Subversion-Projekte lars-tiefland.laravel_shop

<?php declare(strict_types=1);

namespace PhpParser;

class NodeTraverser implements NodeTraverserInterface

{

    /**

     * If NodeVisitor::enterNode() returns DONT_TRAVERSE_CHILDREN, child nodes

     * of the current node will not be traversed for any visitors.

     *

     * For subsequent visitors enterNode() will still be called on the current

     * node and leaveNode() will also be invoked for the current node.

     */

    const DONT_TRAVERSE_CHILDREN = 1;

    /**

     * If NodeVisitor::enterNode() or NodeVisitor::leaveNode() returns

     * STOP_TRAVERSAL, traversal is aborted.

     *

     * The afterTraverse() method will still be invoked.

     */

    const STOP_TRAVERSAL = 2;

    /**

     * If NodeVisitor::leaveNode() returns REMOVE_NODE for a node that occurs

     * in an array, it will be removed from the array.

     *

     * For subsequent visitors leaveNode() will still be invoked for the

     * removed node.

     */

    const REMOVE_NODE = 3;

    /**

     * If NodeVisitor::enterNode() returns DONT_TRAVERSE_CURRENT_AND_CHILDREN, child nodes

     * of the current node will not be traversed for any visitors.

     *

     * For subsequent visitors enterNode() will not be called as well.

     * leaveNode() will be invoked for visitors that has enterNode() method invoked.

     */

    const DONT_TRAVERSE_CURRENT_AND_CHILDREN = 4;

    /** @var NodeVisitor[] Visitors */

    protected $visitors = [];

    /** @var bool Whether traversal should be stopped */

    protected $stopTraversal;

    public function __construct() {

        // for BC

    }

    /**

     * Adds a visitor.

     *

     * @param NodeVisitor $visitor Visitor to add

     */

    public function addVisitor(NodeVisitor $visitor) {

        $this->visitors[] = $visitor;

    }

    /**

     * Removes an added visitor.

     *

     * @param NodeVisitor $visitor

     */

    public function removeVisitor(NodeVisitor $visitor) {

        foreach ($this->visitors as $index => $storedVisitor) {

            if ($storedVisitor === $visitor) {

                unset($this->visitors[$index]);

                break;

            }

        }

    }

    /**

     * Traverses an array of nodes using the registered visitors.

     *

     * @param Node[] $nodes Array of nodes

     *

     * @return Node[] Traversed array of nodes

     */

    public function traverse(array $nodes) : array {

        $this->stopTraversal = false;

        foreach ($this->visitors as $visitor) {

            if (null !== $return = $visitor->beforeTraverse($nodes)) {

                $nodes = $return;

            }

        }

        $nodes = $this->traverseArray($nodes);

        foreach ($this->visitors as $visitor) {

            if (null !== $return = $visitor->afterTraverse($nodes)) {

                $nodes = $return;

            }

        }

        return $nodes;

    }

    /**

     * Recursively traverse a node.

     *

     * @param Node $node Node to traverse.

     *

     * @return Node Result of traversal (may be original node or new one)

     */

    protected function traverseNode(Node $node) : Node {

        foreach ($node->getSubNodeNames() as $name) {

            $subNode =& $node->$name;

            if (\is_array($subNode)) {

                $subNode = $this->traverseArray($subNode);

                if ($this->stopTraversal) {

                    break;

                }

            } elseif ($subNode instanceof Node) {

                $traverseChildren = true;

                $breakVisitorIndex = null;

                foreach ($this->visitors as $visitorIndex => $visitor) {

                    $return = $visitor->enterNode($subNode);

                    if (null !== $return) {

                        if ($return instanceof Node) {

                            $this->ensureReplacementReasonable($subNode, $return);

                            $subNode = $return;

                        } elseif (self::DONT_TRAVERSE_CHILDREN === $return) {

                            $traverseChildren = false;

                        } elseif (self::DONT_TRAVERSE_CURRENT_AND_CHILDREN === $return) {

                            $traverseChildren = false;

                            $breakVisitorIndex = $visitorIndex;

                            break;

                        } elseif (self::STOP_TRAVERSAL === $return) {

                            $this->stopTraversal = true;

                            break 2;

                        } else {

                            throw new \LogicException(

                                'enterNode() returned invalid value of type ' . gettype($return)

                            );

                        }

                    }

                }

                if ($traverseChildren) {

                    $subNode = $this->traverseNode($subNode);

                    if ($this->stopTraversal) {

                        break;

                    }

                }

                foreach ($this->visitors as $visitorIndex => $visitor) {

                    $return = $visitor->leaveNode($subNode);

                    if (null !== $return) {

                        if ($return instanceof Node) {

                            $this->ensureReplacementReasonable($subNode, $return);

                            $subNode = $return;

                        } elseif (self::STOP_TRAVERSAL === $return) {

                            $this->stopTraversal = true;

                            break 2;

                        } elseif (\is_array($return)) {

                            throw new \LogicException(

                                'leaveNode() may only return an array ' .

                                'if the parent structure is an array'

                            );

                        } else {

                            throw new \LogicException(

                                'leaveNode() returned invalid value of type ' . gettype($return)

                            );

                        }

                    }

                    if ($breakVisitorIndex === $visitorIndex) {

                        break;

                    }

                }

            }

        }

        return $node;

    }

    /**

     * Recursively traverse array (usually of nodes).

     *

     * @param array $nodes Array to traverse

     *

     * @return array Result of traversal (may be original array or changed one)

     */

    protected function traverseArray(array $nodes) : array {

        $doNodes = [];

        foreach ($nodes as $i => &$node) {

            if ($node instanceof Node) {

                $traverseChildren = true;

                $breakVisitorIndex = null;

                foreach ($this->visitors as $visitorIndex => $visitor) {

                    $return = $visitor->enterNode($node);

                    if (null !== $return) {

                        if ($return instanceof Node) {

                            $this->ensureReplacementReasonable($node, $return);

                            $node = $return;

                        } elseif (self::DONT_TRAVERSE_CHILDREN === $return) {

                            $traverseChildren = false;

                        } elseif (self::DONT_TRAVERSE_CURRENT_AND_CHILDREN === $return) {

                            $traverseChildren = false;

                            $breakVisitorIndex = $visitorIndex;

                            break;

                        } elseif (self::STOP_TRAVERSAL === $return) {

                            $this->stopTraversal = true;

                            break 2;

                        } else {

                            throw new \LogicException(

                                'enterNode() returned invalid value of type ' . gettype($return)

                            );

                        }

                    }

                }

                if ($traverseChildren) {

                    $node = $this->traverseNode($node);

                    if ($this->stopTraversal) {

                        break;

                    }

                }

                foreach ($this->visitors as $visitorIndex => $visitor) {

                    $return = $visitor->leaveNode($node);

                    if (null !== $return) {

                        if ($return instanceof Node) {

                            $this->ensureReplacementReasonable($node, $return);

                            $node = $return;

                        } elseif (\is_array($return)) {

                            $doNodes[] = [$i, $return];

                            break;

                        } elseif (self::REMOVE_NODE === $return) {

                            $doNodes[] = [$i, []];

                            break;

                        } elseif (self::STOP_TRAVERSAL === $return) {

                            $this->stopTraversal = true;

                            break 2;

                        } elseif (false === $return) {

                            throw new \LogicException(

                                'bool(false) return from leaveNode() no longer supported. ' .

                                'Return NodeTraverser::REMOVE_NODE instead'

                            );

                        } else {

                            throw new \LogicException(

                                'leaveNode() returned invalid value of type ' . gettype($return)

                            );

                        }

                    }

                    if ($breakVisitorIndex === $visitorIndex) {

                        break;

                    }

                }

            } elseif (\is_array($node)) {

                throw new \LogicException('Invalid node structure: Contains nested arrays');

            }

        }

        if (!empty($doNodes)) {

            while (list($i, $replace) = array_pop($doNodes)) {

                array_splice($nodes, $i, 1, $replace);

            }

        }

        return $nodes;

    }

    private function ensureReplacementReasonable($old, $new) {

        if ($old instanceof Node\Stmt && $new instanceof Node\Expr) {

            throw new \LogicException(

                "Trying to replace statement ({$old->getType()}) " .

                "with expression ({$new->getType()}). Are you missing a " .

                "Stmt_Expression wrapper?"

            );

        }

        if ($old instanceof Node\Expr && $new instanceof Node\Stmt) {

            throw new \LogicException(

                "Trying to replace expression ({$old->getType()}) " .

                "with statement ({$new->getType()})"

            );

        }

    }

}