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   1  <?php
   2  
   3  /**
   4  * @package   s9e\TextFormatter
   5  * @copyright Copyright (c) 2010-2022 The s9e authors
   6  * @license   http://www.opensource.org/licenses/mit-license.php The MIT License
   7  */
   8  namespace s9e\TextFormatter;
   9  
  10  use DOMDocument;
  11  use InvalidArgumentException;
  12  
  13  abstract class Renderer
  14  {
  15      /**
  16      * @var array Associative array of [paramName => paramValue]
  17      */
  18      protected $params = [];
  19  
  20      /**
  21      * @var string Saved locale
  22      */
  23      protected $savedLocale = '0';
  24  
  25      /**
  26      * Create a return a new DOMDocument loaded with given XML
  27      *
  28      * @param  string      $xml Source XML
  29      * @return DOMDocument
  30      */
  31  	protected function loadXML($xml)
  32      {
  33          $this->checkUnsupported($xml);
  34  
  35          // Activate small nodes allocation and relax LibXML's hardcoded limits if applicable. Limits
  36          // on tags can be set during configuration
  37          $flags = (LIBXML_VERSION >= 20700) ? LIBXML_COMPACT | LIBXML_PARSEHUGE : 0;
  38  
  39          $useErrors = libxml_use_internal_errors(true);
  40          $dom       = new DOMDocument;
  41          $success   = $dom->loadXML($xml, $flags);
  42          libxml_use_internal_errors($useErrors);
  43  
  44          if (!$success)
  45          {
  46              throw new InvalidArgumentException('Cannot load XML: ' . libxml_get_last_error()->message);
  47          }
  48  
  49          return $dom;
  50      }
  51  
  52      /**
  53      * Render an intermediate representation
  54      *
  55      * @param  string $xml Intermediate representation
  56      * @return string      Rendered result
  57      */
  58  	public function render($xml)
  59      {
  60          if (substr($xml, 0, 3) === '<t>' && substr($xml, -4) === '</t>')
  61          {
  62              return $this->renderPlainText($xml);
  63          }
  64          else
  65          {
  66              return $this->renderRichText(preg_replace('(<[eis]>[^<]*</[eis]>)', '', $xml));
  67          }
  68      }
  69  
  70      /**
  71      * Render an intermediate representation of plain text
  72      *
  73      * @param  string $xml Intermediate representation
  74      * @return string      Rendered result
  75      */
  76  	protected function renderPlainText($xml)
  77      {
  78          // Remove the <t> and </t> tags
  79          $html = substr($xml, 3, -4);
  80  
  81          // Replace all <br/> with <br>
  82          $html = str_replace('<br/>', '<br>', $html);
  83  
  84          // Decode encoded characters from the Supplementary Multilingual Plane
  85          $html = $this->decodeSMP($html);
  86  
  87          return $html;
  88      }
  89  
  90      /**
  91      * Render an intermediate representation of rich text
  92      *
  93      * @param  string $xml Intermediate representation
  94      * @return string      Rendered result
  95      */
  96      abstract protected function renderRichText($xml);
  97  
  98      /**
  99      * Get the value of a parameter
 100      *
 101      * @param  string $paramName
 102      * @return string
 103      */
 104  	public function getParameter($paramName)
 105      {
 106          return $this->params[$paramName] ?? '';
 107      }
 108  
 109      /**
 110      * Get the values of all parameters
 111      *
 112      * @return array Associative array of parameter names and values
 113      */
 114  	public function getParameters()
 115      {
 116          return $this->params;
 117      }
 118  
 119      /**
 120      * Set the value of a parameter from the stylesheet
 121      *
 122      * @param  string $paramName  Parameter name
 123      * @param  mixed  $paramValue Parameter's value
 124      * @return void
 125      */
 126  	public function setParameter($paramName, $paramValue)
 127      {
 128          $this->params[$paramName] = (string) $paramValue;
 129      }
 130  
 131      /**
 132      * Set the values of several parameters from the stylesheet
 133      *
 134      * @param  array $params Associative array of [parameter name => parameter value]
 135      * @return void
 136      */
 137  	public function setParameters(array $params)
 138      {
 139          foreach ($params as $paramName => $paramValue)
 140          {
 141              $this->setParameter($paramName, $paramValue);
 142          }
 143      }
 144  
 145      /**
 146      * Test for the presence of unsupported XML and throw an exception if found
 147      *
 148      * @param  string $xml XML
 149      * @return void
 150      */
 151  	protected function checkUnsupported($xml)
 152      {
 153          if (preg_match('((?<=<)[!?])', $xml, $m))
 154          {
 155              $errors = [
 156                  '!' => 'DTDs, CDATA nodes and comments are not allowed',
 157                  '?' => 'Processing instructions are not allowed'
 158              ];
 159  
 160              throw new InvalidArgumentException($errors[$m[0]]);
 161          }
 162      }
 163  
 164      /**
 165      * Decode encoded characters from the Supplementary Multilingual Plane
 166      *
 167      * @param  string $str Encoded string
 168      * @return string      Decoded string
 169      */
 170  	protected function decodeSMP($str)
 171      {
 172          if (strpos($str, '&#') === false)
 173          {
 174              return $str;
 175          }
 176  
 177          return preg_replace_callback('(&#(?:x[0-9A-Fa-f]+|[0-9]+);)', __CLASS__ . '::decodeEntity', $str);
 178      }
 179  
 180      /**
 181      * Decode a matched SGML entity
 182      *
 183      * @param  string[] $m Captures from PCRE
 184      * @return string      Decoded entity
 185      */
 186  	protected static function decodeEntity(array $m)
 187      {
 188          return htmlspecialchars(html_entity_decode($m[0], ENT_QUOTES, 'UTF-8'), ENT_COMPAT);
 189      }
 190  
 191      /**
 192      * Restore the original locale
 193      */
 194  	protected function restoreLocale(): void
 195      {
 196          if ($this->savedLocale !== 'C')
 197          {
 198              setlocale(LC_NUMERIC, $this->savedLocale);
 199          }
 200      }
 201  
 202      /**
 203      * Temporarily set the locale to C
 204      */
 205  	protected function setLocale(): void
 206      {
 207          $this->savedLocale = setlocale(LC_NUMERIC, '0');
 208          if ($this->savedLocale !== 'C')
 209          {
 210              setlocale(LC_NUMERIC, 'C');
 211          }
 212      }
 213  }