oa_diff.module

<?php

/**
 * @file
 * Builds placeholder replacement tokens for diff-related data.
 *
 * Written by Mike Potter, Phase2 Technology
 * Similar to Diff module, but allows a specific revision to be indicated
 * [node:oa-diff:###] where ### is the specific revision id
 * [node:oa-diff:###:###] to specify the two revisions to diff between
 */

/**
 * Implements hook_token_info().
 */
function oa_diff_token_info() {
  $node['oa-diff'] = array(
    'name' => t('Revision difference'),
    'description' => t('The differences between a specific node version and its previous revision.'),
  );

  return array(
    'tokens' => array('node' => $node),
  );
}

/**
 * Implements hook_tokens().
 */
function oa_diff_tokens($type, $tokens, array $data = array(), array $options = array()) {
  $sanitize = !empty($options['sanitize']);
  // similar to regular diff module, but we do not sanitize results because results
  // are always an HTML table
  $replacements = array();

  if ($type == 'node' && !empty($data['node'])) {
    $node = $data['node'];
    foreach ($tokens as $name => $original) {
      $values = explode(':', $name);
      if (!empty($values[0]) && ($values[0] == 'oa-diff')) {
        $revisions = node_revision_list($node);
        if (count($revisions) == 1) {
          $replacements[$original] = '';
        }
        else {
          module_load_include('inc', 'diff', 'diff.pages');
          if (isset($values[1]) && is_numeric($values[1])) {
            $vid = $values[1];
            if (isset($values[2]) && is_numeric($values[2])) {
              $next_vid = $values[2];
            }
            else {
              $next_vid = _diff_get_next_vid($revisions, $vid);
            }
          }
          else {
            $next_vid = $node->vid;
            $vid = _diff_get_previous_vid($revisions, $next_vid);
          }

          if ($next_vid) {
            $state = 'raw_plain';
            $build = diff_diffs_show($node, $vid, $next_vid, $state);
            unset($build['diff_table']['#rows']['logs']);
            unset($build['diff_table']['#rows']['states']);
            unset($build['diff_table']['#rows']['navigation']);
            unset($build['diff_table']['#header']);
            unset($build['diff_preview']);

            $output = drupal_render_children($build);
            // prevent overflow of messages
            if (strlen($output) > 2048) {
              $output = t('Too many differences to list.  See Revisions for details.');
            }
            $replacements[$original] = $output;
          }
          else {
            $replacements[$original] = '';
          }
        }
      }
    }
  }
  return $replacements;
}

/**
 * Implements hook_init().
 */
function oa_diff_init() {
  drupal_add_css(drupal_get_path('module', 'oa_diff') . '/oa_diff.css');
}

function oa_diff_diff_field_settings_alter(&$settings, $context) {
  $field = $context['field'];
  if ($field['field_name'] == 'body') {
    $settings['markdown'] = 'oa_html_to_text';
  }
}

/**
 * Convert HTML to text
 * same as core drupal_html_to_text but no line wrapping!
 * and <P> is converted to a single line-break
 */
function oa_html_to_text($string, $allowed_tags = NULL) {
  // Cache list of supported tags.
  static $supported_tags;
  if (empty($supported_tags)) {
    $supported_tags = array(
      'a',
      'em',
      'i',
      'strong',
      'b',
      'br',
      'p',
      'blockquote',
      'ul',
      'ol',
      'li',
      'dl',
      'dt',
      'dd',
      'h1',
      'h2',
      'h3',
      'h4',
      'h5',
      'h6',
      'hr',
    );
  }

  // Make sure only supported tags are kept.
  $allowed_tags = isset($allowed_tags) ? array_intersect($supported_tags, $allowed_tags) : $supported_tags;

  // Make sure tags, entities and attributes are well-formed and properly nested.
  $string = _filter_htmlcorrector(filter_xss($string, $allowed_tags));

  // Apply inline styles.
  $string = preg_replace('!</?(em|i)((?> +)[^>]*)?>!i', '/', $string);
  $string = preg_replace('!</?(strong|b)((?> +)[^>]*)?>!i', '*', $string);

  // Replace inline <a> tags with the text of link and a footnote.
  // 'See <a href="http://drupal.org">the Drupal site</a>' becomes
  // 'See the Drupal site [1]' with the URL included as a footnote.
  _drupal_html_to_mail_urls(NULL, TRUE);
  $pattern = '@(<a[^>]+?href="([^"]*)"[^>]*?>(.+?)</a>)@i';
  $string = preg_replace_callback($pattern, '_drupal_html_to_mail_urls', $string);
  $urls = _drupal_html_to_mail_urls();
  $footnotes = '';
  if (count($urls)) {
    $footnotes .= "\n";
    for ($i = 0, $max = count($urls); $i < $max; $i++) {
      $footnotes .= '[' . ($i + 1) . '] ' . $urls[$i] . "\n";
    }
  }

  // Split tags from text.
  $split = preg_split('/<([^>]+?)>/', $string, -1, PREG_SPLIT_DELIM_CAPTURE);
  // Note: PHP ensures the array consists of alternating delimiters and literals
  // and begins and ends with a literal (inserting $null as required).

  $tag = FALSE; // Odd/even counter (tag or no tag)
  $casing = NULL; // Case conversion function
  $output = '';
  $indent = array(); // All current indentation string chunks
  $lists = array(); // Array of counters for opened lists
  foreach ($split as $value) {
    $chunk = NULL; // Holds a string ready to be formatted and output.

    // Process HTML tags (but don't output any literally).
    if ($tag) {
      list($tagname) = explode(' ', strtolower($value), 2);
      switch ($tagname) {
        // List counters
        case 'ul':
          array_unshift($lists, '*');
          break;
        case 'ol':
          array_unshift($lists, 1);
          break;
        case '/ul':
        case '/ol':
          array_shift($lists);
          $chunk = ''; // Ensure blank new-line.
          break;

          // Quotation/list markers, non-fancy headers
        case 'blockquote':
          // Format=flowed indentation cannot be mixed with lists.
          $indent[] = count($lists) ? ' "' : '>';
          break;
        case 'li':
          $indent[] = isset($lists[0]) && is_numeric($lists[0]) ? ' ' . $lists[0]++ . ') ' : ' * ';
          break;
        case 'dd':
          $indent[] = '    ';
          break;
        case 'h3':
          $indent[] = '.... ';
          break;
        case 'h4':
          $indent[] = '.. ';
          break;
        case '/blockquote':
          if (count($lists)) {
            // Append closing quote for inline quotes (immediately).
            $output = rtrim($output, "> \n") . "\"\n";
            $chunk = ''; // Ensure blank new-line.
          }
          // Fall-through
        case '/li':
        case '/dd':
          array_pop($indent);
          break;
        case '/h3':
        case '/h4':
          array_pop($indent);
        case '/h5':
        case '/h6':
          $chunk = ''; // Ensure blank new-line.
          break;

          // Fancy headers
        case 'h1':
          $indent[] = '======== ';
          $casing = 'drupal_strtoupper';
          break;
        case 'h2':
          $indent[] = '-------- ';
          $casing = 'drupal_strtoupper';
          break;
        case '/h1':
        case '/h2':
          $casing = NULL;
          // Pad the line with dashes.
          $output = _drupal_html_to_text_pad($output, ($tagname == '/h1') ? '=' : '-', ' ');
          array_pop($indent);
          $chunk = ''; // Ensure blank new-line.
          break;

          // Horizontal rulers
        case 'hr':
          // Insert immediately.
          $output .= drupal_wrap_mail('', implode('', $indent)) . "\n";
          $output = _drupal_html_to_text_pad($output, '-');
          break;

          // Paragraphs and definition lists
//        case '/p':
        case '/dl':
          $chunk = ''; // Ensure blank new-line.
          break;
      }
    }
    // Process blocks of text.
    else {
      // Convert inline HTML text to plain text; not removing line-breaks or
      // white-space, since that breaks newlines when sanitizing plain-text.
      $value = trim(decode_entities($value));
      if (drupal_strlen($value)) {
        $chunk = $value;
      }
    }

    // See if there is something waiting to be output.
    if (isset($chunk)) {
      // Apply any necessary case conversion.
      if (isset($casing)) {
        $chunk = $casing($chunk);
      }
      // Format it and apply the current indentation.
      $output .= $chunk . MAIL_LINE_ENDINGS;
      // Remove non-quotation markers from indentation.
      $indent = array_map('_drupal_html_to_text_clean', $indent);
    }

    $tag = !$tag;
  }

  return $output . $footnotes;
}