site/static/blog/tos_2/wasm_exec.js

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// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//
// This file has been modified for use by the TinyGo compiler.
var term = new Terminal({
cols: 80,
rows: 20,
disableStdin: true,
});
term.open(document.getElementById('terminal'));
(() => {
// Map web browser API and Node.js API to a single common API (preferring web standards over Node.js API).
const isNodeJS = typeof process !== "undefined";
if (isNodeJS) {
global.require = require;
global.fs = require("fs");
const nodeCrypto = require("crypto");
global.crypto = {
getRandomValues(b) {
nodeCrypto.randomFillSync(b);
},
};
global.performance = {
now() {
const [sec, nsec] = process.hrtime();
return sec * 1000 + nsec / 1000000;
},
};
const util = require("util");
global.TextEncoder = util.TextEncoder;
global.TextDecoder = util.TextDecoder;
} else {
if (typeof window !== "undefined") {
window.global = window;
} else if (typeof self !== "undefined") {
self.global = self;
} else {
throw new Error("cannot export Go (neither window nor self is defined)");
}
let outputBuf = "";
global.fs = {
constants: { O_WRONLY: -1, O_RDWR: -1, O_CREAT: -1, O_TRUNC: -1, O_APPEND: -1, O_EXCL: -1 }, // unused
writeSync(fd, buf) {
outputBuf += decoder.decode(buf);
const nl = outputBuf.lastIndexOf("\n");
if (nl != -1) {
console.log(outputBuf.substr(0, nl));
outputBuf = outputBuf.substr(nl + 1);
}
return buf.length;
},
write(fd, buf, offset, length, position, callback) {
if (offset !== 0 || length !== buf.length || position !== null) {
throw new Error("not implemented");
}
const n = this.writeSync(fd, buf);
callback(null, n);
},
open(path, flags, mode, callback) {
const err = new Error("not implemented");
err.code = "ENOSYS";
callback(err);
},
fsync(fd, callback) {
callback(null);
},
};
}
const encoder = new TextEncoder("utf-8");
const decoder = new TextDecoder("utf-8");
var logLine = [];
global.Go = class {
constructor() {
this._callbackTimeouts = new Map();
this._nextCallbackTimeoutID = 1;
const mem = () => {
// The buffer may change when requesting more memory.
return new DataView(this._inst.exports.memory.buffer);
}
const setInt64 = (addr, v) => {
mem().setUint32(addr + 0, v, true);
mem().setUint32(addr + 4, Math.floor(v / 4294967296), true);
}
const getInt64 = (addr) => {
const low = mem().getUint32(addr + 0, true);
const high = mem().getInt32(addr + 4, true);
return low + high * 4294967296;
}
const loadValue = (addr) => {
const f = mem().getFloat64(addr, true);
if (f === 0) {
return undefined;
}
if (!isNaN(f)) {
return f;
}
const id = mem().getUint32(addr, true);
return this._values[id];
}
const storeValue = (addr, v) => {
const nanHead = 0x7FF80000;
if (typeof v === "number") {
if (isNaN(v)) {
mem().setUint32(addr + 4, nanHead, true);
mem().setUint32(addr, 0, true);
return;
}
if (v === 0) {
mem().setUint32(addr + 4, nanHead, true);
mem().setUint32(addr, 1, true);
return;
}
mem().setFloat64(addr, v, true);
return;
}
switch (v) {
case undefined:
mem().setFloat64(addr, 0, true);
return;
case null:
mem().setUint32(addr + 4, nanHead, true);
mem().setUint32(addr, 2, true);
return;
case true:
mem().setUint32(addr + 4, nanHead, true);
mem().setUint32(addr, 3, true);
return;
case false:
mem().setUint32(addr + 4, nanHead, true);
mem().setUint32(addr, 4, true);
return;
}
let ref = this._refs.get(v);
if (ref === undefined) {
ref = this._values.length;
this._values.push(v);
this._refs.set(v, ref);
}
let typeFlag = 0;
switch (typeof v) {
case "string":
typeFlag = 1;
break;
case "symbol":
typeFlag = 2;
break;
case "function":
typeFlag = 3;
break;
}
mem().setUint32(addr + 4, nanHead | typeFlag, true);
mem().setUint32(addr, ref, true);
}
const loadSlice = (array, len, cap) => {
return new Uint8Array(this._inst.exports.memory.buffer, array, len);
}
const loadSliceOfValues = (array, len, cap) => {
const a = new Array(len);
for (let i = 0; i < len; i++) {
a[i] = loadValue(array + i * 8);
}
return a;
}
const loadString = (ptr, len) => {
return decoder.decode(new DataView(this._inst.exports.memory.buffer, ptr, len));
}
const timeOrigin = Date.now() - performance.now();
this.importObject = {
env: {
io_get_stdout: function() {
return 1;
},
random_i32: function() {
return Math.floor(Math.random()*4294967295);
},
log_write: function(level, ptr, len) {
for (let i=0; i<len; i++) {
let c = mem().getUint8(ptr+i);
if (c == 13) { // CR
// ignore
} else if (c == 10) { // LF
// write line
let line = decoder.decode(new Uint8Array(logLine));
logLine = [];
console.log(line);
} else {
logLine.push(c);
}
}
},
resource_write: function(fd, ptr, len) {
if (fd == 1) {
for (let i=0; i<len; i++) {
let c = mem().getUint8(ptr+i);
if (c == 13) { // CR
// ignore
} else if (c == 10) { // LF
// write line
let line = decoder.decode(new Uint8Array(logLine));
logLine = [];
term.write(line);
console.log(line);
} else {
logLine.push(c);
}
}
} else {
console.error('invalid file descriptor:', fd);
}
},
// func ticks() float64
"runtime.ticks": () => {
return timeOrigin + performance.now();
},
// func sleepTicks(timeout float64)
"runtime.sleepTicks": (timeout) => {
// Do not sleep, only reactivate scheduler after the given timeout.
setTimeout(this._inst.exports.go_scheduler, timeout);
},
// func stringVal(value string) ref
"syscall/js.stringVal": (ret_ptr, value_ptr, value_len) => {
const s = loadString(value_ptr, value_len);
storeValue(ret_ptr, s);
},
// func valueGet(v ref, p string) ref
"syscall/js.valueGet": (retval, v_addr, p_ptr, p_len) => {
let prop = loadString(p_ptr, p_len);
let value = loadValue(v_addr);
let result = Reflect.get(value, prop);
storeValue(retval, result);
},
// func valueSet(v ref, p string, x ref)
"syscall/js.valueSet": (v_addr, p_ptr, p_len, x_addr) => {
const v = loadValue(v_addr);
const p = loadString(p_ptr, p_len);
const x = loadValue(x_addr);
Reflect.set(v, p, x);
},
// func valueIndex(v ref, i int) ref
//"syscall/js.valueIndex": (sp) => {
// storeValue(sp + 24, Reflect.get(loadValue(sp + 8), getInt64(sp + 16)));
//},
// valueSetIndex(v ref, i int, x ref)
//"syscall/js.valueSetIndex": (sp) => {
// Reflect.set(loadValue(sp + 8), getInt64(sp + 16), loadValue(sp + 24));
//},
// func valueCall(v ref, m string, args []ref) (ref, bool)
"syscall/js.valueCall": (ret_addr, v_addr, m_ptr, m_len, args_ptr, args_len, args_cap) => {
const v = loadValue(v_addr);
const name = loadString(m_ptr, m_len);
const args = loadSliceOfValues(args_ptr, args_len, args_cap);
try {
const m = Reflect.get(v, name);
storeValue(ret_addr, Reflect.apply(m, v, args));
mem().setUint8(ret_addr + 8, 1);
} catch (err) {
storeValue(ret_addr, err);
mem().setUint8(ret_addr + 8, 0);
}
},
// func valueInvoke(v ref, args []ref) (ref, bool)
//"syscall/js.valueInvoke": (sp) => {
// try {
// const v = loadValue(sp + 8);
// const args = loadSliceOfValues(sp + 16);
// storeValue(sp + 40, Reflect.apply(v, undefined, args));
// mem().setUint8(sp + 48, 1);
// } catch (err) {
// storeValue(sp + 40, err);
// mem().setUint8(sp + 48, 0);
// }
//},
// func valueNew(v ref, args []ref) (ref, bool)
"syscall/js.valueNew": (ret_addr, v_addr, args_ptr, args_len, args_cap) => {
const v = loadValue(v_addr);
const args = loadSliceOfValues(args_ptr, args_len, args_cap);
try {
storeValue(ret_addr, Reflect.construct(v, args));
mem().setUint8(ret_addr + 8, 1);
} catch (err) {
storeValue(ret_addr, err);
mem().setUint8(ret_addr+ 8, 0);
}
},
// func valueLength(v ref) int
//"syscall/js.valueLength": (sp) => {
// setInt64(sp + 16, parseInt(loadValue(sp + 8).length));
//},
// valuePrepareString(v ref) (ref, int)
"syscall/js.valuePrepareString": (ret_addr, v_addr) => {
const s = String(loadValue(v_addr));
const str = encoder.encode(s);
storeValue(ret_addr, str);
setInt64(ret_addr + 8, str.length);
},
// valueLoadString(v ref, b []byte)
"syscall/js.valueLoadString": (v_addr, slice_ptr, slice_len, slice_cap) => {
const str = loadValue(v_addr);
loadSlice(slice_ptr, slice_len, slice_cap).set(str);
},
// func valueInstanceOf(v ref, t ref) bool
//"syscall/js.valueInstanceOf": (sp) => {
// mem().setUint8(sp + 24, loadValue(sp + 8) instanceof loadValue(sp + 16));
//},
}
};
}
async run(instance) {
this._inst = instance;
this._values = [ // TODO: garbage collection
NaN,
0,
null,
true,
false,
global,
this._inst.exports.memory,
this,
];
this._refs = new Map();
this._callbackShutdown = false;
this.exited = false;
const mem = new DataView(this._inst.exports.memory.buffer)
while (true) {
const callbackPromise = new Promise((resolve) => {
this._resolveCallbackPromise = () => {
if (this.exited) {
throw new Error("bad callback: Go program has already exited");
}
setTimeout(resolve, 0); // make sure it is asynchronous
};
});
this._inst.exports.cwa_main();
if (this.exited) {
break;
}
await callbackPromise;
}
}
static _makeCallbackHelper(id, pendingCallbacks, go) {
return function () {
pendingCallbacks.push({ id: id, args: arguments });
go._resolveCallbackPromise();
};
}
static _makeEventCallbackHelper(preventDefault, stopPropagation, stopImmediatePropagation, fn) {
return function (event) {
if (preventDefault) {
event.preventDefault();
}
if (stopPropagation) {
event.stopPropagation();
}
if (stopImmediatePropagation) {
event.stopImmediatePropagation();
}
fn(event);
};
}
}
if (isNodeJS) {
if (process.argv.length != 3) {
process.stderr.write("usage: go_js_wasm_exec [wasm binary] [arguments]\n");
process.exit(1);
}
const go = new Go();
WebAssembly.instantiate(fs.readFileSync(process.argv[2]), go.importObject).then((result) => {
process.on("exit", (code) => { // Node.js exits if no callback is pending
if (code === 0 && !go.exited) {
// deadlock, make Go print error and stack traces
go._callbackShutdown = true;
}
});
return go.run(result.instance);
}).catch((err) => {
throw err;
});
}
})();