phyng phyng

WebAssembly 导学

提起 WebAssembly/Wasm 可能会想起它是一种可以在浏览器里运行 C/C++/Rust 的技术，实际上它是一个虚拟机标准，它的实现可以在 MCU（单片机）、移动设备、桌面电脑到服务器里面跑，可以嵌入到浏览器、嵌入到应用程序或者独立运行，没有具体的边界。

特点：

编译一次到处可运行（有点类似JVM虚拟机），源语言可以是 C/C++，Rust，Go，Swift ，TypeScript，C#，Kotlin 等等。
具体的功能依赖于导入的接口（Import API），否则只是一个单纯的运算器（栈式虚拟机）。目前接口主要有 Web JS 和 WASI 两种，前者用在浏览器里，后者可以作为独立应用程序（比如调用文件系统、socket 等）。
在 WASM 虚拟机里，只能调用宿主导入的方法和共享的内存，无法直接调用宿主的资源（比如 Web DOM 对象、文件系统等），所以天然具有沙盘安全特性。
性能很好，提供了接近本地程序的性能，同一段简单的 C 计算程序，以 WASM 方式运行大概慢 1 倍左右，相对一般动态语言慢几倍到上百倍来说，性能已非常突出。

Step 1. Run command: expo eject in root of expo project.

Step 2. Choose 2nd option: Eject to ExpoKit and follow step to step from Expo command to eject it completely.

Step 3 (Optional) Install dependencies (normally, Expo will auto run this command)

yarn install

All of the following information is based on go version go1.17.1 darwin/amd64.

GOOS	Out of the Box
`aix`	✅
`android`	✅

Suppose you're opening an issue and there's a lot noisey logs that may be useful.

Rather than wrecking readability, wrap it in a <details> tag!

<details>
 Summary Goes Here

	import cProfile
	import pstats
	from io import StringIO
	import logging
	import os
	import time

	PROFILE_LIMIT = int(os.environ.get("PROFILE_LIMIT", 30))
	PROFILER = bool(int(os.environ.get("PROFILER", 1)))

	import platform
	import unittest
	from http import HTTPStatus
	from urllib.parse import urlencode, unquote

	import aiohttp
	import asynctest
	from aiohttp import web
	from aiohttp.test_utils import TestClient
	from multidict import MultiDict

	import sys

	def j(lineno):
	frame = sys._getframe().f_back
	called_from = frame

	def hook(frame, event, arg):
	if event == 'line' and frame == called_from:
	try:
	frame.f_lineno = lineno

	var webpack = require('webpack');
	var MemoryFS = require('memory-fs');
	var SingleEntryDependency = require('webpack/lib/dependencies/SingleEntryDependency');
	var fs = new MemoryFS();

	fs.mkdirpSync('/src');
	fs.writeFileSync('/src/app.js', 'require("./dep.js")', 'utf-8');
	fs.writeFileSync('/src/dep.js', 'module.exports = function(msg){console.log(msg)}', 'utf-8');
	fs.writeFileSync('/src/extra-entry.js', 'require("./dep.js")', 'utf-8');

	npm set registry https://r.npm.taobao.org # 注册模块镜像
	npm set disturl https://npm.taobao.org/dist # node-gyp 编译依赖的 node 源码镜像

	## 以下选择添加
	npm set sass_binary_site https://npm.taobao.org/mirrors/node-sass # node-sass 二进制包镜像
	npm set electron_mirror https://npm.taobao.org/mirrors/electron/ # electron 二进制包镜像
	npm set ELECTRON_MIRROR https://cdn.npm.taobao.org/dist/electron/ # electron 二进制包镜像
	npm set puppeteer_download_host https://npm.taobao.org/mirrors # puppeteer 二进制包镜像
	npm set chromedriver_cdnurl https://npm.taobao.org/mirrors/chromedriver # chromedriver 二进制包镜像
	npm set operadriver_cdnurl https://npm.taobao.org/mirrors/operadriver # operadriver 二进制包镜像

	running install_scripts
	Traceback (most recent call last):
	File "<string>", line 1, in <module>
	File "/tmp/pip-build-v7Avhg/cryptography/setup.py", line 318, in <module>
	**keywords_with_side_effects(sys.argv)
	File "/usr/lib/pypy/lib-python/2.7/distutils/core.py", line 151, in setup
	dist.run_commands()
	File "/usr/lib/pypy/lib-python/2.7/distutils/dist.py", line 953, in run_commands
	self.run_command(cmd)
	File "/usr/lib/pypy/lib-python/2.7/distutils/dist.py", line 972, in run_command