<?php
/**
 * Class Minify_Cache_File 
 * @package Minify
 */

class Minify_Cache_File {
 
 public function __construct($path = '', $fileLocking = false)
 {
 if (! $path) {
 $path = self::tmp();
 }
 $this->_locking = $fileLocking;
 $this->_path = $path;
 }

 /**
 * Write data to cache.
 *
 * @param string $id cache id (e.g. a filename)
 * 
 * @param string $data
 * 
 * @return bool success
 */
 public function store($id, $data)
 {
 $flag = $this->_locking
 ? LOCK_EX
 : null;
 $file = $this->_path . '/' . $id;
 if (! @file_put_contents($file, $data, $flag)) {
 $this->_log("Minify_Cache_File: Write failed to '$file'");
 }
 // write control
 if ($data !== $this->fetch($id)) {
 @unlink($file);
 $this->_log("Minify_Cache_File: Post-write read failed for '$file'");
 return false;
 }
 return true;
 }
 
 /**
 * Get the size of a cache entry
 *
 * @param string $id cache id (e.g. a filename)
 * 
 * @return int size in bytes
 */
 public function getSize($id)
 {
 return filesize($this->_path . '/' . $id);
 }
 
 /**
 * Does a valid cache entry exist?
 *
 * @param string $id cache id (e.g. a filename)
 * 
 * @param int $srcMtime mtime of the original source file(s)
 * 
 * @return bool exists
 */
 public function isValid($id, $srcMtime)
 {
 $file = $this->_path . '/' . $id;
 return (is_file($file) && (filemtime($file) >= $srcMtime));
 }
 
 /**
 * Send the cached content to output
 *
 * @param string $id cache id (e.g. a filename)
 */
 public function display($id)
 {
 if ($this->_locking) {
 $fp = fopen($this->_path . '/' . $id, 'rb');
 flock($fp, LOCK_SH);
 fpassthru($fp);
 flock($fp, LOCK_UN);
 fclose($fp);
 } else {
 readfile($this->_path . '/' . $id); 
 }
 }
 
	/**
 * Fetch the cached content
 *
 * @param string $id cache id (e.g. a filename)
 * 
 * @return string
 */
 public function fetch($id)
 {
 if ($this->_locking) {
 $fp = fopen($this->_path . '/' . $id, 'rb');
 flock($fp, LOCK_SH);
 $ret = stream_get_contents($fp);
 flock($fp, LOCK_UN);
 fclose($fp);
 return $ret;
 } else {
 return file_get_contents($this->_path . '/' . $id);
 }
 }
 
 /**
 * Fetch the cache path used
 *
 * @return string
 */
 public function getPath()
 {
 return $this->_path;
 }

 /**
 * Get a usable temp directory
 *
 * Adapted from Solar/Dir.php
 * @author Paul M. Jones <pmjones@solarphp.com>
 * @license http://opensource.org/licenses/bsd-license.php BSD
 * @link http://solarphp.com/trac/core/browser/trunk/Solar/Dir.php
 *
 * @return string
 */
 public static function tmp()
 {
 static $tmp = null;
 if (! $tmp) {
 $tmp = function_exists('sys_get_temp_dir')
 ? sys_get_temp_dir()
 : self::_tmp();
 $tmp = rtrim($tmp, DIRECTORY_SEPARATOR);
 }
 return $tmp;
 }

 /**
 * Returns the OS-specific directory for temporary files
 *
 * @author Paul M. Jones <pmjones@solarphp.com>
 * @license http://opensource.org/licenses/bsd-license.php BSD
 * @link http://solarphp.com/trac/core/browser/trunk/Solar/Dir.php
 *
 * @return string
 */
 protected static function _tmp()
 {
 // non-Windows system?
 if (strtolower(substr(PHP_OS, 0, 3)) != 'win') {
 $tmp = empty($_ENV['TMPDIR']) ? getenv('TMPDIR') : $_ENV['TMPDIR'];
 if ($tmp) {
 return $tmp;
 } else {
 return '/tmp';
 }
 }
 // Windows 'TEMP'
 $tmp = empty($_ENV['TEMP']) ? getenv('TEMP') : $_ENV['TEMP'];
 if ($tmp) {
 return $tmp;
 }
 // Windows 'TMP'
 $tmp = empty($_ENV['TMP']) ? getenv('TMP') : $_ENV['TMP'];
 if ($tmp) {
 return $tmp;
 }
 // Windows 'windir'
 $tmp = empty($_ENV['windir']) ? getenv('windir') : $_ENV['windir'];
 if ($tmp) {
 return $tmp;
 }
 // final fallback for Windows
 return getenv('SystemRoot') . '\\temp';
 }

 /**
 * Send message to the Minify logger
 * @param string $msg
 * @return null
 */
 protected function _log($msg)
 {
 Minify_Logger::log($msg);
 }
 
 private $_path = null;
 private $_locking = null;
}