File: LimitChunkCountPlugin.js

package info (click to toggle)
node-webpack 4.43.0-6~bpo10%2B1
  • links: PTS, VCS
  • area: main
  • in suites: buster-backports
  • size: 21,220 kB
  • sloc: javascript: 69,992; makefile: 22
file content (231 lines) | stat: -rw-r--r-- 7,601 bytes parent folder | download | duplicates (2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/
"use strict";

const validateOptions = require("schema-utils").validate;
const schema = require("../../schemas/plugins/optimize/LimitChunkCountPlugin.json");
const LazyBucketSortedSet = require("../util/LazyBucketSortedSet");

/** @typedef {import("../../declarations/plugins/optimize/LimitChunkCountPlugin").LimitChunkCountPluginOptions} LimitChunkCountPluginOptions */
/** @typedef {import("../Chunk")} Chunk */
/** @typedef {import("../Compiler")} Compiler */

/**
 * @typedef {Object} ChunkCombination
 * @property {boolean} deleted this is set to true when combination was removed
 * @property {number} sizeDiff
 * @property {number} integratedSize
 * @property {Chunk} a
 * @property {Chunk} b
 * @property {number} aIdx
 * @property {number} bIdx
 * @property {number} aSize
 * @property {number} bSize
 */

const addToSetMap = (map, key, value) => {
	const set = map.get(key);
	if (set === undefined) {
		map.set(key, new Set([value]));
	} else {
		set.add(value);
	}
};

class LimitChunkCountPlugin {
	/**
	 * @param {LimitChunkCountPluginOptions=} options options object
	 */
	constructor(options) {
		if (!options) options = {};

		validateOptions(schema, options, "Limit Chunk Count Plugin");
		this.options = options;
	}

	/**
	 * @param {Compiler} compiler the webpack compiler
	 * @returns {void}
	 */
	apply(compiler) {
		const options = this.options;
		compiler.hooks.compilation.tap("LimitChunkCountPlugin", compilation => {
			compilation.hooks.optimizeChunksAdvanced.tap(
				"LimitChunkCountPlugin",
				chunks => {
					const maxChunks = options.maxChunks;
					if (!maxChunks) return;
					if (maxChunks < 1) return;
					if (chunks.length <= maxChunks) return;

					let remainingChunksToMerge = chunks.length - maxChunks;

					// order chunks in a deterministic way
					const orderedChunks = chunks.slice().sort((a, b) => a.compareTo(b));

					// create a lazy sorted data structure to keep all combinations
					// this is large. Size = chunks * (chunks - 1) / 2
					// It uses a multi layer bucket sort plus normal sort in the last layer
					// It's also lazy so only accessed buckets are sorted
					const combinations = new LazyBucketSortedSet(
						// Layer 1: ordered by largest size benefit
						c => c.sizeDiff,
						(a, b) => b - a,
						// Layer 2: ordered by smallest combined size
						c => c.integratedSize,
						(a, b) => a - b,
						// Layer 3: ordered by position difference in orderedChunk (-> to be deterministic)
						c => c.bIdx - c.aIdx,
						(a, b) => a - b,
						// Layer 4: ordered by position in orderedChunk (-> to be deterministic)
						(a, b) => a.bIdx - b.bIdx
					);

					// we keep a mappng from chunk to all combinations
					// but this mapping is not kept up-to-date with deletions
					// so `deleted` flag need to be considered when iterating this
					/** @type {Map<Chunk, Set<ChunkCombination>>} */
					const combinationsByChunk = new Map();

					orderedChunks.forEach((b, bIdx) => {
						// create combination pairs with size and integrated size
						for (let aIdx = 0; aIdx < bIdx; aIdx++) {
							const a = orderedChunks[aIdx];
							const integratedSize = a.integratedSize(b, options);

							// filter pairs that do not have an integratedSize
							// meaning they can NOT be integrated!
							if (integratedSize === false) continue;

							const aSize = a.size(options);
							const bSize = b.size(options);
							const c = {
								deleted: false,
								sizeDiff: aSize + bSize - integratedSize,
								integratedSize,
								a,
								b,
								aIdx,
								bIdx,
								aSize,
								bSize
							};
							combinations.add(c);
							addToSetMap(combinationsByChunk, a, c);
							addToSetMap(combinationsByChunk, b, c);
						}
						return combinations;
					});

					// list of modified chunks during this run
					// combinations affected by this change are skipped to allow
					// futher optimizations
					/** @type {Set<Chunk>} */
					const modifiedChunks = new Set();

					let changed = false;
					// eslint-disable-next-line no-constant-condition
					loop: while (true) {
						const combination = combinations.popFirst();
						if (combination === undefined) break;

						combination.deleted = true;
						const { a, b, integratedSize } = combination;

						// skip over pair when
						// one of the already merged chunks is a parent of one of the chunks
						if (modifiedChunks.size > 0) {
							const queue = new Set(a.groupsIterable);
							for (const group of b.groupsIterable) {
								queue.add(group);
							}
							for (const group of queue) {
								for (const mChunk of modifiedChunks) {
									if (mChunk !== a && mChunk !== b && mChunk.isInGroup(group)) {
										// This is a potential pair which needs recalculation
										// We can't do that now, but it merge before following pairs
										// so we leave space for it, and consider chunks as modified
										// just for the worse case
										remainingChunksToMerge--;
										if (remainingChunksToMerge <= 0) break loop;
										modifiedChunks.add(a);
										modifiedChunks.add(b);
										continue loop;
									}
								}
								for (const parent of group.parentsIterable) {
									queue.add(parent);
								}
							}
						}

						// merge the chunks
						if (a.integrate(b, "limit")) {
							chunks.splice(chunks.indexOf(b), 1);

							// flag chunk a as modified as further optimization are possible for all children here
							modifiedChunks.add(a);

							changed = true;
							remainingChunksToMerge--;
							if (remainingChunksToMerge <= 0) break;

							// Update all affected combinations
							// delete all combination with the removed chunk
							// we will use combinations with the kept chunk instead
							for (const combination of combinationsByChunk.get(b)) {
								if (combination.deleted) continue;
								combination.deleted = true;
								combinations.delete(combination);
							}

							// Update combinations with the kept chunk with new sizes
							for (const combination of combinationsByChunk.get(a)) {
								if (combination.deleted) continue;
								if (combination.a === a) {
									// Update size
									const newIntegratedSize = a.integratedSize(
										combination.b,
										options
									);
									if (newIntegratedSize === false) {
										combination.deleted = true;
										combinations.delete(combination);
										continue;
									}
									const finishUpdate = combinations.startUpdate(combination);
									combination.integratedSize = newIntegratedSize;
									combination.aSize = integratedSize;
									combination.sizeDiff =
										combination.bSize + integratedSize - newIntegratedSize;
									finishUpdate();
								} else if (combination.b === a) {
									// Update size
									const newIntegratedSize = combination.a.integratedSize(
										a,
										options
									);
									if (newIntegratedSize === false) {
										combination.deleted = true;
										combinations.delete(combination);
										continue;
									}
									const finishUpdate = combinations.startUpdate(combination);
									combination.integratedSize = newIntegratedSize;
									combination.bSize = integratedSize;
									combination.sizeDiff =
										integratedSize + combination.aSize - newIntegratedSize;
									finishUpdate();
								}
							}
						}
					}
					if (changed) return true;
				}
			);
		});
	}
}
module.exports = LimitChunkCountPlugin;