SmartDaoWorker.php

<?php
/***************************************************************************
 *   Copyright (C) 2005-2008 by Konstantin V. Arkhipov                     *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU Lesser General Public License as        *
 *   published by the Free Software Foundation; either version 3 of the    *
 *   License, or (at your option) any later version.                       *
 *                                                                         *
 ***************************************************************************/

namespace OnPHP\Main\DAO\Worker;

use OnPHP\Core\Base\Assert;
use OnPHP\Core\Base\Identifiable;
use OnPHP\Core\Cache\Cache;
use OnPHP\Core\Cache\SemaphorePool;
use OnPHP\Core\OSQL\SelectQuery;
use OnPHP\Main\DAO\GenericDAO;
use OnPHP\Main\DAO\Uncacher\UncacherSmartDaoWorkerLists;

/**
 * Transparent caching DAO worker.
 * 
 * @see CommonDaoWorker for manual-caching one.
 * @see VoodooDaoWorker for greedy though non-blocking brother.
 * 
 * @ingroup DAO
**/
final class SmartDaoWorker extends TransparentDaoWorker
{
	private $indexKey	= null;

	public function __construct(GenericDAO $dao)
	{
		parent::__construct($dao);

		$this->indexKey =
			$this->watermark
			.$this->className
			.self::SUFFIX_INDEX;
	}

	/// cachers
	//@{
	protected function cacheByQuery(
		SelectQuery $query,
		/* Identifiable */ $object,
		$expires = Cache::EXPIRES_FOREVER
	)
	{
		$semKey = $this->keyToInt($this->indexKey);

		$key = $this->makeQueryKey($query, self::SUFFIX_QUERY);

		$pool = SemaphorePool::me();

		if ($pool->get($semKey)) {
			$this->syncMap($key);

			Cache::me()->mark($this->className)->
				add($key, $object, $expires);

			$pool->free($semKey);
		}

		return $object;
	}

	protected function cacheListByQuery(
		SelectQuery $query,
		/* array || Cache::NOT_FOUND */ $array
	)
	{
		if ($array !== Cache::NOT_FOUND) {
			Assert::isArray($array);
			Assert::isTrue(current($array) instanceof Identifiable);
		}

		$cache = Cache::me();

		$listKey = $this->makeQueryKey($query, self::SUFFIX_LIST);

		$semKey = $this->keyToInt($this->indexKey);

		$pool = SemaphorePool::me();

		if ($pool->get($semKey)) {

			$this->syncMap($listKey);

			$cache->mark($this->className)->
				add($listKey, $array, Cache::EXPIRES_FOREVER);

			if ($array !== Cache::NOT_FOUND)
				foreach ($array as $object)
					$this->cacheById($object);

			$pool->free($semKey);
		}

		return $array;
	}
	//@}

	/// uncachers
	//@{
	public function uncacheLists()
	{
		$intKey	= $this->keyToInt($this->indexKey);
		return $this->registerUncacher(
			UncacherSmartDaoWorkerLists::create($this->className, $this->indexKey, $intKey)
		);
	}
	//@}

	/// internal helpers
	//@{
	protected function gentlyGetByKey($key)
	{
		if ($object = Cache::me()->mark($this->className)->get($key)) {
			if ($this->checkMap($key)) {
				return $object;
			} else {
				Cache::me()->mark($this->className)->delete($key);
			}
		}

		return null;
	}

	private function syncMap($objectKey)
	{
		$cache = Cache::me();

		$mapExists = true;
		if (!$map = $cache->mark($this->className)->get($this->indexKey)) {
			$map = array();
			$mapExists = false;
		}

		$map[$objectKey] = true;

		if ($mapExists) {
			$cache->mark($this->className)->
				replace($this->indexKey, $map, Cache::EXPIRES_FOREVER);
		} else {
			$cache->mark($this->className)->
				set($this->indexKey, $map, Cache::EXPIRES_FOREVER);
		}

		return true;
	}

	private function checkMap($objectKey)
	{
		$pool = SemaphorePool::me();

		$semKey = $this->keyToInt($this->indexKey);

		if (!$pool->get($semKey))
			return false;

		if (!$map = Cache::me()->mark($this->className)->get($this->indexKey)) {
			$pool->free($semKey);
			return false;
		}

		if (!isset($map[$objectKey])) {
			$pool->free($semKey);
			return false;
		}

		$pool->free($semKey);

		return true;
	}
	//@}
}
?>