Hierarchy.php 24.2 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782
<?php
/**
 * DataObjects that use the Hierarchy extension can be be organised as a hierarchy, with children and parents.
 * The most obvious example of this is SiteTree.
 * @package framework
 * @subpackage model
 */
class Hierarchy extends DataExtension {
	
	protected $markedNodes;
	
	protected $markingFilter;
	
	/**
	 * @var Int
	 */
	protected $_cache_numChildren;
	
	/**
	 * @config
	 * @var integer The lower bounds for the amount of nodes to mark. If set, the logic will expand
	 * nodes until it reaches at least this number, and then stops. Root nodes will always
	 * show regardless of this settting. Further nodes can be lazy-loaded via ajax.
	 * This isn't a hard limit. Example: On a value of 10, with 20 root nodes, each having
	 * 30 children, the actual node count will be 50 (all root nodes plus first expanded child).
	 */
	private static $node_threshold_total = 50;

	/**
	 * @config
	 * @var integer Limit on the maximum children a specific node can display.
	 * Serves as a hard limit to avoid exceeding available server resources
	 * in generating the tree, and browser resources in rendering it.
	 * Nodes with children exceeding this value typically won't display
	 * any children, although this is configurable through the $nodeCountCallback
	 * parameter in {@link getChildrenAsUL()}. "Root" nodes will always show
	 * all children, regardless of this setting.
	 */
	private static $node_threshold_leaf = 250;
	
	public function augmentSQL(SQLQuery &$query) {
	}

	public function augmentDatabase() {
	}
	
	public function augmentWrite(&$manipulation) {
	}

	public static function get_extra_config($class, $extension, $args) {
		return array(
			'has_one' => array('Parent' => $class)
		);
	}

	/**
	 * Validate the owner object - check for existence of infinite loops.
	 */
	public function validate(ValidationResult $validationResult) {
		// The object is new, won't be looping.
		if (!$this->owner->ID) return; 
		// The object has no parent, won't be looping.
		if (!$this->owner->ParentID) return; 
		// The parent has not changed, skip the check for performance reasons.
		if (!$this->owner->isChanged('ParentID')) return; 

		// Walk the hierarchy upwards until we reach the top, or until we reach the originating node again.
		$node = $this->owner;
		while($node) {
			if ($node->ParentID==$this->owner->ID) {
				// Hierarchy is looping.
				$validationResult->error(
					_t(
						'Hierarchy.InfiniteLoopNotAllowed',
						'Infinite loop found within the "{type}" hierarchy. Please change the parent to resolve this',
						'First argument is the class that makes up the hierarchy.',
						array('type' => $this->owner->class)
					),
					'INFINITE_LOOP'
				);
				break;
			}
			$node = $node->ParentID ? $node->Parent() : null;
		}

		// At this point the $validationResult contains the response.
	}

	/**
	 * Returns the children of this DataObject as an XHTML UL. This will be called recursively on each child,
	 * so if they have children they will be displayed as a UL inside a LI.
	 * @param string $attributes Attributes to add to the UL.
	 * @param string|callable $titleEval PHP code to evaluate to start each child - this should include '<li>'
	 * @param string $extraArg Extra arguments that will be passed on to children, for if they overload this function.
	 * @param boolean $limitToMarked Display only marked children.
	 * @param string $childrenMethod The name of the method used to get children from each object
	 * @param boolean $rootCall Set to true for this first call, and then to false for calls inside the recursion. You
	 *                          should not change this.
	 * @param int $nodeCountThreshold See {@link self::$node_threshold_total}
	 * @param callable $nodeCountCallback Called with the node count, which gives the callback an opportunity
	 *                 to intercept the query. Useful e.g. to avoid excessive children listings
	 *                 (Arguments: $parent, $numChildren)
	 *                          
	 * @return string
	 */
	public function getChildrenAsUL($attributes = "", $titleEval = '"<li>" . $child->Title', $extraArg = null, 
			$limitToMarked = false, $childrenMethod = "AllChildrenIncludingDeleted", 
			$numChildrenMethod = "numChildren", $rootCall = true,
			$nodeCountThreshold = null, $nodeCountCallback = null) {

		if(!is_numeric($nodeCountThreshold)) {
			$nodeCountThreshold = Config::inst()->get('Hierarchy', 'node_threshold_total');
		}

		if($limitToMarked && $rootCall) {
			$this->markingFinished($numChildrenMethod);
		}


		if($nodeCountCallback) {
			$nodeCountWarning = $nodeCountCallback($this->owner, $this->owner->$numChildrenMethod());	
			if($nodeCountWarning) return $nodeCountWarning;
		}
		
		
		if($this->owner->hasMethod($childrenMethod)) {
			$children = $this->owner->$childrenMethod($extraArg);
		} else {
			user_error(sprintf("Can't find the method '%s' on class '%s' for getting tree children", 
				$childrenMethod, get_class($this->owner)), E_USER_ERROR);
		}

		if($children) {

			if($attributes) {
				$attributes = " $attributes";
			}
			
			$output = "<ul$attributes>\n";
		
			foreach($children as $child) {
				if(!$limitToMarked || $child->isMarked()) {
					$foundAChild = true;
					if(is_callable($titleEval)) {
						$output .= $titleEval($child, $numChildrenMethod);
					} else {
						$output .= eval("return $titleEval;");
					}
					$output .= "\n";

					$numChildren = $child->$numChildrenMethod();

					if(
						// Always traverse into opened nodes (they might be exposed as parents of search results)
						$child->isExpanded()
						// Only traverse into children if we haven't reached the maximum node count already.
						// Otherwise, the remaining nodes are lazy loaded via ajax.
						&& $child->isMarked()
					) {
						// Additionally check if node count requirements are met
						$nodeCountWarning = $nodeCountCallback ? $nodeCountCallback($child, $numChildren) : null;
						if($nodeCountWarning) {
							$output .= $nodeCountWarning;
							$child->markClosed();
						} else {
							$output .= $child->getChildrenAsUL("", $titleEval, $extraArg, $limitToMarked,
								$childrenMethod,	$numChildrenMethod, false, $nodeCountThreshold);
						}
					} elseif($child->isTreeOpened()) {
						// Since we're not loading children, don't mark it as open either
						$child->markClosed();
					}
					$output .= "</li>\n";
				}
			}
			
			$output .= "</ul>\n";
		}
		
		if(isset($foundAChild) && $foundAChild) {
			return $output;
		}
	}
	
	/**
	 * Mark a segment of the tree, by calling mark().
	 * The method performs a breadth-first traversal until the number of nodes is more than minCount.
	 * This is used to get a limited number of tree nodes to show in the CMS initially.
	 * 
	 * This method returns the number of nodes marked.  After this method is called other methods 
	 * can check isExpanded() and isMarked() on individual nodes.
	 * 
	 * @param int $nodeCountThreshold See {@link getChildrenAsUL()}
	 * @return int The actual number of nodes marked.
	 */
	public function markPartialTree($nodeCountThreshold = 30, $context = null,
			$childrenMethod = "AllChildrenIncludingDeleted", $numChildrenMethod = "numChildren") {

		if(!is_numeric($nodeCountThreshold)) $nodeCountThreshold = 30;

		$this->markedNodes = array($this->owner->ID => $this->owner);
		$this->owner->markUnexpanded();

		// foreach can't handle an ever-growing $nodes list
		while(list($id, $node) = each($this->markedNodes)) {
			$children = $this->markChildren($node, $context, $childrenMethod, $numChildrenMethod);
			if($nodeCountThreshold && sizeof($this->markedNodes) > $nodeCountThreshold) {
				// Undo marking children as opened since they're lazy loaded
				if($children) foreach($children as $child) $child->markClosed();
				break;
			}
		}		
		return sizeof($this->markedNodes);
	}
	
	/**
	 * Filter the marking to only those object with $node->$parameterName = $parameterValue
	 * @param string $parameterName The parameter on each node to check when marking.
	 * @param mixed $parameterValue The value the parameter must be to be marked.
	 */
	public function setMarkingFilter($parameterName, $parameterValue) {
		$this->markingFilter = array(
			"parameter" => $parameterName,
			"value" => $parameterValue
		);
	}

	/**
	 * Filter the marking to only those where the function returns true.
	 * The node in question will be passed to the function.
	 * @param string $funcName The function name.
	 */
	public function setMarkingFilterFunction($funcName) {
		$this->markingFilter = array(
			"func" => $funcName,
		);
	}

	/**
	 * Returns true if the marking filter matches on the given node.
	 * @param DataObject $node Node to check.
	 * @return boolean
	 */
	public function markingFilterMatches($node) {
		if(!$this->markingFilter) {
			return true;
		}

		if(isset($this->markingFilter['parameter']) && $parameterName = $this->markingFilter['parameter']) {
			if(is_array($this->markingFilter['value'])){
				$ret = false;
				foreach($this->markingFilter['value'] as $value) {
					$ret = $ret||$node->$parameterName==$value;
					if($ret == true) {
						break;
					}
				}
				return $ret;		
			} else {
				return ($node->$parameterName == $this->markingFilter['value']);
			}
		} else if ($func = $this->markingFilter['func']) {
			return call_user_func($func, $node);
		}
	}

	/**
	 * Mark all children of the given node that match the marking filter.
	 * @param DataObject $node Parent node.
	 * @return DataList
	 */
	public function markChildren($node, $context = null, $childrenMethod = "AllChildrenIncludingDeleted",
			$numChildrenMethod = "numChildren") {
		if($node->hasMethod($childrenMethod)) {
			$children = $node->$childrenMethod($context);
		} else {
			user_error(sprintf("Can't find the method '%s' on class '%s' for getting tree children", 
				$childrenMethod, get_class($node)), E_USER_ERROR);
		}
		
		$node->markExpanded();
		if($children) {
			foreach($children as $child) {
				$markingMatches = $this->markingFilterMatches($child);
				if($markingMatches) {
					if($child->$numChildrenMethod()) {
						$child->markUnexpanded();
					} else {
						$child->markExpanded();
					}
					$this->markedNodes[$child->ID] = $child;
				}
			}
		}

		return $children;
	}
	
	/**
	 * Ensure marked nodes that have children are also marked expanded.
	 * Call this after marking but before iterating over the tree.
	 */
	protected function markingFinished($numChildrenMethod = "numChildren") {
		// Mark childless nodes as expanded.
		if($this->markedNodes) {
			foreach($this->markedNodes as $id => $node) {
				if(!$node->isExpanded() && !$node->$numChildrenMethod()) {
					$node->markExpanded();
				}
			}
		}
	}
	
	/**
	 * Return CSS classes of 'unexpanded', 'closed', both, or neither, as well as a
	 * 'jstree-*' state depending on the marking of this DataObject.
	 * 
	 * @return string
	 */
	public function markingClasses($numChildrenMethod="numChildren") {
		$classes = '';
		if(!$this->isExpanded()) {
			$classes .= " unexpanded";
		}
		
		// Set jstree open state, or mark it as a leaf (closed) if there are no children
		if(!$this->$numChildrenMethod()) {
			$classes .= " jstree-leaf closed";
		} elseif($this->isTreeOpened()) {
			$classes .= " jstree-open";
		} else {
			$classes .= " jstree-closed closed";
		}
		return $classes;
	}
	
	/**
	 * Mark the children of the DataObject with the given ID.
	 * @param int $id ID of parent node.
	 * @param boolean $open If this is true, mark the parent node as opened.
	 */
	public function markById($id, $open = false) {
		if(isset($this->markedNodes[$id])) {
			$this->markChildren($this->markedNodes[$id]);
			if($open) {
				$this->markedNodes[$id]->markOpened();
			}
			return true;
		} else {
			return false;
		}
	}

	/**
	 * Expose the given object in the tree, by marking this page and all it ancestors.
	 * @param DataObject $childObj 
	 */
	public function markToExpose($childObj) {
		if(is_object($childObj)){
			$stack = array_reverse($childObj->parentStack());
			foreach($stack as $stackItem) {
				$this->markById($stackItem->ID, true);
			}
		}
	}
	
	/**
	 * Return the IDs of all the marked nodes
	 */
	public function markedNodeIDs() {
		return array_keys($this->markedNodes);
	}

	/**
	 * Return an array of this page and its ancestors, ordered item -> root.
	 * @return array
	 */
	public function parentStack() {
		$p = $this->owner;
		
		while($p) {
			$stack[] = $p;
			$p = $p->ParentID ? $p->Parent() : null;
		}
		
		return $stack;
	}
	
	/**
	 * True if this DataObject is marked.
	 * @var boolean
	 */
	protected static $marked = array();
	
	/**
	 * True if this DataObject is expanded.
	 * @var boolean
	 */
	protected static $expanded = array();
	
	/**
	 * True if this DataObject is opened.
	 * @var boolean
	 */
	protected static $treeOpened = array();
	
	/**
	 * Mark this DataObject as expanded.
	 */
	public function markExpanded() {
		self::$marked[ClassInfo::baseDataClass($this->owner->class)][$this->owner->ID] = true;
		self::$expanded[ClassInfo::baseDataClass($this->owner->class)][$this->owner->ID] = true;
	}
	
	/**
	 * Mark this DataObject as unexpanded.
	 */
	public function markUnexpanded() {
		self::$marked[ClassInfo::baseDataClass($this->owner->class)][$this->owner->ID] = true;
		self::$expanded[ClassInfo::baseDataClass($this->owner->class)][$this->owner->ID] = false;
	}
	
	/**
	 * Mark this DataObject's tree as opened.
	 */
	public function markOpened() {
		self::$marked[ClassInfo::baseDataClass($this->owner->class)][$this->owner->ID] = true;
		self::$treeOpened[ClassInfo::baseDataClass($this->owner->class)][$this->owner->ID] = true;
	}

	/**
	 * Mark this DataObject's tree as closed.
	 */
	public function markClosed() {
		if(isset(self::$treeOpened[ClassInfo::baseDataClass($this->owner->class)][$this->owner->ID])) {
			unset(self::$treeOpened[ClassInfo::baseDataClass($this->owner->class)][$this->owner->ID]);	
		}
	}
	
	/**
	 * Check if this DataObject is marked.
	 * @return boolean
	 */
	public function isMarked() {
		$baseClass = ClassInfo::baseDataClass($this->owner->class);
		$id = $this->owner->ID;
		return isset(self::$marked[$baseClass][$id]) ? self::$marked[$baseClass][$id] : false;
	}
	
	/**
	 * Check if this DataObject is expanded.
	 * @return boolean
	 */
	public function isExpanded() {
		$baseClass = ClassInfo::baseDataClass($this->owner->class);
		$id = $this->owner->ID;
		return isset(self::$expanded[$baseClass][$id]) ? self::$expanded[$baseClass][$id] : false;
	}
	
	/**
	 * Check if this DataObject's tree is opened.
	 */
	public function isTreeOpened() {
		$baseClass = ClassInfo::baseDataClass($this->owner->class);
		$id = $this->owner->ID;
		return isset(self::$treeOpened[$baseClass][$id]) ? self::$treeOpened[$baseClass][$id] : false;
	}

	/**
	 * Get a list of this DataObject's and all it's descendants IDs.
	 * @return int
	 */
	public function getDescendantIDList() {
		$idList = array();
		$this->loadDescendantIDListInto($idList);
		return $idList;
	}
	
	/**
	 * Get a list of this DataObject's and all it's descendants ID, and put it in $idList.
	 * @var array $idList Array to put results in.
	 */
	public function loadDescendantIDListInto(&$idList) {
		if($children = $this->AllChildren()) {
			foreach($children as $child) {
				if(in_array($child->ID, $idList)) {
					continue;
				}
				$idList[] = $child->ID;
				$ext = $child->getExtensionInstance('Hierarchy');
				$ext->setOwner($child);
				$ext->loadDescendantIDListInto($idList);
				$ext->clearOwner();
			}
		}
	}
	
	/**
	 * Get the children for this DataObject.
	 * @return ArrayList
	 */
	public function Children() {
		if(!(isset($this->_cache_children) && $this->_cache_children)) { 
			$result = $this->owner->stageChildren(false); 
			$this->_cache_children = $result->filterByCallback(function($item) {	
				return $item->canView();
			});
					} 
		return $this->_cache_children;
	}

	/**
	 * Return all children, including those 'not in menus'.
	 * @return SS_List
	 */
	public function AllChildren() {
		return $this->owner->stageChildren(true);
	}

	/**
	 * Return all children, including those that have been deleted but are still in live.
	 * Deleted children will be marked as "DeletedFromStage"
	 * Added children will be marked as "AddedToStage"
	 * Modified children will be marked as "ModifiedOnStage"
	 * Everything else has "SameOnStage" set, as an indicator that this information has been looked up.
	 * @return SS_List
	 */
	public function AllChildrenIncludingDeleted($context = null) {
		return $this->doAllChildrenIncludingDeleted($context);
	}
	
	/**
	 * @see AllChildrenIncludingDeleted
	 *
	 * @param unknown_type $context
	 * @return SS_List
	 */
	public function doAllChildrenIncludingDeleted($context = null) {
		if(!$this->owner) user_error('Hierarchy::doAllChildrenIncludingDeleted() called without $this->owner');
		
		$baseClass = ClassInfo::baseDataClass($this->owner->class);
		if($baseClass) {
			$stageChildren = $this->owner->stageChildren(true);
			
			// Add live site content that doesn't exist on the stage site, if required.
			if($this->owner->hasExtension('Versioned')) {
				// Next, go through the live children.  Only some of these will be listed					
				$liveChildren = $this->owner->liveChildren(true, true);
				if($liveChildren) {
					$merged = new ArrayList();
					$merged->merge($stageChildren);
					$merged->merge($liveChildren);
					$stageChildren = $merged;
				}
			}

			$this->owner->extend("augmentAllChildrenIncludingDeleted", $stageChildren, $context); 
			
		} else {
			user_error("Hierarchy::AllChildren() Couldn't determine base class for '{$this->owner->class}'",
				E_USER_ERROR);
		}
		
		return $stageChildren;
	}
	
	/**
	 * Return all the children that this page had, including pages that were deleted
	 * from both stage & live.
	 */
	public function AllHistoricalChildren() {
		if(!$this->owner->hasExtension('Versioned')) {
			throw new Exception('Hierarchy->AllHistoricalChildren() only works with Versioned extension applied');
		}
		
		$baseClass=ClassInfo::baseDataClass($this->owner->class);
		return Versioned::get_including_deleted($baseClass, 
			"\"ParentID\" = " . (int)$this->owner->ID, "\"$baseClass\".\"ID\" ASC");
	}
	
	/**
	 * Return the number of children that this page ever had, including pages that were deleted
	 */
	public function numHistoricalChildren() {
		if(!$this->owner->hasExtension('Versioned')) {
			throw new Exception('Hierarchy->AllHistoricalChildren() only works with Versioned extension applied');
		}

		return Versioned::get_including_deleted(ClassInfo::baseDataClass($this->owner->class), 
			"\"ParentID\" = " . (int)$this->owner->ID)->count();
	}

	/**
	 * Return the number of direct children.
	 * By default, values are cached after the first invocation.
	 * Can be augumented by {@link augmentNumChildrenCountQuery()}.
	 * 
	 * @param Boolean $cache
	 * @return int
	 */
	public function numChildren($cache = true) {
		// Build the cache for this class if it doesn't exist.
		if(!$cache || !is_numeric($this->_cache_numChildren)) {
			// Hey, this is efficient now!
			// We call stageChildren(), because Children() has canView() filtering
			$this->_cache_numChildren = (int)$this->owner->stageChildren(true)->Count();
		}

		// If theres no value in the cache, it just means that it doesn't have any children.
		return $this->_cache_numChildren;
	}

	/**
	 * Return children from the stage site
	 * 
	 * @param showAll Inlcude all of the elements, even those not shown in the menus.
	 *   (only applicable when extension is applied to {@link SiteTree}).
	 * @return DataList
	 */
	public function stageChildren($showAll = false) {
		$baseClass = ClassInfo::baseDataClass($this->owner->class);
		$staged = $baseClass::get()
			->filter('ParentID', (int)$this->owner->ID)
			->exclude('ID', (int)$this->owner->ID);
		if (!$showAll && $this->owner->db('ShowInMenus')) {
			$staged = $staged->filter('ShowInMenus', 1);
		}
		$this->owner->extend("augmentStageChildren", $staged, $showAll);
		return $staged;
	}

	/**
	 * Return children from the live site, if it exists.
	 * 
	 * @param boolean $showAll Include all of the elements, even those not shown in the menus.
	 *   (only applicable when extension is applied to {@link SiteTree}).
	 * @param boolean $onlyDeletedFromStage Only return items that have been deleted from stage
	 * @return SS_List
	 */
	public function liveChildren($showAll = false, $onlyDeletedFromStage = false) {
		if(!$this->owner->hasExtension('Versioned')) {
			throw new Exception('Hierarchy->liveChildren() only works with Versioned extension applied');
		}

		$baseClass = ClassInfo::baseDataClass($this->owner->class);
		$children = $baseClass::get()
			->filter('ParentID', (int)$this->owner->ID)
			->exclude('ID', (int)$this->owner->ID)
			->setDataQueryParam(array(
				'Versioned.mode' => $onlyDeletedFromStage ? 'stage_unique' : 'stage',
				'Versioned.stage' => 'Live'
			));
		
		if(!$showAll) $children = $children->filter('ShowInMenus', 1);

		return $children;
	}
	
	/**
	 * Get the parent of this class.
	 * @return DataObject
	 */
	public function getParent($filter = '') {
		if($p = $this->owner->__get("ParentID")) {
			$tableClasses = ClassInfo::dataClassesFor($this->owner->class);
			$baseClass = array_shift($tableClasses);
			$filter .= ($filter) ? " AND " : ""."\"$baseClass\".\"ID\" = $p";
			return DataObject::get_one($this->owner->class, $filter);
		}
	}
	
	/**
	 * Return all the parents of this class in a set ordered from the lowest to highest parent.
	 *
	 * @return SS_List
	 */
	public function getAncestors() {
		$ancestors = new ArrayList();
		$object    = $this->owner;
		
		while($object = $object->getParent()) {
			$ancestors->push($object);
		}
		
		return $ancestors;
	}

	/**
	 * Returns a human-readable, flattened representation of the path to the object,
	 * using its {@link Title()} attribute.
	 * 
	 * @param String
	 * @return String
	 */
	public function getBreadcrumbs($separator = ' &raquo; ') {
		$crumbs = array();
		$ancestors = array_reverse($this->owner->getAncestors()->toArray());
		foreach($ancestors as $ancestor) $crumbs[] = $ancestor->Title;
		$crumbs[] = $this->owner->Title;
		return implode($separator, $crumbs);
	}
	
	/**
	 * Get the next node in the tree of the type. If there is no instance of the className descended from this node,
	 * then search the parents.
	 * 
	 * @todo Write!
	 */
	public function naturalPrev( $className, $afterNode = null ) {
		return null;
	}

	/**
	 * Get the next node in the tree of the type. If there is no instance of the className descended from this node,
	 * then search the parents.
	 * @param string $className Class name of the node to find.
	 * @param string|int $root ID/ClassName of the node to limit the search to
	 * @param DataObject afterNode Used for recursive calls to this function
	 * @return DataObject
	 */
	public function naturalNext( $className = null, $root = 0, $afterNode = null ) {
		// If this node is not the node we are searching from, then we can possibly return this
		// node as a solution
		if($afterNode && $afterNode->ID != $this->owner->ID) {
			if(!$className || ($className && $this->owner->class == $className)) {
				return $this->owner;
			}
		}
			
		$nextNode = null;
		$baseClass = ClassInfo::baseDataClass($this->owner->class);
		
		$children = $baseClass::get()
			->filter('ParentID', (int)$this->owner->ID)
			->sort('Sort', 'ASC');
		if ($afterNode) {
			$children = $children->filter('Sort:GreaterThan', $afterNode->Sort);
		}
		
		// Try all the siblings of this node after the given node
		/*if( $siblings = DataObject::get( ClassInfo::baseDataClass($this->owner->class), 
		"\"ParentID\"={$this->owner->ParentID}" . ( $afterNode ) ? "\"Sort\" 
		> {$afterNode->Sort}" : "" , '\"Sort\" ASC' ) ) $searchNodes->merge( $siblings );*/
		
		if($children) {
			foreach($children as $node) {
				if($nextNode = $node->naturalNext($className, $node->ID, $this->owner)) {
					break;
				}
			}
			
			if($nextNode) {
				return $nextNode;
			}
		}
		
		// if this is not an instance of the root class or has the root id, search the parent
		if(!(is_numeric($root) && $root == $this->owner->ID || $root == $this->owner->class)
				&& ($parent = $this->owner->Parent())) {
			
			return $parent->naturalNext( $className, $root, $this->owner );
		}
		
		return null;
	}
	
	public function flushCache() {
		$this->_cache_children = null;
		$this->_cache_numChildren = null;
		self::$marked = array();
		self::$expanded = array();
		self::$treeOpened = array();
	}

	public static function reset() {
		self::$marked = array();
		self::$expanded = array();
		self::$treeOpened = array();
	}

}