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- 'use strict';
- var identity = require('../nodes/identity.js');
- var visit = require('../visit.js');
- /**
- * Verify that the input string is a valid anchor.
- *
- * Will throw on errors.
- */
- function anchorIsValid(anchor) {
- if (/[\x00-\x19\s,[\]{}]/.test(anchor)) {
- const sa = JSON.stringify(anchor);
- const msg = `Anchor must not contain whitespace or control characters: ${sa}`;
- throw new Error(msg);
- }
- return true;
- }
- function anchorNames(root) {
- const anchors = new Set();
- visit.visit(root, {
- Value(_key, node) {
- if (node.anchor)
- anchors.add(node.anchor);
- }
- });
- return anchors;
- }
- /** Find a new anchor name with the given `prefix` and a one-indexed suffix. */
- function findNewAnchor(prefix, exclude) {
- for (let i = 1; true; ++i) {
- const name = `${prefix}${i}`;
- if (!exclude.has(name))
- return name;
- }
- }
- function createNodeAnchors(doc, prefix) {
- const aliasObjects = [];
- const sourceObjects = new Map();
- let prevAnchors = null;
- return {
- onAnchor: (source) => {
- aliasObjects.push(source);
- if (!prevAnchors)
- prevAnchors = anchorNames(doc);
- const anchor = findNewAnchor(prefix, prevAnchors);
- prevAnchors.add(anchor);
- return anchor;
- },
- /**
- * With circular references, the source node is only resolved after all
- * of its child nodes are. This is why anchors are set only after all of
- * the nodes have been created.
- */
- setAnchors: () => {
- for (const source of aliasObjects) {
- const ref = sourceObjects.get(source);
- if (typeof ref === 'object' &&
- ref.anchor &&
- (identity.isScalar(ref.node) || identity.isCollection(ref.node))) {
- ref.node.anchor = ref.anchor;
- }
- else {
- const error = new Error('Failed to resolve repeated object (this should not happen)');
- error.source = source;
- throw error;
- }
- }
- },
- sourceObjects
- };
- }
- exports.anchorIsValid = anchorIsValid;
- exports.anchorNames = anchorNames;
- exports.createNodeAnchors = createNodeAnchors;
- exports.findNewAnchor = findNewAnchor;
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