update implementation

reference-implementation/lib/ReadableStream-impl.js

@@ -29,7 +29,7 @@ exports.implementation = class ReadableStreamImpl {
         this, underlyingSource, underlyingSourceDict, highWaterMark
       );
     } else {
-      assert(!('type' in underlyingSourceDict));
+      assert(!('type' in underlyingSourceDict) || underlyingSourceDict.type === 'transfer');
       const sizeAlgorithm = ExtractSizeAlgorithm(strategy);
       const highWaterMark = ExtractHighWaterMark(strategy, 1);
       aos.SetUpReadableStreamDefaultControllerFromUnderlyingSource(

reference-implementation/lib/ReadableStreamDefaultController-impl.js

@@ -17,12 +17,14 @@ exports.implementation = class ReadableStreamDefaultControllerImpl {
     aos.ReadableStreamDefaultControllerClose(this);
   }
 
-  enqueue(chunk) {
+  enqueue(chunk, optionsOrTransfer) {
+    const hasTransfer = optionsOrTransfer && !Array.isArray(optionsOrTransfer);
+    const transfer = hasTransfer ? optionsOrTransfer.transfer : optionsOrTransfer;
     if (aos.ReadableStreamDefaultControllerCanCloseOrEnqueue(this) === false) {
       throw new TypeError('The stream is not in a state that permits enqueue');
     }
 
-    return aos.ReadableStreamDefaultControllerEnqueue(this, chunk);
+    return aos.ReadableStreamDefaultControllerEnqueue(this, chunk, transfer);
   }
 
   error(e) {

reference-implementation/lib/ReadableStreamDefaultController.webidl

@@ -1,8 +1,13 @@
+dictionary StructuredSerializeOptions {
+  sequence<object> transfer = [];
+};
+
 [Exposed=(Window,Worker,Worklet)]
 interface ReadableStreamDefaultController {
   readonly attribute unrestricted double? desiredSize;
 
   undefined close();
-  undefined enqueue(optional any chunk);
+  undefined enqueue(any chunk, sequence<object> transfer);
+  undefined enqueue(optional any chunk, optional StructuredSerializeOptions options = { });
   undefined error(optional any e);
 };

reference-implementation/lib/UnderlyingSource.webidl

@@ -12,4 +12,4 @@ callback UnderlyingSourceStartCallback = any (ReadableStreamController controlle
 callback UnderlyingSourcePullCallback = Promise<undefined> (ReadableStreamController controller);
 callback UnderlyingSourceCancelCallback = Promise<undefined> (optional any reason);
 
-enum ReadableStreamType { "bytes" };
+enum ReadableStreamType { "bytes", "transfer" };

reference-implementation/lib/abstract-ops/miscellaneous.js

@@ -20,3 +20,11 @@ exports.CloneAsUint8Array = O => {
   const buffer = O.buffer.slice(O.byteOffset, O.byteOffset + O.byteLength);
   return new Uint8Array(buffer);
 };
+
+exports.StructuredTransferOrClone = (value, transfer) => {
+  // FIXME: We should check whether value is an array buffer or is transferable and update transfer accordingly.
+  if (structuredClone)
+    return structuredClone(value, transfer);
+
+  return JSON.parse(JSON.stringify(value));
+};

reference-implementation/lib/abstract-ops/queue-with-sizes.js

@@ -1,6 +1,6 @@
 'use strict';
 const assert = require('assert');
-const { IsNonNegativeNumber } = require('./miscellaneous.js');
+const { IsNonNegativeNumber, StructuredTransferOrClone } = require('./miscellaneous.js');
 
 exports.DequeueValue = container => {
   assert('_queue' in container && '_queueTotalSize' in container);
@@ -15,7 +15,7 @@ exports.DequeueValue = container => {
   return pair.value;
 };
 
-exports.EnqueueValueWithSize = (container, value, size) => {
+exports.EnqueueValueWithSize = (container, value, size, transfer) => {
   assert('_queue' in container && '_queueTotalSize' in container);
 
   if (!IsNonNegativeNumber(size)) {
@@ -24,7 +24,9 @@ exports.EnqueueValueWithSize = (container, value, size) => {
   if (size === Infinity) {
     throw new RangeError('Size must be a finite, non-NaN, non-negative number.');
   }
-
+  if (container.isTransferring) {
+    value = StructuredTransferOrClone(value, transfer);
+  }
   container._queue.push({ value, size });
   container._queueTotalSize += size;
 };
@@ -40,6 +42,18 @@ exports.PeekQueueValue = container => {
 exports.ResetQueue = container => {
   assert('_queue' in container && '_queueTotalSize' in container);
 
+  if (container.isTransferring) {
+    while (container._queue.length > 0) {
+      const value = exports.DequeueValue(container);
+      if (typeof value.close === 'function') {
+        try {
+          value.close();
+        } catch (closeException) {
+          // Nothing to do.
+        }
+      }
+    }
+  }
   container._queue = [];
   container._queueTotalSize = 0;
 };

reference-implementation/lib/abstract-ops/readable-streams.js

@@ -6,7 +6,7 @@ const { promiseResolvedWith, promiseRejectedWith, newPromise, resolvePromise, re
   require('../helpers/webidl.js');
 const { CanTransferArrayBuffer, CopyDataBlockBytes, CreateArrayFromList, IsDetachedBuffer, TransferArrayBuffer } =
   require('./ecmascript.js');
-const { CloneAsUint8Array, IsNonNegativeNumber } = require('./miscellaneous.js');
+const { CloneAsUint8Array, IsNonNegativeNumber, StructuredTransferOrClone } = require('./miscellaneous.js');
 const { EnqueueValueWithSize, ResetQueue } = require('./queue-with-sizes.js');
 const { AcquireWritableStreamDefaultWriter, IsWritableStreamLocked, WritableStreamAbort,
         WritableStreamDefaultWriterCloseWithErrorPropagation, WritableStreamDefaultWriterRelease,
@@ -89,7 +89,7 @@ function CreateReadableStream(startAlgorithm, pullAlgorithm, cancelAlgorithm, hi
 
   const controller = ReadableStreamDefaultController.new(globalThis);
   SetUpReadableStreamDefaultController(
-    stream, controller, startAlgorithm, pullAlgorithm, cancelAlgorithm, highWaterMark, sizeAlgorithm
+    stream, controller, startAlgorithm, pullAlgorithm, cancelAlgorithm, highWaterMark, sizeAlgorithm, false
   );
 
   return stream;
@@ -340,7 +340,7 @@ function ReadableStreamTee(stream, cloneForBranch2) {
   if (ReadableByteStreamController.isImpl(stream._controller)) {
     return ReadableByteStreamTee(stream);
   }
-  return ReadableStreamDefaultTee(stream, cloneForBranch2);
+  return ReadableStreamDefaultTee(stream, stream._controller.isTransferring ? true : cloneForBranch2);
 }
 
 function ReadableStreamDefaultTee(stream, cloneForBranch2) {
@@ -392,10 +392,10 @@ function ReadableStreamDefaultTee(stream, cloneForBranch2) {
           // }
 
           if (canceled1 === false) {
-            ReadableStreamDefaultControllerEnqueue(branch1._controller, chunk1);
+            ReadableStreamDefaultControllerEnqueue(branch1._controller, chunk1, undefined);
           }
           if (canceled2 === false) {
-            ReadableStreamDefaultControllerEnqueue(branch2._controller, chunk2);
+            ReadableStreamDefaultControllerEnqueue(branch2._controller, chunk2, undefined);
           }
 
           reading = false;
@@ -1074,14 +1074,22 @@ function ReadableStreamDefaultControllerClose(controller) {
   }
 }
 
-function ReadableStreamDefaultControllerEnqueue(controller, chunk) {
+function ReadableStreamDefaultControllerEnqueue(controller, chunk, transfer) {
   if (ReadableStreamDefaultControllerCanCloseOrEnqueue(controller) === false) {
     return;
   }
 
   const stream = controller._stream;
 
   if (IsReadableStreamLocked(stream) === true && ReadableStreamGetNumReadRequests(stream) > 0) {
+    if (controller.isTransferring) {
+      try {
+        chunk = StructuredTransferOrClone(chunk, transfer);
+      } catch (chunkCloneError) {
+        ReadableStreamDefaultControllerError(controller, chunkCloneError);
+        throw chunkCloneError;
+      }
+    }
     ReadableStreamFulfillReadRequest(stream, chunk, false);
   } else {
     let chunkSize;
@@ -1093,7 +1101,7 @@ function ReadableStreamDefaultControllerEnqueue(controller, chunk) {
     }
 
     try {
-      EnqueueValueWithSize(controller, chunk, chunkSize);
+      EnqueueValueWithSize(controller, chunk, chunkSize, transfer);
     } catch (enqueueE) {
       ReadableStreamDefaultControllerError(controller, enqueueE);
       throw enqueueE;
@@ -1148,7 +1156,7 @@ function ReadableStreamDefaultControllerCanCloseOrEnqueue(controller) {
 }
 
 function SetUpReadableStreamDefaultController(
-  stream, controller, startAlgorithm, pullAlgorithm, cancelAlgorithm, highWaterMark, sizeAlgorithm) {
+  stream, controller, startAlgorithm, pullAlgorithm, cancelAlgorithm, highWaterMark, sizeAlgorithm, isTransferring) {
   assert(stream._controller === undefined);
 
   controller._stream = stream;
@@ -1169,6 +1177,8 @@ function SetUpReadableStreamDefaultController(
   controller._pullAlgorithm = pullAlgorithm;
   controller._cancelAlgorithm = cancelAlgorithm;
 
+  controller.isTransferring = isTransferring;
+
   stream._controller = controller;
 
   const startResult = startAlgorithm();
@@ -1195,7 +1205,7 @@ function SetUpReadableStreamDefaultControllerFromUnderlyingSource(
   let startAlgorithm = () => undefined;
   let pullAlgorithm = () => promiseResolvedWith(undefined);
   let cancelAlgorithm = () => promiseResolvedWith(undefined);
-
+  const isTransferring = underlyingSourceDict.type === 'transfer';
   if ('start' in underlyingSourceDict) {
     startAlgorithm = () => underlyingSourceDict.start.call(underlyingSource, controller);
   }
@@ -1207,8 +1217,8 @@ function SetUpReadableStreamDefaultControllerFromUnderlyingSource(
   }
 
   SetUpReadableStreamDefaultController(
-    stream, controller, startAlgorithm, pullAlgorithm, cancelAlgorithm, highWaterMark, sizeAlgorithm
-  );
+    stream, controller, startAlgorithm, pullAlgorithm, cancelAlgorithm, highWaterMark, sizeAlgorithm,
+    isTransferring);
 }
 
 // Byte stream controllers

reference-implementation/lib/abstract-ops/transform-streams.js

@@ -155,7 +155,7 @@ function TransformStreamDefaultControllerEnqueue(controller, chunk) {
   // accept TransformStreamDefaultControllerEnqueue() calls.
 
   try {
-    ReadableStreamDefaultControllerEnqueue(readableController, chunk);
+    ReadableStreamDefaultControllerEnqueue(readableController, chunk, undefined);
   } catch (e) {
     // This happens when readableStrategy.size() throws.
     TransformStreamErrorWritableAndUnblockWrite(stream, e);

reference-implementation/lib/abstract-ops/writable-streams.js

@@ -637,7 +637,7 @@ function WritableStreamDefaultControllerClearAlgorithms(controller) {
 }
 
 function WritableStreamDefaultControllerClose(controller) {
-  EnqueueValueWithSize(controller, closeSentinel, 0);
+  EnqueueValueWithSize(controller, closeSentinel, 0, undefined);
   WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller);
 }
 
@@ -729,7 +729,7 @@ function WritableStreamDefaultControllerProcessWrite(controller, chunk) {
 
 function WritableStreamDefaultControllerWrite(controller, chunk, chunkSize) {
   try {
-    EnqueueValueWithSize(controller, chunk, chunkSize);
+    EnqueueValueWithSize(controller, chunk, chunkSize, undefined);
   } catch (enqueueE) {
     WritableStreamDefaultControllerErrorIfNeeded(controller, enqueueE);
     return;