1// Copyright 2018 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5"use strict";
6
7(() => {
8 const enosys = () => {
9 const err = new Error("not implemented");
10 err.code = "ENOSYS";
11 return err;
12 };
13
14 if (!globalThis.fs) {
15 let outputBuf = "";
16 globalThis.fs = {
17 constants: { O_WRONLY: -1, O_RDWR: -1, O_CREAT: -1, O_TRUNC: -1, O_APPEND: -1, O_EXCL: -1 }, // unused
18 writeSync(fd, buf) {
19 outputBuf += decoder.decode(buf);
20 const nl = outputBuf.lastIndexOf("\n");
21 if (nl != -1) {
22 console.log(outputBuf.substring(0, nl));
23 outputBuf = outputBuf.substring(nl + 1);
24 }
25 return buf.length;
26 },
27 write(fd, buf, offset, length, position, callback) {
28 if (offset !== 0 || length !== buf.length || position !== null) {
29 callback(enosys());
30 return;
31 }
32 const n = this.writeSync(fd, buf);
33 callback(null, n);
34 },
35 chmod(path, mode, callback) { callback(enosys()); },
36 chown(path, uid, gid, callback) { callback(enosys()); },
37 close(fd, callback) { callback(enosys()); },
38 fchmod(fd, mode, callback) { callback(enosys()); },
39 fchown(fd, uid, gid, callback) { callback(enosys()); },
40 fstat(fd, callback) { callback(enosys()); },
41 fsync(fd, callback) { callback(null); },
42 ftruncate(fd, length, callback) { callback(enosys()); },
43 lchown(path, uid, gid, callback) { callback(enosys()); },
44 link(path, link, callback) { callback(enosys()); },
45 lstat(path, callback) { callback(enosys()); },
46 mkdir(path, perm, callback) { callback(enosys()); },
47 open(path, flags, mode, callback) { callback(enosys()); },
48 read(fd, buffer, offset, length, position, callback) { callback(enosys()); },
49 readdir(path, callback) { callback(enosys()); },
50 readlink(path, callback) { callback(enosys()); },
51 rename(from, to, callback) { callback(enosys()); },
52 rmdir(path, callback) { callback(enosys()); },
53 stat(path, callback) { callback(enosys()); },
54 symlink(path, link, callback) { callback(enosys()); },
55 truncate(path, length, callback) { callback(enosys()); },
56 unlink(path, callback) { callback(enosys()); },
57 utimes(path, atime, mtime, callback) { callback(enosys()); },
58 };
59 }
60
61 if (!globalThis.process) {
62 globalThis.process = {
63 getuid() { return -1; },
64 getgid() { return -1; },
65 geteuid() { return -1; },
66 getegid() { return -1; },
67 getgroups() { throw enosys(); },
68 pid: -1,
69 ppid: -1,
70 umask() { throw enosys(); },
71 cwd() { throw enosys(); },
72 chdir() { throw enosys(); },
73 }
74 }
75
76 if (!globalThis.crypto) {
77 throw new Error("globalThis.crypto is not available, polyfill required (crypto.getRandomValues only)");
78 }
79
80 if (!globalThis.performance) {
81 throw new Error("globalThis.performance is not available, polyfill required (performance.now only)");
82 }
83
84 if (!globalThis.TextEncoder) {
85 throw new Error("globalThis.TextEncoder is not available, polyfill required");
86 }
87
88 if (!globalThis.TextDecoder) {
89 throw new Error("globalThis.TextDecoder is not available, polyfill required");
90 }
91
92 const encoder = new TextEncoder("utf-8");
93 const decoder = new TextDecoder("utf-8");
94
95 globalThis.Go = class {
96 constructor() {
97 this.argv = ["js"];
98 this.env = {};
99 this.exit = (code) => {
100 if (code !== 0) {
101 console.warn("exit code:", code);
102 }
103 };
104 this._exitPromise = new Promise((resolve) => {
105 this._resolveExitPromise = resolve;
106 });
107 this._pendingEvent = null;
108 this._scheduledTimeouts = new Map();
109 this._nextCallbackTimeoutID = 1;
110
111 const setInt64 = (addr, v) => {
112 this.mem.setUint32(addr + 0, v, true);
113 this.mem.setUint32(addr + 4, Math.floor(v / 4294967296), true);
114 }
115
116 const getInt64 = (addr) => {
117 const low = this.mem.getUint32(addr + 0, true);
118 const high = this.mem.getInt32(addr + 4, true);
119 return low + high * 4294967296;
120 }
121
122 const loadValue = (addr) => {
123 const f = this.mem.getFloat64(addr, true);
124 if (f === 0) {
125 return undefined;
126 }
127 if (!isNaN(f)) {
128 return f;
129 }
130
131 const id = this.mem.getUint32(addr, true);
132 return this._values[id];
133 }
134
135 const storeValue = (addr, v) => {
136 const nanHead = 0x7FF80000;
137
138 if (typeof v === "number" && v !== 0) {
139 if (isNaN(v)) {
140 this.mem.setUint32(addr + 4, nanHead, true);
141 this.mem.setUint32(addr, 0, true);
142 return;
143 }
144 this.mem.setFloat64(addr, v, true);
145 return;
146 }
147
148 if (v === undefined) {
149 this.mem.setFloat64(addr, 0, true);
150 return;
151 }
152
153 let id = this._ids.get(v);
154 if (id === undefined) {
155 id = this._idPool.pop();
156 if (id === undefined) {
157 id = this._values.length;
158 }
159 this._values[id] = v;
160 this._goRefCounts[id] = 0;
161 this._ids.set(v, id);
162 }
163 this._goRefCounts[id]++;
164 let typeFlag = 0;
165 switch (typeof v) {
166 case "object":
167 if (v !== null) {
168 typeFlag = 1;
169 }
170 break;
171 case "string":
172 typeFlag = 2;
173 break;
174 case "symbol":
175 typeFlag = 3;
176 break;
177 case "function":
178 typeFlag = 4;
179 break;
180 }
181 this.mem.setUint32(addr + 4, nanHead | typeFlag, true);
182 this.mem.setUint32(addr, id, true);
183 }
184
185 const loadSlice = (addr) => {
186 const array = getInt64(addr + 0);
187 const len = getInt64(addr + 8);
188 return new Uint8Array(this._inst.exports.mem.buffer, array, len);
189 }
190
191 const loadSliceOfValues = (addr) => {
192 const array = getInt64(addr + 0);
193 const len = getInt64(addr + 8);
194 const a = new Array(len);
195 for (let i = 0; i < len; i++) {
196 a[i] = loadValue(array + i * 8);
197 }
198 return a;
199 }
200
201 const loadString = (addr) => {
202 const saddr = getInt64(addr + 0);
203 const len = getInt64(addr + 8);
204 return decoder.decode(new DataView(this._inst.exports.mem.buffer, saddr, len));
205 }
206
207 const timeOrigin = Date.now() - performance.now();
208 this.importObject = {
209 go: {
210 // Go's SP does not change as long as no Go code is running. Some operations (e.g. calls, getters and setters)
211 // may synchronously trigger a Go event handler. This makes Go code get executed in the middle of the imported
212 // function. A goroutine can switch to a new stack if the current stack is too small (see morestack function).
213 // This changes the SP, thus we have to update the SP used by the imported function.
214
215 // func wasmExit(code int32)
216 "runtime.wasmExit": (sp) => {
217 sp >>>= 0;
218 const code = this.mem.getInt32(sp + 8, true);
219 this.exited = true;
220 delete this._inst;
221 delete this._values;
222 delete this._goRefCounts;
223 delete this._ids;
224 delete this._idPool;
225 this.exit(code);
226 },
227
228 // func wasmWrite(fd uintptr, p unsafe.Pointer, n int32)
229 "runtime.wasmWrite": (sp) => {
230 sp >>>= 0;
231 const fd = getInt64(sp + 8);
232 const p = getInt64(sp + 16);
233 const n = this.mem.getInt32(sp + 24, true);
234 fs.writeSync(fd, new Uint8Array(this._inst.exports.mem.buffer, p, n));
235 },
236
237 // func resetMemoryDataView()
238 "runtime.resetMemoryDataView": (sp) => {
239 sp >>>= 0;
240 this.mem = new DataView(this._inst.exports.mem.buffer);
241 },
242
243 // func nanotime1() int64
244 "runtime.nanotime1": (sp) => {
245 sp >>>= 0;
246 setInt64(sp + 8, (timeOrigin + performance.now()) * 1000000);
247 },
248
249 // func walltime() (sec int64, nsec int32)
250 "runtime.walltime": (sp) => {
251 sp >>>= 0;
252 const msec = (new Date).getTime();
253 setInt64(sp + 8, msec / 1000);
254 this.mem.setInt32(sp + 16, (msec % 1000) * 1000000, true);
255 },
256
257 // func scheduleTimeoutEvent(delay int64) int32
258 "runtime.scheduleTimeoutEvent": (sp) => {
259 sp >>>= 0;
260 const id = this._nextCallbackTimeoutID;
261 this._nextCallbackTimeoutID++;
262 this._scheduledTimeouts.set(id, setTimeout(
263 () => {
264 this._resume();
265 while (this._scheduledTimeouts.has(id)) {
266 // for some reason Go failed to register the timeout event, log and try again
267 // (temporary workaround for https://github.com/golang/go/issues/28975)
268 console.warn("scheduleTimeoutEvent: missed timeout event");
269 this._resume();
270 }
271 },
272 getInt64(sp + 8) + 1, // setTimeout has been seen to fire up to 1 millisecond early
273 ));
274 this.mem.setInt32(sp + 16, id, true);
275 },
276
277 // func clearTimeoutEvent(id int32)
278 "runtime.clearTimeoutEvent": (sp) => {
279 sp >>>= 0;
280 const id = this.mem.getInt32(sp + 8, true);
281 clearTimeout(this._scheduledTimeouts.get(id));
282 this._scheduledTimeouts.delete(id);
283 },
284
285 // func getRandomData(r []byte)
286 "runtime.getRandomData": (sp) => {
287 sp >>>= 0;
288 crypto.getRandomValues(loadSlice(sp + 8));
289 },
290
291 // func finalizeRef(v ref)
292 "syscall/js.finalizeRef": (sp) => {
293 sp >>>= 0;
294 const id = this.mem.getUint32(sp + 8, true);
295 this._goRefCounts[id]--;
296 if (this._goRefCounts[id] === 0) {
297 const v = this._values[id];
298 this._values[id] = null;
299 this._ids.delete(v);
300 this._idPool.push(id);
301 }
302 },
303
304 // func stringVal(value string) ref
305 "syscall/js.stringVal": (sp) => {
306 sp >>>= 0;
307 storeValue(sp + 24, loadString(sp + 8));
308 },
309
310 // func valueGet(v ref, p string) ref
311 "syscall/js.valueGet": (sp) => {
312 sp >>>= 0;
313 const result = Reflect.get(loadValue(sp + 8), loadString(sp + 16));
314 sp = this._inst.exports.getsp() >>> 0; // see comment above
315 storeValue(sp + 32, result);
316 },
317
318 // func valueSet(v ref, p string, x ref)
319 "syscall/js.valueSet": (sp) => {
320 sp >>>= 0;
321 Reflect.set(loadValue(sp + 8), loadString(sp + 16), loadValue(sp + 32));
322 },
323
324 // func valueDelete(v ref, p string)
325 "syscall/js.valueDelete": (sp) => {
326 sp >>>= 0;
327 Reflect.deleteProperty(loadValue(sp + 8), loadString(sp + 16));
328 },
329
330 // func valueIndex(v ref, i int) ref
331 "syscall/js.valueIndex": (sp) => {
332 sp >>>= 0;
333 storeValue(sp + 24, Reflect.get(loadValue(sp + 8), getInt64(sp + 16)));
334 },
335
336 // valueSetIndex(v ref, i int, x ref)
337 "syscall/js.valueSetIndex": (sp) => {
338 sp >>>= 0;
339 Reflect.set(loadValue(sp + 8), getInt64(sp + 16), loadValue(sp + 24));
340 },
341
342 // func valueCall(v ref, m string, args []ref) (ref, bool)
343 "syscall/js.valueCall": (sp) => {
344 sp >>>= 0;
345 try {
346 const v = loadValue(sp + 8);
347 const m = Reflect.get(v, loadString(sp + 16));
348 const args = loadSliceOfValues(sp + 32);
349 const result = Reflect.apply(m, v, args);
350 sp = this._inst.exports.getsp() >>> 0; // see comment above
351 storeValue(sp + 56, result);
352 this.mem.setUint8(sp + 64, 1);
353 } catch (err) {
354 sp = this._inst.exports.getsp() >>> 0; // see comment above
355 storeValue(sp + 56, err);
356 this.mem.setUint8(sp + 64, 0);
357 }
358 },
359
360 // func valueInvoke(v ref, args []ref) (ref, bool)
361 "syscall/js.valueInvoke": (sp) => {
362 sp >>>= 0;
363 try {
364 const v = loadValue(sp + 8);
365 const args = loadSliceOfValues(sp + 16);
366 const result = Reflect.apply(v, undefined, args);
367 sp = this._inst.exports.getsp() >>> 0; // see comment above
368 storeValue(sp + 40, result);
369 this.mem.setUint8(sp + 48, 1);
370 } catch (err) {
371 sp = this._inst.exports.getsp() >>> 0; // see comment above
372 storeValue(sp + 40, err);
373 this.mem.setUint8(sp + 48, 0);
374 }
375 },
376
377 // func valueNew(v ref, args []ref) (ref, bool)
378 "syscall/js.valueNew": (sp) => {
379 sp >>>= 0;
380 try {
381 const v = loadValue(sp + 8);
382 const args = loadSliceOfValues(sp + 16);
383 const result = Reflect.construct(v, args);
384 sp = this._inst.exports.getsp() >>> 0; // see comment above
385 storeValue(sp + 40, result);
386 this.mem.setUint8(sp + 48, 1);
387 } catch (err) {
388 sp = this._inst.exports.getsp() >>> 0; // see comment above
389 storeValue(sp + 40, err);
390 this.mem.setUint8(sp + 48, 0);
391 }
392 },
393
394 // func valueLength(v ref) int
395 "syscall/js.valueLength": (sp) => {
396 sp >>>= 0;
397 setInt64(sp + 16, parseInt(loadValue(sp + 8).length));
398 },
399
400 // valuePrepareString(v ref) (ref, int)
401 "syscall/js.valuePrepareString": (sp) => {
402 sp >>>= 0;
403 const str = encoder.encode(String(loadValue(sp + 8)));
404 storeValue(sp + 16, str);
405 setInt64(sp + 24, str.length);
406 },
407
408 // valueLoadString(v ref, b []byte)
409 "syscall/js.valueLoadString": (sp) => {
410 sp >>>= 0;
411 const str = loadValue(sp + 8);
412 loadSlice(sp + 16).set(str);
413 },
414
415 // func valueInstanceOf(v ref, t ref) bool
416 "syscall/js.valueInstanceOf": (sp) => {
417 sp >>>= 0;
418 this.mem.setUint8(sp + 24, (loadValue(sp + 8) instanceof loadValue(sp + 16)) ? 1 : 0);
419 },
420
421 // func copyBytesToGo(dst []byte, src ref) (int, bool)
422 "syscall/js.copyBytesToGo": (sp) => {
423 sp >>>= 0;
424 const dst = loadSlice(sp + 8);
425 const src = loadValue(sp + 32);
426 if (!(src instanceof Uint8Array || src instanceof Uint8ClampedArray)) {
427 this.mem.setUint8(sp + 48, 0);
428 return;
429 }
430 const toCopy = src.subarray(0, dst.length);
431 dst.set(toCopy);
432 setInt64(sp + 40, toCopy.length);
433 this.mem.setUint8(sp + 48, 1);
434 },
435
436 // func copyBytesToJS(dst ref, src []byte) (int, bool)
437 "syscall/js.copyBytesToJS": (sp) => {
438 sp >>>= 0;
439 const dst = loadValue(sp + 8);
440 const src = loadSlice(sp + 16);
441 if (!(dst instanceof Uint8Array || dst instanceof Uint8ClampedArray)) {
442 this.mem.setUint8(sp + 48, 0);
443 return;
444 }
445 const toCopy = src.subarray(0, dst.length);
446 dst.set(toCopy);
447 setInt64(sp + 40, toCopy.length);
448 this.mem.setUint8(sp + 48, 1);
449 },
450
451 "debug": (value) => {
452 console.log(value);
453 },
454 }
455 };
456 }
457
458 async run(instance) {
459 if (!(instance instanceof WebAssembly.Instance)) {
460 throw new Error("Go.run: WebAssembly.Instance expected");
461 }
462 this._inst = instance;
463 this.mem = new DataView(this._inst.exports.mem.buffer);
464 this._values = [ // JS values that Go currently has references to, indexed by reference id
465 NaN,
466 0,
467 null,
468 true,
469 false,
470 globalThis,
471 this,
472 ];
473 this._goRefCounts = new Array(this._values.length).fill(Infinity); // number of references that Go has to a JS value, indexed by reference id
474 this._ids = new Map([ // mapping from JS values to reference ids
475 [0, 1],
476 [null, 2],
477 [true, 3],
478 [false, 4],
479 [globalThis, 5],
480 [this, 6],
481 ]);
482 this._idPool = []; // unused ids that have been garbage collected
483 this.exited = false; // whether the Go program has exited
484
485 // Pass command line arguments and environment variables to WebAssembly by writing them to the linear memory.
486 let offset = 4096;
487
488 const strPtr = (str) => {
489 const ptr = offset;
490 const bytes = encoder.encode(str + "\0");
491 new Uint8Array(this.mem.buffer, offset, bytes.length).set(bytes);
492 offset += bytes.length;
493 if (offset % 8 !== 0) {
494 offset += 8 - (offset % 8);
495 }
496 return ptr;
497 };
498
499 const argc = this.argv.length;
500
501 const argvPtrs = [];
502 this.argv.forEach((arg) => {
503 argvPtrs.push(strPtr(arg));
504 });
505 argvPtrs.push(0);
506
507 const keys = Object.keys(this.env).sort();
508 keys.forEach((key) => {
509 argvPtrs.push(strPtr(`${key}=${this.env[key]}`));
510 });
511 argvPtrs.push(0);
512
513 const argv = offset;
514 argvPtrs.forEach((ptr) => {
515 this.mem.setUint32(offset, ptr, true);
516 this.mem.setUint32(offset + 4, 0, true);
517 offset += 8;
518 });
519
520 // The linker guarantees global data starts from at least wasmMinDataAddr.
521 // Keep in sync with cmd/link/internal/ld/data.go:wasmMinDataAddr.
522 const wasmMinDataAddr = 4096 + 8192;
523 if (offset >= wasmMinDataAddr) {
524 throw new Error("total length of command line and environment variables exceeds limit");
525 }
526
527 this._inst.exports.run(argc, argv);
528 if (this.exited) {
529 this._resolveExitPromise();
530 }
531 await this._exitPromise;
532 }
533
534 _resume() {
535 if (this.exited) {
536 throw new Error("Go program has already exited");
537 }
538 this._inst.exports.resume();
539 if (this.exited) {
540 this._resolveExitPromise();
541 }
542 }
543
544 _makeFuncWrapper(id) {
545 const go = this;
546 return function () {
547 const event = { id: id, this: this, args: arguments };
548 go._pendingEvent = event;
549 go._resume();
550 return event.result;
551 };
552 }
553 }
554})();