comparison vendor/nikic/php-parser/lib/PhpParser/NodeTraverser.php @ 0:c75dbcec494b

Initial commit from drush-created site

+<?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;
+
+    /** @var NodeVisitor[] Visitors */
+    protected $visitors;
+
+    /** @var bool Whether traversal should be stopped */
+    protected $stopTraversal;
+
+    /**
+     * Constructs a node traverser.
+     */
+    public function __construct() {
+        $this->visitors = [];
+    }
+
+    /**
+     * 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) {
+                $traverseChildren = true;
+                foreach ($this->visitors as $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::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 $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)
+                            );
+                        }
+                    }
+                }
+            }
+        }
+
+        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) {
+                $traverseChildren = true;
+                foreach ($this->visitors as $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::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 $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)
+                            );
+                        }
+                    }
+                }
+            } 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()})"
+            );
+        }
+    }
+}