1. sfValidatorFromDescription.class.php
  2. /**
 * sfValidatorFromDescription converts a string to a validator.
 *
 * @package    symfony
 * @subpackage validator
 * @author     Fabien Potencier 
 * @version    SVN: $Id: sfValidatorFromDescription.class.php 21908 2009-09-11 12:06:21Z fabien $
 */
  3. class sfValidatorFromDescription extends sfValidatorDecorator
  4. {
  5.   protected
  6.     $tokens = array(),
  7.     $string = '';
  9.   /**
  10.    * @see sfValidatorBase
  11.    */
  12.   public function __construct($string, $options = array(), $messages = array())
  13.   {
  14.     $this->string = $string;
  15.     $this->tokens = $this->tokenize($string);
  17.     parent::__construct($options, $messages);
  18.   }
  20.   /**
  21.    * Returns a PHP representation for the validator.
  22.    *
  23.    * This PHP representation can be evaled to return the object validator.
  24.    *
  25.    * This is mainly useful to cache the result of the validator string parsing.
  26.    *
  27.    * @return string The PHP representation for the validator
  28.    */
  29.   public function asPhp()
  30.   {
  31.     return $this->reduceTokens($this->tokens, 'asPhp');
  32.   }
  34.   /**
  35.    * @see sfValidatorDecorator
  36.    */
  37.   public function getValidator()
  38.   {
  39.     if (null === $this->validator)
  40.     {
  41.       $this->validator = $this->reduceTokens($this->tokens, 'getValidator');
  42.     }
  44.     return $this->validator;
  45.   }
  47.   /**
  48.    * Tokenizes a validator string to a list of tokens in RPN.
  49.    *
  50.    * @param  string $string  A validator string
  51.    *
  52.    * @return array  An array of tokens
  53.    */
  54.   protected function tokenize($string)
  55.   {
  56.     $tokens = array();
  57.     $len = strlen($string);
  58.     $i = 0;
  59.     while ($i < $len)
  60.     {
  61.       if (preg_match('/^([a-z0-9_\-]+)\s*(<=|>=|<|>|==|!=)/i', substr($string, $i), $match))
  62.       {
  63.         // schema compare validator
  64.         $i += strlen($match[0]);
  66.         $leftField = $match[1];
  67.         $operator = $match[2];
  69.         // arguments (optional)
  70.         $arguments = $this->parseArguments($string, $i);
  72.         // rightField
  73.         if (!preg_match('/\s*([a-z0-9_\-]+)/', substr($string, $i), $match))
  74.         {
  75.           throw new DomainException('Parsing problem.');
  76.         }
  78.         $i += strlen($match[0]);
  79.         $rightField = $match[1];
  81.         $tokens[] = new sfValidatorFDToken('sfValidatorSchemaCompare', array($leftField, $operator, $rightField, $arguments[0], isset($arguments[1]) ? $arguments[1] : array()));
  82.       }
  83.       else if (preg_match('/^(and|or)/i', substr($string, $i), $match))
  84.       {
  85.         // all, any validador
  86.         $i += strlen($match[0]);
  88.         // arguments (optional)
  89.         $arguments = $this->parseArguments($string, $i);
  91.         $tokens[] = new sfValidatorFDTokenOperator(strtolower($match[1]), $arguments);
  92.       }
  93.       else if (preg_match('/^(?:([a-z0-9_\-]+)\:)?([a-z0-9_\-]+)/i', substr($string, $i), $match))
  94.       {
  95.         // single validator (optionally filtered)
  96.         $i += strlen($match[0]);
  98.         $class = 'sfValidator'.$match[2];
  99.         $arguments = $this->parseArguments($string, $i);
  100.         $token = new sfValidatorFDToken($class, array($arguments[0], isset($arguments[1]) ? $arguments[1] : array()));
  101.         if ($match[1])
  102.         {
  103.           $token = new sfValidatorFDTokenFilter($match[1], $token);
  104.         }
  106.         $tokens[] = $token;
  107.       }
  108.       else if ('(' == $string[$i])
  109.       {
  110.         $tokens[] = new sfValidatorFDTokenLeftBracket();
  111.         ++$i;
  112.       }
  113.       else if (')' == $string[$i])
  114.       {
  115.         $tokens[] = new sfValidatorFDTokenRightBracket();
  116.         ++$i;
  117.       }
  118.       else if (in_array($string[$i], array(' ', "\t", "\r", "\n")))
  119.       {
  120.         ++$i;
  121.       }
  122.       else
  123.       {
  124.         throw new DomainException(sprintf('Unable to parse string (%s).', $string));
  125.       }
  126.     }
  128.     return $this->convertInfixToRpn($tokens);
  129.   }
  131.   /**
  132.    * Parses validator arguments.
  133.    *
  134.    * @param  string  $string  The string to parse
  135.    * @param  integer $i       The indice to start the parsing
  136.    *
  137.    * @return array   An array of parameters
  138.    */
  139.   protected function parseArguments($string, &$i)
  140.   {
  141.     $len = strlen($string);
  143.     if ($i + 1 > $len || '(' != $string[$i])
  144.     {
  145.       return array(array(), array());
  146.     }
  148.     ++$i;
  150.     $args = '';
  151.     $opened = 0;
  152.     while ($i < $len)
  153.     {
  154.       if ('(' == $string[$i])
  155.       {
  156.         ++$opened;
  157.       }
  158.       else if (')' == $string[$i])
  159.       {
  160.         if (!$opened)
  161.         {
  162.           break;
  163.         }
  165.         --$opened;
  166.       }
  168.       $args .= $string[$i++];
  169.     }
  171.     ++$i;
  173.     return sfYamlInline::load('['.(!$args ? '{}' : $args).']');
  174.   }
  176.   /**
  177.    * Converts a token array from an infix notation to a RPN.
  178.    *
  179.    * @param  array $tokens  An array of tokens in infix notation
  180.    *
  181.    * @return array An array of token in RPN
  182.    */
  183.   protected function convertInfixToRpn($tokens)
  184.   {
  185.     $outputStack = array();
  186.     $operatorStack = array();
  187.     $precedences = array('and' => 2, 'or' => 1, '(' => 0);
  189.     // based on the shunting yard algorithm
  190.     foreach ($tokens as $token)
  191.     {
  192.       switch (get_class($token))
  193.       {
  194.         case 'sfValidatorFDToken':
  195.           $outputStack[] = $token;
  196.           break;
  197.         case 'sfValidatorFDTokenLeftBracket':
  198.           $operatorStack[] = $token;
  199.           break;
  200.         case 'sfValidatorFDTokenRightBracket':
  201.           while (!$operatorStack[count($operatorStack) - 1] instanceof sfValidatorFDTokenLeftBracket)
  202.           {
  203.             $outputStack[] = array_pop($operatorStack);
  204.           }
  205.           array_pop($operatorStack);
  206.           break;
  207.         case 'sfValidatorFDTokenOperator':
  208.           while (count($operatorStack) && $precedences[$token->__toString()] <= $precedences[$operatorStack[count($operatorStack) - 1]->__toString()])
  209.           {
  210.             $outputStack[] = array_pop($operatorStack);
  211.           }
  212.           $operatorStack[] = $token;
  213.           break;
  214.         default:
  215.           $outputStack[] = $token;
  216.       }
  217.     }
  219.     while (count($operatorStack))
  220.     {
  221.       $token = array_pop($operatorStack);
  222.       if ($token instanceof sfValidatorFDTokenLeftBracket || $token instanceof sfValidatorFDTokenRightBracket)
  223.       {
  224.         throw new DomainException(sprintf('Uneven parenthesis in string (%s).', $this->string));
  225.       }
  227.       $outputStack[] = $token;
  228.     }
  230.     return $outputStack;
  231.   }
  233.   /**
  234.    * Reduces tokens to a single token and convert it with the given method.
  235.    *
  236.    * @param  array  $tokens  An array of tokens
  237.    * @param  string $method  The method name to execute on each token
  238.    *
  239.    * @return mixed  A single validator representation
  240.    */
  241.   protected function reduceTokens($tokens, $method)
  242.   {
  243.     if (1 == count($tokens))
  244.     {
  245.       return $tokens[0]->$method();
  246.     }
  248.     // reduce to a single validator
  249.     while (count($tokens) > 1)
  250.     {
  251.       $i = 0;
  252.       while (isset($tokens[$i]) && !$tokens[$i] instanceof sfValidatorFDTokenOperator)
  253.       {
  254.         $i++;
  255.       }
  257.       $tokens[$i] = $tokens[$i]->$method($tokens[$i - 2], $tokens[$i - 1]);
  258.       unset($tokens[$i - 1], $tokens[$i - 2]);
  260.       $tokens = array_values($tokens);
  261.     }
  263.     return $tokens[0];
  264.   }
  265. }
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