RubberFileSystem.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\Core\Cache;

use OnPHP\Core\Exception\WrongArgumentException;
use OnPHP\Main\Util\FileUtils;
use OnPHP\Core\Exception\BaseException;
use OnPHP\Core\Base\Assert;

/**
 * Simple filesystem cache.
 * 
 * @ingroup Cache
**/
final class RubberFileSystem extends CachePeer
{
	private $directory	= null;

	/**
	 * @return RubberFileSystem
	**/
	public static function create($directory = 'cache/')
	{
		return new self($directory);
	}

	public function __construct($directory = 'cache/')
	{
		$directory = ONPHP_TEMP_PATH.$directory;

		if (!is_writable($directory)) {
			if (!mkdir($directory, 0700, true)) {
				throw new WrongArgumentException(
					"can not write to '{$directory}'"
				);
			}
		}

		if ($directory[strlen($directory) - 1] != DIRECTORY_SEPARATOR)
			$directory .= DIRECTORY_SEPARATOR;

		$this->directory = $directory;
	}

	public function isAlive()
	{
		if (!is_writable($this->directory))
			return mkdir($this->directory, 0700, true);
		else
			return true;
	}

	/**
	 * @return RubberFileSystem
	**/
	public function clean()
	{
		// just to return 'true'
		FileUtils::removeDirectory($this->directory, true);

		return parent::clean();
	}

	public function increment($key, int $value = 1)
	{
		$path = $this->makePath($key);

		if (null !== ($current = $this->operate($path))) {
			$this->operate($path, $current += $value);

			return $current;
		}

		return null;
	}

	public function decrement($key, int $value = 1)
	{
		$path = $this->makePath($key);

		if (null !== ($current = $this->operate($path))) {
			$this->operate($path, $current -= $value);

			return $current;
		}

		return null;
	}

	public function get($key)
	{
		$path = $this->makePath($key);

		if (is_readable($path)) {

			if (filemtime($path) <= time()) {
				try {
					unlink($path);
				} catch (BaseException $e) {
					// we're in race with unexpected clean()
				}
				return null;
			}

			return $this->operate($path);
		}

		return null;
	}

	public function delete($key)
	{
		try {
			unlink($this->makePath($key));
		} catch (BaseException $e) {
			return false;
		}

		return true;
	}

	public function append($key, $data)
	{
		$path = $this->makePath($key);

		$directory = dirname($path);

		if (!file_exists($directory)) {
			try {
				mkdir($directory);
			} catch (BaseException $e) {
				// we're in race
			}
		}

		if (!is_writable($path))
			return false;

		try {
			$fp = fopen($path, 'ab');
		} catch (BaseException $e) {
			return false;
		}

		fwrite($fp, $data);

		fclose($fp);

		return true;
	}

	protected function store($action, $key, $value, $expires = 0)
	{
		$path = $this->makePath($key);
		$time = time();

		$directory = dirname($path);

		if (!file_exists($directory)) {
			try {
				mkdir($directory);
			} catch (BaseException $e) {
				// we're in race
			}
		}

		// do not add, if file exist and not expired
		if (
			$action == 'add'
			&& is_readable($path)
			&& filemtime($path) > $time
		)
			return true;

		// do not replace, when file not exist or expired
		if ($action == 'replace') {

			if (!is_readable($path)) {
				return false;
			} elseif (filemtime($path) <= $time) {
				$this->delete($key);
				return false;
			}
		}

		$this->operate($path, $value, $expires);

		return true;
	}

	private function operate($path, $value = null, $expires = null)
	{
		$key = hexdec(substr(md5($path), 3, 2)) + 1;

		$pool = SemaphorePool::me();

		if (!$pool->get($key))
			return null;

		try {
			$old = umask(0077);
			$fp = fopen($path, $value !== null ? 'wb' : 'rb');
			umask($old);
		} catch (BaseException $e) {
			$pool->drop($key);
			return null;
		}

		if ($value !== null) {
			fwrite($fp, $this->prepareData($value));
			fclose($fp);

			if ($expires < parent::TIME_SWITCH)
				$expires += time();

			try {
				touch($path, $expires);
			} catch (BaseException $e) {
				// race-removed
			}

			return $pool->drop($key);
		} else {
			if (($size = filesize($path)) > 0)
				$data = fread($fp, $size);
			else
				$data = null;

			fclose($fp);

			$pool->drop($key);

			return $data ? $this->restoreData($data) : null;
		}

		Assert::isUnreachable();
	}

	private function makePath($key)
	{
		return
			$this->directory
			.$key[0].$key[1]
			.DIRECTORY_SEPARATOR
			.substr($key, 2);
	}
}
?>