# golang 部分

参考 https://geektutu.com/post/quick-go-wasm.html

# 开发

package main  
  
import "syscall/js"  //  goland可能会报错，忽略即可
  
func main() {  
   alert := js.Global().Get("alert")  
   alert.Invoke("Hello World!")  
}

# 编译

不能用 go build 直接编译
windows 下面可以在 git bash 窗口编译

GOOS=js GOARCH=wasm go build -o static/main.wasm

编译后，会在项目目录下生成 static/main.wasm

# vue 部分

# 创建项目

	npm init vite vue-wasm
	cd vue-wasm
	npm install
	npm run dev

# 引入 wasm

把 wasm_exec.js (注意有不同的版本，报错了可以换版本) 以及 main.wasm 文件复制到 vue 项目下 /static

	// 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.

	(() => {
	// Map multiple JavaScript environments to a single common API,
	// preferring web standards over Node.js API. // // Environments considered: // - Browsers // - Node.js // - Electron // - Parcel // - Webpack
	if (typeof global !== "undefined") {
	// global already exists
	} else if (typeof window !== "undefined") {
	window.global = window;
	} else if (typeof self !== "undefined") {
	self.global = self;
	} else {
	throw new Error("cannot export Go (neither global, window nor self is defined)");
	}

	if (!global.require && typeof require !== "undefined") {
	global.require = require;
	}

	if (!global.fs && global.require) {
	const fs = require("fs");
	if (typeof fs === "object" && fs !== null && Object.keys(fs).length !== 0) {
	global.fs = fs;
	}
	}

	const enosys = () => {
	const err = new Error("not implemented");
	err.code = "ENOSYS";
	return err;
	};

	if (!global.fs) {
	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) {
	callback(enosys());
	return; }
	const n = this.writeSync(fd, buf);
	callback(null, n);
	},
	chmod(path, mode, callback) { callback(enosys()); },
	chown(path, uid, gid, callback) { callback(enosys()); },
	close(fd, callback) { callback(enosys()); },
	fchmod(fd, mode, callback) { callback(enosys()); },
	fchown(fd, uid, gid, callback) { callback(enosys()); },
	fstat(fd, callback) { callback(enosys()); },
	fsync(fd, callback) { callback(null); },
	ftruncate(fd, length, callback) { callback(enosys()); },
	lchown(path, uid, gid, callback) { callback(enosys()); },
	link(path, link, callback) { callback(enosys()); },
	lstat(path, callback) { callback(enosys()); },
	mkdir(path, perm, callback) { callback(enosys()); },
	open(path, flags, mode, callback) { callback(enosys()); },
	read(fd, buffer, offset, length, position, callback) { callback(enosys()); },
	readdir(path, callback) { callback(enosys()); },
	readlink(path, callback) { callback(enosys()); },
	rename(from, to, callback) { callback(enosys()); },
	rmdir(path, callback) { callback(enosys()); },
	stat(path, callback) { callback(enosys()); },
	symlink(path, link, callback) { callback(enosys()); },
	truncate(path, length, callback) { callback(enosys()); },
	unlink(path, callback) { callback(enosys()); },
	utimes(path, atime, mtime, callback) { callback(enosys()); },
	};
	}

	if (!global.process) {
	global.process = {
	getuid() { return -1; },
	getgid() { return -1; },
	geteuid() { return -1; },
	getegid() { return -1; },
	getgroups() { throw enosys(); },
	pid: -1,
	ppid: -1,
	umask() { throw enosys(); },
	cwd() { throw enosys(); },
	chdir() { throw enosys(); },
	}
	}

	if (!global.crypto && global.require) {
	const nodeCrypto = require("crypto");
	global.crypto = {
	getRandomValues(b) {
	nodeCrypto.randomFillSync(b);
	},
	};
	}
	if (!global.crypto) {
	throw new Error("global.crypto is not available, polyfill required (getRandomValues only)");
	}

	if (!global.performance) {
	global.performance = {
	now() {
	const [sec, nsec] = process.hrtime();
	return sec * 1000 + nsec / 1000000;
	},
	};
	}

	if (!global.TextEncoder && global.require) {
	global.TextEncoder = require("util").TextEncoder;
	}
	if (!global.TextEncoder) {
	throw new Error("global.TextEncoder is not available, polyfill required");
	}

	if (!global.TextDecoder && global.require) {
	global.TextDecoder = require("util").TextDecoder;
	}
	if (!global.TextDecoder) {
	throw new Error("global.TextDecoder is not available, polyfill required");
	}

	// End of polyfills for common API.

	const encoder = new TextEncoder("utf-8");
	const decoder = new TextDecoder("utf-8");

	global.Go = class {
	constructor() {
	this.argv = ["js"];
	this.env = {};
	this.exit = (code) => {
	if (code !== 0) {
	console.warn("exit code:", code);
	}
	};
	this._exitPromise = new Promise((resolve) => {
	this._resolveExitPromise = resolve;
	});
	this._pendingEvent = null;
	this._scheduledTimeouts = new Map();
	this._nextCallbackTimeoutID = 1;

	const setInt64 = (addr, v) => {
	this.mem.setUint32(addr + 0, v, true);
	this.mem.setUint32(addr + 4, Math.floor(v / 4294967296), true);
	}

	const getInt64 = (addr) => {
	const low = this.mem.getUint32(addr + 0, true);
	const high = this.mem.getInt32(addr + 4, true);
	return low + high * 4294967296;
	}

	const loadValue = (addr) => {
	const f = this.mem.getFloat64(addr, true);
	if (f === 0) {
	return undefined;
	}
	if (!isNaN(f)) {
	return f;
	}

	const id = this.mem.getUint32(addr, true);
	return this._values[id];
	}

	const storeValue = (addr, v) => {
	const nanHead = 0x7FF80000;

	if (typeof v === "number" && v !== 0) {
	if (isNaN(v)) {
	this.mem.setUint32(addr + 4, nanHead, true);
	this.mem.setUint32(addr, 0, true);
	return; }
	this.mem.setFloat64(addr, v, true);
	return; }

	if (v === undefined) {
	this.mem.setFloat64(addr, 0, true);
	return; }

	let id = this._ids.get(v);
	if (id === undefined) {
	id = this._idPool.pop();
	if (id === undefined) {
	id = this._values.length;
	}
	this._values[id] = v;
	this._goRefCounts[id] = 0;
	this._ids.set(v, id);
	}
	this._goRefCounts[id]++;
	let typeFlag = 0;
	switch (typeof v) {
	case "object":
	if (v !== null) {
	typeFlag = 1;
	}
	break;
	case "string":
	typeFlag = 2;
	break; case "symbol":
	typeFlag = 3;
	break; case "function":
	typeFlag = 4;
	break; }
	this.mem.setUint32(addr + 4, nanHead \| typeFlag, true);
	this.mem.setUint32(addr, id, true);
	}

	const loadSlice = (addr) => {
	const array = getInt64(addr + 0);
	const len = getInt64(addr + 8);
	return new Uint8Array(this._inst.exports.mem.buffer, array, len);
	}

	const loadSliceOfValues = (addr) => {
	const array = getInt64(addr + 0);
	const len = getInt64(addr + 8);
	const a = new Array(len);
	for (let i = 0; i < len; i++) {
	a[i] = loadValue(array + i * 8);
	}
	return a;
	}

	const loadString = (addr) => {
	const saddr = getInt64(addr + 0);
	const len = getInt64(addr + 8);
	return decoder.decode(new DataView(this._inst.exports.mem.buffer, saddr, len));
	}

	const timeOrigin = Date.now() - performance.now();
	this.importObject = {
	go: {
	// Go's SP does not change as long as no Go code is running. Some operations (e.g. calls, getters and setters)
	// may synchronously trigger a Go event handler. This makes Go code get executed in the middle of the imported // function. A goroutine can switch to a new stack if the current stack is too small (see morestack function). // This changes the SP, thus we have to update the SP used by the imported function.
	// func wasmExit(code int32) "runtime.wasmExit": (sp) => {
	sp >>>= 0;
	const code = this.mem.getInt32(sp + 8, true);
	this.exited = true;
	delete this._inst;
	delete this._values;
	delete this._goRefCounts;
	delete this._ids;
	delete this._idPool;
	this.exit(code);
	},

	// func wasmWrite(fd uintptr, p unsafe.Pointer, n int32)
	"runtime.wasmWrite": (sp) => {
	sp >>>= 0;
	const fd = getInt64(sp + 8);
	const p = getInt64(sp + 16);
	const n = this.mem.getInt32(sp + 24, true);
	fs.writeSync(fd, new Uint8Array(this._inst.exports.mem.buffer, p, n));
	},

	// func resetMemoryDataView()
	"runtime.resetMemoryDataView": (sp) => {
	sp >>>= 0;
	this.mem = new DataView(this._inst.exports.mem.buffer);
	},

	// func nanotime1() int64
	"runtime.nanotime1": (sp) => {
	sp >>>= 0;
	setInt64(sp + 8, (timeOrigin + performance.now()) * 1000000);
	},

	// func walltime() (sec int64, nsec int32)
	"runtime.walltime": (sp) => {
	sp >>>= 0;
	const msec = (new Date).getTime();
	setInt64(sp + 8, msec / 1000);
	this.mem.setInt32(sp + 16, (msec % 1000) * 1000000, true);
	},

	// func scheduleTimeoutEvent(delay int64) int32
	"runtime.scheduleTimeoutEvent": (sp) => {
	sp >>>= 0;
	const id = this._nextCallbackTimeoutID;
	this._nextCallbackTimeoutID++;
	this._scheduledTimeouts.set(id, setTimeout(
	() => {
	this._resume();
	while (this._scheduledTimeouts.has(id)) {
	// for some reason Go failed to register the timeout event, log and try again
	// (temporary workaround for https://github.com/golang/go/issues/28975) console.warn("scheduleTimeoutEvent: missed timeout event");
	this._resume();
	}
	},
	getInt64(sp + 8) + 1, // setTimeout has been seen to fire up to 1 millisecond early
	));
	this.mem.setInt32(sp + 16, id, true);
	},

	// func clearTimeoutEvent(id int32)
	"runtime.clearTimeoutEvent": (sp) => {
	sp >>>= 0;
	const id = this.mem.getInt32(sp + 8, true);
	clearTimeout(this._scheduledTimeouts.get(id));
	this._scheduledTimeouts.delete(id);
	},

	// func getRandomData(r []byte)
	"runtime.getRandomData": (sp) => {
	sp >>>= 0;
	crypto.getRandomValues(loadSlice(sp + 8));
	},

	// func finalizeRef(v ref)
	"syscall/js.finalizeRef": (sp) => {
	sp >>>= 0;
	const id = this.mem.getUint32(sp + 8, true);
	this._goRefCounts[id]--;
	if (this._goRefCounts[id] === 0) {
	const v = this._values[id];
	this._values[id] = null;
	this._ids.delete(v);
	this._idPool.push(id);
	}
	},

	// func stringVal(value string) ref
	"syscall/js.stringVal": (sp) => {
	sp >>>= 0;
	storeValue(sp + 24, loadString(sp + 8));
	},

	// func valueGet(v ref, p string) ref
	"syscall/js.valueGet": (sp) => {
	sp >>>= 0;
	const result = Reflect.get(loadValue(sp + 8), loadString(sp + 16));
	sp = this._inst.exports.getsp() >>> 0; // see comment above
	storeValue(sp + 32, result);
	},

	// func valueSet(v ref, p string, x ref)
	"syscall/js.valueSet": (sp) => {
	sp >>>= 0;
	Reflect.set(loadValue(sp + 8), loadString(sp + 16), loadValue(sp + 32));
	},

	// func valueDelete(v ref, p string)
	"syscall/js.valueDelete": (sp) => {
	sp >>>= 0;
	Reflect.deleteProperty(loadValue(sp + 8), loadString(sp + 16));
	},

	// func valueIndex(v ref, i int) ref
	"syscall/js.valueIndex": (sp) => {
	sp >>>= 0;
	storeValue(sp + 24, Reflect.get(loadValue(sp + 8), getInt64(sp + 16)));
	},

	// valueSetIndex(v ref, i int, x ref)
	"syscall/js.valueSetIndex": (sp) => {
	sp >>>= 0;
	Reflect.set(loadValue(sp + 8), getInt64(sp + 16), loadValue(sp + 24));
	},

	// func valueCall(v ref, m string, args []ref) (ref, bool)
	"syscall/js.valueCall": (sp) => {
	sp >>>= 0;
	try {
	const v = loadValue(sp + 8);
	const m = Reflect.get(v, loadString(sp + 16));
	const args = loadSliceOfValues(sp + 32);
	const result = Reflect.apply(m, v, args);
	sp = this._inst.exports.getsp() >>> 0; // see comment above
	storeValue(sp + 56, result);
	this.mem.setUint8(sp + 64, 1);
	} catch (err) {
	sp = this._inst.exports.getsp() >>> 0; // see comment above
	storeValue(sp + 56, err);
	this.mem.setUint8(sp + 64, 0);
	}
	},

	// func valueInvoke(v ref, args []ref) (ref, bool)
	"syscall/js.valueInvoke": (sp) => {
	sp >>>= 0;
	try {
	const v = loadValue(sp + 8);
	const args = loadSliceOfValues(sp + 16);
	const result = Reflect.apply(v, undefined, args);
	sp = this._inst.exports.getsp() >>> 0; // see comment above
	storeValue(sp + 40, result);
	this.mem.setUint8(sp + 48, 1);
	} catch (err) {
	sp = this._inst.exports.getsp() >>> 0; // see comment above
	storeValue(sp + 40, err);
	this.mem.setUint8(sp + 48, 0);
	}
	},

	// func valueNew(v ref, args []ref) (ref, bool)
	"syscall/js.valueNew": (sp) => {
	sp >>>= 0;
	try {
	const v = loadValue(sp + 8);
	const args = loadSliceOfValues(sp + 16);
	const result = Reflect.construct(v, args);
	sp = this._inst.exports.getsp() >>> 0; // see comment above
	storeValue(sp + 40, result);
	this.mem.setUint8(sp + 48, 1);
	} catch (err) {
	sp = this._inst.exports.getsp() >>> 0; // see comment above
	storeValue(sp + 40, err);
	this.mem.setUint8(sp + 48, 0);
	}
	},

	// func valueLength(v ref) int
	"syscall/js.valueLength": (sp) => {
	sp >>>= 0;
	setInt64(sp + 16, parseInt(loadValue(sp + 8).length));
	},

	// valuePrepareString(v ref) (ref, int)
	"syscall/js.valuePrepareString": (sp) => {
	sp >>>= 0;
	const str = encoder.encode(String(loadValue(sp + 8)));
	storeValue(sp + 16, str);
	setInt64(sp + 24, str.length);
	},

	// valueLoadString(v ref, b []byte)
	"syscall/js.valueLoadString": (sp) => {
	sp >>>= 0;
	const str = loadValue(sp + 8);
	loadSlice(sp + 16).set(str);
	},

	// func valueInstanceOf(v ref, t ref) bool
	"syscall/js.valueInstanceOf": (sp) => {
	sp >>>= 0;
	this.mem.setUint8(sp + 24, (loadValue(sp + 8) instanceof loadValue(sp + 16)) ? 1 : 0);
	},

	// func copyBytesToGo(dst []byte, src ref) (int, bool)
	"syscall/js.copyBytesToGo": (sp) => {
	sp >>>= 0;
	const dst = loadSlice(sp + 8);
	const src = loadValue(sp + 32);
	if (!(src instanceof Uint8Array \|\| src instanceof Uint8ClampedArray)) {
	this.mem.setUint8(sp + 48, 0);
	return; }
	const toCopy = src.subarray(0, dst.length);
	dst.set(toCopy);
	setInt64(sp + 40, toCopy.length);
	this.mem.setUint8(sp + 48, 1);
	},

	// func copyBytesToJS(dst ref, src []byte) (int, bool)
	"syscall/js.copyBytesToJS": (sp) => {
	sp >>>= 0;
	const dst = loadValue(sp + 8);
	const src = loadSlice(sp + 16);
	if (!(dst instanceof Uint8Array \|\| dst instanceof Uint8ClampedArray)) {
	this.mem.setUint8(sp + 48, 0);
	return; }
	const toCopy = src.subarray(0, dst.length);
	dst.set(toCopy);
	setInt64(sp + 40, toCopy.length);
	this.mem.setUint8(sp + 48, 1);
	},

	"debug": (value) => {
	console.log(value);
	},
	}
	};
	}

	async run(instance) {
	if (!(instance instanceof WebAssembly.Instance)) {
	throw new Error("Go.run: WebAssembly.Instance expected");
	}
	this._inst = instance;
	this.mem = new DataView(this._inst.exports.mem.buffer);
	this._values = [ // JS values that Go currently has references to, indexed by reference id
	NaN,
	0,
	null, true, false, global,
	this, ];
	this._goRefCounts = new Array(this._values.length).fill(Infinity); // number of references that Go has to a JS value, indexed by reference id
	this._ids = new Map([ // mapping from JS values to reference ids
	[0, 1],
	[null, 2],
	[true, 3],
	[false, 4],
	[global, 5],
	[this, 6],
	]);
	this._idPool = []; // unused ids that have been garbage collected
	this.exited = false; // whether the Go program has exited

	// Pass command line arguments and environment variables to WebAssembly by writing them to the linear memory. let offset = 4096;

	const strPtr = (str) => {
	const ptr = offset;
	const bytes = encoder.encode(str + "\0");
	new Uint8Array(this.mem.buffer, offset, bytes.length).set(bytes);
	offset += bytes.length;
	if (offset % 8 !== 0) {
	offset += 8 - (offset % 8);
	}
	return ptr;
	};

	const argc = this.argv.length;

	const argvPtrs = [];
	this.argv.forEach((arg) => {
	argvPtrs.push(strPtr(arg));
	});
	argvPtrs.push(0);

	const keys = Object.keys(this.env).sort();
	keys.forEach((key) => {
	argvPtrs.push(strPtr(`${key}=${this.env[key]}`));
	});
	argvPtrs.push(0);

	const argv = offset;
	argvPtrs.forEach((ptr) => {
	this.mem.setUint32(offset, ptr, true);
	this.mem.setUint32(offset + 4, 0, true);
	offset += 8;
	});

	this._inst.exports.run(argc, argv);
	if (this.exited) {
	this._resolveExitPromise();
	}
	await this._exitPromise;
	}

	_resume() {
	if (this.exited) {
	throw new Error("Go program has already exited");
	}
	this._inst.exports.resume();
	if (this.exited) {
	this._resolveExitPromise();
	}
	}

	_makeFuncWrapper(id) {
	const go = this;
	return function () {
	const event = { id: id, this: this, args: arguments };
	go._pendingEvent = event;
	go._resume();
	return event.result;
	};
	}
	}

	if (
	typeof module !== "undefined" &&
	global.require &&
	global.require.main === module &&
	global.process &&
	global.process.versions &&
	!global.process.versions.electron
	) {
	if (process.argv.length < 3) {
	console.error("usage: go_js_wasm_exec [wasm binary] [arguments]");
	process.exit(1);
	}

	const go = new Go();
	go.argv = process.argv.slice(2);
	go.env = Object.assign({ TMPDIR: require("os").tmpdir() }, process.env);
	go.exit = process.exit;
	WebAssembly.instantiate(fs.readFileSync(process.argv[2]), go.importObject).then((result) => {
	process.on("exit", (code) => { // Node.js exits if no event handler is pending
	if (code === 0 && !go.exited) {
	// deadlock, make Go print error and stack traces
	go._pendingEvent = { id: 0 };
	go._resume();
	}
	});
	return go.run(result.instance);
	}).catch((err) => {
	console.error(err);
	process.exit(1);
	});
	}
	})();


	2. 在index.html中引入wasm_exec.js
	```js
	<head>
	<meta charset="UTF-8" />
	<link rel="icon" type="image/svg+xml" href="/vite.svg" />
	<meta name="viewport" content="width=device-width, initial-scale=1.0" />
	<script src="static/wasm_exec.js"></script>
	<title>Vite + Vue + TS</title>
	</head>

# 调用 go 代码

在 HelloWorld.vue 组件中调用 wasm 函数

<script setup lang="ts">  
import { ref,defineProps } from 'vue'  
defineProps<{ msg: string }>()  
  
const run = ()=>{  
  const go = new window.Go();  
  WebAssembly.instantiateStreaming(fetch("../../static/main.wasm"),go.importObject).  
  then((result)=>go.run(result.instance));  
}  
  
</script>  
  
<template>  
  <h1>{{ msg }}</h1>  
  
  <div class="card-body">  
    <p class="text-muted">  
      点击“运行”，在控制台输出日志 <code>Hello, WebAssembly!</code>  
    </p>    <div class="live-preview">  
      <button          @click="run()"  
          class="btn btn-success"  
          id="runButton"  
      >  
        运行  
      </button>  
    </div>  </div>  
</template>  
  
<style scoped>  
.read-the-docs {  
  color: #888;  
}  
</style>

# 问题

# 是否支持跨域

不能

	func main() {
	alert := js.Global().Get("alert")
	alert.Invoke("Hello World!")

	url := "https://www.baidu.com/" // 要获取数据的 URL

	response, err := http.Get(url)
	if err != nil {
	fmt.Printf("获取URL数据时出错：%s", err)
	return
	}
	defer response.Body.Close()

	body, err := ioutil.ReadAll(response.Body)
	if err != nil {
	fmt.Printf("读取响应内容时出错：%s", err)
	return
	}

	fmt.Println(string(body))
	}

浏览器报了跨域错误

# 是否支持多协程

支持

	func main() {
	alert := js.Global().Get("alert")
	alert.Invoke("Hello World!")

	sleep := func(x int, wg *sync.WaitGroup) {
	defer wg.Done()
	time.Sleep(time.Second * time.Duration(x))
	fmt.Printf("我是coroutine:%d\n", x)
	}

	var wg sync.WaitGroup
	fmt.Println("开启两个协程")

	wg.Add(1)
	go sleep(1, &wg)
	wg.Add(1)
	go sleep(2, &wg)
	wg.Wait()
	fmt.Println("All workers done")
	}

# golang 部分

# 开发

# 编译

# vue 部分

# 创建项目

# 引入 wasm

# 调用 go 代码

# 问题

# 是否支持跨域

# 是否支持多协程

本周看了啥-2023年7月15日

桌游