text: 'use strict'
  
  const BB = require('bluebird')
  
  const cacache = require('cacache')
  const Fetcher = require('../fetch')
  const fs = require('fs')
  const pipe = BB.promisify(require('mississippi').pipe)
  const through = require('mississippi').through
  
  const readFileAsync = BB.promisify(fs.readFile)
  const statAsync = BB.promisify(fs.stat)
  
  const MAX_BULK_SIZE = 2 * 1024 * 1024 // 2MB
  
  // `file` packages refer to local tarball files.
  const fetchFile = module.exports = Object.create(null)
  
  Fetcher.impl(fetchFile, {
    manifest (spec, opts) {
      // We can't do much here. `finalizeManifest` will take care of
      // calling `tarball` to fill out all the necessary details.
      return BB.resolve(null)
    },
  
    // All the heavy lifting for `file` packages is done here.
    // They're never cached. We just read straight out of the file.
    // TODO - maybe they *should* be cached?
    tarball (spec, opts) {
      const src = spec._resolved || spec.fetchSpec
      const stream = through()
      statAsync(src).then(stat => {
        if (spec._resolved) { stream.emit('manifest', spec) }
        if (stat.size <= MAX_BULK_SIZE) {
          // YAY LET'S DO THING IN BULK
          return readFileAsync(src).then(data => {
            if (opts.cache) {
              return cacache.put(
                opts.cache, `pacote:tarball:file:${src}`, data, {
                  integrity: opts.integrity
                }
              ).then(integrity => ({data, integrity}))
            } else {
              return {data}
            }
          }).then(info => {
            if (info.integrity) { stream.emit('integrity', info.integrity) }
            stream.write(info.data, () => {
              stream.end()
            })
          })
        } else {
          let integrity
          const cacheWriter = !opts.cache
          ? BB.resolve(null)
          : (pipe(
            fs.createReadStream(src),
            cacache.put.stream(opts.cache, `pacote:tarball:${src}`, {
              integrity: opts.integrity
            }).on('integrity', d => { integrity = d })
          ))
          return cacheWriter.then(() => {
            if (integrity) { stream.emit('integrity', integrity) }
            return pipe(fs.createReadStream(src), stream)
          })
        }
      }, err => stream.emit('error', err))
      return stream
    },
  
    fromManifest (manifest, spec, opts) {
      return this.tarball(manifest || spec, opts)
    }
  })
  