@zkochan/pnpm/lib/install.js

A fast implementation of npm install

var debug = require('debug')('pnpm:install')
var npa = require('npm-package-arg')
var getUuid = require('node-uuid')
var fs = require('mz/fs')
var thenify = require('thenify')
var lock = thenify(require('lockfile').lock)
var unlock = thenify(require('lockfile').unlock)
var checkLock = thenify(require('lockfile').unlock)

var join = require('path').join
var dirname = require('path').dirname
var basename = require('path').basename
var abspath = require('path').resolve

var fetch = require('./fetch')
var resolve = require('./resolve')

var mkdirp = require('./fs/mkdirp')
var obliterate = require('./fs/obliterate')
var requireJson = require('./fs/require_json')
var relSymlink = require('./fs/rel_symlink')

var linkBins = require('./install/link_bins')
var linkBundledDeps = require('./install/link_bundled_deps')
var isAvailable = require('./install/is_available')
var postInstall = require('./install/post_install')

/*
 * Installs a package.
 *
 *     install(ctx, 'rimraf@2', './node_modules')
 *
 * Parameters:
 *
 * - `ctx` (Object) - the context.
 *   - `root` (String) - root path of the package.
 *   - `tmp` (String) - temp dir
 *   - `log` (Function) - logger
 *
 * What it does:
 *
 * - resolve() - resolve from registry.npmjs.org
 * - fetch() - download tarball into node_modules/.tmp/{uuid}
 * - recurse into its dependencies
 * - run postinstall hooks
 * - move .tmp/{uuid} into node_modules/{name}@{version}
 * - symlink node_modules/{name}
 * - symlink bins
 */

module.exports = function install (ctx, pkgSpec, modules, options) {
  debug('installing ' + pkgSpec)
  if (!ctx.builds) ctx.builds = {}
  if (!ctx.fetches) ctx.fetches = {}
  if (!ctx.ignoreScripts) ctx.ignoreScripts = options && options.ignoreScripts

  var pkg = {
    // Preliminary spec data
    // => { raw, name, scope, type, spec, rawSpec }
    spec: npa(pkgSpec),

    // Dependency path to the current package. Not actually needed anmyore
    // outside getting its length
    // => ['babel-core@6.4.5', 'babylon@6.4.5', 'babel-runtime@5.8.35']
    keypath: (options && options.keypath || []),

    // Full name of package as it should be put in the store. Aim to make
    // this as friendly as possible as this will appear in stack traces.
    // => 'lodash@4.0.0'
    // => '@rstacruz!tap-spec@4.1.1'
    // => 'rstacruz!pnpm@0a1b382da'
    // => 'foobar@9a3b283ac'
    fullname: undefined,

    // Distribution data from resolve() => { shasum, tarball }
    dist: undefined,

    // package.json data as retrieved from resolve() => { name, version, ... }
    data: undefined
  }

  var paths = {
    // Module storage => './node_modules'
    modules: modules,

    // Temporary destination while building
    tmp: join(ctx.store, '..', '.tmp', getUuid()),

    // Final destination => store + '/lodash@4.0.0'
    target: undefined
  }

  var log = ctx.log(pkg.spec) // function

  // it might be a bundleDependency, in which case, don't bother
  return isAvailable(pkg.spec, modules)
    .then(_ => _
      ? saveCachedResolution()
        .then(data => log('package.json', data))
      : resolve(Object.assign({}, pkg.spec, {root: ctx.root}), log)
        .then(saveResolution)
        .then(_ => log('resolved', pkg))
        .then(_ => buildToStoreCached(ctx, paths, pkg, log))
        .then(_ => mkdirp(paths.modules))
        .then(_ => symlinkToModules(join(paths.target, '_'), paths.modules))
        // link node_modules/.bin
        .then(_ => linkBins(paths.modules, join(paths.tmp, '_'), join(paths.target, '_')))
        .then(_ => log('package.json', requireJson(join(paths.target, '_', 'package.json')))))
    // done
    .then(_ => {
      if (!ctx.installs) ctx.installs = {}
      ctx.installs[pkg.fullname] = pkg
    })
    .then(_ => log('done'))
    .then(_ => pkg)
    .catch(err => {
      log('error', err)
      throw err
    })

  // set metadata as fetched from resolve()
  function saveResolution (res) {
    pkg.name = res.name
    pkg.fullname = res.fullname
    pkg.version = res.version
    pkg.dist = res.dist
    paths.target = join(ctx.store, res.fullname)
  }

  function saveCachedResolution () {
    var target = join(modules, pkg.spec.name)
    return fs.lstat(target)
      .then(stat => {
        if (stat.isSymbolicLink()) {
          return fs.readlink(target)
            .then(path => save(abspath(path, target)))
        } else {
          return save(target)
        }
      })

    function save (fullpath) {
      var data = requireJson(join(fullpath, 'package.json'))
      pkg.name = data.name
      pkg.fullname = basename(fullpath)
      pkg.version = data.version
      pkg.data = data
      paths.target = fullpath
    }
  }
}

/*
 * Builds to `.store/lodash@4.0.0` (paths.target)
 * If an ongoing build is already working, use it. Also, if that ongoing build
 * is part of the dependency chain (ie, it's a circular dependency), use its stub
 */

function buildToStoreCached (ctx, paths, pkg, log) {
  // If a package is requested for a second time (usually when many packages depend
  // on the same thing), only resolve until it's fetched (not built).
  if (ctx.builds[pkg.fullname]) return ctx.fetches[pkg.fullname]

  return make(paths.target, ctx.builds[pkg.fullname], _ =>
    memoize(ctx.builds, pkg.fullname, _ =>
      Promise.resolve()
        .then(_ => memoize(ctx.fetches, pkg.fullname, _ =>
          fetchToStore(ctx, paths, pkg, log)))
        .then(_ => buildInStore(ctx, paths, pkg, log))
    ))
}

/*
 * Builds to `.store/lodash@4.0.0` (paths.target)
 * Fetches from npm, recurses to dependencies, runs lifecycle scripts, etc
 */

function fetchToStore (ctx, paths, pkg, log) {
  return Promise.resolve()
    // symlink .tmp/0a1b2c3d -> .store/lodash@4.0.0
    // so that when any other module requires it, it's available even
    // if it's partially built
    .then(_ => mkdirp(dirname(paths.target)))
    .then(_ => relSymlink(paths.tmp, paths.target))

    // download and untar
    .then(_ => log('download-queued'))
    .then(_ => mkdirp(ctx.store))
    .then(_ => mkdirp(join(paths.tmp, '_')))
    .then(_ => lock(join(paths.tmp, '.pnpm_inprogress')))
    .then(_ => fetch(join(paths.tmp, '_'), pkg.dist, log))
    .then(_ => pkg.dist.local ? fs.unlink(pkg.dist.tarball) : Promise.resolve())

    // TODO: this is the point it becomes partially useable.
    // ie, it can now be symlinked into .store/foo@1.0.0.
    // it is only here that it should be available for ciruclar dependencies.
}

function buildInStore (ctx, paths, pkg, log) {
  var installAll = require('./install_multiple')
  var fulldata

  return Promise.resolve()
    .then(_ => { fulldata = requireJson(abspath(join(paths.tmp, '_', 'package.json'))) })
    .then(_ => log('package.json', fulldata))

    .then(_ => linkBundledDeps(join(paths.tmp, '_')))

    // recurse down to dependencies
    .then(_ => log('dependencies'))
    .then(_ => installAll(ctx,
      fulldata.dependencies,
      fulldata.optionalDependencies,
      join(paths.tmp, '_', 'node_modules'),
      {
        keypath: pkg.keypath.concat([ pkg.fullname ]),
        dependent: pkg.fullname
      }))

    // symlink itself; . -> node_modules/lodash@4.0.0
    // this way it can require itself
    .then(_ => symlinkSelf(paths.tmp, fulldata, pkg.keypath.length))

    // postinstall hooks
    .then(_ => !ctx.ignoreScripts && postInstall(paths.tmp, fulldata, installLogger(log, pkg)))

    // move to .store/lodash@4.0.0; remove the stub done earlier
    .then(_ => unlock(join(paths.tmp, '.pnpm_inprogress')))
    // we need to make sure that symlinkToModules for another project dependent
    // on this package will not get called inbetween `unlink` and `rename`
    // the easiest way to achieve this is to make them synchronous
    .then(_ => {
      fs.unlinkSync(paths.target)
      fs.renameSync(paths.tmp, paths.target)
    })
}

function installLogger (log, pkg) {
  return (stream, line) => {
    require('debug')('pnpm:post_install')('%s %s', pkg.fullname, line)
    log(stream, { name: pkg.fullname, line: line })
  }
}

/*
 * Symlink a package into its own node_modules. this way, babel-runtime@5 can
 * require('babel-runtime') within itself.
 */

function symlinkSelf (target, pkg, depth) {
  debug('symlinkSelf %s', pkg.name)
  if (depth === 0) {
    return Promise.resolve()
  } else {
    return mkdirp(join(target, 'node_modules'))
      .then(_ => relSymlink(
        join('..', '_'),
        join(target, 'node_modules', escapeName(pkg.name))))
  }
}

function escapeName (name) {
  return name && name.replace('/', '%2f')
}

/*
 * Perform the final symlinking of ./.store/x@1.0.0 -> ./x.
 *
 *     target = '/node_modules/.store/lodash@4.0.0'
 *     modules = './node_modules'
 *     symlinkToModules(fullname, modules)
 */

function symlinkToModules (target, modules) {
  // TODO: uncomment to make things fail
  var pkgData = requireJson(join(target, 'package.json'))
  if (!pkgData.name) { throw new Error('Invalid package.json for ' + target) }

  // lodash -> .store/lodash@4.0.0
  // .store/foo@1.0.0/node_modules/lodash -> ../../../.store/lodash@4.0.0
  // .tmp/01234567890/node_modules/lodash -> ../../../.store/lodash@4.0.0
  var out = join(modules, pkgData.name)
  return mkdirp(dirname(out))
    .then(_ => relSymlink(target, out))
}

/*
 * If `path` doesn't exist, run `fn()`.
 * If it exists and is not in progress, don't do anything.
 * If it's in progress, check if we're working on it. If we're not,
 * obliterate it and run `fn()`.
 */

function make (path, isWorking, fn) {
  return fs.stat(path)
  .then(_ => {
    return checkLock(join(path, '.pnpm_inprogress'))
    .then(isLocked => {
      if (isLocked && !isWorking) return obliterate(path).then(fn)
    })
  })
  .catch(err => {
    if (err.code !== 'ENOENT') throw err
    return fn()
  })
}

/*
 * Save promises for later
 */

function memoize (locks, key, fn) {
  if (locks && locks[key]) return locks[key]
  locks[key] = fn()
  return locks[key]
}