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   1  <?php
   2  
   3  /*
   4   * This file is part of Twig.
   5   *
   6   * (c) Fabien Potencier
   7   * (c) Armin Ronacher
   8   *
   9   * For the full copyright and license information, please view the LICENSE
  10   * file that was distributed with this source code.
  11   */
  12  
  13  namespace Twig;
  14  
  15  use Twig\Error\SyntaxError;
  16  
  17  /**
  18   * Represents a token stream.
  19   *
  20   * @author Fabien Potencier <fabien@symfony.com>
  21   */
  22  final class TokenStream
  23  {
  24      private $tokens;
  25      private $current = 0;
  26      private $source;
  27  
  28      public function __construct(array $tokens, Source $source = null)
  29      {
  30          $this->tokens = $tokens;
  31          $this->source = $source ?: new Source('', '');
  32      }
  33  
  34      public function __toString()
  35      {
  36          return implode("\n", $this->tokens);
  37      }
  38  
  39      public function injectTokens(array $tokens)
  40      {
  41          $this->tokens = array_merge(\array_slice($this->tokens, 0, $this->current), $tokens, \array_slice($this->tokens, $this->current));
  42      }
  43  
  44      /**
  45       * Sets the pointer to the next token and returns the old one.
  46       */
  47      public function next(): Token
  48      {
  49          if (!isset($this->tokens[++$this->current])) {
  50              throw new SyntaxError('Unexpected end of template.', $this->tokens[$this->current - 1]->getLine(), $this->source);
  51          }
  52  
  53          return $this->tokens[$this->current - 1];
  54      }
  55  
  56      /**
  57       * Tests a token, sets the pointer to the next one and returns it or throws a syntax error.
  58       *
  59       * @return Token|null The next token if the condition is true, null otherwise
  60       */
  61      public function nextIf($primary, $secondary = null)
  62      {
  63          if ($this->tokens[$this->current]->test($primary, $secondary)) {
  64              return $this->next();
  65          }
  66      }
  67  
  68      /**
  69       * Tests a token and returns it or throws a syntax error.
  70       */
  71      public function expect($type, $value = null, string $message = null): Token
  72      {
  73          $token = $this->tokens[$this->current];
  74          if (!$token->test($type, $value)) {
  75              $line = $token->getLine();
  76              throw new SyntaxError(sprintf('%sUnexpected token "%s"%s ("%s" expected%s).',
  77                  $message ? $message.'. ' : '',
  78                  Token::typeToEnglish($token->getType()),
  79                  $token->getValue() ? sprintf(' of value "%s"', $token->getValue()) : '',
  80                  Token::typeToEnglish($type), $value ? sprintf(' with value "%s"', $value) : ''),
  81                  $line,
  82                  $this->source
  83              );
  84          }
  85          $this->next();
  86  
  87          return $token;
  88      }
  89  
  90      /**
  91       * Looks at the next token.
  92       */
  93      public function look(int $number = 1): Token
  94      {
  95          if (!isset($this->tokens[$this->current + $number])) {
  96              throw new SyntaxError('Unexpected end of template.', $this->tokens[$this->current + $number - 1]->getLine(), $this->source);
  97          }
  98  
  99          return $this->tokens[$this->current + $number];
 100      }
 101  
 102      /**
 103       * Tests the current token.
 104       */
 105      public function test($primary, $secondary = null): bool
 106      {
 107          return $this->tokens[$this->current]->test($primary, $secondary);
 108      }
 109  
 110      /**
 111       * Checks if end of stream was reached.
 112       */
 113      public function isEOF(): bool
 114      {
 115          return /* Token::EOF_TYPE */ -1 === $this->tokens[$this->current]->getType();
 116      }
 117  
 118      public function getCurrent(): Token
 119      {
 120          return $this->tokens[$this->current];
 121      }
 122  
 123      /**
 124       * Gets the source associated with this stream.
 125       *
 126       * @internal
 127       */
 128      public function getSourceContext(): Source
 129      {
 130          return $this->source;
 131      }
 132  }
 133  
 134  class_alias('Twig\TokenStream', 'Twig_TokenStream');