Version 4.5.0

system/3rd_party/graphql-php/Validator/Rules/NoFragmentCycles.php

@@ -0,0 +1,104 @@
+<?php
+namespace GraphQL\Validator\Rules;
+
+
+use GraphQL\Error\Error;
+use GraphQL\Language\AST\FragmentDefinitionNode;
+use GraphQL\Language\AST\FragmentSpreadNode;
+use GraphQL\Language\AST\Node;
+use GraphQL\Language\AST\NodeKind;
+use GraphQL\Language\Visitor;
+use GraphQL\Utils\Utils;
+use GraphQL\Validator\ValidationContext;
+
+class NoFragmentCycles extends AbstractValidationRule
+{
+    static function cycleErrorMessage($fragName, array $spreadNames = [])
+    {
+        $via = !empty($spreadNames) ? ' via ' . implode(', ', $spreadNames) : '';
+        return "Cannot spread fragment \"$fragName\" within itself$via.";
+    }
+
+    public $visitedFrags;
+
+    public $spreadPath;
+
+    public $spreadPathIndexByName;
+
+    public function getVisitor(ValidationContext $context)
+    {
+        // Tracks already visited fragments to maintain O(N) and to ensure that cycles
+        // are not redundantly reported.
+        $this->visitedFrags = [];
+
+        // Array of AST nodes used to produce meaningful errors
+        $this->spreadPath = [];
+
+        // Position in the spread path
+        $this->spreadPathIndexByName = [];
+
+        return [
+            NodeKind::OPERATION_DEFINITION => function () {
+                return Visitor::skipNode();
+            },
+            NodeKind::FRAGMENT_DEFINITION => function (FragmentDefinitionNode $node) use ($context) {
+                if (!isset($this->visitedFrags[$node->name->value])) {
+                    $this->detectCycleRecursive($node, $context);
+                }
+                return Visitor::skipNode();
+            }
+        ];
+    }
+
+    private function detectCycleRecursive(FragmentDefinitionNode $fragment, ValidationContext $context)
+    {
+        $fragmentName = $fragment->name->value;
+        $this->visitedFrags[$fragmentName] = true;
+
+        $spreadNodes = $context->getFragmentSpreads($fragment);
+
+        if (empty($spreadNodes)) {
+            return;
+        }
+
+        $this->spreadPathIndexByName[$fragmentName] = count($this->spreadPath);
+
+        for ($i = 0; $i < count($spreadNodes); $i++) {
+            $spreadNode = $spreadNodes[$i];
+            $spreadName = $spreadNode->name->value;
+            $cycleIndex = isset($this->spreadPathIndexByName[$spreadName]) ? $this->spreadPathIndexByName[$spreadName] : null;
+
+            if ($cycleIndex === null) {
+                $this->spreadPath[] = $spreadNode;
+                if (empty($this->visitedFrags[$spreadName])) {
+                    $spreadFragment = $context->getFragment($spreadName);
+                    if ($spreadFragment) {
+                        $this->detectCycleRecursive($spreadFragment, $context);
+                    }
+                }
+                array_pop($this->spreadPath);
+            } else {
+                $cyclePath = array_slice($this->spreadPath, $cycleIndex);
+                $nodes = $cyclePath;
+
+                if (is_array($spreadNode)) {
+                    $nodes = array_merge($nodes, $spreadNode);
+                } else {
+                    $nodes[] = $spreadNode;
+                }
+
+                $context->reportError(new Error(
+                    self::cycleErrorMessage(
+                        $spreadName,
+                        Utils::map($cyclePath, function ($s) {
+                            return $s->name->value;
+                        })
+                    ),
+                    $nodes
+                ));
+            }
+        }
+
+        $this->spreadPathIndexByName[$fragmentName] = null;
+    }
+}