index.mjs

// Copyright 2021 Google LLC
// 
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//     https://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import fs from 'fs-extra'
import * as globbyModule from 'globby'
import os from 'os'
import path from 'path'
import {promisify, inspect} from 'util'
import {spawn} from 'child_process'
import {createInterface} from 'readline'
import {default as nodeFetch} from 'node-fetch'
import which from 'which'
import chalk from 'chalk'
import minimist from 'minimist'
import psTreeModule from 'ps-tree'

export {chalk, fs, os, path}
export const sleep = promisify(setTimeout)
export const argv = minimist(process.argv.slice(2))
export const globby = Object.assign(function globby(...args) {
  return globbyModule.globby(...args)
}, globbyModule)
export const glob = globby
const psTree = promisify(psTreeModule)

export function registerGlobals() {
  Object.assign(global, {
    $,
    argv,
    cd,
    chalk,
    fetch,
    fs,
    glob,
    globby,
    nothrow,
    os,
    path,
    question,
    sleep,
  })
}

export function $(pieces, ...args) {
  let {verbose, cwd, shell, prefix} = $
  let __from = (new Error().stack.split(/^\s*at\s/m)[2]).trim()

  let cmd = pieces[0], i = 0
  while (i < args.length) {
    let s
    if (Array.isArray(args[i])) {
      s = args[i].map(x => $.quote(substitute(x))).join(' ')
    } else {
      s = $.quote(substitute(args[i]))
    }
    cmd += s + pieces[++i]
  }

  let resolve, reject
  let promise = new ProcessPromise((...args) => [resolve, reject] = args)

  promise._run = () => {
    if (promise.child) return
    if (promise._prerun) promise._prerun()
    if (verbose) {
      printCmd(cmd)
    }

    let child = spawn(prefix + cmd, {
      cwd,
      shell: typeof shell === 'string' ? shell : true,
      stdio: [promise._inheritStdin ? 'inherit' : 'pipe', 'pipe', 'pipe'],
      windowsHide: true,
    })

    child.on('exit', code => {
      child.on('close', () => {
        let output = new ProcessOutput({
          code, stdout, stderr, combined,
          message: `${stderr || '\n'}    at ${__from}\n    exit code: ${code}` + (exitCodeInfo(code) ? ' (' + exitCodeInfo(code) + ')' : '')
        });
        (code === 0 || promise._nothrow ? resolve : reject)(output)
        promise._resolved = true
      })
    })

    let stdout = '', stderr = '', combined = ''
    let onStdout = data => {
      if (verbose) process.stdout.write(data)
      stdout += data
      combined += data
    }
    let onStderr = data => {
      if (verbose) process.stderr.write(data)
      stderr += data
      combined += data
    }
    if (!promise._piped) child.stdout.on('data', onStdout)
    child.stderr.on('data', onStderr)
    promise.child = child
    if (promise._postrun) promise._postrun()
  }
  setTimeout(promise._run, 0) // Make sure all subprocesses started.
  return promise
}

$.verbose = !argv.quiet
if (typeof argv.shell === 'string') {
  $.shell = argv.shell
  $.prefix = ''
} else {
  try {
    $.shell = which.sync('bash')
    $.prefix = 'set -euo pipefail;'
  } catch (e) {
    $.prefix = '' // Bash not found, no prefix.
  }
}
if (typeof argv.prefix === 'string') {
  $.prefix = argv.prefix
}
$.quote = quote
$.cwd = undefined

export function cd(path) {
  if ($.verbose) console.log('$', colorize(`cd ${path}`))
  if (!fs.existsSync(path)) {
    let __from = (new Error().stack.split(/^\s*at\s/m)[2]).trim()
    console.error(`cd: ${path}: No such directory`)
    console.error(`    at ${__from}`)
    process.exit(1)
  }
  $.cwd = path
}

export async function question(query, options) {
  let completer = undefined
  if (Array.isArray(options?.choices)) {
    completer = function completer(line) {
      const completions = options.choices
      const hits = completions.filter((c) => c.startsWith(line))
      return [hits.length ? hits : completions, line]
    }
  }
  const rl = createInterface({
    input: process.stdin,
    output: process.stdout,
    completer,
  })
  const question = (q) => new Promise((resolve) => rl.question(q ?? '', resolve))
  let answer = await question(query)
  rl.close()
  return answer
}

export async function fetch(url, init) {
  if ($.verbose) {
    if (typeof init !== 'undefined') {
      console.log('$', colorize(`fetch ${url}`), init)
    } else {
      console.log('$', colorize(`fetch ${url}`))
    }
  }
  return nodeFetch(url, init)
}

export function nothrow(promise) {
  promise._nothrow = true
  return promise
}

export class ProcessPromise extends Promise {
  child = undefined
  _nothrow = false
  _resolved = false
  _inheritStdin = true
  _piped = false
  _prerun = undefined
  _postrun = undefined

  get stdin() {
    this._inheritStdin = false
    this._run()
    return this.child.stdin
  }

  get stdout() {
    this._inheritStdin = false
    this._run()
    return this.child.stdout
  }

  get stderr() {
    this._inheritStdin = false
    this._run()
    return this.child.stderr
  }

  get exitCode() {
    return this
      .then(p => p.exitCode)
      .catch(p => p.exitCode)
  }

  then(onfulfilled, onrejected) {
    if (this._run) this._run()
    return super.then(onfulfilled, onrejected)
  }

  pipe(dest) {
    if (typeof dest === 'string') {
      throw new Error('The pipe() method does not take strings. Forgot $?')
    }
    if (this._resolved === true) {
      throw new Error('The pipe() method shouldn\'t be called after promise is already resolved!')
    }
    this._piped = true
    if (dest instanceof ProcessPromise) {
      dest._inheritStdin = false
      dest._prerun = this._run
      dest._postrun = () => this.stdout.pipe(dest.child.stdin)
      return dest
    } else {
      this._postrun = () => this.stdout.pipe(dest)
      return this
    }
  }

  async kill(signal = 'SIGTERM') {
    let children = await psTree(this.child.pid)
    for (const p of children) {
      try {
        process.kill(p.PID, signal)
      } catch (e) {
      }
    }
    try {
      process.kill(this.child.pid, signal)
    } catch (e) {
    }
  }
}

export class ProcessOutput extends Error {
  #code = 0
  #stdout = ''
  #stderr = ''
  #combined = ''

  constructor({code, stdout, stderr, combined, message}) {
    super(message)
    this.#code = code
    this.#stdout = stdout
    this.#stderr = stderr
    this.#combined = combined
  }

  toString() {
    return this.#combined
  }

  get stdout() {
    return this.#stdout
  }

  get stderr() {
    return this.#stderr
  }

  get exitCode() {
    return this.#code
  }

  [inspect.custom]() {
    let stringify = (s, c) => s.length === 0 ? '\'\'' : c(inspect(s))
    return `ProcessOutput {
  stdout: ${stringify(this.stdout, chalk.green)},
  stderr: ${stringify(this.stderr, chalk.red)},
  exitCode: ${(this.exitCode === 0 ? chalk.green : chalk.red)(this.exitCode)}${(exitCodeInfo(this.exitCode) ? chalk.grey(' (' + exitCodeInfo(this.exitCode) + ')') : '')}
}`
  }
}

function printCmd(cmd) {
  if (/\n/.test(cmd)) {
    console.log(cmd
      .split('\n')
      .map((line, i) => (i === 0 ? '$' : '>') + ' ' + colorize(line))
      .join('\n'))
  } else {
    console.log('$', colorize(cmd))
  }
}

function colorize(cmd) {
  return cmd.replace(/^[\w_.-]+(\s|$)/, substr => {
    return chalk.greenBright(substr)
  })
}

function substitute(arg) {
  if (arg instanceof ProcessOutput) {
    return arg.stdout.replace(/\n$/, '')
  }
  return `${arg}`
}

function quote(arg) {
  if (/^[a-z0-9/_.-]+$/i.test(arg) || arg === '') {
    return arg
  }
  return `$'`
    + arg
      .replace(/\\/g, '\\\\')
      .replace(/'/g, '\\\'')
      .replace(/\f/g, '\\f')
      .replace(/\n/g, '\\n')
      .replace(/\r/g, '\\r')
      .replace(/\t/g, '\\t')
      .replace(/\v/g, '\\v')
      .replace(/\0/g, '\\0')
    + `'`
}

function exitCodeInfo(exitCode) {
  return {
    2: 'Misuse of shell builtins',
    126: 'Invoked command cannot execute',
    127: 'Command not found',
    128: 'Invalid exit argument',
    129: 'Hangup',
    130: 'Interrupt',
    131: 'Quit and dump core',
    132: 'Illegal instruction',
    133: 'Trace/breakpoint trap',
    134: 'Process aborted',
    135: 'Bus error: "access to undefined portion of memory object"',
    136: 'Floating point exception: "erroneous arithmetic operation"',
    137: 'Kill (terminate immediately)',
    138: 'User-defined 1',
    139: 'Segmentation violation',
    140: 'User-defined 2',
    141: 'Write to pipe with no one reading',
    142: 'Signal raised by alarm',
    143: 'Termination (request to terminate)',
    145: 'Child process terminated, stopped (or continued*)',
    146: 'Continue if stopped',
    147: 'Stop executing temporarily',
    148: 'Terminal stop signal',
    149: 'Background process attempting to read from tty ("in")',
    150: 'Background process attempting to write to tty ("out")',
    151: 'Urgent data available on socket',
    152: 'CPU time limit exceeded',
    153: 'File size limit exceeded',
    154: 'Signal raised by timer counting virtual time: "virtual timer expired"',
    155: 'Profiling timer expired',
    157: 'Pollable event',
    159: 'Bad syscall',
  }[exitCode]
}