<?php
/**
 * Joomla! Content Management System
 *
 * @copyright  (C) 2007 Open Source Matters, Inc. <https://www.joomla.org>
 * @license    GNU General Public License version 2 or later; see LICENSE.txt
 */

namespace Joomla\CMS\Cache\Storage;

defined('JPATH_PLATFORM') or die;

use Joomla\CMS\Cache\CacheStorage;
use Joomla\CMS\Log\Log;

/**
 * File cache storage handler
 *
 * @since  1.7.0
 * @note   For performance reasons this class does not use the Filesystem package's API
 */
class FileStorage extends CacheStorage
{
	/**
	 * Root path
	 *
	 * @var    string
	 * @since  1.7.0
	 */
	protected $_root;

	/**
	 * Locked resources
	 *
	 * @var    array
	 * @since  3.7.0
	 *
	 */
	protected $_locked_files = array();

	/**
	 * Constructor
	 *
	 * @param   array  $options  Optional parameters
	 *
	 * @since   1.7.0
	 */
	public function __construct($options = array())
	{
		parent::__construct($options);
		$this->_root = $options['cachebase'];

		// Workaround for php 5.3
		$locked_files = &$this->_locked_files;

		// Remove empty locked files at script shutdown.
		$clearAtShutdown = function () use (&$locked_files)
		{
			foreach ($locked_files as $path => $handle)
			{
				if (is_resource($handle))
				{
					@flock($handle, LOCK_UN);
					@fclose($handle);
				}

				// Delete only the existing file if it is empty.
				if (@filesize($path) === 0)
				{
					@unlink($path);
				}

				unset($locked_files[$path]);
			}
		};

		register_shutdown_function($clearAtShutdown);
	}

	/**
	 * Check if the cache contains data stored by ID and group
	 *
	 * @param   string  $id     The cache data ID
	 * @param   string  $group  The cache data group
	 *
	 * @return  boolean
	 *
	 * @since   3.7.0
	 */
	public function contains($id, $group)
	{
		return $this->_checkExpire($id, $group);
	}

	/**
	 * Get cached data by ID and group
	 *
	 * @param   string   $id         The cache data ID
	 * @param   string   $group      The cache data group
	 * @param   boolean  $checkTime  True to verify cache time expiration threshold
	 *
	 * @return  mixed  Boolean false on failure or a cached data object
	 *
	 * @since   1.7.0
	 */
	public function get($id, $group, $checkTime = true)
	{
		$path  = $this->_getFilePath($id, $group);
		$close = false;

		if ($checkTime == false || ($checkTime == true && $this->_checkExpire($id, $group) === true))
		{
			if (file_exists($path))
			{
				if (isset($this->_locked_files[$path]))
				{
					$_fileopen = $this->_locked_files[$path];
				}
				else
				{
					$_fileopen = @fopen($path, 'rb');

					// There is no lock, we have to close file after store data
					$close = true;
				}

				if ($_fileopen)
				{
					// On Windows system we can not use file_get_contents on the file locked by yourself
					$data = stream_get_contents($_fileopen);

					if ($close)
					{
						@fclose($_fileopen);
					}

					if ($data !== false)
					{
						// Remove the initial die() statement
						return str_replace('<?php die("Access Denied"); ?>#x#', '', $data);
					}
				}
			}
		}

		return false;
	}

	/**
	 * Get all cached data
	 *
	 * @return  mixed  Boolean false on failure or a cached data object
	 *
	 * @since   1.7.0
	 */
	public function getAll()
	{
		$path    = $this->_root;
		$folders = $this->_folders($path);
		$data    = array();

		foreach ($folders as $folder)
		{
			$files = $this->_filesInFolder($path . '/' . $folder);
			$item  = new CacheStorageHelper($folder);

			foreach ($files as $file)
			{
				$item->updateSize(filesize($path . '/' . $folder . '/' . $file));
			}

			$data[$folder] = $item;
		}

		return $data;
	}

	/**
	 * Store the data to cache by ID and group
	 *
	 * @param   string  $id     The cache data ID
	 * @param   string  $group  The cache data group
	 * @param   string  $data   The data to store in cache
	 *
	 * @return  boolean
	 *
	 * @since   1.7.0
	 */
	public function store($id, $group, $data)
	{
		$path  = $this->_getFilePath($id, $group);
		$close = false;

		// Prepend a die string
		$data = '<?php die("Access Denied"); ?>#x#' . $data;

		if (isset($this->_locked_files[$path]))
		{
			$_fileopen = $this->_locked_files[$path];

			// Because lock method uses flag c+b we have to truncate it manually
			@ftruncate($_fileopen, 0);
		}
		else
		{
			$_fileopen = @fopen($path, 'wb');

			// There is no lock, we have to close file after store data
			$close = true;
		}

		if ($_fileopen)
		{
			$length = strlen($data);
			$result = @fwrite($_fileopen, $data, $length);

			if ($close)
			{
				@fclose($_fileopen);
			}

			return $result === $length;
		}

		return false;
	}

	/**
	 * Remove a cached data entry by ID and group
	 *
	 * @param   string  $id     The cache data ID
	 * @param   string  $group  The cache data group
	 *
	 * @return  boolean
	 *
	 * @since   1.7.0
	 */
	public function remove($id, $group)
	{
		$path = $this->_getFilePath($id, $group);

		if (!@unlink($path))
		{
			return false;
		}

		return true;
	}

	/**
	 * Clean cache for a group given a mode.
	 *
	 * group mode    : cleans all cache in the group
	 * notgroup mode : cleans all cache not in the group
	 *
	 * @param   string  $group  The cache data group
	 * @param   string  $mode   The mode for cleaning cache [group|notgroup]
	 *
	 * @return  boolean
	 *
	 * @since   1.7.0
	 */
	public function clean($group, $mode = null)
	{
		$return = true;
		$folder = $group;

		if (trim($folder) == '')
		{
			$mode = 'notgroup';
		}

		switch ($mode)
		{
			case 'notgroup' :
				$folders = $this->_folders($this->_root);

				for ($i = 0, $n = count($folders); $i < $n; $i++)
				{
					if ($folders[$i] != $folder)
					{
						$return |= $this->_deleteFolder($this->_root . '/' . $folders[$i]);
					}
				}

				break;

			case 'group' :
			default :
				if (is_dir($this->_root . '/' . $folder))
				{
					$return = $this->_deleteFolder($this->_root . '/' . $folder);
				}

				break;
		}

		return (bool) $return;
	}

	/**
	 * Garbage collect expired cache data
	 *
	 * @return  boolean
	 *
	 * @since   1.7.0
	 */
	public function gc()
	{
		$result = true;

		// Files older than lifeTime get deleted from cache
		$files = $this->_filesInFolder($this->_root, '', true, true, array('.svn', 'CVS', '.DS_Store', '__MACOSX', 'index.html'));

		foreach ($files as $file)
		{
			$time = @filemtime($file);

			if (($time + $this->_lifetime) < $this->_now || empty($time))
			{
				$result |= @unlink($file);
			}
		}

		return (bool) $result;
	}

	/**
	 * Lock cached item
	 *
	 * @param   string   $id        The cache data ID
	 * @param   string   $group     The cache data group
	 * @param   integer  $locktime  Cached item max lock time
	 *
	 * @return  mixed  Boolean false if locking failed or an object containing properties lock and locklooped
	 *
	 * @since   1.7.0
	 */
	public function lock($id, $group, $locktime)
	{
		$returning             = new \stdClass;
		$returning->locklooped = false;

		$looptime  = $locktime * 10;
		$path      = $this->_getFilePath($id, $group);
		$_fileopen = @fopen($path, 'c+b');

		if (!$_fileopen)
		{
			$returning->locked = false;

			return $returning;
		}

		$data_lock = (bool) @flock($_fileopen, LOCK_EX|LOCK_NB);

		if ($data_lock === false)
		{
			$lock_counter = 0;

			// Loop until you find that the lock has been released.
			// That implies that data get from other thread has finished
			while ($data_lock === false)
			{
				if ($lock_counter > $looptime)
				{
					break;
				}

				usleep(100);
				$data_lock = (bool) @flock($_fileopen, LOCK_EX|LOCK_NB);
				$lock_counter++;
			}

			$returning->locklooped = true;
		}

		if ($data_lock === true)
		{
			// Remember resource, flock release lock if you unset/close resource
			$this->_locked_files[$path] = $_fileopen;
		}

		$returning->locked = $data_lock;

		return $returning;
	}

	/**
	 * Unlock cached item
	 *
	 * @param   string  $id     The cache data ID
	 * @param   string  $group  The cache data group
	 *
	 * @return  boolean
	 *
	 * @since   1.7.0
	 */
	public function unlock($id, $group = null)
	{
		$path = $this->_getFilePath($id, $group);

		if (isset($this->_locked_files[$path]))
		{
			$ret = (bool) @flock($this->_locked_files[$path], LOCK_UN);
			@fclose($this->_locked_files[$path]);
			unset($this->_locked_files[$path]);

			return $ret;
		}

		return true;
	}

	/**
	 * Check if a cache object has expired
	 *
	 * Using @ error suppressor here because between if we did a file_exists() and then filemsize() there will
	 * be a little time space when another process can delete the file and then you get PHP Warning
	 *
	 * @param   string  $id     Cache ID to check
	 * @param   string  $group  The cache data group
	 *
	 * @return  boolean  True if the cache ID is valid
	 *
	 * @since   1.7.0
	 */
	protected function _checkExpire($id, $group)
	{
		$path = $this->_getFilePath($id, $group);

		// Check prune period
		if (file_exists($path))
		{
			$time = @filemtime($path);

			if (($time + $this->_lifetime) < $this->_now || empty($time))
			{
				@unlink($path);

				return false;
			}

			// If, right now, the file does not exist then return false
			if (@filesize($path) == 0)
			{
				return false;
			}

			return true;
		}

		return false;
	}

	/**
	 * Get a cache file path from an ID/group pair
	 *
	 * @param   string  $id     The cache data ID
	 * @param   string  $group  The cache data group
	 *
	 * @return  boolean|string  The path to the data object or boolean false if the cache directory does not exist
	 *
	 * @since   1.7.0
	 */
	protected function _getFilePath($id, $group)
	{
		$name = $this->_getCacheId($id, $group);
		$dir  = $this->_root . '/' . $group;

		// If the folder doesn't exist try to create it
		if (!is_dir($dir))
		{
			// Make sure the index file is there
			$indexFile = $dir . '/index.html';
			@mkdir($dir) && file_put_contents($indexFile, '<!DOCTYPE html><title></title>');
		}

		// Make sure the folder exists
		if (!is_dir($dir))
		{
			return false;
		}

		return $dir . '/' . $name . '.php';
	}

	/**
	 * Quickly delete a folder of files
	 *
	 * @param   string  $path  The path to the folder to delete.
	 *
	 * @return  boolean
	 *
	 * @since   1.7.0
	 */
	protected function _deleteFolder($path)
	{
		// Sanity check
		if (!$path || !is_dir($path) || empty($this->_root))
		{
			// Bad programmer! Bad, bad programmer!
			Log::add(__METHOD__ . ' ' . \JText::_('JLIB_FILESYSTEM_ERROR_DELETE_BASE_DIRECTORY'), Log::WARNING, 'jerror');

			return false;
		}

		$path = $this->_cleanPath($path);

		// Check to make sure path is inside cache folder, we do not want to delete Joomla root!
		$pos = strpos($path, $this->_cleanPath($this->_root));

		if ($pos === false || $pos > 0)
		{
			Log::add(__METHOD__ . ' ' . \JText::sprintf('JLIB_FILESYSTEM_ERROR_PATH_IS_NOT_A_FOLDER', $path), Log::WARNING, 'jerror');

			return false;
		}

		// Remove all the files in folder if they exist; disable all filtering
		$files = $this->_filesInFolder($path, '.', false, true, array(), array());

		if (!empty($files) && !is_array($files))
		{
			if (@unlink($files) !== true)
			{
				return false;
			}
		}
		elseif (!empty($files) && is_array($files))
		{
			foreach ($files as $file)
			{
				$file = $this->_cleanPath($file);

				// In case of restricted permissions we zap it one way or the other as long as the owner is either the webserver or the ftp
				if (@unlink($file) !== true)
				{
					Log::add(__METHOD__ . ' ' . \JText::sprintf('JLIB_FILESYSTEM_DELETE_FAILED', basename($file)), Log::WARNING, 'jerror');

					return false;
				}
			}
		}

		// Remove sub-folders of folder; disable all filtering
		$folders = $this->_folders($path, '.', false, true, array(), array());

		foreach ($folders as $folder)
		{
			if (is_link($folder))
			{
				// Don't descend into linked directories, just delete the link.
				if (@unlink($folder) !== true)
				{
					return false;
				}
			}
			elseif ($this->_deleteFolder($folder) !== true)
			{
				return false;
			}
		}

		// In case of restricted permissions we zap it one way or the other as long as the owner is either the webserver or the ftp
		if (@rmdir($path))
		{
			return true;
		}

		Log::add(__METHOD__ . ' ' . \JText::sprintf('JLIB_FILESYSTEM_ERROR_FOLDER_DELETE', $path), Log::WARNING, 'jerror');

		return false;
	}

	/**
	 * Function to strip additional / or \ in a path name
	 *
	 * @param   string  $path  The path to clean
	 * @param   string  $ds    Directory separator (optional)
	 *
	 * @return  string  The cleaned path
	 *
	 * @since   1.7.0
	 */
	protected function _cleanPath($path, $ds = DIRECTORY_SEPARATOR)
	{
		$path = trim($path);

		if (empty($path))
		{
			return $this->_root;
		}

		// Remove double slashes and backslashes and convert all slashes and backslashes to DIRECTORY_SEPARATOR
		$path = preg_replace('#[/\\\\]+#', $ds, $path);

		return $path;
	}

	/**
	 * Utility function to quickly read the files in a folder.
	 *
	 * @param   string   $path           The path of the folder to read.
	 * @param   string   $filter         A filter for file names.
	 * @param   mixed    $recurse        True to recursively search into sub-folders, or an integer to specify the maximum depth.
	 * @param   boolean  $fullpath       True to return the full path to the file.
	 * @param   array    $exclude        Array with names of files which should not be shown in the result.
	 * @param   array    $excludefilter  Array of folder names to exclude
	 *
	 * @return  array  Files in the given folder.
	 *
	 * @since   1.7.0
	 */
	protected function _filesInFolder($path, $filter = '.', $recurse = false, $fullpath = false,
		$exclude = array('.svn', 'CVS', '.DS_Store', '__MACOSX'), $excludefilter = array('^\..*', '.*~'))
	{
		$arr = array();

		// Check to make sure the path valid and clean
		$path = $this->_cleanPath($path);

		// Is the path a folder?
		if (!is_dir($path))
		{
			Log::add(__METHOD__ . ' ' . \JText::sprintf('JLIB_FILESYSTEM_ERROR_PATH_IS_NOT_A_FOLDER', $path), Log::WARNING, 'jerror');

			return false;
		}

		// Read the source directory.
		if (!($handle = @opendir($path)))
		{
			return $arr;
		}

		if (count($excludefilter))
		{
			$excludefilter = '/(' . implode('|', $excludefilter) . ')/';
		}
		else
		{
			$excludefilter = '';
		}

		while (($file = readdir($handle)) !== false)
		{
			if (($file != '.') && ($file != '..') && (!in_array($file, $exclude)) && (!$excludefilter || !preg_match($excludefilter, $file)))
			{
				$dir   = $path . '/' . $file;
				$isDir = is_dir($dir);

				if ($isDir)
				{
					if ($recurse)
					{
						if (is_int($recurse))
						{
							$arr2 = $this->_filesInFolder($dir, $filter, $recurse - 1, $fullpath);
						}
						else
						{
							$arr2 = $this->_filesInFolder($dir, $filter, $recurse, $fullpath);
						}

						$arr = array_merge($arr, $arr2);
					}
				}
				else
				{
					if (preg_match("/$filter/", $file))
					{
						if ($fullpath)
						{
							$arr[] = $path . '/' . $file;
						}
						else
						{
							$arr[] = $file;
						}
					}
				}
			}
		}

		closedir($handle);

		return $arr;
	}

	/**
	 * Utility function to read the folders in a folder.
	 *
	 * @param   string   $path           The path of the folder to read.
	 * @param   string   $filter         A filter for folder names.
	 * @param   mixed    $recurse        True to recursively search into sub-folders, or an integer to specify the maximum depth.
	 * @param   boolean  $fullpath       True to return the full path to the folders.
	 * @param   array    $exclude        Array with names of folders which should not be shown in the result.
	 * @param   array    $excludefilter  Array with regular expressions matching folders which should not be shown in the result.
	 *
	 * @return  array  Folders in the given folder.
	 *
	 * @since   1.7.0
	 */
	protected function _folders($path, $filter = '.', $recurse = false, $fullpath = false, $exclude = array('.svn', 'CVS', '.DS_Store', '__MACOSX'),
		$excludefilter = array('^\..*'))
	{
		$arr = array();

		// Check to make sure the path valid and clean
		$path = $this->_cleanPath($path);

		// Is the path a folder?
		if (!is_dir($path))
		{
			Log::add(__METHOD__ . ' ' . \JText::sprintf('JLIB_FILESYSTEM_ERROR_PATH_IS_NOT_A_FOLDER', $path), Log::WARNING, 'jerror');

			return false;
		}

		// Read the source directory
		if (!($handle = @opendir($path)))
		{
			return $arr;
		}

		if (count($excludefilter))
		{
			$excludefilter_string = '/(' . implode('|', $excludefilter) . ')/';
		}
		else
		{
			$excludefilter_string = '';
		}

		while (($file = readdir($handle)) !== false)
		{
			if (($file != '.') && ($file != '..')
				&& (!in_array($file, $exclude))
				&& (empty($excludefilter_string) || !preg_match($excludefilter_string, $file)))
			{
				$dir   = $path . '/' . $file;
				$isDir = is_dir($dir);

				if ($isDir)
				{
					// Removes filtered directories
					if (preg_match("/$filter/", $file))
					{
						if ($fullpath)
						{
							$arr[] = $dir;
						}
						else
						{
							$arr[] = $file;
						}
					}

					if ($recurse)
					{
						if (is_int($recurse))
						{
							$arr2 = $this->_folders($dir, $filter, $recurse - 1, $fullpath, $exclude, $excludefilter);
						}
						else
						{
							$arr2 = $this->_folders($dir, $filter, $recurse, $fullpath, $exclude, $excludefilter);
						}

						$arr = array_merge($arr, $arr2);
					}
				}
			}
		}

		closedir($handle);

		return $arr;
	}
}
