webpack/lib/node/ReadFileCompileAsyncWasmPlugin.js

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.

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

"use strict";

const { WEBASSEMBLY_MODULE_TYPE_ASYNC } = require("../ModuleTypeConstants");
const RuntimeGlobals = require("../RuntimeGlobals");
const Template = require("../Template");
const AsyncWasmLoadingRuntimeModule = require("../wasm-async/AsyncWasmLoadingRuntimeModule");

/** @typedef {import("../Chunk")} Chunk */
/** @typedef {import("../Compiler")} Compiler */

/**
 * @typedef {object} ReadFileCompileAsyncWasmPluginOptions
 * @property {boolean=} import use import?
 */

const PLUGIN_NAME = "ReadFileCompileAsyncWasmPlugin";

class ReadFileCompileAsyncWasmPlugin {
	/**
	 * @param {ReadFileCompileAsyncWasmPluginOptions=} options options object
	 */
	constructor({ import: useImport = false } = {}) {
		this._import = useImport;
	}

	/**
	 * Apply the plugin
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		compiler.hooks.thisCompilation.tap(PLUGIN_NAME, compilation => {
			const globalWasmLoading = compilation.outputOptions.wasmLoading;
			/**
			 * @param {Chunk} chunk chunk
			 * @returns {boolean} true, if wasm loading is enabled for the chunk
			 */
			const isEnabledForChunk = chunk => {
				const options = chunk.getEntryOptions();
				const wasmLoading =
					options && options.wasmLoading !== undefined
						? options.wasmLoading
						: globalWasmLoading;
				return wasmLoading === "async-node";
			};

			/**
			 * @type {(path: string) => string} callback to generate code to load the wasm file
			 */
			const generateLoadBinaryCode = this._import
				? path =>
						Template.asString([
							"Promise.all([import('fs'), import('url')]).then(([{ readFile }, { URL }]) => new Promise((resolve, reject) => {",
							Template.indent([
								`readFile(new URL(${path}, ${compilation.outputOptions.importMetaName}.url), (err, buffer) => {`,
								Template.indent([
									"if (err) return reject(err);",
									"",
									"// Fake fetch response",
									"resolve({",
									Template.indent(["arrayBuffer() { return buffer; }"]),
									"});"
								]),
								"});"
							]),
							"}))"
						])
				: path =>
						Template.asString([
							"new Promise(function (resolve, reject) {",
							Template.indent([
								"try {",
								Template.indent([
									"var { readFile } = require('fs');",
									"var { join } = require('path');",
									"",
									`readFile(join(__dirname, ${path}), function(err, buffer){`,
									Template.indent([
										"if (err) return reject(err);",
										"",
										"// Fake fetch response",
										"resolve({",
										Template.indent(["arrayBuffer() { return buffer; }"]),
										"});"
									]),
									"});"
								]),
								"} catch (err) { reject(err); }"
							]),
							"})"
						]);

			compilation.hooks.runtimeRequirementInTree
				.for(RuntimeGlobals.instantiateWasm)
				.tap(PLUGIN_NAME, (chunk, set, { chunkGraph }) => {
					if (!isEnabledForChunk(chunk)) return;
					if (
						!chunkGraph.hasModuleInGraph(
							chunk,
							m => m.type === WEBASSEMBLY_MODULE_TYPE_ASYNC
						)
					) {
						return;
					}
					compilation.addRuntimeModule(
						chunk,
						new AsyncWasmLoadingRuntimeModule({
							generateLoadBinaryCode,
							supportsStreaming: false
						})
					);
				});
		});
	}
}

module.exports = ReadFileCompileAsyncWasmPlugin;