WB 2.11.0

<?php

/*

 * This file is part of Twig.

 *

 * (c) 2009 Fabien Potencier

 *

 * For the full copyright and license information, please view the LICENSE

 * file that was distributed with this source code.

 */

/**

 * Stores the Twig configuration.

 *

 * @author Fabien Potencier <fabien@symfony.com>

 */

class Twig_Environment

{

    const VERSION = '1.24.0';

    protected $charset;

    protected $loader;

    protected $debug;

    protected $autoReload;

    protected $cache;

    protected $lexer;

    protected $parser;

    protected $compiler;

    protected $baseTemplateClass;

    protected $extensions;

    protected $parsers;

    protected $visitors;

    protected $filters;

    protected $tests;

    protected $functions;

    protected $globals;

    protected $runtimeInitialized = false;

    protected $extensionInitialized = false;

    protected $loadedTemplates;

    protected $strictVariables;

    protected $unaryOperators;

    protected $binaryOperators;

    protected $templateClassPrefix = '__TwigTemplate_';

    protected $functionCallbacks = array();

    protected $filterCallbacks = array();

    protected $staging;

    private $originalCache;

    private $bcWriteCacheFile = false;

    private $bcGetCacheFilename = false;

    private $lastModifiedExtension = 0;

    /**

     * Constructor.

     *

     * Available options:

     *

     *  * debug: When set to true, it automatically set "auto_reload" to true as

     *           well (default to false).

     *

     *  * charset: The charset used by the templates (default to UTF-8).

     *

     *  * base_template_class: The base template class to use for generated

     *                         templates (default to Twig_Template).

     *

     *  * cache: An absolute path where to store the compiled templates,

     *           a Twig_Cache_Interface implementation,

     *           or false to disable compilation cache (default).

     *

     *  * auto_reload: Whether to reload the template if the original source changed.

     *                 If you don't provide the auto_reload option, it will be

     *                 determined automatically based on the debug value.

     *

     *  * strict_variables: Whether to ignore invalid variables in templates

     *                      (default to false).

     *

     *  * autoescape: Whether to enable auto-escaping (default to html):

     *                  * false: disable auto-escaping

     *                  * true: equivalent to html

     *                  * html, js: set the autoescaping to one of the supported strategies

     *                  * filename: set the autoescaping strategy based on the template filename extension

     *                  * PHP callback: a PHP callback that returns an escaping strategy based on the template "filename"

     *

     *  * optimizations: A flag that indicates which optimizations to apply

     *                   (default to -1 which means that all optimizations are enabled;

     *                   set it to 0 to disable).

     *

     * @param Twig_LoaderInterface $loader  A Twig_LoaderInterface instance

     * @param array                $options An array of options

     */

    public function __construct(Twig_LoaderInterface $loader = null, $options = array())

    {

        if (null !== $loader) {

            $this->setLoader($loader);

        } else {

            @trigger_error('Not passing a Twig_LoaderInterface as the first constructor argument of Twig_Environment is deprecated since version 1.21.', E_USER_DEPRECATED);

        }

        $options = array_merge(array(

            'debug' => false,

            'charset' => 'UTF-8',

            'base_template_class' => 'Twig_Template',

            'strict_variables' => false,

            'autoescape' => 'html',

            'cache' => false,

            'auto_reload' => null,

            'optimizations' => -1,

        ), $options);

        $this->debug = (bool) $options['debug'];

        $this->charset = strtoupper($options['charset']);

        $this->baseTemplateClass = $options['base_template_class'];

        $this->autoReload = null === $options['auto_reload'] ? $this->debug : (bool) $options['auto_reload'];

        $this->strictVariables = (bool) $options['strict_variables'];

        $this->setCache($options['cache']);

        $this->addExtension(new Twig_Extension_Core());

        $this->addExtension(new Twig_Extension_Escaper($options['autoescape']));

        $this->addExtension(new Twig_Extension_Optimizer($options['optimizations']));

        $this->staging = new Twig_Extension_Staging();

        // For BC

        if (is_string($this->originalCache)) {

            $r = new ReflectionMethod($this, 'writeCacheFile');

            if ($r->getDeclaringClass()->getName() !== __CLASS__) {

                @trigger_error('The Twig_Environment::writeCacheFile method is deprecated since version 1.22 and will be removed in Twig 2.0.', E_USER_DEPRECATED);

                $this->bcWriteCacheFile = true;

            }

            $r = new ReflectionMethod($this, 'getCacheFilename');

            if ($r->getDeclaringClass()->getName() !== __CLASS__) {

                @trigger_error('The Twig_Environment::getCacheFilename method is deprecated since version 1.22 and will be removed in Twig 2.0.', E_USER_DEPRECATED);

                $this->bcGetCacheFilename = true;

            }

        }

    }

    /**

     * Gets the base template class for compiled templates.

     *

     * @return string The base template class name

     */

    public function getBaseTemplateClass()

    {

        return $this->baseTemplateClass;

    }

    /**

     * Sets the base template class for compiled templates.

     *

     * @param string $class The base template class name

     */

    public function setBaseTemplateClass($class)

    {

        $this->baseTemplateClass = $class;

    }

    /**

     * Enables debugging mode.

     */

    public function enableDebug()

    {

        $this->debug = true;

    }

    /**

     * Disables debugging mode.

     */

    public function disableDebug()

    {

        $this->debug = false;

    }

    /**

     * Checks if debug mode is enabled.

     *

     * @return bool true if debug mode is enabled, false otherwise

     */

    public function isDebug()

    {

        return $this->debug;

    }

    /**

     * Enables the auto_reload option.

     */

    public function enableAutoReload()

    {

        $this->autoReload = true;

    }

    /**

     * Disables the auto_reload option.

     */

    public function disableAutoReload()

    {

        $this->autoReload = false;

    }

    /**

     * Checks if the auto_reload option is enabled.

     *

     * @return bool true if auto_reload is enabled, false otherwise

     */

    public function isAutoReload()

    {

        return $this->autoReload;

    }

    /**

     * Enables the strict_variables option.

     */

    public function enableStrictVariables()

    {

        $this->strictVariables = true;

    }

    /**

     * Disables the strict_variables option.

     */

    public function disableStrictVariables()

    {

        $this->strictVariables = false;

    }

    /**

     * Checks if the strict_variables option is enabled.

     *

     * @return bool true if strict_variables is enabled, false otherwise

     */

    public function isStrictVariables()

    {

        return $this->strictVariables;

    }

    /**

     * Gets the current cache implementation.

     *

     * @param bool $original Whether to return the original cache option or the real cache instance

     *

     * @return Twig_CacheInterface|string|false A Twig_CacheInterface implementation,

     *                                          an absolute path to the compiled templates,

     *                                          or false to disable cache

     */

    public function getCache($original = true)

    {

        return $original ? $this->originalCache : $this->cache;

    }

    /**

     * Sets the current cache implementation.

     *

     * @param Twig_CacheInterface|string|false $cache A Twig_CacheInterface implementation,

     *                                                an absolute path to the compiled templates,

     *                                                or false to disable cache

     */

    public function setCache($cache)

    {

        if (is_string($cache)) {

            $this->originalCache = $cache;

            $this->cache = new Twig_Cache_Filesystem($cache);

        } elseif (false === $cache) {

            $this->originalCache = $cache;

            $this->cache = new Twig_Cache_Null();

        } elseif (null === $cache) {

            @trigger_error('Using "null" as the cache strategy is deprecated since version 1.23 and will be removed in Twig 2.0.', E_USER_DEPRECATED);

            $this->originalCache = false;

            $this->cache = new Twig_Cache_Null();

        } elseif ($cache instanceof Twig_CacheInterface) {

            $this->originalCache = $this->cache = $cache;

        } else {

            throw new LogicException(sprintf('Cache can only be a string, false, or a Twig_CacheInterface implementation.'));

        }

    }

    /**

     * Gets the cache filename for a given template.

     *

     * @param string $name The template name

     *

     * @return string|false The cache file name or false when caching is disabled

     *

     * @deprecated since 1.22 (to be removed in 2.0)

     */

    public function getCacheFilename($name)

    {

        @trigger_error(sprintf('The %s method is deprecated since version 1.22 and will be removed in Twig 2.0.', __METHOD__), E_USER_DEPRECATED);

        $key = $this->cache->generateKey($name, $this->getTemplateClass($name));

        return !$key ? false : $key;

    }

    /**

     * Gets the template class associated with the given string.

     *

     * The generated template class is based on the following parameters:

     *

     *  * The cache key for the given template;

     *  * The currently enabled extensions;

     *  * Whether the Twig C extension is available or not.

     *

     * @param string   $name  The name for which to calculate the template class name

     * @param int|null $index The index if it is an embedded template

     *

     * @return string The template class name

     */

    public function getTemplateClass($name, $index = null)

    {

        $key = $this->getLoader()->getCacheKey($name);

        $key .= json_encode(array_keys($this->extensions));

        $key .= function_exists('twig_template_get_attributes');

        return $this->templateClassPrefix.hash('sha256', $key).(null === $index ? '' : '_'.$index);

    }

    /**

     * Gets the template class prefix.

     *

     * @return string The template class prefix

     *

     * @deprecated since 1.22 (to be removed in 2.0)

     */

    public function getTemplateClassPrefix()

    {

        @trigger_error(sprintf('The %s method is deprecated since version 1.22 and will be removed in Twig 2.0.', __METHOD__), E_USER_DEPRECATED);

        return $this->templateClassPrefix;

    }

    /**

     * Renders a template.

     *

     * @param string $name    The template name

     * @param array  $context An array of parameters to pass to the template

     *

     * @return string The rendered template

     *

     * @throws Twig_Error_Loader  When the template cannot be found

     * @throws Twig_Error_Syntax  When an error occurred during compilation

     * @throws Twig_Error_Runtime When an error occurred during rendering

     */

    public function render($name, array $context = array())

    {

        return $this->loadTemplate($name)->render($context);

    }

    /**

     * Displays a template.

     *

     * @param string $name    The template name

     * @param array  $context An array of parameters to pass to the template

     *

     * @throws Twig_Error_Loader  When the template cannot be found

     * @throws Twig_Error_Syntax  When an error occurred during compilation

     * @throws Twig_Error_Runtime When an error occurred during rendering

     */

    public function display($name, array $context = array())

    {

        $this->loadTemplate($name)->display($context);

    }

    /**

     * Loads a template by name.

     *

     * @param string $name  The template name

     * @param int    $index The index if it is an embedded template

     *

     * @return Twig_TemplateInterface A template instance representing the given template name

     *

     * @throws Twig_Error_Loader When the template cannot be found

     * @throws Twig_Error_Syntax When an error occurred during compilation

     */

    public function loadTemplate($name, $index = null)

    {

        $cls = $this->getTemplateClass($name, $index);

        if (isset($this->loadedTemplates[$cls])) {

            return $this->loadedTemplates[$cls];

        }

        if (!class_exists($cls, false)) {

            if ($this->bcGetCacheFilename) {

                $key = $this->getCacheFilename($name);

            } else {

                $key = $this->cache->generateKey($name, $cls);

            }

            if (!$this->isAutoReload() || $this->isTemplateFresh($name, $this->cache->getTimestamp($key))) {

                $this->cache->load($key);

            }

            if (!class_exists($cls, false)) {

                $content = $this->compileSource($this->getLoader()->getSource($name), $name);

                if ($this->bcWriteCacheFile) {

                    $this->writeCacheFile($key, $content);

                } else {

                    $this->cache->write($key, $content);

                }

                eval('?>'.$content);

            }

        }

        if (!$this->runtimeInitialized) {

            $this->initRuntime();

        }

        return $this->loadedTemplates[$cls] = new $cls($this);

    }

    /**

     * Creates a template from source.

     *

     * This method should not be used as a generic way to load templates.

     *

     * @param string $template The template name

     *

     * @return Twig_Template A template instance representing the given template name

     *

     * @throws Twig_Error_Loader When the template cannot be found

     * @throws Twig_Error_Syntax When an error occurred during compilation

     */

    public function createTemplate($template)

    {

        $name = sprintf('__string_template__%s', hash('sha256', uniqid(mt_rand(), true), false));

        $loader = new Twig_Loader_Chain(array(

            new Twig_Loader_Array(array($name => $template)),

            $current = $this->getLoader(),

        ));

        $this->setLoader($loader);

        try {

            $template = $this->loadTemplate($name);

        } catch (Exception $e) {

            $this->setLoader($current);

            throw $e;

        }

        $this->setLoader($current);

        return $template;

    }

    /**

     * Returns true if the template is still fresh.

     *

     * Besides checking the loader for freshness information,

     * this method also checks if the enabled extensions have

     * not changed.

     *

     * @param string $name The template name

     * @param int    $time The last modification time of the cached template

     *

     * @return bool true if the template is fresh, false otherwise

     */

    public function isTemplateFresh($name, $time)

    {

        if (0 === $this->lastModifiedExtension) {

            foreach ($this->extensions as $extension) {

                $r = new ReflectionObject($extension);

                if (file_exists($r->getFileName()) && ($extensionTime = filemtime($r->getFileName())) > $this->lastModifiedExtension) {

                    $this->lastModifiedExtension = $extensionTime;

                }

            }

        }

        return $this->lastModifiedExtension <= $time && $this->getLoader()->isFresh($name, $time);

    }

    /**

     * Tries to load a template consecutively from an array.

     *

     * Similar to loadTemplate() but it also accepts Twig_TemplateInterface instances and an array

     * of templates where each is tried to be loaded.

     *

     * @param string|Twig_Template|array $names A template or an array of templates to try consecutively

     *

     * @return Twig_Template

     *

     * @throws Twig_Error_Loader When none of the templates can be found

     * @throws Twig_Error_Syntax When an error occurred during compilation

     */

    public function resolveTemplate($names)

    {

        if (!is_array($names)) {

            $names = array($names);

        }

        foreach ($names as $name) {

            if ($name instanceof Twig_Template) {

                return $name;

            }

            try {

                return $this->loadTemplate($name);

            } catch (Twig_Error_Loader $e) {

            }

        }

        if (1 === count($names)) {

            throw $e;

        }

        throw new Twig_Error_Loader(sprintf('Unable to find one of the following templates: "%s".', implode('", "', $names)));

    }

    /**

     * Clears the internal template cache.

     *

     * @deprecated since 1.18.3 (to be removed in 2.0)

     */

    public function clearTemplateCache()

    {

        @trigger_error(sprintf('The %s method is deprecated since version 1.18.3 and will be removed in Twig 2.0.', __METHOD__), E_USER_DEPRECATED);

        $this->loadedTemplates = array();

    }

    /**

     * Clears the template cache files on the filesystem.

     *

     * @deprecated since 1.22 (to be removed in 2.0)

     */

    public function clearCacheFiles()

    {

        @trigger_error(sprintf('The %s method is deprecated since version 1.22 and will be removed in Twig 2.0.', __METHOD__), E_USER_DEPRECATED);

        if (is_string($this->originalCache)) {

            foreach (new RecursiveIteratorIterator(new RecursiveDirectoryIterator($this->originalCache), RecursiveIteratorIterator::LEAVES_ONLY) as $file) {

                if ($file->isFile()) {

                    @unlink($file->getPathname());

                }

            }

        }

    }

    /**

     * Gets the Lexer instance.

     *

     * @return Twig_LexerInterface A Twig_LexerInterface instance

     */

    public function getLexer()

    {

        if (null === $this->lexer) {

            $this->lexer = new Twig_Lexer($this);

        }

        return $this->lexer;

    }

    /**

     * Sets the Lexer instance.

     *

     * @param Twig_LexerInterface $lexer A Twig_LexerInterface instance

     */

    public function setLexer(Twig_LexerInterface $lexer)

    {

        $this->lexer = $lexer;

    }

    /**

     * Tokenizes a source code.

     *

     * @param string $source The template source code

     * @param string $name   The template name

     *

     * @return Twig_TokenStream A Twig_TokenStream instance

     *

     * @throws Twig_Error_Syntax When the code is syntactically wrong

     */

    public function tokenize($source, $name = null)

    {

        return $this->getLexer()->tokenize($source, $name);

    }

    /**

     * Gets the Parser instance.

     *

     * @return Twig_ParserInterface A Twig_ParserInterface instance

     */

    public function getParser()

    {

        if (null === $this->parser) {

            $this->parser = new Twig_Parser($this);

        }

        return $this->parser;

    }

    /**

     * Sets the Parser instance.

     *

     * @param Twig_ParserInterface $parser A Twig_ParserInterface instance

     */

    public function setParser(Twig_ParserInterface $parser)

    {

        $this->parser = $parser;

    }

    /**

     * Converts a token stream to a node tree.

     *

     * @param Twig_TokenStream $stream A token stream instance

     *

     * @return Twig_Node_Module A node tree

     *

     * @throws Twig_Error_Syntax When the token stream is syntactically or semantically wrong

     */

    public function parse(Twig_TokenStream $stream)

    {

        return $this->getParser()->parse($stream);

    }

    /**

     * Gets the Compiler instance.

     *

     * @return Twig_CompilerInterface A Twig_CompilerInterface instance

     */

    public function getCompiler()

    {

        if (null === $this->compiler) {

            $this->compiler = new Twig_Compiler($this);

        }

        return $this->compiler;

    }

    /**

     * Sets the Compiler instance.

     *

     * @param Twig_CompilerInterface $compiler A Twig_CompilerInterface instance

     */

    public function setCompiler(Twig_CompilerInterface $compiler)

    {

        $this->compiler = $compiler;

    }

    /**

     * Compiles a node and returns the PHP code.

     *

     * @param Twig_NodeInterface $node A Twig_NodeInterface instance

     *

     * @return string The compiled PHP source code

     */

    public function compile(Twig_NodeInterface $node)

    {

        return $this->getCompiler()->compile($node)->getSource();

    }

    /**

     * Compiles a template source code.

     *

     * @param string $source The template source code

     * @param string $name   The template name

     *

     * @return string The compiled PHP source code

     *

     * @throws Twig_Error_Syntax When there was an error during tokenizing, parsing or compiling

     */

    public function compileSource($source, $name = null)

    {

        try {

            $compiled = $this->compile($this->parse($this->tokenize($source, $name)), $source);

            if (isset($source[0])) {

                $compiled .= '/* '.str_replace(array('*/', "\r\n", "\r", "\n"), array('*//* ', "\n", "\n", "*/\n/* "), $source)."*/\n";

            }

            return $compiled;

        } catch (Twig_Error $e) {

            $e->setTemplateFile($name);

            throw $e;

        } catch (Exception $e) {

            throw new Twig_Error_Syntax(sprintf('An exception has been thrown during the compilation of a template ("%s").', $e->getMessage()), -1, $name, $e);

        }

    }

    /**

     * Sets the Loader instance.

     *

     * @param Twig_LoaderInterface $loader A Twig_LoaderInterface instance

     */

    public function setLoader(Twig_LoaderInterface $loader)

    {

        $this->loader = $loader;

    }

    /**

     * Gets the Loader instance.

     *

     * @return Twig_LoaderInterface A Twig_LoaderInterface instance

     */

    public function getLoader()

    {

        if (null === $this->loader) {

            throw new LogicException('You must set a loader first.');

        }

        return $this->loader;

    }

    /**

     * Sets the default template charset.

     *

     * @param string $charset The default charset

     */

    public function setCharset($charset)

    {

        $this->charset = strtoupper($charset);

    }

    /**

     * Gets the default template charset.

     *

     * @return string The default charset

     */

    public function getCharset()

    {

        return $this->charset;

    }

    /**

     * Initializes the runtime environment.

     *

     * @deprecated since 1.23 (to be removed in 2.0)

     */

    public function initRuntime()

    {

        $this->runtimeInitialized = true;

        foreach ($this->getExtensions() as $name => $extension) {

            if (!$extension instanceof Twig_Extension_InitRuntimeInterface) {

                $m = new ReflectionMethod($extension, 'initRuntime');

                if ('Twig_Extension' !== $m->getDeclaringClass()->getName()) {

                    @trigger_error(sprintf('Defining the initRuntime() method in the "%s" extension is deprecated since version 1.23. Use the `needs_environment` option to get the Twig_Environment instance in filters, functions, or tests; or explicitly implement Twig_Extension_InitRuntimeInterface if needed (not recommended).', $name), E_USER_DEPRECATED);

                }

            }

            $extension->initRuntime($this);

        }

    }

    /**

     * Returns true if the given extension is registered.

     *

     * @param string $name The extension name

     *

     * @return bool Whether the extension is registered or not

     */

    public function hasExtension($name)

    {

        return isset($this->extensions[$name]);

    }

    /**

     * Gets an extension by name.

     *

     * @param string $name The extension name

     *

     * @return Twig_ExtensionInterface A Twig_ExtensionInterface instance

     */

    public function getExtension($name)

    {

        if (!isset($this->extensions[$name])) {

            throw new Twig_Error_Runtime(sprintf('The "%s" extension is not enabled.', $name));

        }

        return $this->extensions[$name];

    }

    /**

     * Registers an extension.

     *

     * @param Twig_ExtensionInterface $extension A Twig_ExtensionInterface instance

     */

    public function addExtension(Twig_ExtensionInterface $extension)

    {

        $name = $extension->getName();

        if ($this->extensionInitialized) {

            throw new LogicException(sprintf('Unable to register extension "%s" as extensions have already been initialized.', $name));

        }

        if (isset($this->extensions[$name])) {

            @trigger_error(sprintf('The possibility to register the same extension twice ("%s") is deprecated since version 1.23 and will be removed in Twig 2.0. Use proper PHP inheritance instead.', $name), E_USER_DEPRECATED);

        }

        $this->lastModifiedExtension = 0;

        $this->extensions[$name] = $extension;

    }

    /**

     * Removes an extension by name.

     *

     * This method is deprecated and you should not use it.

     *

     * @param string $name The extension name

     *

     * @deprecated since 1.12 (to be removed in 2.0)

     */

    public function removeExtension($name)

    {

        @trigger_error(sprintf('The %s method is deprecated since version 1.12 and will be removed in Twig 2.0.', __METHOD__), E_USER_DEPRECATED);

        if ($this->extensionInitialized) {

            throw new LogicException(sprintf('Unable to remove extension "%s" as extensions have already been initialized.', $name));

        }

        unset($this->extensions[$name]);

    }

    /**

     * Registers an array of extensions.

     *

     * @param array $extensions An array of extensions

     */

    public function setExtensions(array $extensions)

    {

        foreach ($extensions as $extension) {

            $this->addExtension($extension);

        }

    }

    /**

     * Returns all registered extensions.

     *

     * @return array An array of extensions

     */

    public function getExtensions()

    {

        return $this->extensions;

    }

    /**

     * Registers a Token Parser.

     *

     * @param Twig_TokenParserInterface $parser A Twig_TokenParserInterface instance

     */

    public function addTokenParser(Twig_TokenParserInterface $parser)

    {

        if ($this->extensionInitialized) {

            throw new LogicException('Unable to add a token parser as extensions have already been initialized.');

        }

        $this->staging->addTokenParser($parser);

    }

    /**

     * Gets the registered Token Parsers.

     *

     * @return Twig_TokenParserBrokerInterface A broker containing token parsers

     */

    public function getTokenParsers()

    {

        if (!$this->extensionInitialized) {

            $this->initExtensions();

        }

        return $this->parsers;

    }

    /**

     * Gets registered tags.

     *

     * Be warned that this method cannot return tags defined by Twig_TokenParserBrokerInterface classes.

     *

     * @return Twig_TokenParserInterface[] An array of Twig_TokenParserInterface instances

     */

    public function getTags()

    {

        $tags = array();

        foreach ($this->getTokenParsers()->getParsers() as $parser) {

            if ($parser instanceof Twig_TokenParserInterface) {

                $tags[$parser->getTag()] = $parser;

            }

        }

        return $tags;

    }

    /**

     * Registers a Node Visitor.

     *

     * @param Twig_NodeVisitorInterface $visitor A Twig_NodeVisitorInterface instance

     */

    public function addNodeVisitor(Twig_NodeVisitorInterface $visitor)

    {

        if ($this->extensionInitialized) {

            throw new LogicException('Unable to add a node visitor as extensions have already been initialized.');

        }

        $this->staging->addNodeVisitor($visitor);

    }

    /**

     * Gets the registered Node Visitors.

     *

     * @return Twig_NodeVisitorInterface[] An array of Twig_NodeVisitorInterface instances

     */

    public function getNodeVisitors()

    {

        if (!$this->extensionInitialized) {

            $this->initExtensions();

        }

        return $this->visitors;

    }

    /**

     * Registers a Filter.

     *

     * @param string|Twig_SimpleFilter               $name   The filter name or a Twig_SimpleFilter instance

     * @param Twig_FilterInterface|Twig_SimpleFilter $filter A Twig_FilterInterface instance or a Twig_SimpleFilter instance

     */

    public function addFilter($name, $filter = null)

    {

        if (!$name instanceof Twig_SimpleFilter && !($filter instanceof Twig_SimpleFilter || $filter instanceof Twig_FilterInterface)) {

            throw new LogicException('A filter must be an instance of Twig_FilterInterface or Twig_SimpleFilter');

        }

        if ($name instanceof Twig_SimpleFilter) {

            $filter = $name;

            $name = $filter->getName();

        } else {

            @trigger_error(sprintf('Passing a name as a first argument to the %s method is deprecated since version 1.21. Pass an instance of "Twig_SimpleFilter" instead when defining filter "%s".', __METHOD__, $name), E_USER_DEPRECATED);

        }

        if ($this->extensionInitialized) {

            throw new LogicException(sprintf('Unable to add filter "%s" as extensions have already been initialized.', $name));

        }

        $this->staging->addFilter($name, $filter);

    }

    /**

     * Get a filter by name.

     *

     * Subclasses may override this method and load filters differently;

     * so no list of filters is available.

     *

     * @param string $name The filter name

     *

     * @return Twig_Filter|false A Twig_Filter instance or false if the filter does not exist

     */

    public function getFilter($name)

    {

        if (!$this->extensionInitialized) {

            $this->initExtensions();

        }

        if (isset($this->filters[$name])) {

            return $this->filters[$name];

        }

        foreach ($this->filters as $pattern => $filter) {

            $pattern = str_replace('\\*', '(.*?)', preg_quote($pattern, '#'), $count);

            if ($count) {

                if (preg_match('#^'.$pattern.'$#', $name, $matches)) {

                    array_shift($matches);

                    $filter->setArguments($matches);

                    return $filter;

                }

            }

        }

        foreach ($this->filterCallbacks as $callback) {

            if (false !== $filter = call_user_func($callback, $name)) {

                return $filter;

            }

        }

        return false;

    }

    public function registerUndefinedFilterCallback($callable)

    {

        $this->filterCallbacks[] = $callable;

    }

    /**

     * Gets the registered Filters.

     *

     * Be warned that this method cannot return filters defined with registerUndefinedFilterCallback.

     *

     * @return Twig_FilterInterface[] An array of Twig_FilterInterface instances

     *

     * @see registerUndefinedFilterCallback

     */

    public function getFilters()

    {

        if (!$this->extensionInitialized) {

            $this->initExtensions();

        }

        return $this->filters;