silverstripe-cms/code/WidgetAreaEditor.php

<?php
/**
 * Special field type for selecting and configuring widgets on a page.
 * @package cms
 * @subpackage content
 */
class WidgetAreaEditor extends FormField {
	function FieldHolder() {
		return $this->renderWith("WidgetAreaEditor");
	}
	
	function AvailableWidgets() {
		$classes = ClassInfo::subclassesFor('Widget');
		array_shift($classes);
		$widgets= new DataObjectSet();
		
		foreach($classes as $class) {
			$widgets->push(singleton($class));
		}
		
		return $widgets;
	}
	
	function UsedWidgets() {
		$relationName = $this->name;
		
		$widgets = $this->form->getRecord()->$relationName()->Widgets();
		
		return $widgets;
	}
	
	function IdxField() {
		return $this->id() . 'ID';
	}
	
	function Value() {
		$relationName = $this->name;
		return $this->form->getRecord()->$relationName()->ID;
	}
	
	function saveInto(DataObject $record) {
		$name = $this->name;
		$idName = $name . "ID";
		
		
		$widgetarea = $record->$name();
		
		$widgetarea->write();
		$record->$idName = $widgetarea->ID;
		
		$widgets = $widgetarea->Widgets();
		
		// store the field IDs and delete the missing fields
		// alternatively, we could delete all the fields and re add them
		$missingWidgets = array();
        
	    foreach($widgets as $existingWidget){
	    	$missingWidgets[$existingWidget->ID] = $existingWidget;
	    }    	    
         
	   	// write the new widgets to the database
		if(isset($_REQUEST['Widget'])){

			foreach(array_keys( $_REQUEST['Widget'] ) as $newWidgetID ) {
				$newWidgetData  = $_REQUEST['Widget'][$newWidgetID];
				
				// `ParentID`=0 is for the new page
		  		$widget = DataObject::get_one( 'Widget', "(`ParentID`='{$record->$name()->ID}' OR `ParentID`=0) AND `Widget`.`ID`='$newWidgetID'" ); 
		  		
		  		// check if we are updating an existing widget
		  		if($widget && isset($missingWidgets[$widget->ID]))
		  			unset($missingWidgets[$widget->ID] );
		  		
		  		// create a new object
		  		if(!$widget && !empty($newWidgetData['Type']) && class_exists($newWidgetData['Type'])) {
		  			$widget = new $newWidgetData['Type']();
		  			$widget->ID = 0;
		  			$widget->ParentID = $record->$name()->ID;
		  			
		  			if(!is_subclass_of($widget, 'Widget')) {
		  				$widget = null;
		  			}
		  		}
		  		
		  		if($widget) {
		  			if($widget->ParentID == 0) {
		  				$widget->ParentID = $record->$name()->ID;
		  			}
		  			$widget->populateFromPostData($newWidgetData);
		  			//$editable->write();
		  		}
		    }
		}
    
    	// remove the fields not saved
    	foreach($missingWidgets as $removedWidget) {
    		if(isset($removedWidget) && is_numeric($removedWidget->ID)) $removedWidget->delete();
    	}
	}
}

?>