throw new \RuntimeException('Unable to write output.');
Chris@0:             // @codeCoverageIgnoreEnd
Chris@0:         }
Chris@0: 
Chris@0:         fflush($pipe);
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Close the current pager process.
Chris@0:      */
Chris@0:     public function close()
Chris@0:     {
Chris@0:         if (isset($this->pipe)) {
Chris@0:             fclose($this->pipe);
Chris@0:         }
Chris@0: 
Chris@0:         if (isset($this->proc)) {
Chris@0:             $exit = proc_close($this->proc);
Chris@0:             if ($exit !== 0) {
Chris@0:                 throw new \RuntimeException('Error closing output stream');
Chris@0:             }
Chris@0:         }
Chris@0: 
Chris@0:         unset($this->pipe, $this->proc);
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Get a pipe for paging output.
Chris@0:      *
Chris@0:      * If no active pager process exists, fork one and return its input pipe.
Chris@0:      */
Chris@0:     private function getPipe()
Chris@0:     {
Chris@0:         if (!isset($this->pipe) || !isset($this->proc)) {
Chris@0:             $desc = array(array('pipe', 'r'), $this->stream, fopen('php://stderr', 'w'));
Chris@0:             $this->proc = proc_open($this->cmd, $desc, $pipes);
Chris@0: 
Chris@0:             if (!is_resource($this->proc)) {
Chris@0:                 throw new \RuntimeException('Error opening output stream');
Chris@0:             }
Chris@0: 
Chris@0:             $this->pipe = $pipes[0];
Chris@0:         }
Chris@0: 
Chris@0:         return $this->pipe;
Chris@0:     }
Chris@0: }