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

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+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+const { STAGE_BASIC } = require("../OptimizationStages");
+const createSchemaValidation = require("../util/create-schema-validation");
+const { runtimeEqual } = require("../util/runtime");
+
+/** @typedef {import("../../declarations/plugins/optimize/MergeDuplicateChunksPlugin").MergeDuplicateChunksPluginOptions} MergeDuplicateChunksPluginOptions */
+/** @typedef {import("../Compiler")} Compiler */
+
+const validate = createSchemaValidation(
+	require("../../schemas/plugins/optimize/MergeDuplicateChunksPlugin.check.js"),
+	() =>
+		require("../../schemas/plugins/optimize/MergeDuplicateChunksPlugin.json"),
+	{
+		name: "Merge Duplicate Chunks Plugin",
+		baseDataPath: "options"
+	}
+);
+
+class MergeDuplicateChunksPlugin {
+	/**
+	 * @param {MergeDuplicateChunksPluginOptions} options options object
+	 */
+	constructor(options = { stage: STAGE_BASIC }) {
+		validate(options);
+		this.options = options;
+	}
+
+	/**
+	 * @param {Compiler} compiler the compiler
+	 * @returns {void}
+	 */
+	apply(compiler) {
+		compiler.hooks.compilation.tap(
+			"MergeDuplicateChunksPlugin",
+			compilation => {
+				compilation.hooks.optimizeChunks.tap(
+					{
+						name: "MergeDuplicateChunksPlugin",
+						stage: this.options.stage
+					},
+					chunks => {
+						const { chunkGraph, moduleGraph } = compilation;
+
+						// remember already tested chunks for performance
+						const notDuplicates = new Set();
+
+						// for each chunk
+						for (const chunk of chunks) {
+							// track a Set of all chunk that could be duplicates
+							let possibleDuplicates;
+							for (const module of chunkGraph.getChunkModulesIterable(chunk)) {
+								if (possibleDuplicates === undefined) {
+									// when possibleDuplicates is not yet set,
+									// create a new Set from chunks of the current module
+									// including only chunks with the same number of modules
+									for (const dup of chunkGraph.getModuleChunksIterable(
+										module
+									)) {
+										if (
+											dup !== chunk &&
+											chunkGraph.getNumberOfChunkModules(chunk) ===
+												chunkGraph.getNumberOfChunkModules(dup) &&
+											!notDuplicates.has(dup)
+										) {
+											// delay allocating the new Set until here, reduce memory pressure
+											if (possibleDuplicates === undefined) {
+												possibleDuplicates = new Set();
+											}
+											possibleDuplicates.add(dup);
+										}
+									}
+									// when no chunk is possible we can break here
+									if (possibleDuplicates === undefined) break;
+								} else {
+									// validate existing possible duplicates
+									for (const dup of possibleDuplicates) {
+										// remove possible duplicate when module is not contained
+										if (!chunkGraph.isModuleInChunk(module, dup)) {
+											possibleDuplicates.delete(dup);
+										}
+									}
+									// when all chunks has been removed we can break here
+									if (possibleDuplicates.size === 0) break;
+								}
+							}
+
+							// when we found duplicates
+							if (
+								possibleDuplicates !== undefined &&
+								possibleDuplicates.size > 0
+							) {
+								outer: for (const otherChunk of possibleDuplicates) {
+									if (otherChunk.hasRuntime() !== chunk.hasRuntime()) continue;
+									if (chunkGraph.getNumberOfEntryModules(chunk) > 0) continue;
+									if (chunkGraph.getNumberOfEntryModules(otherChunk) > 0)
+										continue;
+									if (!runtimeEqual(chunk.runtime, otherChunk.runtime)) {
+										for (const module of chunkGraph.getChunkModulesIterable(
+											chunk
+										)) {
+											const exportsInfo = moduleGraph.getExportsInfo(module);
+											if (
+												!exportsInfo.isEquallyUsed(
+													chunk.runtime,
+													otherChunk.runtime
+												)
+											) {
+												continue outer;
+											}
+										}
+									}
+									// merge them
+									if (chunkGraph.canChunksBeIntegrated(chunk, otherChunk)) {
+										chunkGraph.integrateChunks(chunk, otherChunk);
+										compilation.chunks.delete(otherChunk);
+									}
+								}
+							}
+
+							// don't check already processed chunks twice
+							notDuplicates.add(chunk);
+						}
+					}
+				);
+			}
+		);
+	}
+}
+module.exports = MergeDuplicateChunksPlugin;