fix(file): include integrity hash for streamed tarballs too

Author: zkat

lib/fetchers/file.js

@@ -5,7 +5,7 @@ const BB = require('bluebird')
 const cacache = require('cacache')
 const Fetcher = require('../fetch')
 const fs = require('fs')
-const pipe = require('mississippi').pipe
+const pipe = BB.promisify(require('mississippi').pipe)
 const through = require('mississippi').through
 
 const readFileAsync = BB.promisify(fs.readFile)
@@ -50,7 +50,19 @@ Fetcher.impl(fetchFile, {
           })
         })
       } else {
-        return pipe(fs.createReadStream(src), stream)
+        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