67 lines
2.2 KiB
JavaScript
67 lines
2.2 KiB
JavaScript
import { GraphQLError } from '../../error/GraphQLError';
|
|
export function cycleErrorMessage(fragName, spreadNames) {
|
|
var via = spreadNames.length ? ' via ' + spreadNames.join(', ') : '';
|
|
return "Cannot spread fragment \"".concat(fragName, "\" within itself").concat(via, ".");
|
|
}
|
|
export function NoFragmentCycles(context) {
|
|
// Tracks already visited fragments to maintain O(N) and to ensure that cycles
|
|
// are not redundantly reported.
|
|
var visitedFrags = Object.create(null); // Array of AST nodes used to produce meaningful errors
|
|
|
|
var spreadPath = []; // Position in the spread path
|
|
|
|
var spreadPathIndexByName = Object.create(null);
|
|
return {
|
|
OperationDefinition: function OperationDefinition() {
|
|
return false;
|
|
},
|
|
FragmentDefinition: function FragmentDefinition(node) {
|
|
detectCycleRecursive(node);
|
|
return false;
|
|
}
|
|
}; // This does a straight-forward DFS to find cycles.
|
|
// It does not terminate when a cycle was found but continues to explore
|
|
// the graph to find all possible cycles.
|
|
|
|
function detectCycleRecursive(fragment) {
|
|
if (visitedFrags[fragment.name.value]) {
|
|
return;
|
|
}
|
|
|
|
var fragmentName = fragment.name.value;
|
|
visitedFrags[fragmentName] = true;
|
|
var spreadNodes = context.getFragmentSpreads(fragment.selectionSet);
|
|
|
|
if (spreadNodes.length === 0) {
|
|
return;
|
|
}
|
|
|
|
spreadPathIndexByName[fragmentName] = spreadPath.length;
|
|
|
|
for (var _i2 = 0; _i2 < spreadNodes.length; _i2++) {
|
|
var spreadNode = spreadNodes[_i2];
|
|
var spreadName = spreadNode.name.value;
|
|
var cycleIndex = spreadPathIndexByName[spreadName];
|
|
spreadPath.push(spreadNode);
|
|
|
|
if (cycleIndex === undefined) {
|
|
var spreadFragment = context.getFragment(spreadName);
|
|
|
|
if (spreadFragment) {
|
|
detectCycleRecursive(spreadFragment);
|
|
}
|
|
} else {
|
|
var cyclePath = spreadPath.slice(cycleIndex);
|
|
var fragmentNames = cyclePath.slice(0, -1).map(function (s) {
|
|
return s.name.value;
|
|
});
|
|
context.reportError(new GraphQLError(cycleErrorMessage(spreadName, fragmentNames), cyclePath));
|
|
}
|
|
|
|
spreadPath.pop();
|
|
}
|
|
|
|
spreadPathIndexByName[fragmentName] = undefined;
|
|
}
|
|
}
|