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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\Plugins\Preg;
   9  
  10  use DOMAttr;
  11  use DOMText;
  12  use DOMXPath;
  13  use Exception;
  14  use InvalidArgumentException;
  15  use s9e\TextFormatter\Configurator\Helpers\NodeLocator;
  16  use s9e\TextFormatter\Configurator\Helpers\RegexpParser;
  17  use s9e\TextFormatter\Configurator\Helpers\TemplateLoader;
  18  use s9e\TextFormatter\Configurator\Helpers\TemplateModifier;
  19  use s9e\TextFormatter\Configurator\Items\Regexp;
  20  use s9e\TextFormatter\Configurator\Items\Tag;
  21  use s9e\TextFormatter\Configurator\JavaScript\RegexpConvertor;
  22  use s9e\TextFormatter\Configurator\Validators\TagName;
  23  use s9e\TextFormatter\Plugins\ConfiguratorBase;
  24  
  25  class Configurator extends ConfiguratorBase
  26  {
  27      /**
  28      * @var array[] Captures from current regexp
  29      */
  30      protected $captures;
  31  
  32      /**
  33      * @var array[] List of [tagName, regexp, passthroughIdx]
  34      */
  35      protected $collection = [];
  36  
  37      /**
  38      * @var string Delimiter used in current regexp
  39      */
  40      protected $delimiter;
  41  
  42      /**
  43      * @var string Non-D modifiers used in current regexp
  44      */
  45      protected $modifiers;
  46  
  47      /**
  48      * @var array References used in current template
  49      */
  50      protected $references;
  51  
  52      /**
  53      * @var string Regexp used to find references in the templates. We check that the reference is
  54      *             not preceded with an odd number of backslashes
  55      */
  56      protected $referencesRegexp = '((?<!\\\\)(?:\\\\\\\\)*\\K(?:[$\\\\]\\d+|\\$\\{\\d+\\}))S';
  57  
  58      /**
  59      * {@inheritdoc}
  60      */
  61  	public function asConfig()
  62      {
  63          if (!count($this->collection))
  64          {
  65              return;
  66          }
  67  
  68          $pregs = [];
  69          foreach ($this->collection as list($tagName, $regexp, $passthroughIdx))
  70          {
  71              $captures = RegexpParser::getCaptureNames($regexp);
  72              $pregs[]  = [$tagName, new Regexp($regexp, true), $passthroughIdx, $captures];
  73          }
  74  
  75          return ['generics' => $pregs];
  76      }
  77  
  78      /**
  79      * {@inheritdoc}
  80      */
  81  	public function getJSHints()
  82      {
  83          $hasPassthrough = false;
  84          foreach ($this->collection as list($tagName, $regexp, $passthroughIdx))
  85          {
  86              if ($passthroughIdx)
  87              {
  88                  $hasPassthrough = true;
  89                  break;
  90              }
  91          }
  92  
  93          return ['PREG_HAS_PASSTHROUGH' => $hasPassthrough];
  94      }
  95  
  96      /**
  97      * Configure a pattern-based match
  98      *
  99      * @param  string $regexp   Regexp to be used by the parser
 100      * @param  string $tagName  Name of the tag that holds the matched text
 101      * @return void
 102      */
 103  	public function match($regexp, $tagName)
 104      {
 105          $tagName        = TagName::normalize($tagName);
 106          $passthroughIdx = 0;
 107          $this->parseRegexp($regexp);
 108          foreach ($this->captures as $i => $capture)
 109          {
 110              if (!$this->isCatchAll((string) $capture['expr']))
 111              {
 112                  continue;
 113              }
 114              $passthroughIdx = $i;
 115          }
 116  
 117          $this->collection[] = [$tagName, $regexp, $passthroughIdx];
 118      }
 119  
 120      /**
 121      * Configure a pattern-based replacement
 122      *
 123      * @param  string $regexp   Regexp to be used by the parser
 124      * @param  string $template Template to be used for rendering
 125      * @param  string $tagName  Name of the tag to create. A name based on the regexp is
 126      *                          automatically generated if none is provided
 127      * @return Tag              The tag created to represent this replacement
 128      */
 129  	public function replace($regexp, $template, $tagName = null)
 130      {
 131          if (!isset($tagName))
 132          {
 133              $tagName = 'PREG_' . strtoupper(dechex(crc32($regexp)));
 134          }
 135          $this->parseRegexp($regexp);
 136          $this->parseTemplate($template);
 137  
 138          $passthroughIdx = $this->getPassthroughCapture();
 139          if ($passthroughIdx)
 140          {
 141              $this->captures[$passthroughIdx]['passthrough'] = true;
 142          }
 143  
 144          $regexp   = $this->fixUnnamedCaptures($regexp);
 145          $template = $this->convertTemplate($template, $passthroughIdx);
 146  
 147          $this->collection[] = [$tagName, $regexp, $passthroughIdx];
 148  
 149          return $this->createTag($tagName, $template);
 150      }
 151  
 152      /**
 153      * Add given attribute to given tag based on parsed captures
 154      *
 155      * @param  Tag    $tag
 156      * @param  string $attrName
 157      * @return void
 158      */
 159  	protected function addAttribute(Tag $tag, $attrName)
 160      {
 161          $isUrl = false;
 162          $exprs = [];
 163          foreach ($this->captures as $key => $capture)
 164          {
 165              if ($capture['name'] !== $attrName)
 166              {
 167                  continue;
 168              }
 169              $exprs[] = $capture['expr'];
 170              if (isset($this->references['asUrl'][$key]))
 171              {
 172                  $isUrl = true;
 173              }
 174          }
 175          $exprs = array_unique($exprs);
 176  
 177          $regexp = $this->delimiter . '^';
 178          $regexp .= (count($exprs) === 1) ? $exprs[0] : '(?:' . implode('|', $exprs) . ')';
 179          $regexp .= '$' . $this->delimiter . 'D' . $this->modifiers;
 180  
 181          $attribute = $tag->attributes->add($attrName);
 182  
 183          $filter = $this->configurator->attributeFilters['#regexp'];
 184          $filter->setRegexp($regexp);
 185          $attribute->filterChain[] = $filter;
 186  
 187          if ($isUrl)
 188          {
 189              $filter = $this->configurator->attributeFilters['#url'];
 190              $attribute->filterChain[] = $filter;
 191          }
 192      }
 193  
 194      /**
 195      * Convert a preg-style replacement to a template
 196      *
 197      * @param  string  $template       Original template
 198      * @param  integer $passthroughIdx Index of the passthrough capture
 199      * @return string                  Modified template
 200      */
 201  	protected function convertTemplate($template, $passthroughIdx)
 202      {
 203          // Replace numeric references in the template with the value of the corresponding attribute
 204          // values or passthrough
 205          $template = TemplateModifier::replaceTokens(
 206              $template,
 207              $this->referencesRegexp,
 208              function ($m, $node) use ($passthroughIdx)
 209              {
 210                  $key = (int) trim($m[0], '\\${}');
 211                  if ($key === 0)
 212                  {
 213                      // $0 copies the whole textContent
 214                      return ['expression', '.'];
 215                  }
 216                  if ($key === $passthroughIdx && $node instanceof DOMText)
 217                  {
 218                      // Passthrough capture, does not include start/end tags
 219                      return ['passthrough'];
 220                  }
 221                  if (isset($this->captures[$key]['name']))
 222                  {
 223                      // Normal capture, replaced by the equivalent expression
 224                      return ['expression', '@' . $this->captures[$key]['name']];
 225                  }
 226  
 227                  // Non-existent captures are simply ignored, similarly to preg_replace()
 228                  return ['literal', ''];
 229              }
 230          );
 231  
 232          // Unescape backslashes and special characters in the template
 233          $template = TemplateModifier::replaceTokens(
 234              $template,
 235              '(\\\\+[0-9${\\\\])',
 236              function ($m)
 237              {
 238                  return ['literal', stripslashes($m[0])];
 239              }
 240          );
 241  
 242          return $template;
 243      }
 244  
 245      /**
 246      * Create the tag that matches current regexp
 247      *
 248      * @param  string $tagName
 249      * @param  string $template
 250      * @return Tag
 251      */
 252  	protected function createTag($tagName, $template)
 253      {
 254          $tag = new Tag;
 255          foreach ($this->captures as $key => $capture)
 256          {
 257              if (!isset($capture['name']))
 258              {
 259                  continue;
 260              }
 261  
 262              $attrName = $capture['name'];
 263              if (isset($tag->attributes[$attrName]))
 264              {
 265                  continue;
 266              }
 267  
 268              $this->addAttribute($tag, $attrName);
 269          }
 270          $tag->template = $template;
 271  
 272          // Normalize the tag's template
 273          $this->configurator->templateNormalizer->normalizeTag($tag);
 274  
 275          // Check the safeness of this tag
 276          $this->configurator->templateChecker->checkTag($tag);
 277  
 278          return $this->configurator->tags->add($tagName, $tag);
 279      }
 280  
 281      /**
 282      * Give a name to unnamed captures that are referenced in current replacement
 283      *
 284      * @param  string $regexp Original regexp
 285      * @return string         Modified regexp
 286      */
 287  	protected function fixUnnamedCaptures($regexp)
 288      {
 289          $keys = [];
 290          foreach ($this->references['anywhere'] as $key)
 291          {
 292              $capture = $this->captures[$key];
 293              if (!$key || isset($capture['name']))
 294              {
 295                  continue;
 296              }
 297              // Give the capture a name if it's used as URL or it's not a passthrough
 298              if (isset($this->references['asUrl'][$key]) || !isset($capture['passthrough']))
 299              {
 300                  $keys[] = $key;
 301              }
 302          }
 303  
 304          // Alter the original regexp to inject the subpatterns' names. The position is equal to the
 305          // subpattern's position plus 2, to account for the delimiter at the start of the regexp and
 306          // the opening parenthesis of the subpattern. Also, we need to process them in reverse order
 307          // so that replacements don't change the position of subsequent subpatterns
 308          rsort($keys);
 309          foreach ($keys as $key)
 310          {
 311              $name   = '_' . $key;
 312              $pos    = $this->captures[$key]['pos'];
 313              $regexp = substr_replace($regexp, "?'" . $name . "'", 2 + $pos, 0);
 314              $this->captures[$key]['name'] = $name;
 315          }
 316  
 317          return $regexp;
 318      }
 319  
 320      /**
 321      * Get the index of the capture used for passthrough in current replacement
 322      *
 323      * @return integer
 324      */
 325  	protected function getPassthroughCapture()
 326      {
 327          $passthrough = 0;
 328          foreach ($this->references['inText'] as $key)
 329          {
 330              if (!$this->isCatchAll((string) $this->captures[$key]['expr']))
 331              {
 332                  // Ignore if it's not a catch-all expression such as .*?
 333                  continue;
 334              }
 335              if ($passthrough)
 336              {
 337                  // Abort if there's more than 1 possible passthrough
 338                  $passthrough = 0;
 339                  break;
 340              }
 341              $passthrough = (int) $key;
 342          }
 343  
 344          return $passthrough;
 345      }
 346  
 347      /**
 348      * Parse a regexp and return its info
 349      *
 350      * @param  string $regexp
 351      * @return array
 352      */
 353  	protected function getRegexpInfo($regexp)
 354      {
 355          if (@preg_match_all($regexp, '') === false)
 356          {
 357              throw new InvalidArgumentException('Invalid regexp');
 358          }
 359  
 360          return RegexpParser::parse($regexp);
 361      }
 362  
 363      /**
 364      * Test whether given expression is a catch-all expression such as .*?
 365      *
 366      * @param  string $expr Subpattern
 367      * @return bool
 368      */
 369  	protected function isCatchAll($expr)
 370      {
 371          return (bool) preg_match('(^\\.[*+]\\??$)D', $expr);
 372      }
 373  
 374      /**
 375      * Parse given regexp and store its information
 376      *
 377      * @param  string  $regexp
 378      * @return void
 379      */
 380  	protected function parseRegexp($regexp)
 381      {
 382          $this->captures = [['name' => null, 'expr' => null]];
 383          $regexpInfo = $this->getRegexpInfo($regexp);
 384          $this->delimiter = $regexpInfo['delimiter'];
 385          $this->modifiers = str_replace('D', '', $regexpInfo['modifiers']);
 386          foreach ($regexpInfo['tokens'] as $token)
 387          {
 388              if ($token['type'] !== 'capturingSubpatternStart')
 389              {
 390                  continue;
 391              }
 392              $this->captures[] = [
 393                  'pos'    => $token['pos'],
 394                  'name'   => $token['name'] ?? null,
 395                  'expr'   => $token['content']
 396              ];
 397          }
 398      }
 399  
 400      /**
 401      * Parse given template and store the references it contains
 402      *
 403      * @param  string $template
 404      * @return void
 405      */
 406  	protected function parseTemplate($template)
 407      {
 408          $this->references = [
 409              'anywhere' => [],
 410              'asUrl'    => [],
 411              'inText'   => []
 412          ];
 413  
 414          preg_match_all($this->referencesRegexp, $template, $matches);
 415          foreach ($matches[0] as $match)
 416          {
 417              $key = trim($match, '\\${}');
 418              $this->references['anywhere'][$key] = $key;
 419          }
 420  
 421          $dom   = TemplateLoader::load($template);
 422          $xpath = new DOMXPath($dom);
 423          foreach ($xpath->query('//text()') as $node)
 424          {
 425              preg_match_all($this->referencesRegexp, $node->textContent, $matches);
 426              foreach ($matches[0] as $match)
 427              {
 428                  $key = trim($match, '\\${}');
 429                  $this->references['inText'][$key] = $key;
 430              }
 431          }
 432  
 433          foreach (NodeLocator::getURLNodes($dom) as $node)
 434          {
 435              // We only bother with literal attributes that start with a capture
 436              if ($node instanceof DOMAttr
 437               && preg_match('(^(?:[$\\\\]\\d+|\\$\\{\\d+\\}))', trim($node->value), $m))
 438              {
 439                  $key = trim($m[0], '\\${}');
 440                  $this->references['asUrl'][$key] = $key;
 441              }
 442          }
 443  
 444          $this->removeUnknownReferences();
 445      }
 446  
 447      /**
 448      * Remove references that do not correspond to an existing capture
 449      *
 450      * @return void
 451      */
 452  	protected function removeUnknownReferences()
 453      {
 454          foreach ($this->references as &$references)
 455          {
 456              $references = array_intersect_key($references, $this->captures);
 457          }
 458      }
 459  }