Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like Comment often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Comment, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 23 | class Comment extends DataObject  | 
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                         | 
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| 24 | { | 
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| 25 | |||
| 26 | /**  | 
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| 27 | * @var array  | 
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| 28 | */  | 
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| 29 | private static $db = array(  | 
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| 30 | 'Name' => 'Varchar(200)',  | 
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| 31 | 'Comment' => 'Text',  | 
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| 32 | 'Email' => 'Varchar(200)',  | 
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| 33 | 'URL' => 'Varchar(255)',  | 
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| 34 | 'BaseClass' => 'Varchar(200)',  | 
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| 35 | 'Moderated' => 'Boolean(0)',  | 
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| 36 | 'IsSpam' => 'Boolean(0)',  | 
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| 37 | 'ParentID' => 'Int',  | 
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| 38 | 'AllowHtml' => 'Boolean',  | 
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| 39 | 'SecretToken' => 'Varchar(255)',  | 
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| 40 | 'Depth' => 'Int',  | 
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| 41 | );  | 
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| 42 | |||
| 43 | private static $has_one = array(  | 
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| 44 | "Author" => "Member",  | 
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| 45 | "ParentComment" => "Comment",  | 
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| 46 | );  | 
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| 47 | |||
| 48 | private static $has_many = array(  | 
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| 49 | "ChildComments" => "Comment"  | 
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| 50 | );  | 
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| 51 | |||
| 52 | private static $default_sort = '"Created" DESC';  | 
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| 53 | |||
| 54 | private static $defaults = array(  | 
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| 55 | 'Moderated' => 0,  | 
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| 56 | 'IsSpam' => 0,  | 
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| 57 | );  | 
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| 58 | |||
| 59 | private static $casting = array(  | 
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| 60 | 'Title' => 'Varchar',  | 
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| 61 | 'ParentTitle' => 'Varchar',  | 
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| 62 | 'ParentClassName' => 'Varchar',  | 
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| 63 | 'AuthorName' => 'Varchar',  | 
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| 64 | 'RSSName' => 'Varchar',  | 
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| 65 | 'DeleteLink' => 'Varchar',  | 
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| 66 | 'SpamLink' => 'Varchar',  | 
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| 67 | 'HamLink' => 'Varchar',  | 
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| 68 | 'ApproveLink' => 'Varchar',  | 
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| 69 | 'Permalink' => 'Varchar',  | 
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| 70 | );  | 
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| 71 | |||
| 72 | private static $searchable_fields = array(  | 
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| 73 | 'Name',  | 
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| 74 | 'Email',  | 
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| 75 | 'Comment',  | 
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| 76 | 'Created',  | 
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| 77 | 'BaseClass',  | 
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| 78 | );  | 
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| 79 | |||
| 80 | private static $summary_fields = array(  | 
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| 81 | 'Name' => 'Submitted By',  | 
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| 82 | 'Email' => 'Email',  | 
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| 83 | 'Comment.LimitWordCount' => 'Comment',  | 
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| 84 | 'Created' => 'Date Posted',  | 
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| 85 | 'ParentTitle' => 'Post',  | 
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| 86 | 'IsSpam' => 'Is Spam',  | 
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| 87 | );  | 
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| 88 | |||
| 89 | private static $field_labels = array(  | 
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| 90 | 'Author' => 'Author Member',  | 
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| 91 | );  | 
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| 92 | |||
| 93 | public function onBeforeWrite()  | 
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| 94 |     { | 
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| 95 | parent::onBeforeWrite();  | 
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| 96 | |||
| 97 | // Sanitize HTML, because its expected to be passed to the template unescaped later  | 
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| 98 |         if ($this->AllowHtml) { | 
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| 99 | $this->Comment = $this->purifyHtml($this->Comment);  | 
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| 100 | }  | 
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| 101 | |||
| 102 | // Check comment depth  | 
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| 103 | $this->updateDepth();  | 
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| 104 | }  | 
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| 105 | |||
| 106 | public function onBeforeDelete()  | 
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| 115 | |||
| 116 | /**  | 
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| 117 | * @return Comment_SecurityToken  | 
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| 118 | */  | 
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| 119 | public function getSecurityToken()  | 
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| 123 | |||
| 124 | /**  | 
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| 125 |      * Migrates the old {@link PageComment} objects to {@link Comment} | 
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| 126 | */  | 
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| 127 | public function requireDefaultRecords()  | 
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| 155 | |||
| 156 | /**  | 
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| 157 | * Return a link to this comment  | 
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| 158 | *  | 
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| 159 | * @param string $action  | 
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| 160 | *  | 
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| 161 | * @return string link to this comment.  | 
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| 162 | */  | 
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| 163 | public function Link($action = '')  | 
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| 169 | |||
| 170 | /**  | 
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| 171 |      * Returns the permalink for this {@link Comment}. Inserted into | 
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| 172 | * the ID tag of the comment  | 
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| 173 | *  | 
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| 174 | * @return string  | 
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| 175 | */  | 
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| 176 | public function Permalink()  | 
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| 181 | |||
| 182 | /**  | 
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| 183 | * Translate the form field labels for the CMS administration  | 
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| 184 | *  | 
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| 185 | * @param boolean $includerelations  | 
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| 186 | *  | 
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| 187 | * @return array  | 
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| 188 | */  | 
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| 189 | public function fieldLabels($includerelations = true)  | 
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| 204 | |||
| 205 | /**  | 
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| 206 | * Get the commenting option  | 
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| 207 | *  | 
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| 208 | * @param string $key  | 
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| 209 | *  | 
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| 210 | * @return mixed Result if the setting is available, or null otherwise  | 
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| 211 | */  | 
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| 212 | public function getOption($key)  | 
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| 227 | |||
| 228 | /**  | 
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| 229 |      * Returns the parent {@link DataObject} this comment is attached too | 
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| 230 | *  | 
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| 231 | * @return DataObject  | 
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| 232 | */  | 
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| 233 | public function getParent()  | 
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| 239 | |||
| 240 | |||
| 241 | /**  | 
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| 242 | * Returns a string to help identify the parent of the comment  | 
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| 243 | *  | 
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| 244 | * @return string  | 
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| 245 | */  | 
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| 246 | public function getParentTitle()  | 
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| 252 | |||
| 253 | /**  | 
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| 254 | * Comment-parent classnames obviously vary, return the parent classname  | 
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| 255 | *  | 
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| 256 | * @return string  | 
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| 257 | */  | 
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| 258 | public function getParentClassName()  | 
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| 262 | |||
| 263 | public function castingHelper($field)  | 
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| 271 | |||
| 272 | /**  | 
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| 273 | * Content to be safely escaped on the frontend  | 
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| 274 | *  | 
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| 275 | * @return string  | 
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| 276 | */  | 
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| 277 | public function getEscapedComment()  | 
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| 281 | |||
| 282 | /**  | 
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| 283 | * Return whether this comment is a preview (has not been written to the db)  | 
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| 284 | *  | 
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| 285 | * @return boolean  | 
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| 286 | */  | 
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| 287 | public function isPreview()  | 
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| 291 | |||
| 292 | /**  | 
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| 293 |      * @todo needs to compare to the new {@link Commenting} configuration API | 
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| 294 | *  | 
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| 295 | * @param Member $member  | 
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| 296 | *  | 
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| 297 | * @return bool  | 
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| 298 | */  | 
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| 299 | public function canCreate($member = null)  | 
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| 303 | |||
| 304 | /**  | 
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| 305 |      * Checks for association with a page, and {@link SiteTree->ProvidePermission} | 
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| 306 | * flag being set to true.  | 
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| 307 | *  | 
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| 308 | * @param Member $member  | 
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| 309 | *  | 
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| 310 | * @return Boolean  | 
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| 311 | */  | 
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| 312 | public function canView($member = null)  | 
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| 333 | |||
| 334 | /**  | 
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| 335 | * Checks if the comment can be edited.  | 
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| 336 | *  | 
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| 337 | * @param null|int|Member $member  | 
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| 338 | *  | 
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| 339 | * @return Boolean  | 
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| 340 | */  | 
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| 341 | public function canEdit($member = null)  | 
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| 364 | |||
| 365 | /**  | 
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| 366 | * Checks if the comment can be deleted.  | 
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| 367 | *  | 
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| 368 | * @param null|int|Member $member  | 
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| 369 | *  | 
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| 370 | * @return Boolean  | 
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| 371 | */  | 
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| 372 | public function canDelete($member = null)  | 
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| 387 | |||
| 388 | /**  | 
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| 389 | * Resolves Member object.  | 
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| 390 | *  | 
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| 391 | * @param Member|int|null $member  | 
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| 392 | * @return Member|null  | 
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| 393 | */  | 
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| 394 | protected function getMember($member = null)  | 
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| 406 | |||
| 407 | /**  | 
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| 408 | * Return the authors name for the comment  | 
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| 409 | *  | 
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| 410 | * @return string  | 
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| 411 | */  | 
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| 412 | public function getAuthorName()  | 
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| 420 | |||
| 421 | /**  | 
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| 422 | * Generate a secure admin-action link authorised for the specified member  | 
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| 423 | *  | 
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| 424 | * @param string $action An action on CommentingController to link to  | 
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| 425 | * @param Member $member The member authorised to invoke this action  | 
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| 426 | *  | 
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| 427 | * @return string  | 
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| 428 | */  | 
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| 429 | protected function actionLink($action, $member = null)  | 
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| 449 | |||
| 450 | /**  | 
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| 451 | * Link to delete this comment  | 
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| 452 | *  | 
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| 453 | * @param Member $member  | 
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| 454 | *  | 
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| 455 | * @return string  | 
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| 456 | */  | 
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| 457 | public function DeleteLink($member = null)  | 
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| 463 | |||
| 464 | /**  | 
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| 465 | * Link to mark as spam  | 
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| 466 | *  | 
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| 467 | * @param Member $member  | 
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| 468 | *  | 
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| 469 | * @return string  | 
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| 470 | */  | 
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| 471 | public function SpamLink($member = null)  | 
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| 477 | |||
| 478 | /**  | 
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| 479 | * Link to mark as not-spam (ham)  | 
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| 480 | *  | 
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| 481 | * @param Member $member  | 
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| 482 | *  | 
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| 483 | * @return string  | 
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| 484 | */  | 
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| 485 | public function HamLink($member = null)  | 
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| 491 | |||
| 492 | /**  | 
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| 493 | * Link to approve this comment  | 
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| 494 | *  | 
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| 495 | * @param Member $member  | 
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| 496 | *  | 
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| 497 | * @return string  | 
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| 498 | */  | 
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| 499 | public function ApproveLink($member = null)  | 
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| 505 | |||
| 506 | /**  | 
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| 507 | * Mark this comment as spam  | 
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| 508 | */  | 
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| 509 | public function markSpam()  | 
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| 516 | |||
| 517 | /**  | 
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| 518 | * Mark this comment as approved  | 
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| 519 | */  | 
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| 520 | public function markApproved()  | 
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| 527 | |||
| 528 | /**  | 
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| 529 | * Mark this comment as unapproved  | 
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| 530 | */  | 
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| 531 | public function markUnapproved()  | 
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| 537 | |||
| 538 | /**  | 
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| 539 | * @return string  | 
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| 540 | */  | 
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| 541 | public function SpamClass()  | 
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| 551 | |||
| 552 | /**  | 
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| 553 | * @return string  | 
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| 554 | */  | 
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| 555 | public function getTitle()  | 
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| 567 | |||
| 568 | /*  | 
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| 569 | * Modify the default fields shown to the user  | 
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| 570 | */  | 
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| 571 | public function getCMSFields()  | 
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| 572 |     { | 
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| 573 | $commentField = $this->AllowHtml ? 'HtmlEditorField' : 'TextareaField';  | 
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| 574 | $fields = new FieldList(  | 
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| 575 | $this  | 
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| 576 |                 ->obj('Created') | 
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| 577 |                 ->scaffoldFormField($this->fieldLabel('Created')) | 
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| 578 | ->performReadonlyTransformation(),  | 
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| 579 |             TextField::create('Name', $this->fieldLabel('Name')), | 
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| 580 |             $commentField::create('Comment', $this->fieldLabel('Comment')), | 
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| 581 |             EmailField::create('Email', $this->fieldLabel('Email')), | 
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| 582 |             TextField::create('URL', $this->fieldLabel('URL')), | 
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| 583 | FieldGroup::create(array(  | 
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| 584 |                 CheckboxField::create('Moderated', $this->fieldLabel('Moderated')), | 
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| 585 |                 CheckboxField::create('IsSpam', $this->fieldLabel('IsSpam')), | 
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| 586 | ))  | 
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| 587 |                 ->setTitle(_t('Comment.OPTIONS', 'Options')) | 
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| 588 | ->setDescription(_t(  | 
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| 589 | 'Comment.OPTION_DESCRIPTION',  | 
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| 590 | 'Unmoderated and spam comments will not be displayed until approved'  | 
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| 591 | ))  | 
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| 592 | );  | 
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| 593 | |||
| 594 | // Show member name if given  | 
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| 595 |         if (($author = $this->Author()) && $author->exists()) { | 
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| 596 | $fields->insertAfter(  | 
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| 597 |                 TextField::create('AuthorMember', $this->fieldLabel('Author'), $author->Title) | 
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| 598 | ->performReadonlyTransformation(),  | 
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| 599 | 'Name'  | 
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| 600 | );  | 
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| 601 | }  | 
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| 602 | |||
| 603 | // Show parent comment if given  | 
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| 604 |         if (($parent = $this->ParentComment()) && $parent->exists()) { | 
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| 605 | $fields->push(new HeaderField(  | 
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| 606 | 'ParentComment_Title',  | 
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| 607 |                 _t('Comment.ParentComment_Title', 'This comment is a reply to the below') | 
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| 608 | ));  | 
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| 609 | // Created date  | 
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| 610 | // FIXME - the method setName in DatetimeField is not chainable, hence  | 
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| 611 | // the lack of chaining here  | 
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| 612 | $createdField = $parent  | 
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| 613 |                     ->obj('Created') | 
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| 614 |                     ->scaffoldFormField($parent->fieldLabel('Created')); | 
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| 615 |             $createdField->setName('ParentComment_Created'); | 
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| 616 | $createdField->setValue($parent->Created);  | 
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| 617 | $createdField->performReadonlyTransformation();  | 
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| 618 | $fields->push($createdField);  | 
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| 619 | |||
| 620 | // Name (could be member or string value)  | 
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| 621 | $fields->push(  | 
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| 622 | $parent  | 
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| 623 |                     ->obj('AuthorName') | 
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| 624 |                     ->scaffoldFormField($parent->fieldLabel('AuthorName')) | 
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| 625 |                     ->setName('ParentComment_AuthorName') | 
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| 626 | ->setValue($parent->getAuthorName())  | 
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| 627 | ->performReadonlyTransformation()  | 
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| 628 | );  | 
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| 629 | |||
| 630 | // Comment body  | 
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| 631 | $fields->push(  | 
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| 632 | $parent  | 
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| 633 |                     ->obj('EscapedComment') | 
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| 634 |                     ->scaffoldFormField($parent->fieldLabel('Comment')) | 
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| 635 |                     ->setName('ParentComment_EscapedComment') | 
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| 636 | ->setValue($parent->Comment)  | 
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| 637 | ->performReadonlyTransformation()  | 
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| 638 | );  | 
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| 639 | }  | 
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| 640 | |||
| 641 |         $this->extend('updateCMSFields', $fields); | 
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| 642 | return $fields;  | 
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| 643 | }  | 
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| 644 | |||
| 645 | /**  | 
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| 646 | * @param String $dirtyHtml  | 
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| 647 | *  | 
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| 648 | * @return String  | 
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| 649 | */  | 
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| 650 | public function purifyHtml($dirtyHtml)  | 
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| 651 |     { | 
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| 652 | $purifier = $this->getHtmlPurifierService();  | 
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| 653 | return $purifier->purify($dirtyHtml);  | 
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| 654 | }  | 
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| 655 | |||
| 656 | /**  | 
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| 657 | * @return HTMLPurifier (or anything with a "purify()" method)  | 
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| 658 | */  | 
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| 659 | public function getHtmlPurifierService()  | 
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| 660 |     { | 
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| 661 | $config = HTMLPurifier_Config::createDefault();  | 
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| 662 |         $allowedElements = $this->getOption('html_allowed_elements'); | 
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| 663 |         $config->set('HTML.AllowedElements', $allowedElements); | 
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| 664 | |||
| 665 | // This injector cannot be set unless the 'p' element is allowed  | 
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| 666 |         if (in_array('p', $allowedElements)) { | 
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| 667 |             $config->set('AutoFormat.AutoParagraph', true); | 
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| 668 | }  | 
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| 669 | |||
| 670 |         $config->set('AutoFormat.Linkify', true); | 
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| 671 |         $config->set('URI.DisableExternalResources', true); | 
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| 672 |         $config->set('Cache.SerializerPath', getTempFolder()); | 
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| 673 | return new HTMLPurifier($config);  | 
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| 674 | }  | 
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| 675 | |||
| 676 | /**  | 
            ||
| 677 | * Calculate the Gravatar link from the email address  | 
            ||
| 678 | *  | 
            ||
| 679 | * @return string  | 
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| 680 | */  | 
            ||
| 681 | public function Gravatar()  | 
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| 695 | |||
| 696 | /**  | 
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| 697 | * Determine if replies are enabled for this instance  | 
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| 698 | *  | 
            ||
| 699 | * @return boolean  | 
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| 700 | */  | 
            ||
| 701 | public function getRepliesEnabled()  | 
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| 713 | |||
| 714 | /**  | 
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| 715 | * Returns the list of all replies  | 
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| 716 | *  | 
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| 717 | * @return SS_List  | 
            ||
| 718 | */  | 
            ||
| 719 | public function AllReplies()  | 
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| 736 | |||
| 737 | /**  | 
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| 738 | * Returns the list of replies, with spam and unmoderated items excluded, for use in the frontend  | 
            ||
| 739 | *  | 
            ||
| 740 | * @return SS_List  | 
            ||
| 741 | */  | 
            ||
| 742 | public function Replies()  | 
            ||
| 769 | |||
| 770 | /**  | 
            ||
| 771 | * Returns the list of replies paged, with spam and unmoderated items excluded, for use in the frontend  | 
            ||
| 772 | *  | 
            ||
| 773 | * @return PaginatedList  | 
            ||
| 774 | */  | 
            ||
| 775 | View Code Duplication | public function PagedReplies()  | 
            |
| 787 | |||
| 788 | /**  | 
            ||
| 789 | * Generate a reply form for this comment  | 
            ||
| 790 | *  | 
            ||
| 791 | * @return Form  | 
            ||
| 792 | */  | 
            ||
| 793 | public function ReplyForm()  | 
            ||
| 814 | |||
| 815 | /**  | 
            ||
| 816 | * Refresh of this comment in the hierarchy  | 
            ||
| 817 | */  | 
            ||
| 818 | public function updateDepth()  | 
            ||
| 828 | }  | 
            ||
| 829 | |||
| 830 | |||
| 831 | /**  | 
            ||
| 832 | * Provides the ability to generate cryptographically secure tokens for comment moderation  | 
            ||
| 941 | 
You can fix this by adding a namespace to your class:
When choosing a vendor namespace, try to pick something that is not too generic to avoid conflicts with other libraries.