private static function RouteCompiler::compilePattern

File

drupal/core/vendor/symfony/routing/Symfony/Component/Routing/RouteCompiler.php, line 83

Class

RouteCompiler

RouteCompiler compiles Route instances to CompiledRoute instances.

Namespace

Code

private static function compilePattern(Route $route, $pattern, $isHost) {
  $tokens = array();
  $variables = array();
  $matches = array();
  $pos = 0;
  $defaultSeparator = $isHost ? '.' : '/';

  // Match all variables enclosed in "{}" and iterate over them. But we only want to match the innermost variable
  // in case of nested "{}", e.g. {foo{bar}}. This in ensured because \w does not match "{" or "}" itself.
  preg_match_all('#\\{\\w+\\}#', $pattern, $matches, PREG_OFFSET_CAPTURE | PREG_SET_ORDER);
  foreach ($matches as $match) {
    $varName = substr($match[0][0], 1, -1);

    // get all static text preceding the current variable
    $precedingText = substr($pattern, $pos, $match[0][1] - $pos);
    $pos = $match[0][1] + strlen($match[0][0]);
    $precedingChar = strlen($precedingText) > 0 ? substr($precedingText, -1) : '';
    $isSeparator = '' !== $precedingChar && false !== strpos(static::SEPARATORS, $precedingChar);
    if (is_numeric($varName)) {
      throw new \DomainException(sprintf('Variable name "%s" cannot be numeric in route pattern "%s". Please use a different name.', $varName, $pattern));
    }
    if (in_array($varName, $variables)) {
      throw new \LogicException(sprintf('Route pattern "%s" cannot reference variable name "%s" more than once.', $pattern, $varName));
    }
    if ($isSeparator && strlen($precedingText) > 1) {
      $tokens[] = array(
        'text',
        substr($precedingText, 0, -1),
      );
    }
    elseif (!$isSeparator && strlen($precedingText) > 0) {
      $tokens[] = array(
        'text',
        $precedingText,
      );
    }
    $regexp = $route
      ->getRequirement($varName);
    if (null === $regexp) {
      $followingPattern = (string) substr($pattern, $pos);

      // Find the next static character after the variable that functions as a separator. By default, this separator and '/'
      // are disallowed for the variable. This default requirement makes sure that optional variables can be matched at all
      // and that the generating-matching-combination of URLs unambiguous, i.e. the params used for generating the URL are
      // the same that will be matched. Example: new Route('/{page}.{_format}', array('_format' => 'html'))
      // If {page} would also match the separating dot, {_format} would never match as {page} will eagerly consume everything.
      // Also even if {_format} was not optional the requirement prevents that {page} matches something that was originally
      // part of {_format} when generating the URL, e.g. _format = 'mobile.html'.
      $nextSeparator = self::findNextSeparator($followingPattern);
      $regexp = sprintf('[^%s%s]+', preg_quote($defaultSeparator, self::REGEX_DELIMITER), $defaultSeparator !== $nextSeparator && '' !== $nextSeparator ? preg_quote($nextSeparator, self::REGEX_DELIMITER) : '');
      if ('' !== $nextSeparator && !preg_match('#^\\{\\w+\\}#', $followingPattern) || '' === $followingPattern) {

        // When we have a separator, which is disallowed for the variable, we can optimize the regex with a possessive
        // quantifier. This prevents useless backtracking of PCRE and improves performance by 20% for matching those patterns.
        // Given the above example, there is no point in backtracking into {page} (that forbids the dot) when a dot must follow
        // after it. This optimization cannot be applied when the next char is no real separator or when the next variable is
        // directly adjacent, e.g. '/{x}{y}'.
        $regexp .= '+';
      }
    }
    $tokens[] = array(
      'variable',
      $isSeparator ? $precedingChar : '',
      $regexp,
      $varName,
    );
    $variables[] = $varName;
  }
  if ($pos < strlen($pattern)) {
    $tokens[] = array(
      'text',
      substr($pattern, $pos),
    );
  }

  // find the first optional token
  $firstOptional = PHP_INT_MAX;
  if (!$isHost) {
    for ($i = count($tokens) - 1; $i >= 0; $i--) {
      $token = $tokens[$i];
      if ('variable' === $token[0] && $route
        ->hasDefault($token[3])) {
        $firstOptional = $i;
      }
      else {
        break;
      }
    }
  }

  // compute the matching regexp
  $regexp = '';
  for ($i = 0, $nbToken = count($tokens); $i < $nbToken; $i++) {
    $regexp .= self::computeRegexp($tokens, $i, $firstOptional);
  }
  return array(
    'staticPrefix' => 'text' === $tokens[0][0] ? $tokens[0][1] : '',
    'regex' => self::REGEX_DELIMITER . '^' . $regexp . '$' . self::REGEX_DELIMITER . 's',
    'tokens' => array_reverse($tokens),
    'variables' => $variables,
  );
}