latest-linker.js

#!/usr/bin/env node

'use strict'

const fs       = require('fs')
    , path     = require('path')
    , semver   = require('semver')
    , map      = require('map-async')

    , ltsNames = {
          4 : 'argon'
        , 6 : 'boron'
        , 8 : 'carbon'
        , 10 : 'dubnium'
      }

if (process.argv.length < 3)
  throw new Error('Usage: latest-linker.js <downloads directory> [docs directory]')

const dir = path.resolve(process.argv[2])
    , docsDir = process.argv[3] && path.resolve(process.argv[3])

if (!fs.statSync(dir).isDirectory())
  throw new Error('Usage: latest-linker.js <downloads directory> [docs directory]')

if (docsDir && !fs.statSync(docsDir).isDirectory())
  throw new Error('Usage: latest-linker.js <downloads directory> [docs directory]')


map(
    fs.readdirSync(dir).map((d) => path.join(dir, d))
  , (d, callback) => fs.stat(d, (err, stat) => callback(null, { d: d, stat: stat }))
  , afterMap
)


function afterMap (err, allDirs) {
  if (err)
    throw err

  allDirs = allDirs.filter((d) => d.stat && d.stat.isDirectory())
                   .map((d) => path.basename(d.d))
                   .map((d) => { try { return semver(d) } catch (e) {} })
                   .filter(Boolean)

  makeDocsLinks(allDirs.map((v) => v.raw))

  let dirs = allDirs.filter((d) => semver.satisfies(d, '~0.10 || ~0.12 || >= 1.0'))
                    .map((d) => d.raw)

  dirs.sort((d1, d2) => semver.compare(d1, d2))

  link('0.10', dirs)
  link(0.12, dirs)

  for (let i = 1;; i++)
    if (!link(i, dirs) && i >= 4) break

  let max   = link(null, dirs)
    , tbreg = new RegExp(`(\\w+)-${max}.tar.gz`)

  let tarball = fs.readdirSync(path.join(dir, 'latest'))
                  .filter((f) => tbreg.test(f))

  if (tarball.length != 1)
    throw new Error('Could not find latest.tar.gz')

  tarball = tarball[0]
  let name = tarball.match(tbreg)[1]
  let dst = path.join(dir, `${name}-latest.tar.gz`)
  try { fs.unlinkSync(dst) } catch (e) {}
  fs.symlinkSync(path.join(dir, 'latest', tarball), dst)
}


function makeDocsLinks (versions) {
  if (!docsDir)
    return

  versions.forEach((version) => {
    let src = path.join(dir, version, 'docs')
      , dst = path.join(docsDir, version)

    fs.stat(src, (err, stat) => {
      if (err || !stat.isDirectory())
        return

      fs.unlink(dst, () => {
        fs.symlink(src, dst, (err) => { if (err) throw err })
      })
    })
  })
}


function link (version, dirs) {
  let line  = version && `${version}.x`
    , range = version ? `${Number(version) < 1 ? '~' : '^'}${line}` : '*'
    , max   = semver.maxSatisfying(dirs, range)

  if (!max) return false

  function symlink (name) {
    let dst = path.join(dir, name)
      , src = path.join(dir, max)

    try { fs.unlinkSync(dst) } catch (e) {}
    fs.symlinkSync(src, dst)

    if (!docsDir)
      return

    let dsrc = path.join(dir, max, 'docs')
      , ddst = path.join(docsDir, name)

    try { fs.unlinkSync(ddst) } catch (e) {}
    fs.symlinkSync(dsrc, ddst)
  }

  if (line) {
    symlink(`latest-v${line}`)
    if (ltsNames[version])
      symlink(`latest-${ltsNames[version]}`)
  } else {
    symlink('latest')
  }

  return max
}