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1/*
2 MIT License http://www.opensource.org/licenses/mit-license.php
3 Author Tobias Koppers @sokra
4*/
5
6"use strict";
7
8/** @typedef {import("webpack-sources").Source} Source */
9
10/** @type {WeakMap<Source, WeakMap<Source, boolean>>} */
11const equalityCache = new WeakMap();
12
13/**
14 * @param {Source} a a source
15 * @param {Source} b another source
16 * @returns {boolean} true, when both sources are equal
17 */
18const _isSourceEqual = (a, b) => {
19 // prefer .buffer(), it's called anyway during emit
20 /** @type {Buffer|string} */
21 let aSource = typeof a.buffer === "function" ? a.buffer() : a.source();
22 /** @type {Buffer|string} */
23 let bSource = typeof b.buffer === "function" ? b.buffer() : b.source();
24 if (aSource === bSource) return true;
25 if (typeof aSource === "string" && typeof bSource === "string") return false;
26 if (!Buffer.isBuffer(aSource)) aSource = Buffer.from(aSource, "utf-8");
27 if (!Buffer.isBuffer(bSource)) bSource = Buffer.from(bSource, "utf-8");
28 return aSource.equals(bSource);
29};
30
31/**
32 * @param {Source} a a source
33 * @param {Source} b another source
34 * @returns {boolean} true, when both sources are equal
35 */
36const isSourceEqual = (a, b) => {
37 if (a === b) return true;
38 const cache1 = equalityCache.get(a);
39 if (cache1 !== undefined) {
40 const result = cache1.get(b);
41 if (result !== undefined) return result;
42 }
43 const result = _isSourceEqual(a, b);
44 if (cache1 !== undefined) {
45 cache1.set(b, result);
46 } else {
47 const map = new WeakMap();
48 map.set(b, result);
49 equalityCache.set(a, map);
50 }
51 const cache2 = equalityCache.get(b);
52 if (cache2 !== undefined) {
53 cache2.set(a, result);
54 } else {
55 const map = new WeakMap();
56 map.set(a, result);
57 equalityCache.set(b, map);
58 }
59 return result;
60};
61exports.isSourceEqual = isSourceEqual;