silverstripe-dms/code/cms/DMSGridFieldDeleteAction.php

<?php
/**
 * This class is a {@link GridField} component that adds a delete a DMS document.
 *
 * This component also supports unlinking a relation instead of deleting the object. By default it unlinks, but if
 * this is the last reference to a specific document, it warns the user that continuing with the operation will
 * delete the document completely.
 *
 * <code>
 * $action = new GridFieldDeleteAction(); // delete objects permanently
  * </code>
 *
 * @package dms
 * @subpackage cms
 */
class DMSGridFieldDeleteAction extends GridFieldDeleteAction implements GridField_ColumnProvider, GridField_ActionProvider {

	/**
	 *
	 * @param GridField $gridField
	 * @param DataObject $record
	 * @param string $columnName
	 * @return string - the HTML for the column
	 */
	public function getColumnContent($gridField, $record, $columnName) {
		if($this->removeRelation) {
			$field = GridField_FormAction::create($gridField, 'UnlinkRelation'.$record->ID, false, "unlinkrelation", array('RecordID' => $record->ID))
				->addExtraClass('gridfield-button-unlink')
				->setAttribute('title', _t('GridAction.UnlinkRelation', "Unlink"))
				->setAttribute('data-icon', 'chain--minus');
		} else {
			if(!$record->canDelete()) {
				return;
			}
			$field = GridField_FormAction::create($gridField,  'DeleteRecord'.$record->ID, false, "deleterecord", array('RecordID' => $record->ID))
				->addExtraClass('gridfield-button-delete')
				->setAttribute('title', _t('GridAction.Delete', "Delete"))
				->setAttribute('data-icon', 'cross-circle')
				->setDescription(_t('GridAction.DELETE_DESCRIPTION','Delete'));
		}

		//add a class to the field to if it is the last gridfield in the list
		$numberOfRelations = $record->Pages()->Count();
		$field->addExtraClass('dms-delete') //add a new class for custom JS to handle the delete action
				->setAttribute('data-pages-count', $numberOfRelations)  //add the number of pages attached to this field as a data-attribute
				->removeExtraClass('gridfield-button-delete');  //remove the base gridfield behaviour

		//set a class telling JS what kind of warning to display when clicking the delete button
		if ($numberOfRelations > 1) $field->addExtraClass('dms-delete-link-only');
		else $field->addExtraClass('dms-delete-last-warning');

		//set a class to show if the document is hidden
		if ($record->isHidden()) {
			$field->addExtraClass('dms-document-hidden');
		}

		return $field->Field();
	}

	/**
	 * Handle the actions and apply any changes to the GridField
	 *
	 * @param GridField $gridField
	 * @param string $actionName
	 * @param mixed $arguments
	 * @param array $data - form data
	 * @return void
	 */
	public function handleAction(GridField $gridField, $actionName, $arguments, $data) {
		if($actionName == 'deleterecord' || $actionName == 'unlinkrelation') {
			$item = $gridField->getList()->byID($arguments['RecordID']);
			if(!$item) {
				return;
			}
			if($actionName == 'deleterecord' && !$item->canDelete()) {
				throw new ValidationException(_t('GridFieldAction_Delete.DeletePermissionsFailure',"No delete permissions"),0);
			}

			$delete = false;
			if ($item->Pages()->Count() <= 1) $delete = true;

			$gridField->getList()->remove($item);   //remove the relation
			if ($delete) $item->delete();   //delete the DMSDocument
		}
	}
}