<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <[email protected]>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Symfony\Component\HttpFoundation\File\MimeType;
/**
* A singleton mime type to file extension guesser.
*
* A default guesser is provided.
* You can register custom guessers by calling the register()
* method on the singleton instance:
*
* $guesser = ExtensionGuesser::getInstance();
* $guesser->register(new MyCustomExtensionGuesser());
*
* The last registered guesser is preferred over previously registered ones.
*/
class ExtensionGuesser implements ExtensionGuesserInterface
{
/**
* The singleton instance.
*
* @var ExtensionGuesser
*/
private static $instance = null;
/**
* All registered ExtensionGuesserInterface instances.
*
* @var array
*/
protected $guessers = array();
/**
* Returns the singleton instance.
*
* @return ExtensionGuesser
*/
public static function getInstance()
{
if (null === self::$instance) {
self::$instance = new self();
}
return self::$instance;
}
/**
* Registers all natively provided extension guessers.
*/
private function __construct()
{
$this->register(new MimeTypeExtensionGuesser());
}
/**
* Registers a new extension guesser.
*
* When guessing, this guesser is preferred over previously registered ones.
*
* @param ExtensionGuesserInterface $guesser
*/
public function register(ExtensionGuesserInterface $guesser)
{
array_unshift($this->guessers, $guesser);
}
/**
* Tries to guess the extension.
*
* The mime type is passed to each registered mime type guesser in reverse order
* of their registration (last registered is queried first). Once a guesser
* returns a value that is not NULL, this method terminates and returns the
* value.
*
* @param string $mimeType The mime type
*
* @return string The guessed extension or NULL, if none could be guessed
*/
public function guess($mimeType)
{
foreach ($this->guessers as $guesser) {
if (null !== $extension = $guesser->guess($mimeType)) {
return $extension;
}
}
}
}