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app_vue/node_modules/webpack/lib/FlagDependencyUsagePlugin.js

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+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+const Dependency = require("./Dependency");
+const { UsageState } = require("./ExportsInfo");
+const ModuleGraphConnection = require("./ModuleGraphConnection");
+const { STAGE_DEFAULT } = require("./OptimizationStages");
+const ArrayQueue = require("./util/ArrayQueue");
+const TupleQueue = require("./util/TupleQueue");
+const { getEntryRuntime, mergeRuntimeOwned } = require("./util/runtime");
+
+/** @typedef {import("./Chunk")} Chunk */
+/** @typedef {import("./ChunkGroup")} ChunkGroup */
+/** @typedef {import("./Compiler")} Compiler */
+/** @typedef {import("./DependenciesBlock")} DependenciesBlock */
+/** @typedef {import("./Dependency").ReferencedExport} ReferencedExport */
+/** @typedef {import("./ExportsInfo")} ExportsInfo */
+/** @typedef {import("./Module")} Module */
+/** @typedef {import("./util/runtime").RuntimeSpec} RuntimeSpec */
+
+const { NO_EXPORTS_REFERENCED, EXPORTS_OBJECT_REFERENCED } = Dependency;
+
+const PLUGIN_NAME = "FlagDependencyUsagePlugin";
+const PLUGIN_LOGGER_NAME = `webpack.${PLUGIN_NAME}`;
+
+class FlagDependencyUsagePlugin {
+	/**
+	 * @param {boolean} global do a global analysis instead of per runtime
+	 */
+	constructor(global) {
+		this.global = global;
+	}
+
+	/**
+	 * Apply the plugin
+	 * @param {Compiler} compiler the compiler instance
+	 * @returns {void}
+	 */
+	apply(compiler) {
+		compiler.hooks.compilation.tap(PLUGIN_NAME, compilation => {
+			const moduleGraph = compilation.moduleGraph;
+			compilation.hooks.optimizeDependencies.tap(
+				{ name: PLUGIN_NAME, stage: STAGE_DEFAULT },
+				modules => {
+					if (compilation.moduleMemCaches) {
+						throw new Error(
+							"optimization.usedExports can't be used with cacheUnaffected as export usage is a global effect"
+						);
+					}
+
+					const logger = compilation.getLogger(PLUGIN_LOGGER_NAME);
+					/** @type {Map<ExportsInfo, Module>} */
+					const exportInfoToModuleMap = new Map();
+
+					/** @type {TupleQueue<Module, RuntimeSpec>} */
+					const queue = new TupleQueue();
+
+					/**
+					 * @param {Module} module module to process
+					 * @param {(string[] | ReferencedExport)[]} usedExports list of used exports
+					 * @param {RuntimeSpec} runtime part of which runtime
+					 * @param {boolean} forceSideEffects always apply side effects
+					 * @returns {void}
+					 */
+					const processReferencedModule = (
+						module,
+						usedExports,
+						runtime,
+						forceSideEffects
+					) => {
+						const exportsInfo = moduleGraph.getExportsInfo(module);
+						if (usedExports.length > 0) {
+							if (!module.buildMeta || !module.buildMeta.exportsType) {
+								if (exportsInfo.setUsedWithoutInfo(runtime)) {
+									queue.enqueue(module, runtime);
+								}
+								return;
+							}
+							for (const usedExportInfo of usedExports) {
+								let usedExport;
+								let canMangle = true;
+								if (Array.isArray(usedExportInfo)) {
+									usedExport = usedExportInfo;
+								} else {
+									usedExport = usedExportInfo.name;
+									canMangle = usedExportInfo.canMangle !== false;
+								}
+								if (usedExport.length === 0) {
+									if (exportsInfo.setUsedInUnknownWay(runtime)) {
+										queue.enqueue(module, runtime);
+									}
+								} else {
+									let currentExportsInfo = exportsInfo;
+									for (let i = 0; i < usedExport.length; i++) {
+										const exportInfo = currentExportsInfo.getExportInfo(
+											usedExport[i]
+										);
+										if (canMangle === false) {
+											exportInfo.canMangleUse = false;
+										}
+										const lastOne = i === usedExport.length - 1;
+										if (!lastOne) {
+											const nestedInfo = exportInfo.getNestedExportsInfo();
+											if (nestedInfo) {
+												if (
+													exportInfo.setUsedConditionally(
+														used => used === UsageState.Unused,
+														UsageState.OnlyPropertiesUsed,
+														runtime
+													)
+												) {
+													const currentModule =
+														currentExportsInfo === exportsInfo
+															? module
+															: exportInfoToModuleMap.get(currentExportsInfo);
+													if (currentModule) {
+														queue.enqueue(currentModule, runtime);
+													}
+												}
+												currentExportsInfo = nestedInfo;
+												continue;
+											}
+										}
+										if (
+											exportInfo.setUsedConditionally(
+												v => v !== UsageState.Used,
+												UsageState.Used,
+												runtime
+											)
+										) {
+											const currentModule =
+												currentExportsInfo === exportsInfo
+													? module
+													: exportInfoToModuleMap.get(currentExportsInfo);
+											if (currentModule) {
+												queue.enqueue(currentModule, runtime);
+											}
+										}
+										break;
+									}
+								}
+							}
+						} else {
+							// for a module without side effects we stop tracking usage here when no export is used
+							// This module won't be evaluated in this case
+							// TODO webpack 6 remove this check
+							if (
+								!forceSideEffects &&
+								module.factoryMeta !== undefined &&
+								module.factoryMeta.sideEffectFree
+							) {
+								return;
+							}
+							if (exportsInfo.setUsedForSideEffectsOnly(runtime)) {
+								queue.enqueue(module, runtime);
+							}
+						}
+					};
+
+					/**
+					 * @param {DependenciesBlock} module the module
+					 * @param {RuntimeSpec} runtime part of which runtime
+					 * @param {boolean} forceSideEffects always apply side effects
+					 * @returns {void}
+					 */
+					const processModule = (module, runtime, forceSideEffects) => {
+						/** @type {Map<Module, (string[] | ReferencedExport)[] | Map<string, string[] | ReferencedExport>>} */
+						const map = new Map();
+
+						/** @type {ArrayQueue<DependenciesBlock>} */
+						const queue = new ArrayQueue();
+						queue.enqueue(module);
+						for (;;) {
+							const block = queue.dequeue();
+							if (block === undefined) break;
+							for (const b of block.blocks) {
+								if (
+									!this.global &&
+									b.groupOptions &&
+									b.groupOptions.entryOptions
+								) {
+									processModule(
+										b,
+										b.groupOptions.entryOptions.runtime || undefined,
+										true
+									);
+								} else {
+									queue.enqueue(b);
+								}
+							}
+							for (const dep of block.dependencies) {
+								const connection = moduleGraph.getConnection(dep);
+								if (!connection || !connection.module) {
+									continue;
+								}
+								const activeState = connection.getActiveState(runtime);
+								if (activeState === false) continue;
+								const { module } = connection;
+								if (activeState === ModuleGraphConnection.TRANSITIVE_ONLY) {
+									processModule(module, runtime, false);
+									continue;
+								}
+								const oldReferencedExports = map.get(module);
+								if (oldReferencedExports === EXPORTS_OBJECT_REFERENCED) {
+									continue;
+								}
+								const referencedExports =
+									compilation.getDependencyReferencedExports(dep, runtime);
+								if (
+									oldReferencedExports === undefined ||
+									oldReferencedExports === NO_EXPORTS_REFERENCED ||
+									referencedExports === EXPORTS_OBJECT_REFERENCED
+								) {
+									map.set(module, referencedExports);
+								} else if (
+									oldReferencedExports !== undefined &&
+									referencedExports === NO_EXPORTS_REFERENCED
+								) {
+									continue;
+								} else {
+									let exportsMap;
+									if (Array.isArray(oldReferencedExports)) {
+										exportsMap = new Map();
+										for (const item of oldReferencedExports) {
+											if (Array.isArray(item)) {
+												exportsMap.set(item.join("\n"), item);
+											} else {
+												exportsMap.set(item.name.join("\n"), item);
+											}
+										}
+										map.set(module, exportsMap);
+									} else {
+										exportsMap = oldReferencedExports;
+									}
+									for (const item of referencedExports) {
+										if (Array.isArray(item)) {
+											const key = item.join("\n");
+											const oldItem = exportsMap.get(key);
+											if (oldItem === undefined) {
+												exportsMap.set(key, item);
+											}
+											// if oldItem is already an array we have to do nothing
+											// if oldItem is an ReferencedExport object, we don't have to do anything
+											// as canMangle defaults to true for arrays
+										} else {
+											const key = item.name.join("\n");
+											const oldItem = exportsMap.get(key);
+											if (oldItem === undefined || Array.isArray(oldItem)) {
+												exportsMap.set(key, item);
+											} else {
+												exportsMap.set(key, {
+													name: item.name,
+													canMangle: item.canMangle && oldItem.canMangle
+												});
+											}
+										}
+									}
+								}
+							}
+						}
+
+						for (const [module, referencedExports] of map) {
+							if (Array.isArray(referencedExports)) {
+								processReferencedModule(
+									module,
+									referencedExports,
+									runtime,
+									forceSideEffects
+								);
+							} else {
+								processReferencedModule(
+									module,
+									Array.from(referencedExports.values()),
+									runtime,
+									forceSideEffects
+								);
+							}
+						}
+					};
+
+					logger.time("initialize exports usage");
+					for (const module of modules) {
+						const exportsInfo = moduleGraph.getExportsInfo(module);
+						exportInfoToModuleMap.set(exportsInfo, module);
+						exportsInfo.setHasUseInfo();
+					}
+					logger.timeEnd("initialize exports usage");
+
+					logger.time("trace exports usage in graph");
+
+					/**
+					 * @param {Dependency} dep dependency
+					 * @param {RuntimeSpec} runtime runtime
+					 */
+					const processEntryDependency = (dep, runtime) => {
+						const module = moduleGraph.getModule(dep);
+						if (module) {
+							processReferencedModule(
+								module,
+								NO_EXPORTS_REFERENCED,
+								runtime,
+								true
+							);
+						}
+					};
+					/** @type {RuntimeSpec} */
+					let globalRuntime;
+					for (const [
+						entryName,
+						{ dependencies: deps, includeDependencies: includeDeps, options }
+					] of compilation.entries) {
+						const runtime = this.global
+							? undefined
+							: getEntryRuntime(compilation, entryName, options);
+						for (const dep of deps) {
+							processEntryDependency(dep, runtime);
+						}
+						for (const dep of includeDeps) {
+							processEntryDependency(dep, runtime);
+						}
+						globalRuntime = mergeRuntimeOwned(globalRuntime, runtime);
+					}
+					for (const dep of compilation.globalEntry.dependencies) {
+						processEntryDependency(dep, globalRuntime);
+					}
+					for (const dep of compilation.globalEntry.includeDependencies) {
+						processEntryDependency(dep, globalRuntime);
+					}
+
+					while (queue.length) {
+						const [module, runtime] = /** @type {[Module, RuntimeSpec]} */ (
+							queue.dequeue()
+						);
+						processModule(module, runtime, false);
+					}
+					logger.timeEnd("trace exports usage in graph");
+				}
+			);
+		});
+	}
+}
+
+module.exports = FlagDependencyUsagePlugin;