webpack/lib/wasm/WasmMainTemplatePlugin.js

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

const Template = require("../Template");
const WebAssemblyImportDependency = require("../dependencies/WebAssemblyImportDependency");

// Get all wasm modules
function getAllWasmModules(chunk) {
	const wasmModules = chunk.getAllAsyncChunks();
	const array = [];
	for (const chunk of wasmModules) {
		for (const m of chunk.modulesIterable) {
			if (m.type.startsWith("webassembly")) {
				array.push(m);
			}
		}
	}

	return array;
}

function generateImportObject(module) {
	const depsByRequest = new Map();
	for (const dep of module.dependencies) {
		if (dep instanceof WebAssemblyImportDependency) {
			// Ignore global they will be handled later
			if (dep.description.type === "GlobalType") {
				continue;
			}

			const request = dep.request;
			let array = depsByRequest.get(request);
			if (!array) {
				depsByRequest.set(request, (array = []));
			}
			const exportName = dep.name;
			const usedName = dep.module && dep.module.isUsed(exportName);

			if (usedName !== false) {
				array.push({
					exportName,
					usedName,
					module: dep.module,
					description: dep.description
				});
			}
		}
	}
	const importsCode = [];
	for (const pair of depsByRequest) {
		const properties = [];
		for (const data of pair[1]) {
			const params = data.description.params.map(
				(param, k) => "p" + k + param.valtype
			);

			const result = `__webpack_require__(${JSON.stringify(
				data.module.id
			)})[${JSON.stringify(data.usedName)}](${params})`;

			properties.push(
				`\n\t\t${JSON.stringify(data.exportName)}: function(${params}) {
                      return ${result};
                    }`
			);
		}

		importsCode.push(
			`\n\t${JSON.stringify(pair[0])}: {${properties.join(",")}\n\t}`
		);
	}

	return JSON.stringify(module.id) + ": {" + importsCode.join(",") + "\n},";
}

class WasmMainTemplatePlugin {
	constructor(generateLoadBinaryCode) {
		this.generateLoadBinaryCode = generateLoadBinaryCode;
	}
	apply(mainTemplate) {
		mainTemplate.hooks.localVars.tap(
			"WasmMainTemplatePlugin",
			(source, chunk) => {
				if (!chunk.hasModuleInGraph(m => m.type.startsWith("webassembly")))
					return source;
				return Template.asString([
					source,
					"",
					"// object to store loaded and loading wasm modules",
					"var installedWasmModules = {};"
				]);
			}
		);
		mainTemplate.hooks.requireEnsure.tap(
			"WasmMainTemplatePlugin",
			(source, chunk, hash) => {
				const webassemblyModuleFilename =
					mainTemplate.outputOptions.webassemblyModuleFilename;

				const wasmModules = getAllWasmModules(chunk);
				const importObjects = wasmModules.map(generateImportObject);

				const chunkModuleMaps = chunk.getChunkModuleMaps(m =>
					m.type.startsWith("webassembly")
				);
				if (Object.keys(chunkModuleMaps.id).length === 0) return source;
				const wasmModuleSrcPath = mainTemplate.getAssetPath(
					JSON.stringify(webassemblyModuleFilename),
					{
						hash: `" + ${mainTemplate.renderCurrentHashCode(hash)} + "`,
						hashWithLength: length =>
							`" + ${mainTemplate.renderCurrentHashCode(hash, length)} + "`,
						module: {
							id: '" + wasmModuleId + "',
							hash: `" + ${JSON.stringify(
								chunkModuleMaps.hash
							)}[wasmModuleId] + "`,
							hashWithLength(length) {
								const shortChunkHashMap = Object.create(null);
								for (const wasmModuleId of Object.keys(chunkModuleMaps.hash)) {
									if (typeof chunkModuleMaps.hash[wasmModuleId] === "string")
										shortChunkHashMap[wasmModuleId] = chunkModuleMaps.hash[
											wasmModuleId
										].substr(0, length);
								}
								return `" + ${JSON.stringify(
									shortChunkHashMap
								)}[wasmModuleId] + "`;
							}
						}
					}
				);
				return Template.asString([
					source,
					"",
					"// Fetch + compile chunk loading for webassembly",
					"",
					"var importObjects = {",
					Template.indent([importObjects]),
					"}",
					"",
					`var wasmModules = ${JSON.stringify(
						chunkModuleMaps.id
					)}[chunkId] || [];`,
					"",
					"wasmModules.forEach(function(wasmModuleId) {",
					Template.indent([
						"var installedWasmModuleData = installedWasmModules[wasmModuleId];",
						"",
						'// a Promise means "currently loading" or "already loaded".',
						Template.indent([
							`var importObject = importObjects[wasmModuleId]`,
							`var req = ${this.generateLoadBinaryCode(wasmModuleSrcPath)}`,
							"if(typeof WebAssembly.instantiateStreaming === 'function') {",
							Template.indent([
								"promises.push(WebAssembly.instantiateStreaming(req, importObject)",
								".then(function(res) {",
								Template.indent([
									`${
										mainTemplate.requireFn
									}.w[wasmModuleId] = installedWasmModules[wasmModuleId] = res.instance;`
								]),
								"}))"
							]),
							"} else {",
							Template.indent([
								"var promise = req.then(x => x.arrayBuffer()).then(function(bytes) {",
								Template.indent([
									"return WebAssembly.instantiate(bytes, importObject);"
								]),
								"}).then(function(res) {",
								Template.indent([
									`${
										mainTemplate.requireFn
									}.w[wasmModuleId] = installedWasmModules[wasmModuleId] = res.instance;`,
									"return res.instance"
								]),
								"})",
								"promises.push(promise);"
							]),
							"}"
						])
					]),
					"});"
				]);
			}
		);
		mainTemplate.hooks.requireExtensions.tap(
			"WasmMainTemplatePlugin",
			(source, chunk) => {
				if (!chunk.hasModuleInGraph(m => m.type.startsWith("webassembly")))
					return source;
				return Template.asString([
					source,
					"",
					"// object with all WebAssembly.instance",
					`${mainTemplate.requireFn}.w = {};`
				]);
			}
		);
		mainTemplate.hooks.hash.tap("WasmMainTemplatePlugin", hash => {
			hash.update("WasmMainTemplatePlugin");
			hash.update("1");
			hash.update(`${mainTemplate.outputOptions.webassemblyModuleFilename}`);
		});
	}
}

module.exports = WasmMainTemplatePlugin;