From e1c4e2d1245eb402ace9aa609b51602b0387eaf4 Mon Sep 17 00:00:00 2001
From: Domenic Denicola <d@domenic.me>
Date: Tue, 28 Jun 2016 15:16:10 -0400
Subject: [PATCH] Tweak ReadableByteStreamControllerEnqueue algorithm structure

This makes the parallel nature of the algorithm more clear, in that it handles all three cases of default reader, BYOB reader, and no reader. See http://logs.glob.uno/?c=freenode%23whatwg#c999292.
---
 index.bs                                        | 15 +++++++--------
 reference-implementation/lib/readable-stream.js | 14 ++++++--------
 2 files changed, 13 insertions(+), 16 deletions(-)

diff --git a/index.bs b/index.bs
index 39263fc0b..dbe2841c8 100644
--- a/index.bs
+++ b/index.bs
@@ -2127,15 +2127,14 @@ nothrow>ReadableByteStreamControllerEnqueue ( <var>controller</var>, <var>chunk<
       1. Let _transferredView_ be ! Construct(<a idl>%Uint8Array%</a>, « _transferredBuffer_, _byteOffset_,
          _byteLength_ »).
       1. Perform ! ReadableStreamFulfillReadRequest(_stream_, _transferredView_, *false*).
+  1. Otherwise, if ! ReadableStreamHasBYOBReader(_stream_) is *true*,
+    1. Perform ! ReadableByteStreamControllerEnqueueChunkToQueue(_controller_, _transferredBuffer_, _byteOffset_,
+       _byteLength_).
+    1. Perform ! ReadableByteStreamControllerProcessPullIntoDescriptorsUsingQueue(_controller_).
   1. Otherwise,
-    1. If ! ReadableStreamHasBYOBReader(_stream_) is *true*,
-      1. Perform ! ReadableByteStreamControllerEnqueueChunkToQueue(_controller_, _transferredBuffer_, _byteOffset_,
-         _byteLength_).
-      1. Perform ! ReadableByteStreamControllerProcessPullIntoDescriptorsUsingQueue(_controller_).
-    1. Otherwise,
-      1. Assert: ! IsReadableStreamLocked(_stream_) is *false*.
-      1. Perform ! ReadableByteStreamControllerEnqueueChunkToQueue(_controller_, _transferredBuffer_, _byteOffset_,
-         _byteLength_).
+    1. Assert: ! IsReadableStreamLocked(_stream_) is *false*.
+    1. Perform ! ReadableByteStreamControllerEnqueueChunkToQueue(_controller_, _transferredBuffer_, _byteOffset_,
+       _byteLength_).
 </emu-alg>
 
 <h4 id="readable-byte-stream-controller-enqueue-chunk-to-queue" aoid="ReadableByteStreamControllerEnqueueChunkToQueue"
diff --git a/reference-implementation/lib/readable-stream.js b/reference-implementation/lib/readable-stream.js
index bd8eb9520..332eaf618 100644
--- a/reference-implementation/lib/readable-stream.js
+++ b/reference-implementation/lib/readable-stream.js
@@ -1705,15 +1705,13 @@ function ReadableByteStreamControllerEnqueue(controller, chunk) {
       const transferredView = new Uint8Array(transferredBuffer, byteOffset, byteLength);
       ReadableStreamFulfillReadRequest(stream, transferredView, false);
     }
+  } else if (ReadableStreamHasBYOBReader(stream) === true) {
+    // TODO: Ideally in this branch detaching should happen only if the buffer is not consumed fully.
+    ReadableByteStreamControllerEnqueueChunkToQueue(controller, transferredBuffer, byteOffset, byteLength);
+    ReadableByteStreamControllerProcessPullIntoDescriptorsUsingQueue(controller);
   } else {
-    if (ReadableStreamHasBYOBReader(stream) === true) {
-      // TODO: Ideally in this branch detaching should happen only if the buffer is not consumed fully.
-      ReadableByteStreamControllerEnqueueChunkToQueue(controller, transferredBuffer, byteOffset, byteLength);
-      ReadableByteStreamControllerProcessPullIntoDescriptorsUsingQueue(controller);
-    } else {
-      assert(IsReadableStreamLocked(stream) === false, 'stream must not be locked');
-      ReadableByteStreamControllerEnqueueChunkToQueue(controller, transferredBuffer, byteOffset, byteLength);
-    }
+    assert(IsReadableStreamLocked(stream) === false, 'stream must not be locked');
+    ReadableByteStreamControllerEnqueueChunkToQueue(controller, transferredBuffer, byteOffset, byteLength);
   }
 }