includes/diff/SlotDiffRenderer.php

   1 <?php
   2 /**
   3  * Renders a diff for a single slot.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup DifferenceEngine
  22  */
  23
  24 /**
  25  * Renders a diff for a single slot (that is, a diff between two content objects).
  26  *
  27  * Callers should obtain this class by invoking ContentHandler::getSlotDiffRendererClass
  28  * on the content handler of the new content object (ie. the one shown on the right side
  29  * of the diff), or of the old one if the new one does not exist.
  30  *
  31  * The default implementation just does a text diff on the native text representation.
  32  * Content handler extensions can subclass this to provide a more appropriate diff method by
  33  * overriding ContentHandler::getSlotDiffRendererClass. Other extensions that want to interfere
  34  * with diff generation in some way can use the GetSlotDiffRenderer hook.
  35  *
  36  * @ingroup DifferenceEngine
  37  */
  38 abstract class SlotDiffRenderer {
  39
  40         /**
  41          * Get a diff between two content objects. One of them might be null (meaning a slot was
  42          * created or removed), but both cannot be. $newContent (or if it's null then $oldContent)
  43          * must have the same content model that was used to obtain this diff renderer.
  44          * @param Content|null $oldContent
  45          * @param Content|null $newContent
  46          * @return string
  47          */
  48         abstract public function getDiff( Content $oldContent = null, Content $newContent = null );
  49
  50         /**
  51          * Add modules needed for correct styling/behavior of the diff.
  52          * @param OutputPage $output
  53          */
  54         public function addModules( OutputPage $output ) {
  55         }
  56
  57         /**
  58          * Return any extra keys to split the diff cache by.
  59          * @return array
  60          */
  61         public function getExtraCacheKeys() {
  62                 return [];
  63         }
  64
  65 }