vendor/twig/twig/lib/Twig/NodeVisitor/Optimizer.php

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<?php

/*
 * This file is part of Twig.
 *
 * (c) Fabien Potencier
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * Twig_NodeVisitor_Optimizer tries to optimizes the AST.
 *
 * This visitor is always the last registered one.
 *
 * You can configure which optimizations you want to activate via the
 * optimizer mode.
 *
 * @final
 *
 * @author Fabien Potencier <fabien@symfony.com>
 */
class Twig_NodeVisitor_Optimizer extends Twig_BaseNodeVisitor
{
    const OPTIMIZE_ALL = -1;
    const OPTIMIZE_NONE = 0;
    const OPTIMIZE_FOR = 2;
    const OPTIMIZE_RAW_FILTER = 4;
    const OPTIMIZE_VAR_ACCESS = 8;

    protected $loops = array();
    protected $loopsTargets = array();
    protected $optimizers;
    protected $prependedNodes = array();
    protected $inABody = false;

    /**
     * @param int $optimizers The optimizer mode
     */
    public function __construct($optimizers = -1)
    {
        if (!is_int($optimizers) || $optimizers > (self::OPTIMIZE_FOR | self::OPTIMIZE_RAW_FILTER | self::OPTIMIZE_VAR_ACCESS)) {
            throw new InvalidArgumentException(sprintf('Optimizer mode "%s" is not valid.', $optimizers));
        }

        $this->optimizers = $optimizers;
    }

    protected function doEnterNode(Twig_Node $node, Twig_Environment $env)
    {
        if (self::OPTIMIZE_FOR === (self::OPTIMIZE_FOR & $this->optimizers)) {
            $this->enterOptimizeFor($node, $env);
        }

        if (PHP_VERSION_ID < 50400 && self::OPTIMIZE_VAR_ACCESS === (self::OPTIMIZE_VAR_ACCESS & $this->optimizers) && !$env->isStrictVariables() && !$env->hasExtension('Twig_Extension_Sandbox')) {
            if ($this->inABody) {
                if (!$node instanceof Twig_Node_Expression) {
                    if (get_class($node) !== 'Twig_Node') {
                        array_unshift($this->prependedNodes, array());