webpack/lib/css/CssExportsGenerator.js

/*
	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("../Dependency")} Dependency */
/** @typedef {import("../Generator").GenerateContext} GenerateContext */
/** @typedef {import("../Generator").UpdateHashContext} UpdateHashContext */
/** @typedef {import("../Module").ConcatenationBailoutReasonContext} ConcatenationBailoutReasonContext */
/** @typedef {import("../NormalModule")} NormalModule */
/** @typedef {import("../util/Hash")} Hash */

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

class CssExportsGenerator extends Generator {
	constructor() {
		super();
	}

	// TODO add getConcatenationBailoutReason to allow concatenation
	// but how to make it have a module id

	/**
	 * @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(""));
		const initFragments = [];
		const cssExports = new Map();

		generateContext.runtimeRequirements.add(RuntimeGlobals.module);

		const runtimeRequirements = new Set();

		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,
			cssExports
		};

		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 [k, v] of cssExports) {
				let identifier = Template.toIdentifier(k);
				let i = 0;
				while (usedIdentifiers.has(identifier)) {
					identifier = Template.toIdentifier(k + i);
				}
				usedIdentifiers.add(identifier);
				generateContext.concatenationScope.registerExport(k, identifier);
				source.add(
					`${
						generateContext.runtimeTemplate.supportsConst ? "const" : "var"
					} ${identifier} = ${JSON.stringify(v)};\n`
				);
			}
			return source;
		} else {
			const otherUsed =
				generateContext.moduleGraph
					.getExportsInfo(module)
					.otherExportsInfo.getUsed(generateContext.runtime) !==
				UsageState.Unused;
			if (otherUsed) {
				generateContext.runtimeRequirements.add(
					RuntimeGlobals.makeNamespaceObject
				);
			}
			return new RawSource(
				`${otherUsed ? `${RuntimeGlobals.makeNamespaceObject}(` : ""}${
					module.moduleArgument
				}.exports = {\n${Array.from(
					cssExports,
					([k, v]) => `\t${JSON.stringify(k)}: ${JSON.stringify(v)}`
				).join(",\n")}\n}${otherUsed ? ")" : ""};`
			);
		}
	}

	/**
	 * @param {NormalModule} module fresh module
	 * @returns {Set<string>} 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 }) {}
}

module.exports = CssExportsGenerator;