libraries/classes/OutputBuffering.php

   1 <?php /* vim: set expandtab sw=4 ts=4 sts=4: */
   2 /**
   3  * Output buffering wrapper
   4  *
   5  * @package PhpMyAdmin
   6  */
   7 declare(strict_types=1);
   8
   9 namespace PhpMyAdmin;
  10
  11 /**
  12  * Output buffering wrapper class
  13  *
  14  * @package PhpMyAdmin
  15  */
  16 class OutputBuffering
  17 {
  18     private static $_instance;
  19     private $_mode;
  20     private $_content;
  21     private $_on;
  22
  23     /**
  24      * Initializes class
  25      */
  26     private function __construct()
  27     {
  28         $this->_mode = $this->_getMode();
  29         $this->_on = false;
  30     }
  31
  32     /**
  33      * This function could be used eventually to support more modes.
  34      *
  35      * @return integer  the output buffer mode
  36      */
  37     private function _getMode()
  38     {
  39         $mode = 0;
  40         if ($GLOBALS['cfg']['OBGzip'] && function_exists('ob_start')) {
  41             if (ini_get('output_handler') == 'ob_gzhandler') {
  42                 // If a user sets the output_handler in php.ini to ob_gzhandler, then
  43                 // any right frame file in phpMyAdmin will not be handled properly by
  44                 // the browser. My fix was to check the ini file within the
  45                 // PMA_outBufferModeGet() function.
  46                 $mode = 0;
  47             } elseif (function_exists('ob_get_level') && ob_get_level() > 0) {
  48                 // happens when php.ini's output_buffering is not Off
  49                 ob_end_clean();
  50                 $mode = 1;
  51             } else {
  52                 $mode = 1;
  53             }
  54         }
  55         // Zero (0) is no mode or in other words output buffering is OFF.
  56         // Follow 2^0, 2^1, 2^2, 2^3 type values for the modes.
  57         // Useful if we ever decide to combine modes.  Then a bitmask field of
  58         // the sum of all modes will be the natural choice.
  59         return $mode;
  60     }
  61
  62     /**
  63      * Returns the singleton OutputBuffering object
  64      *
  65      * @return OutputBuffering object
  66      */
  67     public static function getInstance()
  68     {
  69         if (empty(self::$_instance)) {
  70             self::$_instance = new OutputBuffering();
  71         }
  72         return self::$_instance;
  73     }
  74
  75     /**
  76      * This function will need to run at the top of all pages if output
  77      * output buffering is turned on.  It also needs to be passed $mode from
  78      * the PMA_outBufferModeGet() function or it will be useless.
  79      *
  80      * @return void
  81      */
  82     public function start()
  83     {
  84         if (! $this->_on) {
  85             if ($this->_mode && function_exists('ob_gzhandler')) {
  86                 ob_start('ob_gzhandler');
  87             }
  88             ob_start();
  89             if (! defined('TESTSUITE')) {
  90                 header('X-ob_mode: ' . $this->_mode);
  91             }
  92             register_shutdown_function(
  93                 [
  94                     OutputBuffering::class,
  95                     'stop',
  96                 ]
  97             );
  98             $this->_on = true;
  99         }
 100     }
 101
 102     /**
 103      * This function will need to run at the bottom of all pages if output
 104      * buffering is turned on.  It also needs to be passed $mode from the
 105      * PMA_outBufferModeGet() function or it will be useless.
 106      *
 107      * @return void
 108      */
 109     public static function stop()
 110     {
 111         $buffer = OutputBuffering::getInstance();
 112         if ($buffer->_on) {
 113             $buffer->_on = false;
 114             $buffer->_content = ob_get_contents();
 115             if (ob_get_length() > 0) {
 116                 ob_end_clean();
 117             }
 118         }
 119     }
 120
 121     /**
 122      * Gets buffer content
 123      *
 124      * @return string buffer content
 125      */
 126     public function getContents()
 127     {
 128         return $this->_content;
 129     }
 130
 131     /**
 132      * Flushes output buffer
 133      *
 134      * @return void
 135      */
 136     public function flush()
 137     {
 138         if (ob_get_status() && $this->_mode) {
 139             ob_flush();
 140         } else {
 141             flush();
 142         }
 143     }
 144 }