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app_vue/node_modules/webpack/lib/optimize/MangleExportsPlugin.js

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+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+const { UsageState } = require("../ExportsInfo");
+const {
+	numberToIdentifier,
+	NUMBER_OF_IDENTIFIER_START_CHARS,
+	NUMBER_OF_IDENTIFIER_CONTINUATION_CHARS
+} = require("../Template");
+const { assignDeterministicIds } = require("../ids/IdHelpers");
+const { compareSelect, compareStringsNumeric } = require("../util/comparators");
+
+/** @typedef {import("../Compiler")} Compiler */
+/** @typedef {import("../ExportsInfo")} ExportsInfo */
+/** @typedef {import("../ExportsInfo").ExportInfo} ExportInfo */
+
+/**
+ * @param {ExportsInfo} exportsInfo exports info
+ * @returns {boolean} mangle is possible
+ */
+const canMangle = exportsInfo => {
+	if (exportsInfo.otherExportsInfo.getUsed(undefined) !== UsageState.Unused)
+		return false;
+	let hasSomethingToMangle = false;
+	for (const exportInfo of exportsInfo.exports) {
+		if (exportInfo.canMangle === true) {
+			hasSomethingToMangle = true;
+		}
+	}
+	return hasSomethingToMangle;
+};
+
+// Sort by name
+const comparator = compareSelect(e => e.name, compareStringsNumeric);
+/**
+ * @param {boolean} deterministic use deterministic names
+ * @param {ExportsInfo} exportsInfo exports info
+ * @param {boolean | undefined} isNamespace is namespace object
+ * @returns {void}
+ */
+const mangleExportsInfo = (deterministic, exportsInfo, isNamespace) => {
+	if (!canMangle(exportsInfo)) return;
+	const usedNames = new Set();
+	/** @type {ExportInfo[]} */
+	const mangleableExports = [];
+
+	// Avoid to renamed exports that are not provided when
+	// 1. it's not a namespace export: non-provided exports can be found in prototype chain
+	// 2. there are other provided exports and deterministic mode is chosen:
+	//    non-provided exports would break the determinism
+	let avoidMangleNonProvided = !isNamespace;
+	if (!avoidMangleNonProvided && deterministic) {
+		for (const exportInfo of exportsInfo.ownedExports) {
+			if (exportInfo.provided !== false) {
+				avoidMangleNonProvided = true;
+				break;
+			}
+		}
+	}
+	for (const exportInfo of exportsInfo.ownedExports) {
+		const name = exportInfo.name;
+		if (!exportInfo.hasUsedName()) {
+			if (
+				// Can the export be mangled?
+				exportInfo.canMangle !== true ||
+				// Never rename 1 char exports
+				(name.length === 1 && /^[a-zA-Z0-9_$]/.test(name)) ||
+				// Don't rename 2 char exports in deterministic mode
+				(deterministic &&
+					name.length === 2 &&
+					/^[a-zA-Z_$][a-zA-Z0-9_$]|^[1-9][0-9]/.test(name)) ||
+				// Don't rename exports that are not provided
+				(avoidMangleNonProvided && exportInfo.provided !== true)
+			) {
+				exportInfo.setUsedName(name);
+				usedNames.add(name);
+			} else {
+				mangleableExports.push(exportInfo);
+			}
+		}
+		if (exportInfo.exportsInfoOwned) {
+			const used = exportInfo.getUsed(undefined);
+			if (
+				used === UsageState.OnlyPropertiesUsed ||
+				used === UsageState.Unused
+			) {
+				mangleExportsInfo(
+					deterministic,
+					/** @type {ExportsInfo} */ (exportInfo.exportsInfo),
+					false
+				);
+			}
+		}
+	}
+	if (deterministic) {
+		assignDeterministicIds(
+			mangleableExports,
+			e => e.name,
+			comparator,
+			(e, id) => {
+				const name = numberToIdentifier(id);
+				const size = usedNames.size;
+				usedNames.add(name);
+				if (size === usedNames.size) return false;
+				e.setUsedName(name);
+				return true;
+			},
+			[
+				NUMBER_OF_IDENTIFIER_START_CHARS,
+				NUMBER_OF_IDENTIFIER_START_CHARS *
+					NUMBER_OF_IDENTIFIER_CONTINUATION_CHARS
+			],
+			NUMBER_OF_IDENTIFIER_CONTINUATION_CHARS,
+			usedNames.size
+		);
+	} else {
+		const usedExports = [];
+		const unusedExports = [];
+		for (const exportInfo of mangleableExports) {
+			if (exportInfo.getUsed(undefined) === UsageState.Unused) {
+				unusedExports.push(exportInfo);
+			} else {
+				usedExports.push(exportInfo);
+			}
+		}
+		usedExports.sort(comparator);
+		unusedExports.sort(comparator);
+		let i = 0;
+		for (const list of [usedExports, unusedExports]) {
+			for (const exportInfo of list) {
+				let name;
+				do {
+					name = numberToIdentifier(i++);
+				} while (usedNames.has(name));
+				exportInfo.setUsedName(name);
+			}
+		}
+	}
+};
+
+const PLUGIN_NAME = "MangleExportsPlugin";
+
+class MangleExportsPlugin {
+	/**
+	 * @param {boolean} deterministic use deterministic names
+	 */
+	constructor(deterministic) {
+		this._deterministic = deterministic;
+	}
+
+	/**
+	 * Apply the plugin
+	 * @param {Compiler} compiler the compiler instance
+	 * @returns {void}
+	 */
+	apply(compiler) {
+		const { _deterministic: deterministic } = this;
+		compiler.hooks.compilation.tap(PLUGIN_NAME, compilation => {
+			const moduleGraph = compilation.moduleGraph;
+			compilation.hooks.optimizeCodeGeneration.tap(PLUGIN_NAME, modules => {
+				if (compilation.moduleMemCaches) {
+					throw new Error(
+						"optimization.mangleExports can't be used with cacheUnaffected as export mangling is a global effect"
+					);
+				}
+				for (const module of modules) {
+					const isNamespace =
+						module.buildMeta && module.buildMeta.exportsType === "namespace";
+					const exportsInfo = moduleGraph.getExportsInfo(module);
+					mangleExportsInfo(deterministic, exportsInfo, isNamespace);
+				}
+			});
+		});
+	}
+}
+
+module.exports = MangleExportsPlugin;