filter.module 44.3 KB
Newer Older
1
2
3
<?php
// $Id$

Dries's avatar
   
Dries committed
4
5
6
7
8
/**
 * @file
 * Framework for handling filtering of content.
 */

9
10
11
// This is a special format ID which means "use the default format". This value
// can be passed to the filter APIs as a format ID: this is equivalent to not
// passing an explicit format at all.
12
13
define('FILTER_FORMAT_DEFAULT', 0);

14
15
16
17
18
19
define('FILTER_HTML_STRIP', 1);
define('FILTER_HTML_ESCAPE', 2);

define('FILTER_STYLE_ALLOW', 0);
define('FILTER_STYLE_STRIP', 1);

Dries's avatar
Dries committed
20
21
22
23
/**
 * Implementation of hook_help().
 */
function filter_help($section) {
24
  switch ($section) {
25
26
27
28
29
30
31
32
33
34
35
    case 'admin/help#filter':
      $output = '<p>'. t('The filter module allows administrators to configure  text input formats for the site.  For example, an administrator may want a filter to strip out malicious HTML from user\'s comments.  Administrators may also want to make URLs linkable even if they are only entered in an unlinked format.') .'</p>';
      $output .= '<p>'. t('Users can choose between the available input formats when creating or editing content.  Administrators can configure which input formats are available to which user roles, as well as choose a default input format.  Administrators can also create new input formats.  Each input format can be configured to use a selection of filters.') .'</p>';
      $output .= t('<p>You can</p>
<ul>
<li>administer input format permissions and settings  at <a href="%admin-filters">administer &gt;&gt; input formats</a>.</li>
<li>configure the filters for each input format at <a href="%admin-filters">administer &gt;&gt; input formats &gt;&gt; configure</a>.</li>
</ul>
', array('%admin-filters' => url('admin/filters')));
      $output .= '<p>'. t('For more information please read the configuration and customization handbook <a href="%filter">Filter page</a>.', array('%filter' => 'http://www.drupal.org/handbook/modules/filter/')) .'</p>';
      return $output;
Dries's avatar
   
Dries committed
36
    case 'admin/modules#description':
37
      return t('Handles the filtering of content in preparation for display.');
38

Dries's avatar
   
Dries committed
39
    case 'admin/filters':
40
      return t('
Dries's avatar
   
Dries committed
41
<p><em>Input formats</em> define a way of processing user-supplied text in Drupal. Every input format has its own settings of which <em>filters</em> to apply. Possible filters include stripping out malicious HTML and making URLs clickable.</p>
42
43
44
<p>Users can choose between the available input formats when submitting content.</p>
<p>Below you can configure which input formats are available to which roles, as well as choose a default input format (used for imported content, for example).</p>');

45
    case 'admin/filters/'. arg(2):
46
      return t('
Dries's avatar
   
Dries committed
47
<p>Every <em>filter</em> performs one particular change on the user input, for example stripping out malicious HTML or making URLs clickable. Choose which filters you want to apply to text in this input format.</p>
48
<p>If you notice some filters are causing conflicts in the output, you can <a href="%rearrange">rearrange them</a>.</p>', array('%rearrange' => url('admin/filters/'. arg(2) .'/order')));
49

50
    case 'admin/filters/'. arg(2) .'/configure':
51
      return t('
52
<p>If you cannot find the settings for a certain filter, make sure you\'ve enabled it on the <a href="%url">view tab</a> first.</p>', array('%url' => url('admin/filters/'. arg(2))));
53

54
    case 'admin/filters/'. arg(2) .'/order':
55
      return t('
Dries's avatar
   
Dries committed
56
<p>Because of the flexible filtering system, you might encounter a situation where one filter prevents another from doing its job. For example: a word in an URL gets converted into a glossary term, before the URL can be converted in a clickable link. When this happens, you will need to rearrange the order in which filters get executed.</p>
57
58
59
60
61
<p>Filters are executed from top-to-bottom. You can use the weight column to rearrange them: heavier filters \'sink\' to the bottom.</p>');
  }
}

/**
62
 * Implementation of hook_filter_tips().
63
 */
64
function filter_filter_tips($delta, $format, $long = false) {
65
  global $base_url;
66
67
68
69
70
  switch ($delta) {
    case 0:
      switch (variable_get("filter_html_$format", FILTER_HTML_STRIP)) {

        case FILTER_HTML_STRIP:
Dries's avatar
   
Dries committed
71
          if ($allowed_html = variable_get("allowed_html_$format", '<a> <em> <strong> <cite> <code> <ul> <ol> <li> <dl> <dt> <dd>')) {
72
73
            switch ($long) {
              case 0:
74
                return t('Allowed HTML tags') .': '. check_plain($allowed_html);
75
              case 1:
76
                $output = '<p>'. t('Allowed HTML tags') .': '. check_plain($allowed_html) .'</p>';
77
78
79
80
                if (!variable_get("filter_html_help_$format", 1)) {
                  return $output;
                }

81
82
                $output .= t('
<p>This site allows HTML content. While learning all of HTML may feel intimidating, learning how to use a very small number of the most basic HTML "tags" is very easy. This table provides examples for each tag that is enabled on this site.</p>
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
<p>For more information see W3C\'s <a href="http://www.w3.org/TR/html/">HTML Specifications</a> or use your favorite search engine to find other sites that explain HTML.</p>');
                $tips = array(
                  'a' => array( t('Anchors are used to make links to other pages.'), '<a href="'. $base_url .'">'. variable_get('site_name', 'drupal') .'</a>'),
                  'br' => array( t('By default line break tags are automatically added, so use this tag to add additional ones. Use of this tag is different because it is not used with an open/close pair like all the others. Use the extra " /" inside the tag to maintain XHTML 1.0 compatibility'), t('Text with <br />line break')),
                  'p' => array( t('By default paragraph tags are automatically added, so use this tag to add additional ones.'), '<p>'. t('Paragraph one.') .'</p> <p>'. t('Paragraph two.') .'</p>'),
                  'strong' => array( t('Strong'), '<strong>'. t('Strong'). '</strong>'),
                  'em' => array( t('Emphasized'), '<em>'. t('Emphasized') .'</em>'),
                  'cite' => array( t('Cited'), '<cite>'. t('Cited') .'</cite>'),
                  'code' => array( t('Coded text used to show programming source code'), '<code>'. t('Coded') .'</code>'),
                  'b' => array( t('Bolded'), '<b>'. t('Bolded') .'</b>'),
                  'u' => array( t('Underlined'), '<u>'. t('Underlined') .'</u>'),
                  'i' => array( t('Italicized'), '<i>'. t('Italicized') .'</i>'),
                  'sup' => array( t('Superscripted'), t('<sup>Super</sup>scripted')),
                  'sub' => array( t('Subscripted'), t('<sub>Sub</sub>scripted')),
                  'pre' => array( t('Preformatted'), '<pre>'. t('Preformatted') .'</pre>'),
                  'blockquote' => array( t('Block quoted'), '<blockquote>'. t('Block quoted') .'</blockquote>'),
                  'q' => array( t('Quoted inline'), '<q>'. t('Quoted inline') .'</q>'),
                  // Assumes and describes tr, td, th.
                  'table' => array( t('Table'), '<table> <tr><th>'. t('Table header') .'</th></tr> <tr><td>'. t('Table cell') .'</td></tr> </table>'),
                  'tr' => NULL, 'td' => NULL, 'th' => NULL,
                  'del' => array( t('Deleted'), '<del>'. t('Deleted') .'</del>'),
                  'ins' => array( t('Inserted'), '<ins>'. t('Inserted') .'</ins>'),
                   // Assumes and describes li.
                  'ol' => array( t('Ordered list - use the &lt;li&gt; to begin each list item'), '<ol> <li>'. t('First item') .'</li> <li>'. t('Second item') .'</li> </ol>'),
                  'ul' => array( t('Unordered list - use the &lt;li&gt; to begin each list item'), '<ul> <li>'. t('First item') .'</li> <li>'. t('Second item') .'</li> </ul>'),
                  'li' => NULL,
                  // Assumes and describes dt and dd.
                  'dl' => array( t('Definition lists are similar to other HTML lists. &lt;dl&gt; begins the definition list, &lt;dt&gt; begins the definition term and &lt;dd&gt; begins the definition description.'), '<dl> <dt>'. t('First term') .'</dt> <dd>'. t('First definition') .'</dd> <dt>'. t('Second term') .'</dt> <dd>'. t('Second definition') .'</dd> </dl>'),
                  'dt' => NULL, 'dd' => NULL,
                  'h1' => array( t('Header'), '<h1>'. t('Title') .'</h1>'),
                  'h2' => array( t('Header'), '<h2>'. t('Subtitle') .'</h2>'),
                  'h3' => array( t('Header'), '<h3>'. t('Subtitle three') .'</h3>'),
                  'h4' => array( t('Header'), '<h4>'. t('Subtitle four') .'</h4>'),
                  'h5' => array( t('Header'), '<h5>'. t('Subtitle five') .'</h5>'),
                  'h6' => array( t('Header'), '<h6>'. t('Subtitle six') .'</h6>')
                );
                $header = array(t('Tag Description'), t('You Type'), t('You Get'));
                preg_match_all('/<([a-z0-9]+)[^a-z0-9]/i', $allowed_html, $out);
                foreach ($out[1] as $tag) {
                  if (array_key_exists($tag, $tips)) {
                    if ($tips[$tag]) {
                      $rows[] = array(
                        array('data' => $tips[$tag][0], 'class' => 'description'),
126
                        array('data' => '<code>'. check_plain($tips[$tag][1]) .'</code>', 'class' => 'type'),
127
128
129
130
131
132
                        array('data' => $tips[$tag][1], 'class' => 'get')
                      );
                    }
                  }
                  else {
                    $rows[] = array(
133
                      array('data' => t('No help provided for tag %tag.', array('%tag' => check_plain($tag))), 'class' => 'description', 'colspan' => 3),
134
135
136
137
138
                    );
                  }
                }
                $output .= theme('table', $header, $rows);

139
140
                $output .= t('
<p>Most unusual characters can be directly entered without any problems.</p>
141
142
143
144
145
146
147
148
149
150
151
152
<p>If you do encounter problems, try using HTML character entities. A common example looks like &amp;amp; for an ampersand &amp; character. For a full list of entities see HTML\'s <a href="http://www.w3.org/TR/html4/sgml/entities.html">entities</a> page. Some of the available characters include:</p>');
                $entities = array(
                  array( t('Ampersand'), '&amp;'),
                  array( t('Greater than'), '&gt;'),
                  array( t('Less than'), '&lt;'),
                  array( t('Quotation mark'), '&quot;'),
                );
                $header = array(t('Character Description'), t('You Type'), t('You Get'));
                unset($rows);
                foreach ($entities as $entity) {
                  $rows[] = array(
                    array('data' => $entity[0], 'class' => 'description'),
153
                    array('data' => '<code>'. check_plain($entity[1]) .'</code>', 'class' => 'type'),
154
155
156
157
158
159
                    array('data' => $entity[1], 'class' => 'get')
                  );
                }
                $output .= theme('table', $header, $rows);
                return $output;
            }
160
161
          }
          else {
Dries's avatar
Dries committed
162
            return t('No HTML tags allowed');
Dries's avatar
   
Dries committed
163
          }
164
165

        case FILTER_STYLE_STRIP:
Dries's avatar
Dries committed
166
          return t('No HTML tags allowed');
Dries's avatar
   
Dries committed
167
168
      }
      break;
169
170

    case 1:
Dries's avatar
   
Dries committed
171
      switch ($long) {
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
        case 0:
          return t('You may post PHP code. You should include &lt;?php ?&gt; tags.');
        case 1:
          return t('
<h4>Using custom PHP code</h4>
<p>If you know how to script in PHP, Drupal gives you the power to embed any script you like. It will be executed when the page is viewed and dynamically embedded into the page. This gives you amazing flexibility and power, but of course with that comes danger and insecurity if you don\'t write good code. If you are not familiar with PHP, SQL or with the site engine, avoid experimenting with PHP because you can corrupt your database or render your site insecure or even unusable! If you don\'t plan to do fancy stuff with your content then you\'re probably better off with straight HTML.</p>
<p>Remember that the code within each PHP item must be valid PHP code - including things like correctly terminating statements with a semicolon. It is highly recommended that you develop your code separately using a simple test script on top of a test database before migrating to your production environment.</p>
<p>Notes:</p><ul><li>You can use global variables, such as configuration parameters, within the scope of your PHP code but remember that global variables which have been given values in your code will retain these values in the engine afterwards.</li><li>register_globals is now set to <strong>off</strong> by default. If you need form information you need to get it from the "superglobals" $_POST, $_GET, etc.</li><li>You can either use the <code>print</code> or <code>return</code> statement to output the actual content for your item.</li></ul>
<p>A basic example:</p>
<blockquote><p>You want to have a box with the title "Welcome" that you use to greet your visitors. The content for this box could be created by going:</p>
<pre>
  print t("Welcome visitor, ... welcome message goes here ...");
</pre>
<p>If we are however dealing with a registered user, we can customize the message by using:</p>
<pre>
  global $user;
  if ($user->uid) {
    print t("Welcome $user->name, ... welcome message goes here ...");
  }
  else {
    print t("Welcome visitor, ... welcome message goes here ...");
  }
</pre></blockquote>
<p>For more in-depth examples, we recommend that you check the existing Drupal code and use it as a starting point, especially for sidebar boxes.</p>');
      }

198
    case 2:
199
200
201
202
203
204
      switch ($long) {
        case 0:
          return t('Lines and paragraphs break automatically.');
        case 1:
          return t('Lines and paragraphs are automatically recognized. The &lt;br /&gt; line break, &lt;p&gt; paragraph and &lt;/p&gt; close paragraph tags are inserted automatically. If paragraphs are not recognized simply add a couple blank lines.');
      }
205
206
207
  }
}

208

Dries's avatar
   
Dries committed
209
/**
Dries's avatar
   
Dries committed
210
 * Implementation of hook_menu().
Dries's avatar
   
Dries committed
211
 */
Dries's avatar
   
Dries committed
212
function filter_menu($may_cache) {
Dries's avatar
   
Dries committed
213
  $items = array();
214

Dries's avatar
   
Dries committed
215
216
217
  if ($may_cache) {
    $items[] = array('path' => 'admin/filters', 'title' => t('input formats'),
      'callback' => 'filter_admin_overview',
218
      'access' => user_access('administer filters'));
219
220
221
222
223
224
225
226
227
    $items[] = array('path' => 'admin/filters/list', 'title' => t('list'),
      'callback' => 'filter_admin_overview',
      'type' => MENU_DEFAULT_LOCAL_TASK,
      'access' => user_access('administer filters'));
    $items[] = array('path' => 'admin/filters/add', 'title' => t('add input format'),
      'callback' => 'filter_admin_add',
      'type' => MENU_LOCAL_TASK,
      'weight' => 1,
      'access' => user_access('administer filters'));
Dries's avatar
   
Dries committed
228
229
230
    $items[] = array('path' => 'admin/filters/delete', 'title' => t('delete input format'),
      'callback' => 'filter_admin_delete',
      'type' => MENU_CALLBACK,
231
      'access' => user_access('administer filters'));
Dries's avatar
   
Dries committed
232
233
234
235
236
237
238
239
240
241
    $items[] = array('path' => 'filter/tips', 'title' => t('compose tips'),
      'callback' => 'filter_tips_long', 'access' => TRUE,
      'type' => MENU_SUGGESTED_ITEM);
  }
  else {
    if (arg(0) == 'admin' && arg(1) == 'filters' && is_numeric(arg(2))) {
      $formats = filter_formats();

      if (isset($formats[arg(2)])) {
        $items[] = array('path' => 'admin/filters/'. arg(2), 'title' => t("'%format' input format", array('%format' => $formats[arg(2)]->name)),
242
243
244
245
246
247
248
249
250
251
          'callback' => 'filter_admin_format',
          'callback arguments' => array('format' => $formats[arg(2)]),
          'type' => MENU_CALLBACK,
          'access' => user_access('administer filters'));
        $items[] = array('path' => 'admin/filters/'. arg(2) .'/list', 'title' => t('view'),
          'callback' => 'filter_admin_format',
          'callback arguments' => array('format' => $formats[arg(2)]),
          'type' => MENU_DEFAULT_LOCAL_TASK,
          'weight' => 0,
          'access' => user_access('administer filters'));
Dries's avatar
   
Dries committed
252
        $items[] = array('path' => 'admin/filters/'. arg(2) .'/configure', 'title' => t('configure'),
253
254
255
256
          'callback' => 'filter_admin_configure',
          'type' => MENU_LOCAL_TASK,
          'weight' => 1,
          'access' => user_access('administer filters'));
Dries's avatar
   
Dries committed
257
        $items[] = array('path' => 'admin/filters/'. arg(2) .'/order', 'title' => t('rearrange'),
258
259
260
261
          'callback' => 'filter_admin_order',
          'type' => MENU_LOCAL_TASK,
          'weight' => 2,
          'access' => user_access('administer filters'));
Dries's avatar
   
Dries committed
262
      }
263
264
265
    }
  }

Dries's avatar
   
Dries committed
266
  return $items;
267
268
}

Dries's avatar
Dries committed
269
/**
270
 * Implementation of hook_perm().
Dries's avatar
Dries committed
271
 */
272
273
274
275
276
function filter_perm() {
  return array('administer filters');
}

/**
277
 * Displays a list of all input formats and which one is the default
278
279
 */
function filter_admin_overview() {
280
281
282
283
284
285
286

  $edit = isset($_POST['edit']) ? $_POST['edit'] : '';

  // Process form submission to set the default format
  if (is_numeric($edit['default'])) {
    drupal_set_message(t('Default format updated.'));
    variable_set('filter_default_format', $edit['default']);
287
288
  }

289
  // Overview of all formats.
290
291
292
293
294
  $formats = filter_formats();
  $error = false;

  $rows = array();
  foreach ($formats as $id => $format) {
295
296
297
    $roles = array();
    foreach (user_roles() as $rid => $name) {
      //prepare a roles array with roles that may access the filter
298
      if (strstr($format->roles, ",$rid,")) {
299
300
301
        $roles[] = $name;
      }
    }
302
303
    $row = array();
    $default = ($id == variable_get('filter_default_format', 1));
304
    $options[$id] = '';
305
306
307
308
    $form[$format->name]['id'] = array('#type' => 'markup', '#value' => $id);
    $form[$format->name]['roles'] = array('#type' => 'markup', '#value' => $roles ? implode(', ',$roles) : t('No roles may use this format'));
    $form[$format->name]['configure'] = array('#type' => 'markup', '#value' => l(t('configure'), 'admin/filters/'. $id));
    $form[$format->name]['delete'] = array('#type' => 'markup', '#value' => $default ? '' : l('delete', 'admin/filters/delete/'. $id));
309
  }
310
311
  $form['default'] = array('#type' => 'radios', '#options' => $options, '#default_value' => variable_get('filter_default_format', 1));
  $form['submit'] = array('#type' => 'submit', '#value' => t('Set default format'));
312
313
  return drupal_get_form('filter_admin_overview', $form);
}
314

315
316
317
318
function theme_filter_admin_overview($form) {
  foreach ($form as $name => $element) {
    if (isset($element['roles']) && is_array($element['roles'])) {
      $rows[] = array(
319
        form_render($form['default'][$element['id']['#value']]),
320
321
322
323
324
325
326
327
328
329
330
        $name,
        form_render($element['roles']),
        form_render($element['configure']),
        form_render($element['delete'])
      );
      unset($form[$name]);
    }
  }
  $header = array(t('Default'), t('Name'), t('Roles'), array('data' => t('Operations'), 'colspan' => 2));
  $output = theme('table', $header, $rows);
  $output .= form_render($form);
331

Dries's avatar
   
Dries committed
332
  return $output;
333
334
335
}

/**
336
 * Add a new input format.
337
338
 */
function filter_admin_add() {
339
340
  if ($_POST['op']) {
    $edit = $_POST['edit'];
341

342
    filter_admin_filters_save($format->format, $edit);
343
344
  }

345
  $output = filter_admin_format_form($format);
346
  return $output;
347
348
349
}

/**
350
 * Menu callback; confirm deletion of a format.
351
352
353
 */
function filter_admin_delete() {
  $edit = $_POST['edit'];
354
  if ($edit['confirm']) {
355
356
357
358
359
    if ($edit['format'] != variable_get('filter_default_format', 1)) {
      db_query("DELETE FROM {filter_formats} WHERE format = %d", $edit['format']);
      db_query("DELETE FROM {filters} WHERE format = %d", $edit['format']);

      $default = variable_get('filter_default_format', 1);
360
      db_query("UPDATE {node_revisions} SET format = %d WHERE format = %d", $default, $edit['format']);
361
362
363
364
365
      db_query("UPDATE {comments} SET format = %d WHERE format = %d", $default, $edit['format']);
      db_query("UPDATE {boxes} SET format = %d WHERE format = %d", $default, $edit['format']);

      cache_clear_all('filter:'. $edit['format'], true);

366
      drupal_set_message(t('Deleted input format %format.', array('%format' => theme('placeholder', $edit['name']))));
367
368
369
370
371
372
373
    }
    drupal_goto('admin/filters');
  }

  $format = arg(3);
  $format = db_fetch_object(db_query('SELECT * FROM {filter_formats} WHERE format = %d', $format));

374
375
  $form['format'] = array('#type' => 'hidden', '#value' => $format->format);
  $form['name'] = array('#type' => 'hidden', '#value' => $format->name);
376
377
378
379

  return confirm_form('filter_admin_delete', $form, t('Are you sure you want to delete the input format %format?', array('%format' => theme('placeholder', $format->name))), 'admin/filters', t('If you have any content left in this input format, it will be switched to the default input format. This action cannot be undone.'), t('Delete'), t('Cancel'));


380
381
382
}

/**
383
 * Menu callback; configure the filters for a format.
384
 */
385
function filter_admin_format($format) {
386
  if ($_POST['op']) {
387
388
    $edit = $_POST['edit'];
    filter_admin_filters_save($format->format, $edit);
389
390
  }

391
  $output = filter_admin_format_form($format);
392

393
  // Composition tips (guidelines)
394
  $tips = _filter_tips($format->format, false);
395
  $extra = l(t('More information about formatting options'), 'filter/tips');
Dries's avatar
   
Dries committed
396
  $tiplist = theme('filter_tips', $tips, false, $extra);
397
398
399
400
401
402
403
  if (!$tiplist) {
    $tiplist = t('<p>No guidelines available.</p>');
  }
  $group = t('<p>These are the guidelines that users will see for posting in this input format. They are automatically generated from the filter settings.</p>');
  $group .= $tiplist;
  $output .= '<h2>'. t('Formatting guidelines') .'</h2>'. $group;

Dries's avatar
   
Dries committed
404
  return $output;
405
406
}

407
408
409
410
411
412
413
/**
 * Renders a form for a format
 */
function filter_admin_format_form($format) {
  $edit = $_POST['edit'];

  $default = ($format->format == variable_get('filter_default_format', 1));
414
415
  if ($default) {
    $help = t('All roles for the default format must be enabled and cannot be changed.');
416
    $form['default_format'] = array('#type' => 'hidden', '#value' => 1);
417
  }
418
419

  //Add the name of the object
420
421
  $form['name'] = array('#type' => 'fieldset', '#title' => t('Name'));
  $form['name']['name'] = array('#type' => 'textfield', '#default_value' => $format->name, '#size' => 60, '#maxlength' => 127, '#description' => t('Give the name of this filter format'), '#required' => TRUE);
422
423

  //Add a row of checkboxes for form group
424
  $form['roles'] = array('#type' => 'fieldset', '#title' => t('Roles'), '#description' => $default ? $help : t('Choose which roles may use this filter format.'), '#tree' => TRUE);
425
  $form['roles']['hidden'] = array();
426
427
  foreach (user_roles() as $rid => $name) {
    $checked = strstr($format->roles, ",$rid,");
428
    $form['roles'][$rid] = array('#type' => 'checkbox', '#title' => $name, '#default_value' => ($default || $checked));
429
    if ($default) {
430
      $form['roles'][$rid]['#attributes'] = array('disabled' => 'disabled');
431
    }
432
433
434
435
436
  }
  // Table with filters
  $all = filter_list_all();
  $enabled = filter_list_format($format->format);

437
  $form['filters'] = array('#type' => 'fieldset', '#title' => t('Filters'), '#description' => t('Choose the filters that will be used in this filter format'));
438
  foreach ($all as $id => $filter) {
439
    $form['filters'][$id] = array('#type' => 'checkbox', '#title' => $filter->name, '#default_value' => isset($enabled[$id]), '#description' => module_invoke($filter->module, 'filter', 'description', $filter->delta));
440
441
  }

442
  $form['submit'] = array('#type' => 'submit', '#value' => t('Save configuration'));
443

444
  return drupal_get_form('filter_admin_format_form', $form);
445
446
}

447
448
449
450
451
/**
 * Save enabled/disabled status for filters in a format.
 */
function filter_admin_filters_save($format, $toggles) {
  $current = filter_list_format($format);
452
453
  $edit = $_POST['edit'];
  $name = trim($edit['name']);
454
455
  $cache = true;

456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
  //make sure a title is specified
  if (strlen($name) == 0) {
    form_set_error('name', t('You must enter a name for this input format.'));
   return;
  }

  if (!$format) { //add a new filter format.
    $new = true;
    db_query("INSERT INTO {filter_formats} (name) VALUES ('%s')", $name);
    $result = db_fetch_object(db_query("SELECT MAX(format) AS format FROM {filter_formats}"));
    $format = $result->format;
   drupal_set_message(t('Added input format %format.', array('%format' => theme('placeholder', $edit['name']))));
  }
  else {
    drupal_set_message(t('The input format settings have been updated.'));
  }

473
474
475
476
477
478
479
480
481
482
483
484
485
  db_query("DELETE FROM {filters} WHERE format = %d", $format);
  foreach ($toggles as $id => $checked) {
    if ($checked) {
      list($module, $delta) = explode('/', $id);
      // Add new filters to the bottom
      $weight = isset($current[$id]->weight) ? $current[$id]->weight : 10;
      db_query("INSERT INTO {filters} (format, module, delta, weight) VALUES (%d, '%s', %d, %d)", $format, $module, $delta, $weight);

      // Check if there are any 'no cache' filters
      $cache &= !module_invoke($module, 'filter', 'no cache', $delta);
    }
  }

486
  // We store the roles as a string for ease of use.
487
  // we should always set all roles to true when saving a default role.
488
  // We use leading and trailing comma's to allow easy substring matching.
489
  $roles = isset($edit['roles']) ? array_keys($edit['roles']) : array();
490
  $roles = ','. implode(',', ($edit['default_format'] ? user_roles() : $roles)) .',';
491
492

  db_query("UPDATE {filter_formats} SET cache = %d, name='%s', roles = '%s' WHERE format = %d", $cache, $name, $roles, $format);
493
494
495

  cache_clear_all('filter:'. $format, true);

496
497
498
499
500
501
502
  // if a new filter was added, return to the main list of filters, otherwise stay on edit filter page to show new changes
  if ($new) {
    drupal_goto('admin/filters/');
  }
  else {
    drupal_goto('admin/filters/' . arg(2)) ;
  }
503
504
505
}

/**
506
 * Menu callback; display form for ordering filters for a format.
507
508
509
510
511
 */
function filter_admin_order() {
  $format = arg(2);
  if ($_POST['op']) {
    filter_admin_order_save($format, $_POST['edit']);
Dries's avatar
   
Dries committed
512
513
514
  }

  // Get list (with forced refresh)
515
  $filters = filter_list_format($format);
Dries's avatar
   
Dries committed
516

517
  foreach ($filters as $id => $filter) {
518
519
    $form['name'][$id] = array('#type' => 'markup', '#value' => $filter->name);
    $form['weight'][$id] = array('#type' => 'weight', '#default_value' => $filter->weight);
Dries's avatar
   
Dries committed
520
  }
521
  $form['submit'] = array('#type' => 'submit', '#value' => t('Save configuration'));
Dries's avatar
   
Dries committed
522

523
524
  return drupal_get_form('filter_admin_order', $form);
}
Dries's avatar
   
Dries committed
525

526
527
528
529
530
531
532
533
534
535
536
537
538
539
function theme_filter_admin_order($form) {
  $header = array(t('Name'), t('Weight'));
  $rows = array();
  foreach (element_children($form['name']) as $id) {
    // Don't take form control structures
    if (is_array($form['name'][$id])) {
      $rows[] = array(
        form_render($form['name'][$id]),
        form_render($form['weight'][$id]));
    }
  }

  $output = theme('table', $header, $rows);
  $output .= form_render($form);
Dries's avatar
   
Dries committed
540
  return $output;
Dries's avatar
   
Dries committed
541
542
}

Dries's avatar
Dries committed
543
/**
544
545
546
547
548
 * Save the weights of filters in a format.
 */
function filter_admin_order_save($format, $weights) {
  foreach ($weights as $id => $weight) {
    list($module, $delta) = explode('/', $id);
Dries's avatar
   
Dries committed
549
    db_query("UPDATE {filters} SET weight = %d WHERE format = %d AND module = '%s' AND delta = %d", $weight, $format, $module, $delta);
550
  }
551
  drupal_set_message(t('The filter ordering has been saved.'));
552
553

  cache_clear_all('filter:'. $format, true);
554
  drupal_goto($_GET['q']);
555
556
557
}

/**
558
 * Menu callback; display settings defined by filters.
Dries's avatar
Dries committed
559
 */
560
561
562
563
function filter_admin_configure() {
  $format = arg(2);

  $list = filter_list_format($format);
564
  $form = array();
565
  foreach ($list as $filter) {
566
    $form = array_merge($form, module_invoke($filter->module, 'filter', 'settings', $filter->delta, $format));
567
  }
Dries's avatar
   
Dries committed
568

569
570
  if (!empty($form)) {
    $output = system_settings_form('filter_admin_configure', $form);
571
572
573
574
  }
  else {
    $output = t('No settings are available.');
  }
Dries's avatar
   
Dries committed
575

Dries's avatar
   
Dries committed
576
  return $output;
577
578
}

Dries's avatar
Dries committed
579
/**
580
 * Retrieve a list of input formats.
Dries's avatar
Dries committed
581
 */
582
583
584
585
586
587
588
589
590
591
function filter_formats() {
  global $user;
  static $formats;

  // Administrators can always use all input formats.
  $all = user_access('administer filters');

  if (!isset($formats)) {
    $formats = array();

592
    $query = 'SELECT * FROM {filter_formats}';
593

594
    // Build query for selecting the format(s) based on the user's roles.
595
596
597
598
    if (!$all) {
      $where = array();
      foreach ($user->roles as $rid => $role) {
        $where[] = "roles LIKE '%%,%d,%%'";
599
        $args[] = $rid;
600
      }
601
602
      $query .= ' WHERE '. implode(' OR ', $where) . ' OR format = %d';
      $args[] = variable_get('filter_default_format', 1);
603
604
    }

605
    $result = db_query($query, $args);
606
607
608
609
610
611
    while ($format = db_fetch_object($result)) {
      $formats[$format->format] = $format;
    }
  }
  return $formats;
}
612

613
614
615
616
617
618
619
620
621
622
623
624
/**
 * Build a list of all filters.
 */
function filter_list_all() {
  $filters = array();

  foreach (module_list() as $module) {
    $list = module_invoke($module, 'filter', 'list');
    if (is_array($list)) {
      foreach ($list as $delta => $name) {
        $filters[$module .'/'. $delta] = (object)array('module' => $module, 'delta' => $delta, 'name' => $name);
      }
Dries's avatar
   
Dries committed
625
626
627
    }
  }

628
629
630
631
632
633
634
635
636
637
  uasort($filters, '_filter_list_cmp');

  return $filters;
}

/**
 * Helper function for sorting the filter list by filter name.
 */
function _filter_list_cmp($a, $b) {
  return strcmp($a->name, $b->name);
Dries's avatar
   
Dries committed
638
639
}

Dries's avatar
Dries committed
640
/**
641
 * Check if text in a certain input format is allowed to be cached.
Dries's avatar
Dries committed
642
 */
643
644
function filter_format_allowcache($format) {
  static $cache = array();
Dries's avatar
   
Dries committed
645

646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
  if (!isset($cache[$format])) {
    $cache[$format] = db_result(db_query('SELECT cache FROM {filter_formats} WHERE format = %d', $format));
  }
  return $cache[$format];
}

/**
 * Retrieve a list of filters for a certain format.
 */
function filter_list_format($format) {
  static $filters = array();

  if (!is_array($filters[$format])) {
    $filters[$format] = array();
    $result = db_query("SELECT * FROM {filters} WHERE format = %d ORDER BY weight ASC", $format);
    while ($filter = db_fetch_object($result)) {
      $list = module_invoke($filter->module, 'filter', 'list');
      if (is_array($list) && isset($list[$filter->delta])) {
        $filter->name = $list[$filter->delta];
        $filters[$format][$filter->module .'/'. $filter->delta] = $filter;
Dries's avatar
   
Dries committed
666
667
668
669
      }
    }
  }

670
  return $filters[$format];
671
672
}

673
674
/**
 * @name Filtering functions
Dries's avatar
   
Dries committed
675
 * @{
676
677
 * Modules which need to have content filtered can use these functions to
 * interact with the filter system.
678
679
680
681
682
683
684
685
 *
 * For more info, see the hook_filter() documentation.
 *
 * Note: because filters can inject JavaScript or execute PHP code, security is
 * vital here. When a user supplies a $format, you should validate it with
 * filter_access($format) before accepting/using it. This is normally done in
 * the validation stage of the node system. You should for example never make a
 * preview of content in a disallowed format.
686
687
 */

Dries's avatar
Dries committed
688
689
/**
 * Run all the enabled filters on a piece of text.
690
691
692
693
694
695
696
697
698
699
700
701
 *
 * @param $text
 *    The text to be filtered.
 * @param $format
 *    The format of the text to be filtered. Specify FILTER_FORMAT_DEFAULT for
 *    the default format.
 * @param $check
 *    Whether to check the $format with filter_access() first. Defaults to TRUE.
 *    Note that this will check the permissions of the current user, so you
 *    should specify $check = FALSE when viewing other people's content.  When
 *    showing content that is not (yet) stored in the database (eg. upon preview),
 *    set to TRUE so the user's permissions are checked.
Dries's avatar
Dries committed
702
 */
703
function check_markup($text, $format = FILTER_FORMAT_DEFAULT, $check = TRUE) {
704
705
  // When $check = true, do an access check on $format.
  if (isset($text) && (!$check || filter_access($format))) {
706
707
708
709
    if ($format == FILTER_FORMAT_DEFAULT) {
      $format = variable_get('filter_default_format', 1);
    }

710
    // Check for a cached version of this piece of text.
711
712
713
714
715
    $id = 'filter:'. $format .':'. md5($text);
    if ($cached = cache_get($id)) {
      return $cached->data;
    }

716
    // See if caching is allowed for this format.
717
    $cache = filter_format_allowcache($format);
718
719

    // Convert all Windows and Mac newlines to a single newline,
720
    // so filters only need to deal with one possibility.
721
722
    $text = str_replace(array("\r\n", "\r"), "\n", $text);

723
    // Get a complete list of filters, ordered properly.
724
    $filters = filter_list_format($format);
Dries's avatar
   
Dries committed
725

Dries's avatar
Dries committed
726
    // Give filters the chance to escape HTML-like data such as code or formulas.
727
728
    foreach ($filters as $filter) {
      $text = module_invoke($filter->module, 'filter', 'prepare', $filter->delta, $format, $text);
Dries's avatar
   
Dries committed
729
    }
730

731
    // Perform filtering.
732
733
    foreach ($filters as $filter) {
      $text = module_invoke($filter->module, 'filter', 'process', $filter->delta, $format, $text);
734
735
    }

736
    // Store in cache with a minimum expiration time of 1 day.
Dries's avatar
Dries committed
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
    if ($cache) {
      cache_set($id, $text, time() + (60 * 60 * 24));
    }
  }
  else {
    $text = message_na();
  }

  return $text;
}

/**
 * Generate a selector for choosing a format in a form.
 *
 * @param $name
 *   The internal name used to refer to the form element.
 * @param $value
 *   The ID of the format that is currently selected.
 * @return
 *   HTML for the form element.
 */
758
function filter_form($value = FILTER_FORMAT_DEFAULT) {
Dries's avatar
Dries committed
759
760
761
762
763
764
765
766
  if ($value == FILTER_FORMAT_DEFAULT) {
    $value = variable_get('filter_default_format', 1);
  }
  $formats = filter_formats();

  $extra = l(t('More information about formatting options'), 'filter/tips');

  if (count($formats) > 1) {
767
    $form['format'] = array('#type' => 'fieldset', '#title' => t('Input format'), '#collapsible' => TRUE, '#collapsed' => TRUE, '#weight' => -16);
Dries's avatar
Dries committed
768
769
    // Multiple formats available: display radio buttons with tips.
    foreach ($formats as $format) {
770
      $form['format'][$format->format] = array('#type' => 'filter_format', '#title' => $format->name, '#default_value' => $value, '#return_value' => $format->format, '#parents' => array('format'), '#description' => theme('filter_tips', _filter_tips($format->format, false)), '#valid' => 'filter_form');
Dries's avatar
Dries committed
771
    }
772
    return $form;
Dries's avatar
Dries committed
773
774
775
776
  }
  else {
    // Only one format available: use a hidden form item and only show tips.
    $format = array_shift($formats);
777
    $form['format'][$format->name] = array('#type' => 'value', '#value' => $format->format);
Dries's avatar
Dries committed
778
    $tips = _filter_tips(variable_get('filter_default_format', 1), false);
779
    $form['format']['guidelines'] = array('#type' => 'markup', '#title' => t('Formatting guidelines'), '#value' => theme('filter_tips', $tips, false, $extra));
780
    return $form;
Dries's avatar
Dries committed
781
782
783
  }
}

784
function filter_elements() {
785
  $type['filter_format'] = array('#input' => TRUE);
786
787
788
789
790
  return $type;
}

function theme_filter_format($element) {
  $output .= '<div>';
791
792
  $output .= '<label class="option"><input type="radio" class="form-radio" name="' . $element['#name'] . '" value="'. $element['#return_value'] .'"'. (($element['#default_value'] == $element['#return_value']) ? ' checked="checked"' : '') .' /> '. $element['#title'] .'</label>';
  $output .= $element['#description'];
793
794
795
796
  $output .= '</div>';
  return $output;
}

797
798
799
800
801
802
803
804
805
806
807
function filter_form_valid($element) {
  static $validated;
  if ($validated) {
    return;
  }
  $validated = 1;
  $formats = filter_formats();
  if (!isset($formats[$element['#value']])) {
    form_set_error($element['#parents'][0], t('The supplied input format is invalid.'));
  }
}
808

Dries's avatar
Dries committed
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
/**
 * Returns true if the user is allowed to access this format.
 */
function filter_access($format) {
  if (user_access('administer filters') || ($format == FILTER_FORMAT_DEFAULT) || ($format == variable_get('filter_default_format', 1))) {
    return true;
  }
  else {
    $formats = filter_formats();
    return isset($formats[$format]);
  }
}
/**
 * @} End of "Filtering functions".
 */

/**
 * Menu callback; show a page with long filter tips.
 */
function filter_tips_long() {
  $format = arg(2);
  if ($format) {
    $output = theme('filter_tips', _filter_tips($format, true), true);
  }
  else {
    $output = theme('filter_tips', _filter_tips(-1, true), true);
  }
  return $output;
}

/**
 * Helper function for fetching filter tips.
 */
function _filter_tips($format, $long = false) {
  if ($format == -1) {
    $formats = filter_formats();
  }
  else {
    $formats = array(db_fetch_object(db_query("SELECT * FROM {filter_formats} WHERE format = %d", $format)));
  }

  $tips = array();

  foreach ($formats as $format) {
    $filters = filter_list_format($format->format);

    $tips[$format->name] = array();
    foreach ($filters as $id => $filter) {
      if ($tip = module_invoke($filter->module, 'filter_tips', $filter->delta, $format->format, $long)) {
        $tips[$format->name][] = array('tip' => $tip, 'id' => $id);
      }
    }
  }

  return $tips;
}

/**
 * Format a set of filter tips.
 *
 * @ingroup themeable
 */
function theme_filter_tips($tips, $long = false, $extra = '') {
  $output = '';

  $multiple = count($tips) > 1;
  if ($multiple) {
876
    $output = t('input formats') .':';
Dries's avatar
Dries committed
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
  }

  if (count($tips)) {
    if ($multiple) {
      $output .= '<ul>';
    }
    foreach ($tips as $name => $tiplist) {
      if ($multiple) {
        $output .= '<li>';
        $output .= '<strong>'. $name .'</strong>:<br />';
      }

      $tips = '';
      foreach ($tiplist as $tip) {
        $tips .= '<li'. ($long ? ' id="filter-'. str_replace("/", "-", $tip['id']) .'">' : '>') . $tip['tip'] . '</li>';
      }

      if ($tips) {
        $output .= "<ul class=\"tips\">$tips</ul>";
      }

      if ($multiple) {
        $output .= '</li>';
      }
    }
    if ($multiple) {
      $output .= '</ul>';
    }
  }

  return $output;
}

/**
 * @name Standard filters
 * @{
 * Filters implemented by the filter.module.
 */

/**
 * Implementation of hook_filter(). Contains a basic set of essential filters.
 * - HTML filter:
 *     Validates user-supplied HTML, transforming it as necessary.
 * - PHP evaluator:
 *     Executes PHP code.
 * - Line break converter:
 *     Converts newlines into paragraph and break tags.
 */
function filter_filter($op, $delta = 0, $format = -1, $text = '') {
  switch ($op) {
    case 'list':
      return array(0 => t('HTML filter'), 1 => t('PHP evaluator'), 2 => t('Line break converter'));

    case 'no cache':
      return $delta == 1; // No caching for the PHP evaluator.

    case 'description':
      switch ($delta) {
        case 0:
          return t('Allows you to restrict if users can post HTML and which tags to filter out.');
        case 1:
          return t('Runs a piece of PHP code. The usage of this filter should be restricted to administrators only!');
        case 2:
          return t('Converts line breaks into HTML (i.e. &lt;br&gt; and &lt;p&gt; tags).');
        default:
          return;
      }

    case 'process':
      switch ($delta) {
        case 0:
          return _filter_html($text, $format);
        case 1:
          return drupal_eval($text);
        case 2:
          return _filter_autop($text);
        default:
          return $text;
      }

    case 'settings':
      switch ($delta) {
        case 0:
          return _filter_html_settings($format);
        default:
          return;
      }

    default:
      return $text;
  }
}

/**
 * Settings for the HTML filter.
 */
function _filter_html_settings($format) {
974
975
976
977
978
979
  $form['filter_html'] = array('#type' => 'fieldset', '#title' => t('HTML filter'), '#collapsible' => TRUE, '#collapsed' => TRUE);
  $form['filter_html']["filter_html_$format"] = array('#type' => 'radios', '#title' => t('Filter HTML tags'), '#default_value' => variable_get("filter_html_$format", FILTER_HTML_STRIP), '#options' => array(FILTER_HTML_STRIP => t('Strip tags'), FILTER_HTML_ESCAPE => t('Escape tags')), '#description' => t('How to deal with HTML tags in user-contributed content. If set to "Strip tags", dangerous tags are removed (see below). If set to "Escape tags", all HTML is escaped and presented as it was typed.'));
  $form['filter_html']["allowed_html_$format"] = array('#type' => 'textfield', '#title' => t('Allowed HTML tags'), '#default_value' => variable_get("allowed_html_$format", '<a> <em> <strong> <cite> <code> <ul> <ol> <li> <dl> <dt> <dd>'), '#size' => 64, '#maxlength' => 255, '#description' => t('If "Strip tags" is selected, optionally specify tags which should not be stripped. Javascript event attributes are always stripped.'));
  $form['filter_html']["filter_html_help_$format"] = array('#type' => 'checkbox', '#title' => t('Display HTML help'), '#default_value' => variable_get("filter_html_help_$format", 1), '#description' => t('If enabled, Drupal will display some basic HTML help in the long filter tips.'));
  $form['filter_html']["filter_style_$format"] = array('#type' => 'radios', '#title' => t('HTML style attributes'), '#default_value' => variable_get("filter_style_$format", FILTER_STYLE_STRIP), '#options' => array(FILTER_STYLE_ALLOW => t('Allowed'), FILTER_STYLE_STRIP => t('Removed')), '#description' => t('If "Strip tags" is selected, you can choose whether "STYLE" attributes are allowed or removed from input.'));
  $form['filter_html']["filter_html_nofollow_$format"] = array('#type' => 'checkbox', '#title' => t('Spam link deterrent'), '#default_value' => variable_get("filter_html_nofollow_$format", FALSE), '#description' => t('If enabled, Drupal will add rel="nofollow" to all links, as a measure to reduce the effectiveness of spam links. Note: this will also prevent valid links from being followed by search engines, therefore it is likely most effective when enabled for anonymous users.'));
980
981

  return $form;
Dries's avatar
Dries committed
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
}

/**
 * HTML filter. Provides filtering of input into accepted HTML.
 */
function _filter_html($text, $format) {
  if (variable_get("filter_html_$format", FILTER_HTML_STRIP) == FILTER_HTML_STRIP) {
    // Allow users to enter HTML, but filter it
    $text = strip_tags($text, variable_get("allowed_html_$format", '<a> <em> <strong> <cite> <code> <ul> <ol> <li> <dl> <dt> <dd>'));
    if (variable_get("filter_style_$format", FILTER_STYLE_STRIP)) {
      $text = preg_replace('/\Wstyle\s*=[^>]+?>/i', '>', $text);
    }
    $text = preg_replace('/\Won[a-z]+\s*=[^>]+?>/i', '>', $text);
  }

  if (variable_get("filter_html_$format", FILTER_HTML_STRIP) == FILTER_HTML_ESCAPE) {
    // Escape HTML
    $text = check_plain($text);
  }

  if (variable_get("filter_html_nofollow_$format", FALSE)) {
    $text = preg_replace('/<a([^>]+)>/i', '<a\\1 rel="nofollow">', $text);
  }

  return trim($text);
}

/**
 * Convert line breaks into <p> and <br> in an intelligent fashion.
 * Based on: http://photomatt.net/scripts/autop
 */
function _filter_autop($text) {
  // Split at <pre>, <script>, <style> and </pre>, </script>, </style> tags.
  // We don't apply any processing to the contents of these tags to avoid messing
  // up code. We look for matched pairs and allow basic nesting. For example:
  // "processed <pre> ignored <script> ignored </script> ignored </pre> processed"
  $chunks = preg_split('@(</?(?:pre|script|style)[^>]*>)@i', $text, -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).
  $ignore = false;
  $ignoretag = '';
  $output = '';
  foreach ($chunks as $i => $chunk) {
    if ($i % 2) {
      // Opening or closing tag?
      $open = ($chunk{1} != '/');
      list($tag) = split('[ >]', substr($chunk, 2 - $open), 2);
      if (!$ignore) {
        if ($open) {
          $ignore = true;
          $ignoretag = $tag;
        }
      }
      // Only allow a matching tag to close it.
      else if (!$open && $ignoretag == $tag) {
        $ignore = false;
        $ignoretag = '';
      }
    }
    else if (!$ignore) {
      $chunk = preg_replace('|\n*$|', '', $chunk) ."\n\n"; // just to make things a little easier, pad the end
      $chunk = preg_replace('|<br />\s*<br />|', "\n\n", $chunk);
      $chunk = preg_replace('!(<(?:table|ul|ol|li|pre|form|blockquote|h[1-6])[^>]*>)!', "\n$1", $chunk); // Space things out a little
      $chunk = preg_replace('!(</(?:table|ul|ol|li|pre|form|blockquote|h[1-6])>)!', "$1\n", $chunk); // Space things out a little
      $chunk = preg_replace("/\n\n+/", "\n\n", $chunk); // take care of duplicates
      $chunk = preg_replace('/\n?(.+?)(?:\n\s*\n|\z)/s', "<p>$1</p>\n", $chunk); // make paragraphs, including one at the end
      $chunk = preg_replace('|<p>\s*?</p>|', '', $chunk); // under certain strange conditions it could create a P of entirely whitespace
      $chunk = preg_replace("|<p>(<li.+?)</p>|", "$1", $chunk); // problem with nested lists
      $chunk = preg_replace('|<p><blockquote([^>]*)>|i', "<blockquote$1><p>", $chunk);
      $chunk = str_replace('</blockquote></p>', '</p></blockquote>', $chunk);
      $chunk = preg_replace('!<p>\s*(</?(?:table|tr|td|th|div|ul|ol|li|pre|select|form|blockquote|p|h[1-6])[^>]*>)!', "$1", $chunk);
      $chunk = preg_replace('!(</?(?:table|tr|td|th|div|ul|ol|li|pre|select|form|blockquote|p|h[1-6])[^>]*>)\s*</p>!', "$1", $chunk);
      $chunk = preg_replace('|(?<!<br />)\s*\n|', "<br />\n", $chunk); // make line breaks
      $chunk = preg_replace('!(</?(?:table|tr|td|th|div|dl|dd|dt|ul|ol|li|pre|select|form|blockquote|p|h[1-6])[^>]*>)\s*<br />!', "$1", $chunk);
      $chunk = preg_replace('!<br />(\s*</?(?:p|li|div|th|pre|td|ul|ol)>)!', '$1', $chunk);
      $chunk = preg_replace('/&([^#])(?![a-z]{1,8};)/', '&amp;$1', $chunk);
    }
    $output .= $chunk;
  }
  return $output;
}

/**
 * @} End of "Standard filters".
 */