chore(xo-server/ag2s): use async-iterator-to-stream instead

packages/xo-server/package.json

@@ -38,6 +38,7 @@
     "ajv": "^6.1.1",
     "app-conf": "^0.5.0",
     "archiver": "^2.1.0",
+    "async-iterator-to-stream": "^1.0.1",
     "base64url": "^2.0.0",
     "bind-property-descriptor": "^1.0.0",
     "blocked": "^1.2.1",

packages/xo-server/src/ag2s.js

@@ -1,68 +0,0 @@
-import { Readable } from 'stream'
-
-// return the next value of the iterator but if it is a promise, resolve it and
-// reinject it
-//
-// this enables the use of a simple generator instead of an async generator
-// (which are less widely supported)
-const next = async (iterator, arg) => {
-  let cursor = iterator.next(arg)
-  if (typeof cursor.then === 'function') {
-    return cursor
-  }
-  let value
-  while (
-    !cursor.done &&
-    (value = cursor.value) != null &&
-    typeof value.then === 'function'
-  ) {
-    let success = false
-    try {
-      value = await value
-      success = true
-    } catch (error) {
-      cursor = iterator.throw(error)
-    }
-    if (success) {
-      cursor = iterator.next(value)
-    }
-  }
-  return cursor
-}
-
-// Create a readable stream from a generator
-//
-// generator can be async or can yield promises to wait for them
-export const createReadable = (generator, options) => {
-  const readable = new Readable(options)
-  readable._read = size => {
-    const iterator = generator(size)
-    readable._destroy = (error, cb) => {
-      iterator.throw(error)
-      cb(error)
-    }
-    let running = false
-    const read = (readable._read = async size => {
-      if (running) {
-        return
-      }
-      running = true
-      try {
-        let cursor
-        do {
-          cursor = await next(iterator, size)
-          if (cursor.done) {
-            return readable.push(null)
-          }
-        } while (readable.push(cursor.value))
-      } catch (error) {
-        readable.emit('error', error)
-      } finally {
-        running = false
-      }
-    })
-    return read(size)
-  }
-
-  return readable
-}

packages/xo-server/src/vhd-merge.js

@@ -1,6 +1,7 @@
 // TODO: remove once completely merged in vhd.js
 
 import assert from 'assert'
+import asyncIteratorToStream from 'async-iterator-to-stream'
 import concurrency from 'limit-concurrency-decorator'
 import fu from '@nraynaud/struct-fu'
 import isEqual from 'lodash/isEqual'
@@ -9,7 +10,6 @@ import { fromEvent } from 'promise-toolbox'
 
 import type RemoteHandler from './remote-handlers/abstract'
 import constantStream from './constant-stream'
-import { createReadable } from './ag2s'
 import { noop, resolveRelativeFromFile, streamToBuffer } from './utils'
 
 const VHD_UTIL_DEBUG = 0
@@ -769,8 +769,7 @@ export async function chainVhd (
   return false
 }
 
-export const createReadStream = (handler, path) =>
-  createReadable(function * () {
+export const createReadStream = asyncIteratorToStream(function * (handler, path) {
   const fds = []
 
   try {
@@ -806,8 +805,7 @@ export const createReadStream = (handler, path) =>
     }
 
     const bat = Buffer.allocUnsafe(
-        Math.ceil(4 * header.maxTableEntries / VHD_SECTOR_SIZE) *
-          VHD_SECTOR_SIZE
+      Math.ceil(4 * header.maxTableEntries / VHD_SECTOR_SIZE) * VHD_SECTOR_SIZE
     )
     let footer = {
       ...vhd.footer,
@@ -900,7 +898,7 @@ export const createReadStream = (handler, path) =>
       })
     }
   }
-  })
+})
 
 export async function readVhdMetadata (handler: RemoteHandler, path: string) {
   const vhd = new Vhd(handler, path)

yarn.lock

@@ -611,7 +611,7 @@
     pirates "^3.0.1"
     source-map-support "^0.4.2"
 
-"@babel/runtime@^7.0.0-beta.39":
+"@babel/runtime@^7.0.0-beta.39", "@babel/runtime@^7.0.0-beta.42":
   version "7.0.0-beta.42"
   resolved "https://registry.yarnpkg.com/@babel/runtime/-/runtime-7.0.0-beta.42.tgz#352e40c92e0460d3e82f49bd7e79f6cda76f919f"
   dependencies:
@@ -1252,6 +1252,13 @@ async-foreach@^0.1.3:
   version "0.1.3"
   resolved "https://registry.yarnpkg.com/async-foreach/-/async-foreach-0.1.3.tgz#36121f845c0578172de419a97dbeb1d16ec34542"
 
+async-iterator-to-stream@^1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/async-iterator-to-stream/-/async-iterator-to-stream-1.0.1.tgz#e609c9102a17412772b9c94ffb77ddffb9b743b2"
+  dependencies:
+    "@babel/runtime" "^7.0.0-beta.42"
+    readable-stream "^2.3.5"
+
 async-limiter@~1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/async-limiter/-/async-limiter-1.0.0.tgz#78faed8c3d074ab81f22b4e985d79e8738f720f8"