webpack/lib/web/FetchCompileAsyncWasmPlugin.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 AsyncWasmCompileRuntimeModule = require("../wasm-async/AsyncWasmCompileRuntimeModule");
const AsyncWasmLoadingRuntimeModule = require("../wasm-async/AsyncWasmLoadingRuntimeModule");

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

const PLUGIN_NAME = "FetchCompileAsyncWasmPlugin";

/**
 * Enables asynchronous WebAssembly loading through `fetch` for environments
 * that can instantiate fetched binaries at runtime.
 */
class FetchCompileAsyncWasmPlugin {
	/**
	 * Registers compilation hooks that attach the async fetch-based wasm runtime
	 * to chunks containing async WebAssembly modules.
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		compiler.hooks.thisCompilation.tap(PLUGIN_NAME, (compilation) => {
			const globalWasmLoading = compilation.outputOptions.wasmLoading;
			/**
			 * Determines whether the chunk should load async WebAssembly binaries
			 * through the `fetch` backend.
			 * @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 === "fetch";
			};
			/**
			 * Generates the runtime expression that downloads the emitted wasm
			 * binary for an async WebAssembly module.
			 * @param {string} path path to the wasm file
			 * @returns {string} code to load the wasm file
			 */
			const generateLoadBinaryCode = (path) =>
				`fetch(${RuntimeGlobals.publicPath} + ${path})`;

			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;
					}
					set.add(RuntimeGlobals.publicPath);
					compilation.addRuntimeModule(
						chunk,
						new AsyncWasmLoadingRuntimeModule({
							generateLoadBinaryCode,
							supportsStreaming: true
						})
					);
				});

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

module.exports = FetchCompileAsyncWasmPlugin;