2 files changed, 5 insertions, 226 deletions
diff --git a/lib/internal/streams/async_iterator.js b/lib/internal/streams/async_iterator.js
deleted file mode 100644
index 87b7f227d5..0000000000
--- a/lib/internal/streams/async_iterator.js
+++ /dev/null
@@ -1,221 +0,0 @@
-'use strict';
-
-const {
-  ObjectCreate,
-  ObjectGetPrototypeOf,
-  ObjectSetPrototypeOf,
-  Promise,
-  PromiseReject,
-  PromiseResolve,
-  Symbol,
-} = primordials;
-
-const finished = require('internal/streams/end-of-stream');
-const destroyImpl = require('internal/streams/destroy');
-
-const kLastResolve = Symbol('lastResolve');
-const kLastReject = Symbol('lastReject');
-const kError = Symbol('error');
-const kEnded = Symbol('ended');
-const kLastPromise = Symbol('lastPromise');
-const kHandlePromise = Symbol('handlePromise');
-const kStream = Symbol('stream');
-
-let Readable;
-
-function createIterResult(value, done) {
-  return { value, done };
-}
-
-function readAndResolve(iter) {
-  const resolve = iter[kLastResolve];
-  if (resolve !== null) {
-    const data = iter[kStream].read();
-    // We defer if data is null. We can be expecting either 'end' or 'error'.
-    if (data !== null) {
-      iter[kLastPromise] = null;
-      iter[kLastResolve] = null;
-      iter[kLastReject] = null;
-      resolve(createIterResult(data, false));
-    }
-  }
-}
-
-function onReadable(iter) {
-  // We wait for the next tick, because it might
-  // emit an error with `process.nextTick()`.
-  process.nextTick(readAndResolve, iter);
-}
-
-function wrapForNext(lastPromise, iter) {
-  return (resolve, reject) => {
-    lastPromise.then(() => {
-      if (iter[kEnded]) {
-        resolve(createIterResult(undefined, true));
-        return;
-      }
-
-      iter[kHandlePromise](resolve, reject);
-    }, reject);
-  };
-}
-
-const AsyncIteratorPrototype = ObjectGetPrototypeOf(
-  ObjectGetPrototypeOf(async function* () {}).prototype);
-
-function finish(self, err) {
-  return new Promise((resolve, reject) => {
-    const stream = self[kStream];
-
-    finished(stream, (err) => {
-      if (err && err.code !== 'ERR_STREAM_PREMATURE_CLOSE') {
-        reject(err);
-      } else {
-        resolve(createIterResult(undefined, true));
-      }
-    });
-    destroyImpl.destroyer(stream, err);
-  });
-}
-
-const ReadableStreamAsyncIteratorPrototype = ObjectSetPrototypeOf({
-  get stream() {
-    return this[kStream];
-  },
-
-  next() {
-    // If we have detected an error in the meanwhile
-    // reject straight away.
-    const error = this[kError];
-    if (error !== null) {
-      return PromiseReject(error);
-    }
-
-    if (this[kEnded]) {
-      return PromiseResolve(createIterResult(undefined, true));
-    }
-
-    if (this[kStream].destroyed) {
-      return new Promise((resolve, reject) => {
-        if (this[kError]) {
-          reject(this[kError]);
-        } else if (this[kEnded]) {
-          resolve(createIterResult(undefined, true));
-        } else {
-          finished(this[kStream], (err) => {
-            if (err && err.code !== 'ERR_STREAM_PREMATURE_CLOSE') {
-              reject(err);
-            } else {
-              resolve(createIterResult(undefined, true));
-            }
-          });
-        }
-      });
-    }
-
-    // If we have multiple next() calls we will wait for the previous Promise to
-    // finish. This logic is optimized to support for await loops, where next()
-    // is only called once at a time.
-    const lastPromise = this[kLastPromise];
-    let promise;
-
-    if (lastPromise) {
-      promise = new Promise(wrapForNext(lastPromise, this));
-    } else {
-      // Fast path needed to support multiple this.push()
-      // without triggering the next() queue.
-      const data = this[kStream].read();
-      if (data !== null) {
-        return PromiseResolve(createIterResult(data, false));
-      }
-
-      promise = new Promise(this[kHandlePromise]);
-    }
-
-    this[kLastPromise] = promise;
-
-    return promise;
-  },
-
-  return() {
-    return finish(this);
-  },
-
-  throw(err) {
-    return finish(this, err);
-  },
-}, AsyncIteratorPrototype);
-
-const createReadableStreamAsyncIterator = (stream) => {
-  if (typeof stream.read !== 'function') {
-    // v1 stream
-
-    if (!Readable) {
-      Readable = require('_stream_readable');
-    }
-
-    const src = stream;
-    stream = new Readable({ objectMode: true }).wrap(src);
-    finished(stream, (err) => destroyImpl.destroyer(src, err));
-  }
-
-  const iterator = ObjectCreate(ReadableStreamAsyncIteratorPrototype, {
-    [kStream]: { value: stream, writable: true },
-    [kLastResolve]: { value: null, writable: true },
-    [kLastReject]: { value: null, writable: true },
-    [kError]: { value: null, writable: true },
-    [kEnded]: {
-      value: stream.readableEnded || stream._readableState.endEmitted,
-      writable: true
-    },
-    // The function passed to new Promise is cached so we avoid allocating a new
-    // closure at every run.
-    [kHandlePromise]: {
-      value: (resolve, reject) => {
-        const data = iterator[kStream].read();
-        if (data) {
-          iterator[kLastPromise] = null;
-          iterator[kLastResolve] = null;
-          iterator[kLastReject] = null;
-          resolve(createIterResult(data, false));
-        } else {
-          iterator[kLastResolve] = resolve;
-          iterator[kLastReject] = reject;
-        }
-      },
-      writable: true,
-    },
-  });
-  iterator[kLastPromise] = null;
-
-  finished(stream, { writable: false }, (err) => {
-    if (err && err.code !== 'ERR_STREAM_PREMATURE_CLOSE') {
-      const reject = iterator[kLastReject];
-      // Reject if we are waiting for data in the Promise returned by next() and
-      // store the error.
-      if (reject !== null) {
-        iterator[kLastPromise] = null;
-        iterator[kLastResolve] = null;
-        iterator[kLastReject] = null;
-        reject(err);
-      }
-      iterator[kError] = err;
-      return;
-    }
-
-    const resolve = iterator[kLastResolve];
-    if (resolve !== null) {
-      iterator[kLastPromise] = null;
-      iterator[kLastResolve] = null;
-      iterator[kLastReject] = null;
-      resolve(createIterResult(undefined, true));
-    }
-    iterator[kEnded] = true;
-  });
-
-  stream.on('readable', onReadable.bind(null, iterator));
-
-  return iterator;
-};
-
-module.exports = createReadableStreamAsyncIterator;
diff --git a/lib/internal/streams/pipeline.js b/lib/internal/streams/pipeline.js
index 4786b906f4..aaee0d2499 100644
--- a/lib/internal/streams/pipeline.js
+++ b/lib/internal/streams/pipeline.js
@@ -23,7 +23,7 @@ const {
 
 let EE;
 let PassThrough;
-let createReadableStreamAsyncIterator;
+let Readable;
 
 function destroyer(stream, reading, writing, callback) {
   callback = once(callback);
@@ -113,11 +113,11 @@ function makeAsyncIterable(val) {
 }
 
 async function* fromReadable(val) {
-  if (!createReadableStreamAsyncIterator) {
-    createReadableStreamAsyncIterator =
-      require('internal/streams/async_iterator');
+  if (!Readable) {
+    Readable = require('_stream_readable');
   }
-  yield* createReadableStreamAsyncIterator(val);
+
+  yield* Readable.prototype[SymbolAsyncIterator].call(val);
 }
 
 async function pump(iterable, writable, finish) {