<?php declare(strict_types=1);
namespace PhpParser;
class NodeTraverser implements NodeTraverserInterface {
/**
* @deprecated Use NodeVisitor::DONT_TRAVERSE_CHILDREN instead.
*/
public const DONT_TRAVERSE_CHILDREN = NodeVisitor::DONT_TRAVERSE_CHILDREN;
/**
* @deprecated Use NodeVisitor::STOP_TRAVERSAL instead.
*/
public const STOP_TRAVERSAL = NodeVisitor::STOP_TRAVERSAL;
/**
* @deprecated Use NodeVisitor::REMOVE_NODE instead.
*/
public const REMOVE_NODE = NodeVisitor::REMOVE_NODE;
/**
* @deprecated Use NodeVisitor::DONT_TRAVERSE_CURRENT_AND_CHILDREN instead.
*/
public const DONT_TRAVERSE_CURRENT_AND_CHILDREN = NodeVisitor::DONT_TRAVERSE_CURRENT_AND_CHILDREN;
/** @var list<NodeVisitor> Visitors */
protected array $visitors = [];
/** @var bool Whether traversal should be stopped */
protected bool $stopTraversal;
/**
* Create a traverser with the given visitors.
*
* @param NodeVisitor ...$visitors Node visitors
*/
public function __construct(NodeVisitor ...$visitors) {
$this->visitors = $visitors;
}
/**
* Adds a visitor.
*
* @param NodeVisitor $visitor Visitor to add
*/
public function addVisitor(NodeVisitor $visitor): void {
$this->visitors[] = $visitor;
}
/**
* Removes an added visitor.
*/
public function removeVisitor(NodeVisitor $visitor): void {
$index = array_search($visitor, $this->visitors);
if ($index !== false) {
array_splice($this->visitors, $index, 1, []);
}
}
/**
* 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);
for ($i = \count($this->visitors) - 1; $i >= 0; --$i) {
$visitor = $this->visitors[$i];
if (null !== $return = $visitor->afterTraverse($nodes)) {
$nodes = $return;
}
}
return $nodes;
}
/**
* Recursively traverse a node.
*
* @param Node $node Node to traverse.
*/
protected function traverseNode(Node $node): void {
foreach ($node->getSubNodeNames() as $name) {
$subNode = $node->$name;
if (\is_array($subNode)) {
$node->$name = $this->traverseArray($subNode);
if ($this->stopTraversal) {
break;
}
continue;
}
if (!$subNode instanceof Node) {
continue;
}
$traverseChildren = true;
$visitorIndex = -1;
foreach ($this->visitors as $visitorIndex => $visitor) {
$return = $visitor->enterNode($subNode);
if (null !== $return) {
if ($return instanceof Node) {
$this->ensureReplacementReasonable($subNode, $return);
$subNode = $node->$name = $return;
} elseif (NodeVisitor::DONT_TRAVERSE_CHILDREN === $return) {
$traverseChildren = false;
} elseif (NodeVisitor::DONT_TRAVERSE_CURRENT_AND_CHILDREN === $return) {
$traverseChildren = false;
break;
} elseif (NodeVisitor::STOP_TRAVERSAL === $return) {
$this->stopTraversal = true;
break 2;
} elseif (NodeVisitor::REPLACE_WITH_NULL === $return) {
$node->$name = null;
continue 2;
} else {
throw new \LogicException(
'enterNode() returned invalid value of type ' . gettype($return)
);
}
}
}
if ($traverseChildren) {
$this->traverseNode($subNode);
if ($this->stopTraversal) {
break;
}
}
for (; $visitorIndex >= 0; --$visitorIndex) {
$visitor = $this->visitors[$visitorIndex];
$return = $visitor->leaveNode($subNode);
if (null !== $return) {
if ($return instanceof Node) {
$this->ensureReplacementReasonable($subNode, $return);
$subNode = $node->$name = $return;
} elseif (NodeVisitor::STOP_TRAVERSAL === $return) {
$this->stopTraversal = true;
break 2;
} elseif (NodeVisitor::REPLACE_WITH_NULL === $return) {
$node->$name = null;
break;
} 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)
);
}
}
}
}
}
/**
* 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) {
if (\is_array($node)) {
throw new \LogicException('Invalid node structure: Contains nested arrays');
}
continue;
}
$traverseChildren = true;
$visitorIndex = -1;
foreach ($this->visitors as $visitorIndex => $visitor) {
$return = $visitor->enterNode($node);
if (null !== $return) {
if ($return instanceof Node) {
$this->ensureReplacementReasonable($node, $return);
$nodes[$i] = $node = $return;
} elseif (\is_array($return)) {
$doNodes[] = [$i, $return];
continue 2;
} elseif (NodeVisitor::REMOVE_NODE === $return) {
$doNodes[] = [$i, []];
continue 2;
} elseif (NodeVisitor::DONT_TRAVERSE_CHILDREN === $return) {
$traverseChildren = false;
} elseif (NodeVisitor::DONT_TRAVERSE_CURRENT_AND_CHILDREN === $return) {
$traverseChildren = false;
break;
} elseif (NodeVisitor::STOP_TRAVERSAL === $return) {
$this->stopTraversal = true;
break 2;
} elseif (NodeVisitor::REPLACE_WITH_NULL === $return) {
throw new \LogicException(
'REPLACE_WITH_NULL can not be used if the parent structure is an array');
} else {
throw new \LogicException(
'enterNode() returned invalid value of type ' . gettype($return)
);
}
}
}
if ($traverseChildren) {
$this->traverseNode($node);
if ($this->stopTraversal) {
break;
}
}
for (; $visitorIndex >= 0; --$visitorIndex) {
$visitor = $this->visitors[$visitorIndex];
$return = $visitor->leaveNode($node);
if (null !== $return) {
if ($return instanceof Node) {
$this->ensureReplacementReasonable($node, $return);
$nodes[$i] = $node = $return;
} elseif (\is_array($return)) {
$doNodes[] = [$i, $return];
break;
} elseif (NodeVisitor::REMOVE_NODE === $return) {
$doNodes[] = [$i, []];
break;
} elseif (NodeVisitor::STOP_TRAVERSAL === $return) {
$this->stopTraversal = true;
break 2;
} elseif (NodeVisitor::REPLACE_WITH_NULL === $return) {
throw new \LogicException(
'REPLACE_WITH_NULL can not be used if the parent structure is an array');
} else {
throw new \LogicException(
'leaveNode() returned invalid value of type ' . gettype($return)
);
}
}
}
}
if (!empty($doNodes)) {
while (list($i, $replace) = array_pop($doNodes)) {
array_splice($nodes, $i, 1, $replace);
}
}
return $nodes;
}
private function ensureReplacementReasonable(Node $old, Node $new): void {
if ($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()})"
);
}
}
}
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