/
runtime.ts
195 lines (165 loc) · 4.82 KB
/
runtime.ts
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import { readPackageJSON } from "pkg-types";
import {
UMWASM_HELPERS_ID,
UNWASM_EXTERNAL_PREFIX,
WasmAsset,
UnwasmPluginOptions,
} from "./shared";
// https://marketplace.visualstudio.com/items?itemName=Tobermory.es6-string-html
const js = String.raw;
export async function getWasmBinding(
asset: WasmAsset,
opts: UnwasmPluginOptions,
) {
// -- Auto load imports --
const autoImports = await getWasmImports(asset, opts);
// --- Environment dependent code to initialize the wasm module using inlined base 64 or dynamic import ---
const envCode: string = opts.esmImport
? js`
${autoImports.code};
async function _instantiate(imports = _imports) {
const _mod = await import("${UNWASM_EXTERNAL_PREFIX}${asset.name}").then(r => r.default || r);
return WebAssembly.instantiate(_mod, imports)
}
`
: js`
import { base64ToUint8Array } from "${UMWASM_HELPERS_ID}";
${autoImports.code};
function _instantiate(imports = _imports) {
const _data = base64ToUint8Array("${asset.source.toString("base64")}")
return WebAssembly.instantiate(_data, imports)
}
`;
// --- Binding code to export the wasm module exports ---
const canTopAwait = opts.lazy !== true && autoImports.resolved;
// eslint-disable-next-line unicorn/prefer-ternary
if (canTopAwait) {
// -- Non proxied exports when no imports are needed and we can have top-level await ---
return js`
import { getExports } from "${UMWASM_HELPERS_ID}";
${envCode}
const $exports = getExports(await _instantiate());
${asset.exports
.map((name) => `export const ${name} = $exports.${name};`)
.join("\n")}
const defaultExport = () => $exports;
${asset.exports.map((name) => `defaultExport["${name}"] = $exports.${name};`).join("\n")}
export default defaultExport;
`;
} else {
// --- Proxied exports when imports are needed or we can't have top-level await ---
return js`
import { createLazyWasmModule } from "${UMWASM_HELPERS_ID}";
${envCode}
const _mod = createLazyWasmModule(_instantiate);
${asset.exports
.map((name) => `export const ${name} = _mod.${name};`)
.join("\n")}
export default _mod;
`;
}
}
export function getPluginUtils() {
// --- Shared utils for the generated code ---
return js`
export function debug(...args) {
console.log('[wasm] [debug]', ...args);
}
export function getExports(input) {
return input?.instance?.exports || input?.exports || input;
}
export function base64ToUint8Array(str) {
const data = atob(str);
const size = data.length;
const bytes = new Uint8Array(size);
for (let i = 0; i < size; i++) {
bytes[i] = data.charCodeAt(i);
}
return bytes;
}
export function createLazyWasmModule(_instantiator) {
const _exports = Object.create(null);
let _loaded;
let _promise;
const init = (imports) => {
if (_loaded) {
return Promise.resolve(exportsProxy);
}
if (_promise) {
return _promise;
}
return _promise = _instantiator(imports)
.then(r => {
Object.assign(_exports, getExports(r));
_loaded = true;
_promise = undefined;
return exportsProxy;
})
.catch(error => {
_promise = undefined;
console.error('[wasm] [error]', error);
throw error;
});
}
const exportsProxy = new Proxy(_exports, {
get(_, prop) {
if (_loaded) {
return _exports[prop];
}
return (...args) => {
return _loaded
? _exports[prop]?.(...args)
: init().then(() => _exports[prop]?.(...args));
};
},
});
const lazyProxy = new Proxy(() => {}, {
get(_, prop) {
return exportsProxy[prop];
},
apply(_, __, args) {
return init(args[0])
},
});
return lazyProxy;
}
`;
}
export async function getWasmImports(
asset: WasmAsset,
_opts: UnwasmPluginOptions, // eslint-disable-line @typescript-eslint/no-unused-vars
) {
const importNames = Object.keys(asset.imports || {});
if (importNames.length === 0) {
return {
code: "const _imports = { /* no imports */ }",
resolved: true,
};
}
// Try to resolve from nearest package.json
const pkgJSON = await readPackageJSON(asset.id);
let code = "const _imports = {";
let resolved = true;
for (const moduleName of importNames) {
const importNames = asset.imports[moduleName];
const pkgImport =
pkgJSON.imports?.[moduleName] || pkgJSON.imports?.[`#${moduleName}`];
if (pkgImport) {
code = `import * as _imports_${moduleName} from "${pkgImport}";\n${code}`;
} else {
resolved = false;
}
code += `\n ${moduleName}: {`;
for (const name of importNames) {
code += pkgImport
? `\n ${name}: _imports_${moduleName}.${name},\n`
: `\n ${name}: () => { throw new Error("\`${moduleName}.${name}\` is not provided!")},\n`;
}
code += " },\n";
}
code += "};\n";
return {
code,
resolved,
};
}