source.js
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/*
MIT License http://www.opensource.org/licenses/mit-license.php
Author Tobias Koppers @sokra
*/
"use strict";
/** @typedef {import("webpack-sources").Source} Source */
/** @type {WeakMap<Source, WeakMap<Source, boolean>>} */
const equalityCache = new WeakMap();
/**
* @param {Source} a a source
* @param {Source} b another source
* @returns {boolean} true, when both sources are equal
*/
const _isSourceEqual = (a, b) => {
// prefer .buffer(), it's called anyway during emit
/** @type {Buffer|string} */
let aSource = typeof a.buffer === "function" ? a.buffer() : a.source();
/** @type {Buffer|string} */
let bSource = typeof b.buffer === "function" ? b.buffer() : b.source();
if (aSource === bSource) return true;
if (typeof aSource === "string" && typeof bSource === "string") return false;
if (!Buffer.isBuffer(aSource)) aSource = Buffer.from(aSource, "utf-8");
if (!Buffer.isBuffer(bSource)) bSource = Buffer.from(bSource, "utf-8");
return aSource.equals(bSource);
};
/**
* @param {Source} a a source
* @param {Source} b another source
* @returns {boolean} true, when both sources are equal
*/
const isSourceEqual = (a, b) => {
if (a === b) return true;
const cache1 = equalityCache.get(a);
if (cache1 !== undefined) {
const result = cache1.get(b);
if (result !== undefined) return result;
}
const result = _isSourceEqual(a, b);
if (cache1 !== undefined) {
cache1.set(b, result);
} else {
const map = new WeakMap();
map.set(b, result);
equalityCache.set(a, map);
}
const cache2 = equalityCache.get(b);
if (cache2 !== undefined) {
cache2.set(a, result);
} else {
const map = new WeakMap();
map.set(a, result);
equalityCache.set(b, map);
}
return result;
};
exports.isSourceEqual = isSourceEqual;