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FilterSyntaxHighlighter.php in Syntax Highlighter 8

Namespace

Drupal\syntaxhighlighter\Plugin\Filter

File

src/Plugin/Filter/FilterSyntaxHighlighter.php
View source 
<?php

namespace Drupal\syntaxhighlighter\Plugin\Filter;

use Drupal\filter\FilterProcessResult;
use Drupal\filter\Plugin\FilterBase;

/**
 * Provides a filter to highlight source code.
 *
 * @Filter(
 *   id = "filter_syntaxhighlighter",
 *   title = @Translation("Syntax Highlighter"),
 *   description = @Translation("Allow highlighting source code using the SyntaxHighlighter Javascript library"),
 *   type = Drupal\filter\Plugin\FilterInterface::TYPE_TRANSFORM_REVERSIBLE,
 * )
 */
class FilterSyntaxHighlighter extends FilterBase {

  /**
   * Escape the content text in preparation for filtering.
   *
   *  - Change all syntaxhighlighter <pre> tag pairs to
   *    {-_sYnTaXhIgHlIgHtEr_-} {/-_sYnTaXhIgHlIgHtEr_-} pair (so other
   *    filters would not mess with them.
   *
   * Precondition: all the open/close tags much match because search is done
   * on a pair by pair basis. If match is not even, do nothing.
   *
   * All HTML tags and entities inside the SyntaxHighlighter must be properly
   * escaped.
   *
   * For example, in HTML code, change:
   *
   *  - '<' to '&lt;': e.g.  <pre> -> &lt;pre>, <html> -> &lt;html>
   *  - neutralize & in entity: e.g.: &gt; -> &amp;gt;
   *
   * {@inheritdoc}
   */
  public function prepare($text, $langcode) {
    $config = \Drupal::config('syntaxhighlighter.settings');
    $tag_name = $config
      ->get('tagname');
    $pattern = "#<{$tag_name}\\s*([^>]*)>|</\\s*{$tag_name}>#";
    preg_match_all($pattern, $text, $matches, PREG_OFFSET_CAPTURE | PREG_SET_ORDER);
    $output = '';
    $at = 0;
    $n = count($matches);

    // Do nothing if open/close tag match is not even.
    if ($n % 2 !== 0) {
      return $text;
    }
    for ($i = 0; $i < $n; $i += 2) {
      $open_tag = $matches[$i];
      $close_tag = $matches[$i + 1];
      if (strpos($open_tag[1][0], 'brush:')) {
        $output .= substr($text, $at, $open_tag[0][1] - $at);
        $begin = $open_tag[0][1] + strlen($open_tag[0][0]);
        $length = $close_tag[0][1] - $begin;
        $output .= '{' . SYNTAXHIGHLIGHTER_TAG_STRING . ' ' . $open_tag[1][0] . '}' . substr($text, $begin, $length) . '{/' . SYNTAXHIGHLIGHTER_TAG_STRING . '}';
        $at = $close_tag[0][1] + strlen($close_tag[0][0]);
      }
    }
    $output .= substr($text, $at);
    return $output;
  }

  /**
   * Revert back to <pre> tag.
   *
   * {@inheritdoc}
   */
  public function process($text, $langcode) {
    $config = \Drupal::config('syntaxhighlighter.settings');
    $patterns = [
      '#{' . SYNTAXHIGHLIGHTER_TAG_STRING . ' ([^}]+)}#',
      '#{/' . SYNTAXHIGHLIGHTER_TAG_STRING . '}#',
    ];
    $tag_name = $config
      ->get('tagname');
    $replacements = [
      "<{$tag_name} \$1>",
      "</{$tag_name}>",
    ];
    $output = preg_replace($patterns, $replacements, $text);
    return new FilterProcessResult($output);
  }

  /**
   * {@inheritdoc}
   */
  public function tips($long = FALSE) {
    return _syntaxhighlighter_filter_tips(0, 0, TRUE);
  }

}

Classes

Namesort descending Description
FilterSyntaxHighlighter Provides a filter to highlight source code.