mirror of https://github.com/webpack/webpack.git
				
				
				
			
		
			
				
	
	
		
			281 lines
		
	
	
		
			8.7 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
			
		
		
	
	
			281 lines
		
	
	
		
			8.7 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
| /*
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| 	MIT License http://www.opensource.org/licenses/mit-license.php
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| 	Author Tobias Koppers @sokra
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| */
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| 
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| "use strict";
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| 
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| const { STAGE_ADVANCED } = require("../OptimizationStages");
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| const LazyBucketSortedSet = require("../util/LazyBucketSortedSet");
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| const { compareChunks } = require("../util/comparators");
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| const createSchemaValidation = require("../util/create-schema-validation");
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| 
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| /** @typedef {import("../../declarations/plugins/optimize/LimitChunkCountPlugin").LimitChunkCountPluginOptions} LimitChunkCountPluginOptions */
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| /** @typedef {import("../Chunk")} Chunk */
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| /** @typedef {import("../Compiler")} Compiler */
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| 
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| const validate = createSchemaValidation(
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| 	require("../../schemas/plugins/optimize/LimitChunkCountPlugin.check.js"),
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| 	() => require("../../schemas/plugins/optimize/LimitChunkCountPlugin.json"),
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| 	{
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| 		name: "Limit Chunk Count Plugin",
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| 		baseDataPath: "options"
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| 	}
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| );
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| 
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| /**
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|  * @typedef {object} ChunkCombination
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|  * @property {boolean} deleted this is set to true when combination was removed
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|  * @property {number} sizeDiff
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|  * @property {number} integratedSize
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|  * @property {Chunk} a
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|  * @property {Chunk} b
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|  * @property {number} aIdx
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|  * @property {number} bIdx
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|  * @property {number} aSize
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|  * @property {number} bSize
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|  */
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| 
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| /**
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|  * @template K, V
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|  * @param {Map<K, Set<V>>} map map
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|  * @param {K} key key
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|  * @param {V} value value
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|  */
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| const addToSetMap = (map, key, value) => {
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| 	const set = map.get(key);
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| 	if (set === undefined) {
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| 		map.set(key, new Set([value]));
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| 	} else {
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| 		set.add(value);
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| 	}
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| };
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| 
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| class LimitChunkCountPlugin {
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| 	/**
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| 	 * @param {LimitChunkCountPluginOptions=} options options object
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| 	 */
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| 	constructor(options) {
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| 		validate(options);
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| 		this.options = options;
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| 	}
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| 
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| 	/**
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| 	 * @param {Compiler} compiler the webpack compiler
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| 	 * @returns {void}
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| 	 */
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| 	apply(compiler) {
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| 		const options = this.options;
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| 		compiler.hooks.compilation.tap("LimitChunkCountPlugin", compilation => {
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| 			compilation.hooks.optimizeChunks.tap(
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| 				{
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| 					name: "LimitChunkCountPlugin",
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| 					stage: STAGE_ADVANCED
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| 				},
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| 				chunks => {
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| 					const chunkGraph = compilation.chunkGraph;
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| 					const maxChunks =
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| 						/** @type {LimitChunkCountPluginOptions} */
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| 						(options).maxChunks;
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| 					if (!maxChunks) return;
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| 					if (maxChunks < 1) return;
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| 					if (compilation.chunks.size <= maxChunks) return;
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| 
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| 					let remainingChunksToMerge = compilation.chunks.size - maxChunks;
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| 
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| 					// order chunks in a deterministic way
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| 					const compareChunksWithGraph = compareChunks(chunkGraph);
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| 					const orderedChunks = Array.from(chunks).sort(compareChunksWithGraph);
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| 
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| 					// create a lazy sorted data structure to keep all combinations
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| 					// this is large. Size = chunks * (chunks - 1) / 2
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| 					// It uses a multi layer bucket sort plus normal sort in the last layer
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| 					// It's also lazy so only accessed buckets are sorted
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| 					const combinations = new LazyBucketSortedSet(
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| 						// Layer 1: ordered by largest size benefit
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| 						c => c.sizeDiff,
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| 						(a, b) => b - a,
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| 						// Layer 2: ordered by smallest combined size
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| 						/**
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| 						 * @param {ChunkCombination} c combination
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| 						 * @returns {number} integrated size
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| 						 */
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| 						c => c.integratedSize,
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| 						(a, b) => a - b,
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| 						// Layer 3: ordered by position difference in orderedChunk (-> to be deterministic)
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| 						/**
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| 						 * @param {ChunkCombination} c combination
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| 						 * @returns {number} position difference
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| 						 */
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| 						c => c.bIdx - c.aIdx,
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| 						(a, b) => a - b,
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| 						// Layer 4: ordered by position in orderedChunk (-> to be deterministic)
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| 						(a, b) => a.bIdx - b.bIdx
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| 					);
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| 
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| 					// we keep a mapping from chunk to all combinations
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| 					// but this mapping is not kept up-to-date with deletions
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| 					// so `deleted` flag need to be considered when iterating this
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| 					/** @type {Map<Chunk, Set<ChunkCombination>>} */
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| 					const combinationsByChunk = new Map();
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| 
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| 					orderedChunks.forEach((b, bIdx) => {
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| 						// create combination pairs with size and integrated size
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| 						for (let aIdx = 0; aIdx < bIdx; aIdx++) {
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| 							const a = orderedChunks[aIdx];
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| 							// filter pairs that can not be integrated!
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| 							if (!chunkGraph.canChunksBeIntegrated(a, b)) continue;
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| 
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| 							const integratedSize = chunkGraph.getIntegratedChunksSize(
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| 								a,
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| 								b,
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| 								options
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| 							);
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| 
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| 							const aSize = chunkGraph.getChunkSize(a, options);
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| 							const bSize = chunkGraph.getChunkSize(b, options);
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| 							const c = {
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| 								deleted: false,
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| 								sizeDiff: aSize + bSize - integratedSize,
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| 								integratedSize,
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| 								a,
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| 								b,
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| 								aIdx,
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| 								bIdx,
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| 								aSize,
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| 								bSize
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| 							};
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| 							combinations.add(c);
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| 							addToSetMap(combinationsByChunk, a, c);
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| 							addToSetMap(combinationsByChunk, b, c);
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| 						}
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| 						return combinations;
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| 					});
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| 
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| 					// list of modified chunks during this run
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| 					// combinations affected by this change are skipped to allow
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| 					// further optimizations
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| 					/** @type {Set<Chunk>} */
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| 					const modifiedChunks = new Set();
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| 
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| 					let changed = false;
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| 					loop: while (true) {
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| 						const combination = combinations.popFirst();
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| 						if (combination === undefined) break;
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| 
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| 						combination.deleted = true;
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| 						const { a, b, integratedSize } = combination;
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| 
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| 						// skip over pair when
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| 						// one of the already merged chunks is a parent of one of the chunks
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| 						if (modifiedChunks.size > 0) {
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| 							const queue = new Set(a.groupsIterable);
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| 							for (const group of b.groupsIterable) {
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| 								queue.add(group);
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| 							}
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| 							for (const group of queue) {
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| 								for (const mChunk of modifiedChunks) {
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| 									if (mChunk !== a && mChunk !== b && mChunk.isInGroup(group)) {
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| 										// This is a potential pair which needs recalculation
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| 										// We can't do that now, but it merge before following pairs
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| 										// so we leave space for it, and consider chunks as modified
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| 										// just for the worse case
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| 										remainingChunksToMerge--;
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| 										if (remainingChunksToMerge <= 0) break loop;
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| 										modifiedChunks.add(a);
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| 										modifiedChunks.add(b);
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| 										continue loop;
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| 									}
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| 								}
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| 								for (const parent of group.parentsIterable) {
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| 									queue.add(parent);
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| 								}
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| 							}
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| 						}
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| 
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| 						// merge the chunks
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| 						if (chunkGraph.canChunksBeIntegrated(a, b)) {
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| 							chunkGraph.integrateChunks(a, b);
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| 							compilation.chunks.delete(b);
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| 
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| 							// flag chunk a as modified as further optimization are possible for all children here
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| 							modifiedChunks.add(a);
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| 
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| 							changed = true;
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| 							remainingChunksToMerge--;
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| 							if (remainingChunksToMerge <= 0) break;
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| 
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| 							// Update all affected combinations
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| 							// delete all combination with the removed chunk
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| 							// we will use combinations with the kept chunk instead
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| 							for (const combination of /** @type {Set<ChunkCombination>} */ (
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| 								combinationsByChunk.get(a)
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| 							)) {
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| 								if (combination.deleted) continue;
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| 								combination.deleted = true;
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| 								combinations.delete(combination);
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| 							}
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| 
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| 							// Update combinations with the kept chunk with new sizes
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| 							for (const combination of /** @type {Set<ChunkCombination>} */ (
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| 								combinationsByChunk.get(b)
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| 							)) {
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| 								if (combination.deleted) continue;
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| 								if (combination.a === b) {
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| 									if (!chunkGraph.canChunksBeIntegrated(a, combination.b)) {
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| 										combination.deleted = true;
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| 										combinations.delete(combination);
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| 										continue;
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| 									}
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| 									// Update size
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| 									const newIntegratedSize = chunkGraph.getIntegratedChunksSize(
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| 										a,
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| 										combination.b,
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| 										options
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| 									);
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| 									const finishUpdate = combinations.startUpdate(combination);
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| 									combination.a = a;
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| 									combination.integratedSize = newIntegratedSize;
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| 									combination.aSize = integratedSize;
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| 									combination.sizeDiff =
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| 										combination.bSize + integratedSize - newIntegratedSize;
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| 									finishUpdate();
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| 								} else if (combination.b === b) {
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| 									if (!chunkGraph.canChunksBeIntegrated(combination.a, a)) {
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| 										combination.deleted = true;
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| 										combinations.delete(combination);
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| 										continue;
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| 									}
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| 									// Update size
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| 									const newIntegratedSize = chunkGraph.getIntegratedChunksSize(
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| 										combination.a,
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| 										a,
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| 										options
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| 									);
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| 
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| 									const finishUpdate = combinations.startUpdate(combination);
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| 									combination.b = a;
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| 									combination.integratedSize = newIntegratedSize;
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| 									combination.bSize = integratedSize;
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| 									combination.sizeDiff =
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| 										integratedSize + combination.aSize - newIntegratedSize;
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| 									finishUpdate();
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| 								}
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| 							}
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| 							combinationsByChunk.set(
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| 								a,
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| 								/** @type {Set<ChunkCombination>} */ (
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| 									combinationsByChunk.get(b)
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| 								)
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| 							);
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| 							combinationsByChunk.delete(b);
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| 						}
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| 					}
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| 					if (changed) return true;
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| 				}
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| 			);
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| 		});
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| 	}
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| }
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| module.exports = LimitChunkCountPlugin;
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