webpack/lib/ModuleInfoHeaderPlugin.js

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/

"use strict";

const { ConcatSource, RawSource, CachedSource } = require("webpack-sources");
const { UsageState } = require("./ExportsInfo");
const Template = require("./Template");
const JavascriptModulesPlugin = require("./javascript/JavascriptModulesPlugin");

/** @typedef {import("webpack-sources").Source} Source */
/** @typedef {import("./Compiler")} Compiler */
/** @typedef {import("./ExportsInfo")} ExportsInfo */
/** @typedef {import("./ExportsInfo").ExportInfo} ExportInfo */
/** @typedef {import("./Module")} Module */
/** @typedef {import("./ModuleGraph")} ModuleGraph */
/** @typedef {import("./ModuleTemplate")} ModuleTemplate */
/** @typedef {import("./RequestShortener")} RequestShortener */

const joinIterableWithComma = iterable => {
	// This is more performant than Array.from().join(", ")
	// as it doesn't create an array
	let str = "";
	let first = true;
	for (const item of iterable) {
		if (first) {
			first = false;
		} else {
			str += ", ";
		}
		str += item;
	}
	return str;
};

/**
 * @param {ConcatSource} source output
 * @param {string} indent spacing
 * @param {ExportsInfo} exportsInfo data
 * @param {ModuleGraph} moduleGraph moduleGraph
 * @param {RequestShortener} requestShortener requestShortener
 * @param {Set<ExportInfo>} alreadyPrinted deduplication set
 * @returns {void}
 */
const printExportsInfoToSource = (
	source,
	indent,
	exportsInfo,
	moduleGraph,
	requestShortener,
	alreadyPrinted = new Set()
) => {
	const otherExportsInfo = exportsInfo.otherExportsInfo;

	let alreadyPrintedExports = 0;

	// determine exports to print
	const printedExports = [];
	for (const exportInfo of exportsInfo.orderedExports) {
		if (!alreadyPrinted.has(exportInfo)) {
			alreadyPrinted.add(exportInfo);
			printedExports.push(exportInfo);
		} else {
			alreadyPrintedExports++;
		}
	}
	let showOtherExports = false;
	if (!alreadyPrinted.has(otherExportsInfo)) {
		alreadyPrinted.add(otherExportsInfo);
		showOtherExports = true;
	} else {
		alreadyPrintedExports++;
	}

	// print the exports
	for (const exportInfo of printedExports) {
		const target = exportInfo.getTarget(moduleGraph);
		source.add(
			Template.toComment(
				`${indent}export ${JSON.stringify(exportInfo.name).slice(
					1,
					-1
				)} [${exportInfo.getProvidedInfo()}] [${exportInfo.getUsedInfo()}] [${exportInfo.getRenameInfo()}]${
					target
						? ` -> ${target.module.readableIdentifier(requestShortener)}${
								target.export
									? ` .${target.export
											.map(e => JSON.stringify(e).slice(1, -1))
											.join(".")}`
									: ""
						  }`
						: ""
				}`
			) + "\n"
		);
		if (exportInfo.exportsInfo) {
			printExportsInfoToSource(
				source,
				indent + "  ",
				exportInfo.exportsInfo,
				moduleGraph,
				requestShortener,
				alreadyPrinted
			);
		}
	}

	if (alreadyPrintedExports) {
		source.add(
			Template.toComment(
				`${indent}... (${alreadyPrintedExports} already listed exports)`
			) + "\n"
		);
	}

	if (showOtherExports) {
		const target = otherExportsInfo.getTarget(moduleGraph);
		if (
			target ||
			otherExportsInfo.provided !== false ||
			otherExportsInfo.getUsed(undefined) !== UsageState.Unused
		) {
			const title =
				printedExports.length > 0 || alreadyPrintedExports > 0
					? "other exports"
					: "exports";
			source.add(
				Template.toComment(
					`${indent}${title} [${otherExportsInfo.getProvidedInfo()}] [${otherExportsInfo.getUsedInfo()}]${
						target
							? ` -> ${target.module.readableIdentifier(requestShortener)}`
							: ""
					}`
				) + "\n"
			);
		}
	}
};

/** @type {WeakMap<RequestShortener, WeakMap<Module, { header: RawSource, full: WeakMap<Source, CachedSource> }>>} */
const caches = new WeakMap();

class ModuleInfoHeaderPlugin {
	/**
	 * @param {boolean=} verbose add more information like exports, runtime requirements and bailouts
	 */
	constructor(verbose = true) {
		this._verbose = verbose;
	}
	/**
	 * @param {Compiler} compiler the compiler
	 * @returns {void}
	 */
	apply(compiler) {
		const { _verbose: verbose } = this;
		compiler.hooks.compilation.tap("ModuleInfoHeaderPlugin", compilation => {
			const hooks = JavascriptModulesPlugin.getCompilationHooks(compilation);
			hooks.renderModulePackage.tap(
				"ModuleInfoHeaderPlugin",
				(
					moduleSource,
					module,
					{ chunk, chunkGraph, moduleGraph, runtimeTemplate }
				) => {
					const { requestShortener } = runtimeTemplate;
					let cacheEntry;
					let cache = caches.get(requestShortener);
					if (cache === undefined) {
						caches.set(requestShortener, (cache = new WeakMap()));
						cache.set(
							module,
							(cacheEntry = { header: undefined, full: new WeakMap() })
						);
					} else {
						cacheEntry = cache.get(module);
						if (cacheEntry === undefined) {
							cache.set(
								module,
								(cacheEntry = { header: undefined, full: new WeakMap() })
							);
						} else if (!verbose) {
							const cachedSource = cacheEntry.full.get(moduleSource);
							if (cachedSource !== undefined) return cachedSource;
						}
					}
					const source = new ConcatSource();
					let header = cacheEntry.header;
					if (header === undefined) {
						const req = module.readableIdentifier(requestShortener);
						const reqStr = req.replace(/\*\//g, "*_/");
						const reqStrStar = "*".repeat(reqStr.length);
						const headerStr = `/*!****${reqStrStar}****!*\\\n  !*** ${reqStr} ***!\n  \\****${reqStrStar}****/\n`;
						header = new RawSource(headerStr);
						cacheEntry.header = header;
					}
					source.add(header);
					if (verbose) {
						const exportsType = module.buildMeta.exportsType;
						source.add(
							Template.toComment(
								exportsType
									? `${exportsType} exports`
									: "unknown exports (runtime-defined)"
							) + "\n"
						);
						if (exportsType) {
							const exportsInfo = moduleGraph.getExportsInfo(module);
							printExportsInfoToSource(
								source,
								"",
								exportsInfo,
								moduleGraph,
								requestShortener
							);
						}
						source.add(
							Template.toComment(
								`runtime requirements: ${joinIterableWithComma(
									chunkGraph.getModuleRuntimeRequirements(module, chunk.runtime)
								)}`
							) + "\n"
						);
						const optimizationBailout = moduleGraph.getOptimizationBailout(
							module
						);
						if (optimizationBailout) {
							for (const text of optimizationBailout) {
								let code;
								if (typeof text === "function") {
									code = text(requestShortener);
								} else {
									code = text;
								}
								source.add(Template.toComment(`${code}`) + "\n");
							}
						}
						source.add(moduleSource);
						return source;
					} else {
						source.add(moduleSource);
						const cachedSource = new CachedSource(source);
						cacheEntry.full.set(moduleSource, cachedSource);
						return cachedSource;
					}
				}
			);
			hooks.chunkHash.tap("ModuleInfoHeaderPlugin", (chunk, hash) => {
				hash.update("ModuleInfoHeaderPlugin");
				hash.update("1");
			});
		});
	}
}
module.exports = ModuleInfoHeaderPlugin;