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Packs ECMAScript/CommonJs/AMD modules for the browser. Allows you to split your codebase into multiple bundles, which can be loaded on demand. Supports loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.
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/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Sergey Melyukov @smelukov
*/

"use strict";

const { ReplaceSource, RawSource, ConcatSource } = require("webpack-sources");
const { UsageState } = require("../ExportsInfo");
const Generator = require("../Generator");
const RuntimeGlobals = require("../RuntimeGlobals");
const Template = require("../Template");

/** @typedef {import("webpack-sources").Source} Source */
/** @typedef {import("../../declarations/WebpackOptions").CssGeneratorExportsConvention} CssGeneratorExportsConvention */
/** @typedef {import("../../declarations/WebpackOptions").CssGeneratorLocalIdentName} CssGeneratorLocalIdentName */
/** @typedef {import("../Dependency")} Dependency */
/** @typedef {import("../DependencyTemplate").CssDependencyTemplateContext} DependencyTemplateContext */
/** @typedef {import("../DependencyTemplate").CssExportsData} CssExportsData */
/** @typedef {import("../Generator").GenerateContext} GenerateContext */
/** @typedef {import("../Generator").UpdateHashContext} UpdateHashContext */
/** @typedef {import("../Module").ConcatenationBailoutReasonContext} ConcatenationBailoutReasonContext */
/** @typedef {import("../NormalModule")} NormalModule */
/** @typedef {import("../util/Hash")} Hash */

/**
 * @template T
 * @typedef {import("../InitFragment")} InitFragment
 */

const TYPES = new Set(["javascript"]);

class CssExportsGenerator extends Generator {
	/**
	 * @param {CssGeneratorExportsConvention | undefined} convention the convention of the exports name
	 * @param {CssGeneratorLocalIdentName | undefined} localIdentName css export local ident name
	 * @param {boolean} esModule whether to use ES modules syntax
	 */
	constructor(convention, localIdentName, esModule) {
		super();
		/** @type {CssGeneratorExportsConvention | undefined} */
		this.convention = convention;
		/** @type {CssGeneratorLocalIdentName | undefined} */
		this.localIdentName = localIdentName;
		/** @type {boolean} */
		this.esModule = esModule;
	}

	/**
	 * @param {NormalModule} module module for which the bailout reason should be determined
	 * @param {ConcatenationBailoutReasonContext} context context
	 * @returns {string | undefined} reason why this module can't be concatenated, undefined when it can be concatenated
	 */
	getConcatenationBailoutReason(module, context) {
		if (!this.esModule) {
			return "Module is not an ECMAScript module";
		}
		// TODO webpack 6: remove /\[moduleid\]/.test
		if (
			/\[id\]/.test(this.localIdentName) ||
			/\[moduleid\]/.test(this.localIdentName)
		) {
			return "The localIdentName includes moduleId ([id] or [moduleid])";
		}
		return undefined;
	}

	/**
	 * @param {NormalModule} module module for which the code should be generated
	 * @param {GenerateContext} generateContext context for generate
	 * @returns {Source} generated code
	 */
	generate(module, generateContext) {
		const source = new ReplaceSource(new RawSource(""));
		/** @type {InitFragment[]} */
		const initFragments = [];
		/** @type {CssExportsData} */
		const cssExportsData = {
			esModule: this.esModule,
			exports: new Map()
		};

		generateContext.runtimeRequirements.add(RuntimeGlobals.module);

		let chunkInitFragments;
		const runtimeRequirements = new Set();

		/** @type {DependencyTemplateContext} */
		const templateContext = {
			runtimeTemplate: generateContext.runtimeTemplate,
			dependencyTemplates: generateContext.dependencyTemplates,
			moduleGraph: generateContext.moduleGraph,
			chunkGraph: generateContext.chunkGraph,
			module,
			runtime: generateContext.runtime,
			runtimeRequirements: runtimeRequirements,
			concatenationScope: generateContext.concatenationScope,
			codeGenerationResults: generateContext.codeGenerationResults,
			initFragments,
			cssExportsData,
			get chunkInitFragments() {
				if (!chunkInitFragments) {
					const data = generateContext.getData();
					chunkInitFragments = data.get("chunkInitFragments");
					if (!chunkInitFragments) {
						chunkInitFragments = [];
						data.set("chunkInitFragments", chunkInitFragments);
					}
				}

				return chunkInitFragments;
			}
		};

		/**
		 * @param {Dependency} dependency the dependency
		 */
		const handleDependency = dependency => {
			const constructor = /** @type {new (...args: any[]) => Dependency} */ (
				dependency.constructor
			);
			const template = generateContext.dependencyTemplates.get(constructor);
			if (!template) {
				throw new Error(
					"No template for dependency: " + dependency.constructor.name
				);
			}

			template.apply(dependency, source, templateContext);
		};
		module.dependencies.forEach(handleDependency);

		if (generateContext.concatenationScope) {
			const source = new ConcatSource();
			const usedIdentifiers = new Set();
			for (const [name, v] of cssExportsData.exports) {
				let identifier = Template.toIdentifier(name);
				let i = 0;
				while (usedIdentifiers.has(identifier)) {
					identifier = Template.toIdentifier(name + i);
				}
				usedIdentifiers.add(identifier);
				generateContext.concatenationScope.registerExport(name, identifier);
				source.add(
					`${
						generateContext.runtimeTemplate.supportsConst() ? "const" : "var"
					} ${identifier} = ${JSON.stringify(v)};\n`
				);
			}
			return source;
		} else {
			const needNsObj =
				this.esModule &&
				generateContext.moduleGraph
					.getExportsInfo(module)
					.otherExportsInfo.getUsed(generateContext.runtime) !==
					UsageState.Unused;
			if (needNsObj) {
				generateContext.runtimeRequirements.add(
					RuntimeGlobals.makeNamespaceObject
				);
			}
			const exports = [];
			for (let [name, v] of cssExportsData.exports) {
				exports.push(`\t${JSON.stringify(name)}: ${JSON.stringify(v)}`);
			}
			return new RawSource(
				`${needNsObj ? `${RuntimeGlobals.makeNamespaceObject}(` : ""}${
					module.moduleArgument
				}.exports = {\n${exports.join(",\n")}\n}${needNsObj ? ")" : ""};`
			);
		}
	}

	/**
	 * @param {NormalModule} module fresh module
	 * @returns {Set} available types (do not mutate)
	 */
	getTypes(module) {
		return TYPES;
	}

	/**
	 * @param {NormalModule} module the module
	 * @param {string=} type source type
	 * @returns {number} estimate size of the module
	 */
	getSize(module, type) {
		return 42;
	}

	/**
	 * @param {Hash} hash hash that will be modified
	 * @param {UpdateHashContext} updateHashContext context for updating hash
	 */
	updateHash(hash, { module }) {
		hash.update(this.esModule.toString());
	}
}

module.exports = CssExportsGenerator;