libraries/OutputBuffering.class.php

   1 <?php
   2 /* vim: set expandtab sw=4 ts=4 sts=4: */
   3 /**
   4  * Output buffering wrapper
   5  *
   6  * @package PhpMyAdmin
   7  */
   8 if (! defined('PHPMYADMIN')) {
   9     exit;
  10 }
  11
  12 /**
  13  * Output buffering wrapper class
  14  *
  15  * @package PhpMyAdmin
  16  */
  17 class PMA_OutputBuffering
  18 {
  19     private static $_instance;
  20     private $_mode;
  21     private $_content;
  22     private $_on;
  23
  24     /**
  25      * Initializes class
  26      *
  27      * @return void
  28      */
  29     private function __construct()
  30     {
  31         $this->_mode = $this->_getMode();
  32         $this->_on = false;
  33     }
  34
  35     /**
  36      * This function could be used eventually to support more modes.
  37      *
  38      * @return integer  the output buffer mode
  39      */
  40     private function _getMode()
  41     {
  42         $mode = 0;
  43         if ($GLOBALS['cfg']['OBGzip'] && function_exists('ob_start')) {
  44             if (ini_get('output_handler') == 'ob_gzhandler') {
  45                 // If a user sets the output_handler in php.ini to ob_gzhandler, then
  46                 // any right frame file in phpMyAdmin will not be handled properly by
  47                 // the browser. My fix was to check the ini file within the
  48                 // PMA_outBufferModeGet() function.
  49                 $mode = 0;
  50             } elseif (function_exists('ob_get_level') && ob_get_level() > 0) {
  51                 // If output buffering is enabled in php.ini it's not possible to
  52                 // add the ob_gzhandler without a warning message from php 4.3.0.
  53                 // Being better safe than sorry, check for any existing output handler
  54                 // instead of just checking the 'output_buffering' setting.
  55                 $mode = 0;
  56             } else {
  57                 $mode = 1;
  58             }
  59         }
  60         // Zero (0) is no mode or in other words output buffering is OFF.
  61         // Follow 2^0, 2^1, 2^2, 2^3 type values for the modes.
  62         // Usefull if we ever decide to combine modes.  Then a bitmask field of
  63         // the sum of all modes will be the natural choice.
  64         return $mode;
  65     }
  66
  67     /**
  68      * Returns the singleton PMA_OutputBuffering object
  69      *
  70      * @return PMA_OutputBuffering object
  71      */
  72     public static function getInstance()
  73     {
  74         if (empty(self::$_instance)) {
  75             self::$_instance = new PMA_OutputBuffering();
  76         }
  77         return self::$_instance;
  78     }
  79
  80     /**
  81      * This function will need to run at the top of all pages if output
  82      * output buffering is turned on.  It also needs to be passed $mode from
  83      * the PMA_outBufferModeGet() function or it will be useless.
  84      *
  85      * @return void
  86      */
  87     public function start()
  88     {
  89         if (! $this->_on) {
  90             if ($this->_mode) {
  91                 ob_start('ob_gzhandler');
  92             }
  93             ob_start();
  94             if (! defined('TESTSUITE')) {
  95                 header('X-ob_mode: ' . $this->_mode);
  96             }
  97             register_shutdown_function('PMA_OutputBuffering::stop');
  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         $buffer = PMA_OutputBuffering::getInstance();
 112         if ($buffer->_on) {
 113             $buffer->_on = false;
 114             $buffer->_content = ob_get_contents();
 115             ob_end_clean();
 116         }
 117         PMA_Response::response();
 118     }
 119
 120     /**
 121      * Gets buffer content
 122      *
 123      * @return buffer content
 124      */
 125     public function getContents()
 126     {
 127         return $this->_content;
 128     }
 129
 130     /**
 131      * Flushes output buffer
 132      *
 133      * @return void
 134      */
 135     public function flush()
 136     {
 137         if (ob_get_status() && $this->_mode) {
 138             ob_flush();
 139         }
 140         /**
 141          * previously we had here an "else flush()" but some PHP versions
 142          * (at least PHP 5.2.11) have a bug (49816) that produces garbled
 143          * data
 144          */
 145     }
 146 }
 147
 148 ?>