四好公路
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3 years ago
"use strict";
const $Ref = require("./ref");
const Pointer = require("./pointer");
const { ono } = require("@jsdevtools/ono");
const url = require("./util/url");
module.exports = dereference;
/**
* Crawls the JSON schema, finds all JSON references, and dereferences them.
* This method mutates the JSON schema object, replacing JSON references with their resolved value.
*
* @param {$RefParser} parser
* @param {$RefParserOptions} options
*/
function dereference (parser, options) {
// console.log('Dereferencing $ref pointers in %s', parser.$refs._root$Ref.path);
let dereferenced = crawl(parser.schema, parser.$refs._root$Ref.path, "#", new Set(), new Set(), new Map(), parser.$refs, options);
parser.$refs.circular = dereferenced.circular;
parser.schema = dereferenced.value;
}
/**
* Recursively crawls the given value, and dereferences any JSON references.
*
* @param {*} obj - The value to crawl. If it's not an object or array, it will be ignored.
* @param {string} path - The full path of `obj`, possibly with a JSON Pointer in the hash
* @param {string} pathFromRoot - The path of `obj` from the schema root
* @param {Set<object>} parents - An array of the parent objects that have already been dereferenced
* @param {Set<object>} processedObjects - An array of all the objects that have already been processed
* @param {Map<string,object>} dereferencedCache - An map of all the dereferenced objects
* @param {$Refs} $refs
* @param {$RefParserOptions} options
* @returns {{value: object, circular: boolean}}
*/
function crawl (obj, path, pathFromRoot, parents, processedObjects, dereferencedCache, $refs, options) {
let dereferenced;
let result = {
value: obj,
circular: false
};
if (options.dereference.circular === "ignore" || !processedObjects.has(obj)) {
if (obj && typeof obj === "object" && !ArrayBuffer.isView(obj)) {
parents.add(obj);
processedObjects.add(obj);
if ($Ref.isAllowed$Ref(obj, options)) {
dereferenced = dereference$Ref(obj, path, pathFromRoot, parents, processedObjects, dereferencedCache, $refs, options);
result.circular = dereferenced.circular;
result.value = dereferenced.value;
}
else {
for (const key of Object.keys(obj)) {
let keyPath = Pointer.join(path, key);
let keyPathFromRoot = Pointer.join(pathFromRoot, key);
let value = obj[key];
let circular = false;
if ($Ref.isAllowed$Ref(value, options)) {
dereferenced = dereference$Ref(value, keyPath, keyPathFromRoot, parents, processedObjects, dereferencedCache, $refs, options);
circular = dereferenced.circular;
// Avoid pointless mutations; breaks frozen objects to no profit
if (obj[key] !== dereferenced.value) {
obj[key] = dereferenced.value;
}
}
else {
if (!parents.has(value)) {
dereferenced = crawl(value, keyPath, keyPathFromRoot, parents, processedObjects, dereferencedCache, $refs, options);
circular = dereferenced.circular;
// Avoid pointless mutations; breaks frozen objects to no profit
if (obj[key] !== dereferenced.value) {
obj[key] = dereferenced.value;
}
}
else {
circular = foundCircularReference(keyPath, $refs, options);
}
}
// Set the "isCircular" flag if this or any other property is circular
result.circular = result.circular || circular;
}
}
parents.delete(obj);
}
}
return result;
}
/**
* Dereferences the given JSON Reference, and then crawls the resulting value.
*
* @param {{$ref: string}} $ref - The JSON Reference to resolve
* @param {string} path - The full path of `$ref`, possibly with a JSON Pointer in the hash
* @param {string} pathFromRoot - The path of `$ref` from the schema root
* @param {Set<object>} parents - An array of the parent objects that have already been dereferenced
* @param {Set<object>} processedObjects - An array of all the objects that have already been dereferenced
* @param {Map<string,object>} dereferencedCache - An map of all the dereferenced objects
* @param {$Refs} $refs
* @param {$RefParserOptions} options
* @returns {{value: object, circular: boolean}}
*/
function dereference$Ref ($ref, path, pathFromRoot, parents, processedObjects, dereferencedCache, $refs, options) {
// console.log('Dereferencing $ref pointer "%s" at %s', $ref.$ref, path);
let $refPath = url.resolve(path, $ref.$ref);
const cache = dereferencedCache.get($refPath);
if (cache) {
const refKeys = Object.keys($ref);
if (refKeys.length > 1) {
const extraKeys = {};
for (let key of refKeys) {
if (key !== "$ref" && !(key in cache.value)) {
extraKeys[key] = $ref[key];
}
}
return {
circular: cache.circular,
value: Object.assign({}, cache.value, extraKeys),
};
}
return cache;
}
let pointer = $refs._resolve($refPath, path, options);
if (pointer === null) {
return {
circular: false,
value: null,
};
}
// Check for circular references
let directCircular = pointer.circular;
let circular = directCircular || parents.has(pointer.value);
circular && foundCircularReference(path, $refs, options);
// Dereference the JSON reference
let dereferencedValue = $Ref.dereference($ref, pointer.value);
// Crawl the dereferenced value (unless it's circular)
if (!circular) {
// Determine if the dereferenced value is circular
let dereferenced = crawl(dereferencedValue, pointer.path, pathFromRoot, parents, processedObjects, dereferencedCache, $refs, options);
circular = dereferenced.circular;
dereferencedValue = dereferenced.value;
}
if (circular && !directCircular && options.dereference.circular === "ignore") {
// The user has chosen to "ignore" circular references, so don't change the value
dereferencedValue = $ref;
}
if (directCircular) {
// The pointer is a DIRECT circular reference (i.e. it references itself).
// So replace the $ref path with the absolute path from the JSON Schema root
dereferencedValue.$ref = pathFromRoot;
}
const dereferencedObject = {
circular,
value: dereferencedValue
};
// only cache if no extra properties than $ref
if (Object.keys($ref).length === 1) {
dereferencedCache.set($refPath, dereferencedObject);
}
return dereferencedObject;
}
/**
* Called when a circular reference is found.
* It sets the {@link $Refs#circular} flag, and throws an error if options.dereference.circular is false.
*
* @param {string} keyPath - The JSON Reference path of the circular reference
* @param {$Refs} $refs
* @param {$RefParserOptions} options
* @returns {boolean} - always returns true, to indicate that a circular reference was found
*/
function foundCircularReference (keyPath, $refs, options) {
$refs.circular = true;
if (!options.dereference.circular) {
throw ono.reference(`Circular $ref pointer found at ${keyPath}`);
}
return true;
}