<?php

/**

 * CodeIgniter

 *

 * An open source application development framework for PHP

 *

 * This content is released under the MIT License (MIT)

 *

 * Copyright (c) 2014 - 2017, British Columbia Institute of Technology

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 *

 * @package	CodeIgniter

 * @author	EllisLab Dev Team

 * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)

 * @copyright	Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)

 * @license	http://opensource.org/licenses/MIT	MIT License

 * @link	https://codeigniter.com

 * @since	Version 1.0.0

 * @filesource

 */

defined('BASEPATH') OR exit('No direct script access allowed');



/**

 * Output Class

 *

 * Responsible for sending final output to the browser.

 *

 * @package		CodeIgniter

 * @subpackage	Libraries

 * @category	Output

 * @author		EllisLab Dev Team

 * @link		https://codeigniter.com/user_guide/libraries/output.html

 */

class CI_Output {



	/**

	 * Final output string

	 *

	 * @var	string

	 */

	public $final_output;



	/**

	 * Cache expiration time

	 *

	 * @var	int

	 */

	public $cache_expiration = 0;



	/**

	 * List of server headers

	 *

	 * @var	array

	 */

	public $headers = array();



	/**

	 * List of mime types

	 *

	 * @var	array

	 */

	public $mimes =	array();



	/**

	 * Mime-type for the current page

	 *

	 * @var	string

	 */

	protected $mime_type = 'text/html';



	/**

	 * Enable Profiler flag

	 *

	 * @var	bool

	 */

	public $enable_profiler = FALSE;



	/**

	 * php.ini zlib.output_compression flag

	 *

	 * @var	bool

	 */

	protected $_zlib_oc = FALSE;



	/**

	 * CI output compression flag

	 *

	 * @var	bool

	 */

	protected $_compress_output = FALSE;



	/**

	 * List of profiler sections

	 *

	 * @var	array

	 */

	protected $_profiler_sections =	array();



	/**

	 * Parse markers flag

	 *

	 * Whether or not to parse variables like {elapsed_time} and {memory_usage}.

	 *

	 * @var	bool

	 */

	public $parse_exec_vars = TRUE;



	/**

	 * mbstring.func_override flag

	 *

	 * @var	bool

	 */

	protected static $func_override;



	/**

	 * Class constructor

	 *

	 * Determines whether zLib output compression will be used.

	 *

	 * @return	void

	 */

	public function __construct()

	{

		$this->_zlib_oc = (bool) ini_get('zlib.output_compression');

		$this->_compress_output = (

			$this->_zlib_oc === FALSE

			&& config_item('compress_output') === TRUE

			&& extension_loaded('zlib')

		);



		isset(self::$func_override) OR self::$func_override = (extension_loaded('mbstring') && ini_get('mbstring.func_override'));



		// Get mime types for later

		$this->mimes =& get_mimes();



		log_message('info', 'Output Class Initialized');

	}



	// --------------------------------------------------------------------



	/**

	 * Get Output

	 *

	 * Returns the current output string.

	 *

	 * @return	string

	 */

	public function get_output()

	{

		return $this->final_output;

	}



	// --------------------------------------------------------------------



	/**

	 * Set Output

	 *

	 * Sets the output string.

	 *

	 * @param	string	$output	Output data

	 * @return	CI_Output

	 */

	public function set_output($output)

	{

		$this->final_output = $output;

		return $this;

	}



	// --------------------------------------------------------------------



	/**

	 * Append Output

	 *

	 * Appends data onto the output string.

	 *

	 * @param	string	$output	Data to append

	 * @return	CI_Output

	 */

	public function append_output($output)

	{

		$this->final_output .= $output;

		return $this;

	}



	// --------------------------------------------------------------------



	/**

	 * Set Header

	 *

	 * Lets you set a server header which will be sent with the final output.

	 *

	 * Note: If a file is cached, headers will not be sent.

	 * @todo	We need to figure out how to permit headers to be cached.

	 *

	 * @param	string	$header		Header

	 * @param	bool	$replace	Whether to replace the old header value, if already set

	 * @return	CI_Output

	 */

	public function set_header($header, $replace = TRUE)

	{

		// If zlib.output_compression is enabled it will compress the output,

		// but it will not modify the content-length header to compensate for

		// the reduction, causing the browser to hang waiting for more data.

		// We'll just skip content-length in those cases.

		if ($this->_zlib_oc && strncasecmp($header, 'content-length', 14) === 0)

		{

			return $this;

		}



		$this->headers[] = array($header, $replace);

		return $this;

	}



	// --------------------------------------------------------------------



	/**

	 * Set Content-Type Header

	 *

	 * @param	string	$mime_type	Extension of the file we're outputting

	 * @param	string	$charset	Character set (default: NULL)

	 * @return	CI_Output

	 */

	public function set_content_type($mime_type, $charset = NULL)

	{

		if (strpos($mime_type, '/') === FALSE)

		{

			$extension = ltrim($mime_type, '.');



			// Is this extension supported?

			if (isset($this->mimes[$extension]))

			{

				$mime_type =& $this->mimes[$extension];



				if (is_array($mime_type))

				{

					$mime_type = current($mime_type);

				}

			}

		}



		$this->mime_type = $mime_type;



		if (empty($charset))

		{

			$charset = config_item('charset');

		}



		$header = 'Content-Type: '.$mime_type

			.(empty($charset) ? '' : '; charset='.$charset);



		$this->headers[] = array($header, TRUE);

		return $this;

	}



	// --------------------------------------------------------------------



	/**

	 * Get Current Content-Type Header

	 *

	 * @return	string	'text/html', if not already set

	 */

	public function get_content_type()

	{

		for ($i = 0, $c = count($this->headers); $i < $c; $i++)

		{

			if (sscanf($this->headers[$i][0], 'Content-Type: %[^;]', $content_type) === 1)

			{

				return $content_type;

			}

		}



		return 'text/html';

	}



	// --------------------------------------------------------------------



	/**

	 * Get Header

	 *

	 * @param	string	$header

	 * @return	string

	 */

	public function get_header($header)

	{

		// Combine headers already sent with our batched headers

		$headers = array_merge(

			// We only need [x][0] from our multi-dimensional array

			array_map('array_shift', $this->headers),

			headers_list()

		);



		if (empty($headers) OR empty($header))

		{

			return NULL;

		}



		// Count backwards, in order to get the last matching header

		for ($c = count($headers) - 1; $c > -1; $c--)

		{

			if (strncasecmp($header, $headers[$c], $l = self::strlen($header)) === 0)

			{

				return trim(self::substr($headers[$c], $l+1));

			}

		}



		return NULL;

	}



	// --------------------------------------------------------------------



	/**

	 * Set HTTP Status Header

	 *

	 * As of version 1.7.2, this is an alias for common function

	 * set_status_header().

	 *

	 * @param	int	$code	Status code (default: 200)

	 * @param	string	$text	Optional message

	 * @return	CI_Output

	 */

	public function set_status_header($code = 200, $text = '')

	{

		set_status_header($code, $text);

		return $this;

	}



	// --------------------------------------------------------------------



	/**

	 * Enable/disable Profiler

	 *

	 * @param	bool	$val	TRUE to enable or FALSE to disable

	 * @return	CI_Output

	 */

	public function enable_profiler($val = TRUE)

	{

		$this->enable_profiler = is_bool($val) ? $val : TRUE;

		return $this;

	}



	// --------------------------------------------------------------------



	/**

	 * Set Profiler Sections

	 *

	 * Allows override of default/config settings for

	 * Profiler section display.

	 *

	 * @param	array	$sections	Profiler sections

	 * @return	CI_Output

	 */

	public function set_profiler_sections($sections)

	{

		if (isset($sections['query_toggle_count']))

		{

			$this->_profiler_sections['query_toggle_count'] = (int) $sections['query_toggle_count'];

			unset($sections['query_toggle_count']);

		}



		foreach ($sections as $section => $enable)

		{

			$this->_profiler_sections[$section] = ($enable !== FALSE);

		}



		return $this;

	}



	// --------------------------------------------------------------------



	/**

	 * Set Cache

	 *

	 * @param	int	$time	Cache expiration time in minutes

	 * @return	CI_Output

	 */

	public function cache($time)

	{

		$this->cache_expiration = is_numeric($time) ? $time : 0;

		return $this;

	}



	// --------------------------------------------------------------------



	/**

	 * Display Output

	 *

	 * Processes and sends finalized output data to the browser along

	 * with any server headers and profile data. It also stops benchmark

	 * timers so the page rendering speed and memory usage can be shown.

	 *

	 * Note: All "view" data is automatically put into $this->final_output

	 *	 by controller class.

	 *

	 * @uses	CI_Output::$final_output

	 * @param	string	$output	Output data override

	 * @return	void

	 */

	public function _display($output = '')

	{

		// Note:  We use load_class() because we can't use $CI =& get_instance()

		// since this function is sometimes called by the caching mechanism,

		// which happens before the CI super object is available.

		$BM =& load_class('Benchmark', 'core');

		$CFG =& load_class('Config', 'core');



		// Grab the super object if we can.

		if (class_exists('CI_Controller', FALSE))

		{

			$CI =& get_instance();

		}



		// --------------------------------------------------------------------



		// Set the output data

		if ($output === '')

		{

			$output =& $this->final_output;

		}



		// --------------------------------------------------------------------



		// Do we need to write a cache file? Only if the controller does not have its

		// own _output() method and we are not dealing with a cache file, which we

		// can determine by the existence of the $CI object above

		if ($this->cache_expiration > 0 && isset($CI) && ! method_exists($CI, '_output'))

		{

			$this->_write_cache($output);

		}



		// --------------------------------------------------------------------



		// Parse out the elapsed time and memory usage,

		// then swap the pseudo-variables with the data



		$elapsed = $BM->elapsed_time('total_execution_time_start', 'total_execution_time_end');



		if ($this->parse_exec_vars === TRUE)

		{

			$memory	= round(memory_get_usage() / 1024 / 1024, 2).'MB';

			$output = str_replace(array('{elapsed_time}', '{memory_usage}'), array($elapsed, $memory), $output);

		}



		// --------------------------------------------------------------------



		// Is compression requested?

		if (isset($CI) // This means that we're not serving a cache file, if we were, it would already be compressed

			&& $this->_compress_output === TRUE

			&& isset($_SERVER['HTTP_ACCEPT_ENCODING']) && strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') !== FALSE)

		{

			ob_start('ob_gzhandler');

		}



		// --------------------------------------------------------------------



		// Are there any server headers to send?

		if (count($this->headers) > 0)

		{

			foreach ($this->headers as $header)

			{

				@header($header[0], $header[1]);

			}

		}



		// --------------------------------------------------------------------



		// Does the $CI object exist?

		// If not we know we are dealing with a cache file so we'll

		// simply echo out the data and exit.

		if ( ! isset($CI))

		{

			if ($this->_compress_output === TRUE)

			{

				if (isset($_SERVER['HTTP_ACCEPT_ENCODING']) && strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') !== FALSE)

				{

					header('Content-Encoding: gzip');

					header('Content-Length: '.self::strlen($output));

				}

				else

				{

					// User agent doesn't support gzip compression,

					// so we'll have to decompress our cache

					$output = gzinflate(self::substr($output, 10, -8));

				}

			}



			echo $output;

			log_message('info', 'Final output sent to browser');

			log_message('debug', 'Total execution time: '.$elapsed);

			return;

		}



		// --------------------------------------------------------------------



		// Do we need to generate profile data?

		// If so, load the Profile class and run it.

		if ($this->enable_profiler === TRUE)

		{

			$CI->load->library('profiler');

			if ( ! empty($this->_profiler_sections))

			{

				$CI->profiler->set_sections($this->_profiler_sections);

			}



			// If the output data contains closing </body> and </html> tags

			// we will remove them and add them back after we insert the profile data

			$output = preg_replace('|</body>.*?</html>|is', '', $output, -1, $count).$CI->profiler->run();

			if ($count > 0)

			{

				$output .= '</body></html>';

			}

		}



		// Does the controller contain a function named _output()?

		// If so send the output there.  Otherwise, echo it.

		if (method_exists($CI, '_output'))

		{

			$CI->_output($output);

		}

		else

		{

			echo $output; // Send it to the browser!

		}



		log_message('info', 'Final output sent to browser');

		log_message('debug', 'Total execution time: '.$elapsed);

	}



	// --------------------------------------------------------------------



	/**

	 * Write Cache

	 *

	 * @param	string	$output	Output data to cache

	 * @return	void

	 */

	public function _write_cache($output)

	{

		$CI =& get_instance();

		$path = $CI->config->item('cache_path');

		$cache_path = ($path === '') ? APPPATH.'cache/' : $path;



		if ( ! is_dir($cache_path) OR ! is_really_writable($cache_path))

		{

			log_message('error', 'Unable to write cache file: '.$cache_path);

			return;

		}



		$uri = $CI->config->item('base_url')

			.$CI->config->item('index_page')

			.$CI->uri->uri_string();



		if (($cache_query_string = $CI->config->item('cache_query_string')) && ! empty($_SERVER['QUERY_STRING']))

		{

			if (is_array($cache_query_string))

			{

				$uri .= '?'.http_build_query(array_intersect_key($_GET, array_flip($cache_query_string)));

			}

			else

			{

				$uri .= '?'.$_SERVER['QUERY_STRING'];

			}

		}



		$cache_path .= md5($uri);



		if ( ! $fp = @fopen($cache_path, 'w+b'))

		{

			log_message('error', 'Unable to write cache file: '.$cache_path);

			return;

		}



		if (flock($fp, LOCK_EX))

		{

			// If output compression is enabled, compress the cache

			// itself, so that we don't have to do that each time

			// we're serving it

			if ($this->_compress_output === TRUE)

			{

				$output = gzencode($output);



				if ($this->get_header('content-type') === NULL)

				{

					$this->set_content_type($this->mime_type);

				}

			}



			$expire = time() + ($this->cache_expiration * 60);



			// Put together our serialized info.

			$cache_info = serialize(array(

				'expire'	=> $expire,

				'headers'	=> $this->headers

			));



			$output = $cache_info.'ENDCI--->'.$output;



			for ($written = 0, $length = self::strlen($output); $written < $length; $written += $result)

			{

				if (($result = fwrite($fp, self::substr($output, $written))) === FALSE)

				{

					break;

				}

			}



			flock($fp, LOCK_UN);

		}

		else

		{

			log_message('error', 'Unable to secure a file lock for file at: '.$cache_path);

			return;

		}



		fclose($fp);



		if (is_int($result))

		{

			chmod($cache_path, 0640);

			log_message('debug', 'Cache file written: '.$cache_path);



			// Send HTTP cache-control headers to browser to match file cache settings.

			$this->set_cache_header($_SERVER['REQUEST_TIME'], $expire);

		}

		else

		{

			@unlink($cache_path);

			log_message('error', 'Unable to write the complete cache content at: '.$cache_path);

		}

	}



	// --------------------------------------------------------------------



	/**

	 * Update/serve cached output

	 *

	 * @uses	CI_Config

	 * @uses	CI_URI

	 *

	 * @param	object	&$CFG	CI_Config class instance

	 * @param	object	&$URI	CI_URI class instance

	 * @return	bool	TRUE on success or FALSE on failure

	 */

	public function _display_cache(&$CFG, &$URI)

	{

		$cache_path = ($CFG->item('cache_path') === '') ? APPPATH.'cache/' : $CFG->item('cache_path');



		// Build the file path. The file name is an MD5 hash of the full URI

		$uri = $CFG->item('base_url').$CFG->item('index_page').$URI->uri_string;



		if (($cache_query_string = $CFG->item('cache_query_string')) && ! empty($_SERVER['QUERY_STRING']))

		{

			if (is_array($cache_query_string))

			{

				$uri .= '?'.http_build_query(array_intersect_key($_GET, array_flip($cache_query_string)));

			}

			else

			{

				$uri .= '?'.$_SERVER['QUERY_STRING'];

			}

		}



		$filepath = $cache_path.md5($uri);



		if ( ! file_exists($filepath) OR ! $fp = @fopen($filepath, 'rb'))

		{

			return FALSE;

		}



		flock($fp, LOCK_SH);



		$cache = (filesize($filepath) > 0) ? fread($fp, filesize($filepath)) : '';



		flock($fp, LOCK_UN);

		fclose($fp);



		// Look for embedded serialized file info.

		if ( ! preg_match('/^(.*)ENDCI--->/', $cache, $match))

		{

			return FALSE;

		}



		$cache_info = unserialize($match[1]);

		$expire = $cache_info['expire'];



		$last_modified = filemtime($filepath);



		// Has the file expired?

		if ($_SERVER['REQUEST_TIME'] >= $expire && is_really_writable($cache_path))

		{

			// If so we'll delete it.

			@unlink($filepath);

			log_message('debug', 'Cache file has expired. File deleted.');

			return FALSE;

		}

		else

		{

			// Or else send the HTTP cache control headers.

			$this->set_cache_header($last_modified, $expire);

		}



		// Add headers from cache file.

		foreach ($cache_info['headers'] as $header)

		{

			$this->set_header($header[0], $header[1]);

		}



		// Display the cache

		$this->_display(self::substr($cache, self::strlen($match[0])));

		log_message('debug', 'Cache file is current. Sending it to browser.');

		return TRUE;

	}



	// --------------------------------------------------------------------



	/**

	 * Delete cache

	 *

	 * @param	string	$uri	URI string

	 * @return	bool

	 */

	public function delete_cache($uri = '')

	{

		$CI =& get_instance();

		$cache_path = $CI->config->item('cache_path');

		if ($cache_path === '')

		{

			$cache_path = APPPATH.'cache/';

		}



		if ( ! is_dir($cache_path))

		{

			log_message('error', 'Unable to find cache path: '.$cache_path);

			return FALSE;

		}



		if (empty($uri))

		{

			$uri = $CI->uri->uri_string();



			if (($cache_query_string = $CI->config->item('cache_query_string')) && ! empty($_SERVER['QUERY_STRING']))

			{

				if (is_array($cache_query_string))

				{

					$uri .= '?'.http_build_query(array_intersect_key($_GET, array_flip($cache_query_string)));

				}

				else

				{

					$uri .= '?'.$_SERVER['QUERY_STRING'];

				}

			}

		}



		$cache_path .= md5($CI->config->item('base_url').$CI->config->item('index_page').ltrim($uri, '/'));



		if ( ! @unlink($cache_path))

		{

			log_message('error', 'Unable to delete cache file for '.$uri);

			return FALSE;

		}



		return TRUE;

	}



	// --------------------------------------------------------------------



	/**

	 * Set Cache Header

	 *

	 * Set the HTTP headers to match the server-side file cache settings

	 * in order to reduce bandwidth.

	 *

	 * @param	int	$last_modified	Timestamp of when the page was last modified

	 * @param	int	$expiration	Timestamp of when should the requested page expire from cache

	 * @return	void

	 */

	public function set_cache_header($last_modified, $expiration)

	{

		$max_age = $expiration - $_SERVER['REQUEST_TIME'];



		if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) && $last_modified <= strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']))

		{

			$this->set_status_header(304);

			exit;

		}

		else

		{

			header('Pragma: public');

			header('Cache-Control: max-age='.$max_age.', public');

			header('Expires: '.gmdate('D, d M Y H:i:s', $expiration).' GMT');

			header('Last-modified: '.gmdate('D, d M Y H:i:s', $last_modified).' GMT');

		}

	}



	// --------------------------------------------------------------------



	/**

	 * Byte-safe strlen()

	 *

	 * @param	string	$str

	 * @return	int

	 */

	protected static function strlen($str)

	{

		return (self::$func_override)

			? mb_strlen($str, '8bit')

			: strlen($str);

	}



	// --------------------------------------------------------------------



	/**

	 * Byte-safe substr()

	 *

	 * @param	string	$str

	 * @param	int	$start

	 * @param	int	$length

	 * @return	string

	 */

	protected static function substr($str, $start, $length = NULL)

	{

		if (self::$func_override)

		{

			// mb_substr($str, $start, null, '8bit') returns an empty

			// string on PHP 5.3

			isset($length) OR $length = ($start >= 0 ? self::strlen($str) - $start : -$start);

			return mb_substr($str, $start, $length, '8bit');

		}



		return isset($length)

			? substr($str, $start, $length)

			: substr($str, $start);

	}

}

