feat: add wasi preview2 shim for browser and nodejs

packages/preview2-shim/browser/clocks.js

@@ -0,0 +1,47 @@
+export function wallClockNow(clock) {
+  if (clock === 1) {
+    const seconds = BigInt(Math.floor(Date.now() / 1000));
+    const nanoseconds = (Date.now() % 1000) * 1000 * 1000;
+    return { seconds, nanoseconds };
+  }
+  console.log("[clocks] UNKNOWN CLOCK");
+}
+
+export function monotonicClockResolution(clock) {
+  console.log(`[clocks] Monotonic clock resolution ${clock}`);
+}
+
+export function wallClockResolution(clock) {
+  console.log(`[clocks] Wall clock resolution ${clock}`);
+}
+
+let hrStart = hrtimeBigint();
+
+export function monotonicClockNow(clock) {
+  if (clock === 0) {
+    return hrtimeBigint() - hrStart;
+  }
+  console.log("UNKNOWN CLOCK");
+}
+
+function hrtime(previousTimestamp) {
+  const baseNow = Math.floor((Date.now() - performance.now()) * 1e-3);
+  const clocktime = performance.now() * 1e-3;
+  let seconds = Math.floor(clocktime) + baseNow;
+  let nanoseconds = Math.floor((clocktime % 1) * 1e9);
+
+  if (previousTimestamp) {
+    seconds = seconds - previousTimestamp[0];
+    nanoseconds = nanoseconds - previousTimestamp[1];
+    if (nanoseconds < 0) {
+      seconds--;
+      nanoseconds += 1e9;
+    }
+  }
+  return [seconds, nanoseconds];
+}
+
+function hrtimeBigint(time) {
+  const diff = hrtime(time);
+  return BigInt(diff[0] * 1e9 + diff[1]);
+}

packages/preview2-shim/browser/default-clocks.js

@@ -0,0 +1,7 @@
+export function defaultMonotonicClock() {
+  return 0;
+}
+
+export function defaultWallClock() {
+  return 1;
+}

packages/preview2-shim/browser/exit.js

@@ -0,0 +1,21 @@
+class FailureExit extends Error {
+  code = 1;
+  constructor() {
+    super("failure-exit");
+  }
+}
+
+class SuccessfulExit extends Error {
+  code = 0;
+  constructor() {
+    super("successful-exit");
+  }
+}
+
+export function exit(status) {
+  console.log(`[exit] Exit: ${JSON.stringify(status)}`);
+  if (status.tag === "err") {
+    throw new FailureExit();
+  }
+  throw new SuccessfulExit();
+}

packages/preview2-shim/browser/filesystem.js

@@ -0,0 +1,47 @@
+export function flags(fd) {
+  console.log(`[filesystem] FLAGS FOR ${fd}`);
+}
+
+export function setFlags(fd, flags) {
+  console.log(`[filesystem] SET FLAGS ${fd} ${JSON.stringify(flags)}`);
+}
+
+export function close(fd) {
+  console.log(`[filesystem] CLOSE: ${fd}`);
+}
+
+export function removeDirectoryAt(fd, path) {
+  console.log(`[filesystem] RM DIR: ${fd} ${path}`);
+}
+
+export function unlinkFileAt(fd, path) {
+  console.log(`[filesystem] UNLINK: ${fd} ${path}`);
+}
+
+export function writeViaStream(fd, offset) {
+  console.log(`[filesystem] WRITE STREAM ${fd} ${offset}`);
+}
+
+export function appendViaStream(fd, offset) {
+  console.log(`[filesystem] APPEND STREAM ${fd} ${offset}`);
+}
+
+export function readViaStream(fd, offset) {
+  console.log(`[filesystem] READ STREAM ${fd} ${offset}`);
+}
+
+export function openAt(fd, atFlags, path, offset) {
+  console.log(`[filesystem] OPEN AT ${fd}`);
+}
+
+export function stat(fd) {
+  console.log(`[filesystem] STAT: ${fd}`);
+}
+
+export function todoType(fd) {
+  console.log(`[filesystem] TODO TYPE: ${fd}`);
+}
+
+export function closeDirEntryStream(s) {
+  console.log(`[filesystem] CLOSE DIR ENTRY STREAM`);
+}

packages/preview2-shim/browser/http.js

@@ -0,0 +1,28 @@
+import { UnexpectedError } from "../http/error.js";
+
+/**
+ * @param {import("../types/wasi-http").Request} req
+ * @returns {string}
+ */
+export function send(req) {
+  console.log(`[http] Send (browser) ${req.uri}`);
+  try {
+    const xhr = new XMLHttpRequest();
+    xhr.open(req.method.toString(), req.uri, false);
+    xhr.responseType = "arraybuffer";
+    for (let [name, value] of req.headers) {
+      xhr.setRequestHeader(name, value);
+    }
+    xhr.send(req.body.length > 0 ? req.body : null);
+    return {
+      status: xhr.status,
+      headers: xhr
+        .getAllResponseHeaders()
+        .trim()
+        .split(/[\r\n]+/),
+      body: xhr.response.byteLength > 0 ? xhr.response : undefined,
+    };
+  } catch (err) {
+    throw new UnexpectedError(err.message);
+  }
+}

packages/preview2-shim/browser/index.js

@@ -0,0 +1,21 @@
+import * as clocks from "./clocks.js";
+import * as defaultClocks from "./default-clocks.js";
+import * as exit from "./exit.js";
+import * as filesystem from "./filesystem.js";
+import * as io from "./io.js";
+import * as logging from "./logging.js";
+import * as poll from "./poll.js";
+import * as random from "./random.js";
+import * as stderr from "./stderr.js";
+
+export const importObject = {
+    "wasi-clocks": clocks,
+    "wasi-default-clocks": defaultClocks,
+    "wasi-exit": exit,
+    "wasi-filesystem": filesystem,
+    "wasi-io": io,
+    "wasi-logging": logging,
+    "wasi-poll": poll,
+    "wasi-random": random,
+    "wasi-stderr": stderr,
+};

packages/preview2-shim/browser/io.js

@@ -0,0 +1,34 @@
+export function dropInputStream(f) {
+  console.log(`[io] Drop input stream ${f}`);
+}
+
+export function dropOutputStream(f) {
+  console.log(`[io] Drop output stream ${f}`);
+}
+
+export function read(src, len) {
+  console.log(`[io] Read ${src}`);
+}
+
+export function write(dst, buf) {
+  switch (dst) {
+    case 0:
+      throw new Error(`TODO: write stdin`);
+    case 1:
+      const decoder = new TextDecoder();
+      console.log(decoder.decode(buf));
+      return BigInt(buf.byteLength);
+    case 2:
+      throw new Error(`TODO: write stdout`);
+    default:
+      throw new Error(`TODO: write ${dst}`);
+  }
+}
+
+export function skip(src, len) {
+  console.log(`[io] Skip ${src}`);
+}
+
+export function write_repeated(dst, byte, len) {
+  console.log(`[io] Write repeated ${dst}`);
+}

packages/preview2-shim/browser/logging.js

@@ -0,0 +1,12 @@
+const levels = ["trace", "debug", "info", "warn", "error"];
+
+let logLevel = levels.indexOf("warn");
+
+export function setLevel(level) {
+  logLevel = levels.indexOf(level);
+}
+
+export function log(level, context, msg) {
+  if (logLevel > levels.indexOf(level)) return;
+  console[level](`(${context}) ${msg}\n`);
+}

packages/preview2-shim/browser/poll.js

@@ -0,0 +1,3 @@
+export function pollOneoff(f) {
+  console.log(`[poll] Poll oneoff ${f}`);
+}

packages/preview2-shim/browser/random.js

@@ -0,0 +1,19 @@
+const MAX_BYTES = 65536;
+
+export function getRandomBytes(len) {
+  const bytes = new Uint8Array(len);
+
+  if (len > MAX_BYTES) {
+    // this is the max bytes crypto.getRandomValues
+    // can do at once see https://developer.mozilla.org/en-US/docs/Web/API/window.crypto.getRandomValues
+    for (var generated = 0; generated < len; generated += MAX_BYTES) {
+      // buffer.slice automatically checks if the end is past the end of
+      // the buffer so we don't have to here
+      crypto.getRandomValues(bytes.slice(generated, generated + MAX_BYTES));
+    }
+  } else {
+    crypto.getRandomValues(bytes);
+  }
+
+  return bytes;
+}

packages/preview2-shim/browser/stderr.js

@@ -0,0 +1,3 @@
+export function print(message) {
+  console.error(`${message}\n`);
+}

packages/preview2-shim/http/error.js

@@ -0,0 +1,11 @@
+export class UnexpectedError extends Error {
+  /** @type { import("../types/wasi-http").HttpErrorUnexpectedError } */
+  payload;
+  constructor(message = "unexpected-error") {
+    super(message);
+    this.payload = {
+      tag: "unexpected-error",
+      val: message,
+    };
+  }
+}

packages/preview2-shim/http/make-request.js

@@ -0,0 +1,29 @@
+import { runAsWorker } from "synckit";
+
+/**
+ * @param {import("../types/wasi-http").Request} req
+ * @returns {Promise<string>}
+ */
+async function makeRequest(req) {
+  try {
+    let headers = new Headers(req.headers);
+    const resp = await fetch(req.uri, {
+      method: req.method.toString(),
+      headers,
+      body: req.body.length > 0 ? req.body : undefined,
+    });
+    let arrayBuffer = await resp.arrayBuffer();
+    return JSON.stringify({
+      status: resp.status,
+      headers: resp.headers,
+      body:
+        arrayBuffer.byteLength > 0
+          ? Buffer.from(arrayBuffer).toString("base64")
+          : undefined,
+    });
+  } catch (err) {
+    return err.message;
+  }
+}
+
+runAsWorker(makeRequest);

packages/preview2-shim/index.d.ts

@@ -0,0 +1,9 @@
+export * as clocks from "./types/wasi-clocks";
+export * as defaultClocks from "./types/wasi-default-clocks";
+export * as exit from "./types/wasi-exit";
+export * as filesystem from "./types/wasi-filesystem";
+export * as io from "./types/wasi-io";
+export * as logging from "./types/wasi-logging";
+export * as poll from "./types/wasi-poll";
+export * as random from "./types/wasi-random";
+export * as stderr from "./types/wasi-stderr";

packages/preview2-shim/index.js

@@ -0,0 +1 @@
+export * from "./nodejs/index.js";

packages/preview2-shim/nodejs/clocks.js

@@ -0,0 +1,27 @@
+import { hrtime } from "node:process";
+
+export function wallClockNow(clock) {
+  if (clock === 1) {
+    const seconds = BigInt(Math.floor(Date.now() / 1000));
+    const nanoseconds = (Date.now() % 1000) * 1000 * 1000;
+    return { seconds, nanoseconds };
+  }
+  console.log("[clocks] UNKNOWN CLOCK");
+}
+
+export function monotonicClockResolution(clock) {
+  console.log(`[clocks] Monotonic clock resolution ${clock}`);
+}
+
+export function wallClockResolution(clock) {
+  console.log(`[clocks] Wall clock resolution ${clock}`);
+}
+
+let hrStart = hrtime.bigint();
+
+export function monotonicClockNow(clock) {
+  if (clock === 0) {
+    return hrtime.bigint() - hrStart;
+  }
+  console.log("[clocks] UNKNOWN CLOCK");
+}

packages/preview2-shim/nodejs/default-clocks.js

@@ -0,0 +1,7 @@
+export function defaultMonotonicClock() {
+  return 0;
+}
+
+export function defaultWallClock() {
+  return 1;
+}

packages/preview2-shim/nodejs/exit.js

@@ -0,0 +1,4 @@
+export function exit(status) {
+  console.log(`[exit] Exit: ${JSON.stringify(status)}`);
+  process.exit(status.tag === 'err' ? 1 : 0);
+}