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