<?php
/*
* This file is part of the Stash package.
*
* (c) Robert Hafner <tedivm@tedivm.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Stash\Driver;
use Stash;
use Stash\Driver\FileSystem\NativeEncoder;
use Stash\Driver\FileSystem\EncoderInterface;
use Stash\Utilities;
use Stash\Exception\LogicException;
use Stash\Exception\RuntimeException;
/**
* StashFileSystem stores cache objects in the filesystem as native php, making the process of retrieving stored data
* as performance intensive as including a file. Since the data is stored as php this module can see performance
* benefits from php opcode caches like APC and xcache.
*
* @package Stash
* @author Robert Hafner <tedivm@tedivm.com>
*/
class FileSystem extends AbstractDriver
{
/**
* This is the path to the file which will be used to store the cached item. It is based off of the key.
*
* @var string
*/
protected $path;
/**
* This is the array passed from the main Cache class, which needs to be saved
*
* @var array
*/
protected $data;
/**
* This function stores the path information generated by the makePath function so that it does not have to be
* calculated each time the driver is called. This only stores path information, it does not store the data to be
* cached.
*
* @var array
*/
protected $memStore = array();
/**
* The limit of keys to store in memory.
*
* @var int
*/
protected $memStoreLimit;
/**
* This is the base path for the cache items to be saved in. This defaults to a directory in the tmp directory (as
* defined by the configuration) called 'stash_', which it will create if needed.
*
* @var string
*/
protected $cachePath;
/**
* Permissions to use for new files.
*
* @var
*/
protected $filePermissions;
/**
* Permissions to use for new directories.
*
* @var
*/
protected $dirPermissions;
/**
* The level of directories each key will have. This is used to reduce the number of files or directories
* in a single directory to get past various filesystem limits.
*
* @var
*/
protected $directorySplit;
/**
* The hashing algorithm used to normalize keys into filesystem safe values. The only reason this gets changed is
* to lower the path length for windows systems.
*
* @var
*/
protected $keyHashFunction;
/**
* Is this driver disabled.
*
* @var bool
*/
protected $disabled = false;
/**
* @var \Stash\Driver\FileSystem\EncoderInterface
*/
protected $encoder;
/**
* {@inheritdoc}
*/
public function getDefaultOptions()
{
return array(
'filePermissions' => 0660,
'dirPermissions' => 0770,
'dirSplit' => 2,
'memKeyLimit' => 20,
'keyHashFunction' => 'md5',
);
}
/**
* Requests a list of options.
*
* @param array $options
*
* @throws \Stash\Exception\RuntimeException
*/
protected function setOptions(array $options = array())
{
$options += $this->getDefaultOptions();
if (!isset($options['path'])) {
$options['path'] = Utilities::getBaseDirectory($this);
}
$this->cachePath = rtrim($options['path'], '\\/') . DIRECTORY_SEPARATOR;
$this->filePermissions = $options['filePermissions'];
$this->dirPermissions = $options['dirPermissions'];
$this->directorySplit = max((int) $options['dirSplit'], 1);
$this->memStoreLimit = max((int) $options['memKeyLimit'], 0);
if (is_callable($options['keyHashFunction'])) {
$this->keyHashFunction = $options['keyHashFunction'];
} else {
throw new RuntimeException('Key Hash Function is not callable');
}
if (isset($options['encoder'])) {
$encoder = $options['encoder'];
if (is_object($encoder)) {
if (!($encoder instanceof EncoderInterface)) {
throw new RuntimeException('Encoder object must implement EncoderInterface');
}
$this->encoder = new $encoder;
} else {
$encoderInterface = 'Stash\Driver\FileSystem\EncoderInterface';
$encoderClass = 'Stash\Driver\FileSystem\\' . $encoder . 'Encoder';
if (class_exists($encoder) && in_array($encoderInterface, class_implements($encoder))) {
$this->encoder = new $encoder();
} elseif (class_exists($encoderClass) && in_array($encoderInterface, class_implements($encoderClass))) {
$this->encoder = new $encoderClass();
} else {
throw new RuntimeException('Invalid Encoder: ' . $encoder);
}
}
}
Utilities::checkFileSystemPermissions($this->cachePath, $this->dirPermissions);
}
/**
* Converts a key array into a key string.
*
* @param array $key
* @return string
*/
protected function makeKeyString($key)
{
$keyString = '';
foreach ($key as $group) {
$keyString .= $group . '/';
}
return $keyString;
}
/**
* This function retrieves the data from the file. If the file does not exist, or is currently being written to, it
* will return false. If the file is already being written to, this instance of the driver gets disabled so as not
* to have a bunch of writes get queued up when a cache item fails to hit.
*
* {@inheritdoc}
*
* @return bool
*/
public function getData($key)
{
return $this->getEncoder()->deserialize($this->makePath($key));
}
/**
* This function takes the data and stores it to the path specified. If the directory leading up to the path does
* not exist, it creates it.
*
* {@inheritdoc}
*/
public function storeData($key, $data, $expiration)
{
$path = $this->makePath($key);
// MAX_PATH is 260 - http://msdn.microsoft.com/en-us/library/aa365247(VS.85).aspx
if (strlen($path) > 259 && stripos(PHP_OS, 'WIN') === 0) {
throw new Stash\Exception\WindowsPathMaxLengthException();
}
if (!file_exists($path)) {
if (!is_dir(dirname($path))) {
if (!@mkdir(dirname($path), $this->dirPermissions, true)) {
return false;
}
}
if (!(touch($path) && chmod($path, $this->filePermissions))) {
return false;
}
}
$storeString = $this->getEncoder()->serialize($this->makeKeyString($key), $data, $expiration);
$result = file_put_contents($path, $storeString, LOCK_EX);
// If opcache is switched on, it will try to cache the PHP data file
// The new php opcode caching system only revalidates against the source files once every few seconds,
// so some changes will not be caught.
// This fix immediately invalidates that opcode cache after a file is written,
// so that future includes are not using the stale opcode cached file.
if (function_exists('opcache_invalidate')) {
opcache_invalidate($path, true);
}
return false !== $result;
}
/**
* This function takes in an array of strings (the key) and uses them to create a path to save the cache item to.
* It starts with the cachePath (or a new 'cache' directory in the config temp directory) and then uses each element
* of the array as a directory (after putting the element through md5(), which was the most efficient way to make
* sure it was filesystem safe). The last element of the array gets a php extension attached to it.
*
* @param array $key Null arguments return the base directory.
* @throws \Stash\Exception\LogicException
* @return string
*/
protected function makePath($key = null)
{
if (!isset($this->cachePath)) {
throw new LogicException('Unable to load system without a base path.');
}
$basePath = $this->cachePath;
if (!is_array($key) || count($key) == 0) {
return $basePath;
}
// When I profiled this compared to the "implode" function, this was much faster. This is probably due to the
// small size of the arrays and the overhead from function calls. This may seem like a ridiculous
// micro-optimization, but I only did it after profiling the code with xdebug and noticing a legitimate
// difference, most likely due to the number of times this function can get called in a scripts.
// Please don't look at me like that.
$memkey = '';
foreach ($key as $group) {
$memkey .= str_replace('#', ':', $group) . '#';
}
if (isset($this->memStore['keys'][$memkey])) {
return $this->memStore['keys'][$memkey];
} else {
$path = $basePath;
$key = Utilities::normalizeKeys($key, $this->keyHashFunction);
foreach ($key as $value) {
if (strpos($value, '@') === 0) {
$path .= substr($value, 1) . DIRECTORY_SEPARATOR;
continue;
}
$sLen = strlen($value);
$len = floor($sLen / $this->directorySplit);
for ($i = 0; $i < $this->directorySplit; $i++) {
$start = $len * $i;
if ($i == $this->directorySplit) {
$len = $sLen - $start;
}
$path .= substr($value, $start, $len) . DIRECTORY_SEPARATOR;
}
}
$path = rtrim($path, DIRECTORY_SEPARATOR) . $this->getEncoder()->getExtension();
$this->memStore['keys'][$memkey] = $path;
// in most cases the key will be used almost immediately or not at all, so it doesn't need to grow too large
if (count($this->memStore['keys']) > $this->memStoreLimit) {
foreach (array_rand($this->memStore['keys'], ceil($this->memStoreLimit / 2) + 1) as $empty) {
unset($this->memStore['keys'][$empty]);
}
}
return $path;
}
}
/**
* This function clears the data from a key. If a key points to both a directory and a file, both are erased. If
* passed null, the entire cache directory is removed.
*
* {@inheritdoc}
*/
public function clear($key = null)
{
$path = $this->makePath($key);
if (is_file($path)) {
$return = true;
unlink($path);
}
$extension = $this->getEncoder()->getExtension();
if (strpos($path, $extension) !== false) {
$path = substr($path, 0, -(strlen($extension)));
}
if (is_dir($path)) {
return Utilities::deleteRecursive($path, true);
}
return isset($return);
}
/**
* Cleans out the cache directory by removing all stale cache files and empty directories.
*
* {@inheritdoc}
*/
public function purge()
{
$startTime = time();
$filePath = $this->makePath();
$directoryIt = new \RecursiveDirectoryIterator($filePath);
foreach (new \RecursiveIteratorIterator($directoryIt, \RecursiveIteratorIterator::CHILD_FIRST) as $file) {
$filename = $file->getPathname();
if ($file->isDir()) {
$dirFiles = scandir($file->getPathname());
if ($dirFiles && count($dirFiles) == 2) {
$filename = rtrim($filename, '/.');
if (file_exists(($filename))) {
rmdir($filename);
}
}
unset($dirFiles);
continue;
}
if (!file_exists($filename)) {
continue;
}
$data = $this->getEncoder()->deserialize($filename);
if (is_numeric($data['expiration']) && $data['expiration'] <= $startTime) {
unlink($filename);
}
}
unset($directoryIt);
return true;
}
protected function getEncoder()
{
if (!isset($this->encoder)) {
$this->encoder = new \Stash\Driver\FileSystem\NativeEncoder();
}
return $this->encoder;
}
/**
* {@inheritdoc}
*/
public function isPersistent()
{
return true;
}
}