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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "js/Exception.h"
+#include "js/TypeDecls.h"
+#include "js/Value.h"
+#include "mozilla/AlreadyAddRefed.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/dom/AbortSignal.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/Promise-inl.h"
+#include "mozilla/dom/WritableStream.h"
+#include "mozilla/dom/WritableStreamDefaultController.h"
+#include "mozilla/dom/WritableStreamDefaultControllerBinding.h"
+#include "mozilla/dom/UnderlyingSinkBinding.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsDebug.h"
+#include "nsISupports.h"
+
+namespace mozilla::dom {
+
+using namespace streams_abstract;
+
+// Note: Using the individual macros vs NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE
+// because I need to specificy a manual implementation of
+// NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN.
+NS_IMPL_CYCLE_COLLECTION_CLASS(WritableStreamDefaultController)
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(WritableStreamDefaultController)
+ NS_IMPL_CYCLE_COLLECTION_UNLINK(mGlobal, mSignal, mStrategySizeAlgorithm,
+ mAlgorithms, mStream)
+ tmp->mQueue.clear();
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(WritableStreamDefaultController)
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mGlobal, mSignal, mStrategySizeAlgorithm,
+ mAlgorithms, mStream)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(WritableStreamDefaultController)
+ NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
+ // Trace the associated queue.
+ for (const auto& queueEntry : tmp->mQueue) {
+ aCallbacks.Trace(&queueEntry->mValue, "mQueue.mValue", aClosure);
+ }
+NS_IMPL_CYCLE_COLLECTION_TRACE_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(WritableStreamDefaultController)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(WritableStreamDefaultController)
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(WritableStreamDefaultController)
+ NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
+ NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+WritableStreamDefaultController::WritableStreamDefaultController(
+ nsISupports* aGlobal, WritableStream& aStream)
+ : mGlobal(do_QueryInterface(aGlobal)), mStream(&aStream) {
+ mozilla::HoldJSObjects(this);
+}
+
+WritableStreamDefaultController::~WritableStreamDefaultController() {
+ // MG:XXX: LinkedLists are required to be empty at destruction, but it seems
+ // it is possible to have a controller be destructed while still
+ // having entries in its queue.
+ //
+ // This needs to be verified as not indicating some other issue.
+ mQueue.clear();
+ mozilla::DropJSObjects(this);
+}
+
+JSObject* WritableStreamDefaultController::WrapObject(
+ JSContext* aCx, JS::Handle<JSObject*> aGivenProto) {
+ return WritableStreamDefaultController_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+// https://streams.spec.whatwg.org/#ws-default-controller-error
+void WritableStreamDefaultController::Error(JSContext* aCx,
+ JS::Handle<JS::Value> aError,
+ ErrorResult& aRv) {
+ // Step 1. Let state be this.[[stream]].[[state]].
+ // Step 2. If state is not "writable", return.
+ if (mStream->State() != WritableStream::WriterState::Writable) {
+ return;
+ }
+ // Step 3. Perform ! WritableStreamDefaultControllerError(this, e).
+ RefPtr<WritableStreamDefaultController> thisRefPtr = this;
+ WritableStreamDefaultControllerError(aCx, thisRefPtr, aError, aRv);
+}
+
+// https://streams.spec.whatwg.org/#ws-default-controller-private-abort
+already_AddRefed<Promise> WritableStreamDefaultController::AbortSteps(
+ JSContext* aCx, JS::Handle<JS::Value> aReason, ErrorResult& aRv) {
+ // Step 1. Let result be the result of performing this.[[abortAlgorithm]],
+ // passing reason.
+ RefPtr<UnderlyingSinkAlgorithmsBase> algorithms = mAlgorithms;
+ Optional<JS::Handle<JS::Value>> optionalReason(aCx, aReason);
+ RefPtr<Promise> abortPromise =
+ algorithms->AbortCallback(aCx, optionalReason, aRv);
+ if (aRv.Failed()) {
+ return nullptr;
+ }
+
+ // Step 2. Perform ! WritableStreamDefaultControllerClearAlgorithms(this).
+ ClearAlgorithms();
+
+ // Step 3. Return result.
+ return abortPromise.forget();
+}
+
+// https://streams.spec.whatwg.org/#ws-default-controller-private-error
+void WritableStreamDefaultController::ErrorSteps() {
+ // Step 1. Perform ! ResetQueue(this).
+ ResetQueue(this);
+}
+
+void WritableStreamDefaultController::SetSignal(AbortSignal* aSignal) {
+ MOZ_ASSERT(aSignal);
+ mSignal = aSignal;
+}
+
+namespace streams_abstract {
+
+MOZ_CAN_RUN_SCRIPT static void
+WritableStreamDefaultControllerAdvanceQueueIfNeeded(
+ JSContext* aCx, WritableStreamDefaultController* aController,
+ ErrorResult& aRv);
+
+// https://streams.spec.whatwg.org/#set-up-writable-stream-default-controller
+void SetUpWritableStreamDefaultController(
+ JSContext* aCx, WritableStream* aStream,
+ WritableStreamDefaultController* aController,
+ UnderlyingSinkAlgorithmsBase* aAlgorithms, double aHighWaterMark,
+ QueuingStrategySize* aSizeAlgorithm, ErrorResult& aRv) {
+ // Step 1. Assert: stream implements WritableStream.
+ // Step 2. Assert: stream.[[controller]] is undefined.
+ MOZ_ASSERT(!aStream->Controller());
+
+ // Step 3. Set controller.[[stream]] to stream.
+ // Note: Already set in
+ // SetUpWritableStreamDefaultControllerFromUnderlyingSink.
+ MOZ_ASSERT(aController->Stream() == aStream);
+
+ // Step 4. Set stream.[[controller]] to controller.
+ aStream->SetController(*aController);
+
+ // Step 5. Perform ! ResetQueue(controller).
+ ResetQueue(aController);
+
+ // Step 6. Set controller.[[signal]] to a new AbortSignal.
+ RefPtr<AbortSignal> signal = new AbortSignal(aController->GetParentObject(),
+ false, JS::UndefinedHandleValue);
+ aController->SetSignal(signal);
+
+ // Step 7. Set controller.[[started]] to false.
+ aController->SetStarted(false);
+
+ // Step 8. Set controller.[[strategySizeAlgorithm]] to sizeAlgorithm.
+ aController->SetStrategySizeAlgorithm(aSizeAlgorithm);
+
+ // Step 9. Set controller.[[strategyHWM]] to highWaterMark.
+ aController->SetStrategyHWM(aHighWaterMark);
+
+ // Step 10. Set controller.[[writeAlgorithm]] to writeAlgorithm.
+ // Step 11. Set controller.[[closeAlgorithm]] to closeAlgorithm.
+ // Step 12. Set controller.[[abortAlgorithm]] to abortAlgorithm.
+ aController->SetAlgorithms(*aAlgorithms);
+
+ // Step 13. Let backpressure be !
+ // WritableStreamDefaultControllerGetBackpressure(controller).
+ bool backpressure = aController->GetBackpressure();
+
+ // Step 14. Perform ! WritableStreamUpdateBackpressure(stream, backpressure).
+ aStream->UpdateBackpressure(backpressure);
+
+ // Step 15. Let startResult be the result of performing startAlgorithm. (This
+ // may throw an exception.)
+ JS::Rooted<JS::Value> startResult(aCx, JS::UndefinedValue());
+ RefPtr<WritableStreamDefaultController> controller(aController);
+ aAlgorithms->StartCallback(aCx, *controller, &startResult, aRv);
+ if (aRv.Failed()) {
+ return;
+ }
+
+ // Step 16. Let startPromise be a promise resolved with startResult.
+ RefPtr<Promise> startPromise =
+ Promise::CreateInfallible(aStream->GetParentObject());
+ startPromise->MaybeResolve(startResult);
+
+ // Step 17/18.
+ startPromise->AddCallbacksWithCycleCollectedArgs(
+ [](JSContext* aCx, JS::Handle<JS::Value> aValue, ErrorResult& aRv,
+ WritableStreamDefaultController* aController)
+ MOZ_CAN_RUN_SCRIPT_BOUNDARY {
+ // Step 17. Upon fulfillment of startPromise,
+ // Step 17.1. Assert: stream.[[state]] is "writable" or "erroring".
+ MOZ_ASSERT(aController->Stream()->State() ==
+ WritableStream::WriterState::Writable ||
+ aController->Stream()->State() ==
+ WritableStream::WriterState::Erroring);
+ // Step 17.2. Set controller.[[started]] to true.
+ aController->SetStarted(true);
+ // Step 17.3 Perform
+ // !WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller).
+ WritableStreamDefaultControllerAdvanceQueueIfNeeded(
+ aCx, MOZ_KnownLive(aController), aRv);
+ },
+ [](JSContext* aCx, JS::Handle<JS::Value> aValue, ErrorResult& aRv,
+ WritableStreamDefaultController* aController)
+ MOZ_CAN_RUN_SCRIPT_BOUNDARY {
+ RefPtr<WritableStream> stream = aController->Stream();
+ // Step 18. Upon rejection of startPromise with reason r,
+ // Step 18.1. Assert: stream.[[state]] is "writable" or "erroring".
+ MOZ_ASSERT(
+ stream->State() == WritableStream::WriterState::Writable ||
+ stream->State() == WritableStream::WriterState::Erroring);
+ // Step 18.2. Set controller.[[started]] to true.
+ aController->SetStarted(true);
+ // Step 18.3. Perform ! WritableStreamDealWithRejection(stream, r).
+ stream->DealWithRejection(aCx, aValue, aRv);
+ },
+ RefPtr(aController));
+}
+
+// https://streams.spec.whatwg.org/#set-up-writable-stream-default-controller-from-underlying-sink
+void SetUpWritableStreamDefaultControllerFromUnderlyingSink(
+ JSContext* aCx, WritableStream* aStream,
+ JS::Handle<JSObject*> aUnderlyingSink, UnderlyingSink& aUnderlyingSinkDict,
+ double aHighWaterMark, QueuingStrategySize* aSizeAlgorithm,
+ ErrorResult& aRv) {
+ // Step 1.
+ RefPtr<WritableStreamDefaultController> controller =
+ new WritableStreamDefaultController(aStream->GetParentObject(), *aStream);
+
+ // Step 2 - 9.
+ auto algorithms = MakeRefPtr<UnderlyingSinkAlgorithms>(
+ aStream->GetParentObject(), aUnderlyingSink, aUnderlyingSinkDict);
+
+ // Step 10.
+ SetUpWritableStreamDefaultController(aCx, aStream, controller, algorithms,
+ aHighWaterMark, aSizeAlgorithm, aRv);
+}
+
+// https://streams.spec.whatwg.org/#writable-stream-default-controller-process-close
+MOZ_CAN_RUN_SCRIPT static void WritableStreamDefaultControllerProcessClose(
+ JSContext* aCx, WritableStreamDefaultController* aController,
+ ErrorResult& aRv) {
+ // Step 1. Let stream be controller.[[stream]].
+ RefPtr<WritableStream> stream = aController->Stream();
+
+ // Step 2. Perform ! WritableStreamMarkCloseRequestInFlight(stream).
+ stream->MarkCloseRequestInFlight();
+
+ // Step 3. Perform ! DequeueValue(controller).
+ JS::Rooted<JS::Value> value(aCx);
+ DequeueValue(aController, &value);
+
+ // Step 4. Assert: controller.[[queue]] is empty.
+ MOZ_ASSERT(aController->Queue().isEmpty());
+
+ // Step 5. Let sinkClosePromise be the result of performing
+ // controller.[[closeAlgorithm]].
+ RefPtr<UnderlyingSinkAlgorithmsBase> algorithms =
+ aController->GetAlgorithms();
+ RefPtr<Promise> sinkClosePromise = algorithms->CloseCallback(aCx, aRv);
+ if (aRv.Failed()) {
+ return;
+ }
+
+ // Step 6. Perform !
+ // WritableStreamDefaultControllerClearAlgorithms(controller).
+ aController->ClearAlgorithms();
+
+ // Step 7 + 8.
+ sinkClosePromise->AddCallbacksWithCycleCollectedArgs(
+ [](JSContext* aCx, JS::Handle<JS::Value> aValue, ErrorResult& aRv,
+ WritableStreamDefaultController* aController) {
+ RefPtr<WritableStream> stream = aController->Stream();
+ // Step 7. Upon fulfillment of sinkClosePromise,
+ // Step 7.1. Perform ! WritableStreamFinishInFlightClose(stream).
+ stream->FinishInFlightClose();
+ },
+ [](JSContext* aCx, JS::Handle<JS::Value> aValue, ErrorResult& aRv,
+ WritableStreamDefaultController* aController)
+ MOZ_CAN_RUN_SCRIPT_BOUNDARY {
+ RefPtr<WritableStream> stream = aController->Stream();
+ // Step 8. Upon rejection of sinkClosePromise with reason reason,
+ // Step 8.1. Perform
+ // ! WritableStreamFinishInFlightCloseWithError(stream, reason).
+ stream->FinishInFlightCloseWithError(aCx, aValue, aRv);
+ },
+ RefPtr(aController));
+}
+
+// https://streams.spec.whatwg.org/#writable-stream-default-controller-process-write
+MOZ_CAN_RUN_SCRIPT static void WritableStreamDefaultControllerProcessWrite(
+ JSContext* aCx, WritableStreamDefaultController* aController,
+ JS::Handle<JS::Value> aChunk, ErrorResult& aRv) {
+ // Step 1. Let stream be controller.[[stream]].
+ RefPtr<WritableStream> stream = aController->Stream();
+
+ // Step 2. Perform ! WritableStreamMarkFirstWriteRequestInFlight(stream).
+ stream->MarkFirstWriteRequestInFlight();
+
+ // Step 3. Let sinkWritePromise be the result of performing
+ // controller.[[writeAlgorithm]], passing in chunk.
+ RefPtr<UnderlyingSinkAlgorithmsBase> algorithms =
+ aController->GetAlgorithms();
+ RefPtr<Promise> sinkWritePromise =
+ algorithms->WriteCallback(aCx, aChunk, *aController, aRv);
+ if (aRv.Failed()) {
+ return;
+ }
+
+ // Step 4 + 5:
+ sinkWritePromise->AddCallbacksWithCycleCollectedArgs(
+ [](JSContext* aCx, JS::Handle<JS::Value> aValue, ErrorResult& aRv,
+ WritableStreamDefaultController* aController)
+ MOZ_CAN_RUN_SCRIPT_BOUNDARY {
+ RefPtr<WritableStream> stream = aController->Stream();
+
+ // Step 4.1. Perform ! WritableStreamFinishInFlightWrite(stream).
+ stream->FinishInFlightWrite();
+
+ // Step 4.2. Let state be stream.[[state]].
+ WritableStream::WriterState state = stream->State();
+
+ // Step 4.3. Assert: state is "writable" or "erroring".
+ MOZ_ASSERT(state == WritableStream::WriterState::Writable ||
+ state == WritableStream::WriterState::Erroring);
+
+ // Step 4.4. Perform ! DequeueValue(controller).
+ JS::Rooted<JS::Value> value(aCx);
+ DequeueValue(aController, &value);
+
+ // Step 4.5. If ! WritableStreamCloseQueuedOrInFlight(stream) is
+ // false and state is "writable",
+ if (!stream->CloseQueuedOrInFlight() &&
+ state == WritableStream::WriterState::Writable) {
+ // Step 4.5.1. Let backpressure be !
+ // WritableStreamDefaultControllerGetBackpressure(controller).
+ bool backpressure = aController->GetBackpressure();
+ // Step 4.5.2. Perform ! WritableStreamUpdateBackpressure(stream,
+ // backpressure).
+ stream->UpdateBackpressure(backpressure);
+ }
+
+ // Step 4.6. Perform !
+ // WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller).
+ WritableStreamDefaultControllerAdvanceQueueIfNeeded(
+ aCx, MOZ_KnownLive(aController), aRv);
+ },
+ [](JSContext* aCx, JS::Handle<JS::Value> aValue, ErrorResult& aRv,
+ WritableStreamDefaultController* aController)
+ MOZ_CAN_RUN_SCRIPT_BOUNDARY {
+ RefPtr<WritableStream> stream = aController->Stream();
+
+ // Step 5.1. If stream.[[state]] is "writable", perform !
+ // WritableStreamDefaultControllerClearAlgorithms(controller).
+ if (stream->State() == WritableStream::WriterState::Writable) {
+ aController->ClearAlgorithms();
+ }
+
+ // Step 5.2. Perform !
+ // WritableStreamFinishInFlightWriteWithError(stream, reason)
+ stream->FinishInFlightWriteWithError(aCx, aValue, aRv);
+ },
+ RefPtr(aController));
+}
+
+// We use a JS::MagicValue to represent the close sentinel required by the spec.
+// Normal JavaScript code can not generate magic values, so we can use this
+// as a special value. However care has to be taken to not leak the magic value
+// to other code.
+constexpr JSWhyMagic CLOSE_SENTINEL = JS_GENERIC_MAGIC;
+
+// https://streams.spec.whatwg.org/#writable-stream-default-controller-advance-queue-if-needed
+static void WritableStreamDefaultControllerAdvanceQueueIfNeeded(
+ JSContext* aCx, WritableStreamDefaultController* aController,
+ ErrorResult& aRv) {
+ // Step 1. Let stream be controller.[[stream]].
+ RefPtr<WritableStream> stream = aController->Stream();
+
+ // Step 2. If controller.[[started]] is false, return.
+ if (!aController->Started()) {
+ return;
+ }
+
+ // Step 3. If stream.[[inFlightWriteRequest]] is not undefined, return.
+ if (stream->GetInFlightWriteRequest()) {
+ return;
+ }
+
+ // Step 4. Let state be stream.[[state]].
+ WritableStream::WriterState state = stream->State();
+
+ // Step 5. Assert: state is not "closed" or "errored".
+ MOZ_ASSERT(state != WritableStream::WriterState::Closed &&
+ state != WritableStream::WriterState::Errored);
+
+ // Step 6. If state is "erroring",
+ if (state == WritableStream::WriterState::Erroring) {
+ // Step 6.1. Perform ! WritableStreamFinishErroring(stream).
+ stream->FinishErroring(aCx, aRv);
+
+ // Step 6.2. Return.
+ return;
+ }
+
+ // Step 7. If controller.[[queue]] is empty, return.
+ if (aController->Queue().isEmpty()) {
+ return;
+ }
+
+ // Step 8. Let value be ! PeekQueueValue(controller).
+ JS::Rooted<JS::Value> value(aCx);
+ PeekQueueValue(aController, &value);
+
+ // Step 9. If value is the close sentinel, perform !
+ // WritableStreamDefaultControllerProcessClose(controller).
+ if (value.isMagic(CLOSE_SENTINEL)) {
+ WritableStreamDefaultControllerProcessClose(aCx, aController, aRv);
+ return;
+ }
+
+ // Step 10. Otherwise, perform !
+ // WritableStreamDefaultControllerProcessWrite(controller, value).
+ WritableStreamDefaultControllerProcessWrite(aCx, aController, value, aRv);
+}
+
+// https://streams.spec.whatwg.org/#writable-stream-default-controller-close
+void WritableStreamDefaultControllerClose(
+ JSContext* aCx, WritableStreamDefaultController* aController,
+ ErrorResult& aRv) {
+ // Step 1. Perform ! EnqueueValueWithSize(controller, close sentinel, 0).
+ JS::Rooted<JS::Value> aCloseSentinel(aCx, JS::MagicValue(CLOSE_SENTINEL));
+ EnqueueValueWithSize(aController, aCloseSentinel, 0, aRv);
+ MOZ_ASSERT(!aRv.Failed());
+
+ // Step 2. Perform !
+ // WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller).
+ WritableStreamDefaultControllerAdvanceQueueIfNeeded(aCx, aController, aRv);
+}
+
+// https://streams.spec.whatwg.org/#writable-stream-default-controller-write
+void WritableStreamDefaultControllerWrite(
+ JSContext* aCx, WritableStreamDefaultController* aController,
+ JS::Handle<JS::Value> aChunk, double chunkSize, ErrorResult& aRv) {
+ // Step 1. Let enqueueResult be EnqueueValueWithSize(controller, chunk,
+ // chunkSize).
+ IgnoredErrorResult rv;
+ EnqueueValueWithSize(aController, aChunk, chunkSize, rv);
+
+ // Step 2. If enqueueResult is an abrupt completion,
+ if (rv.MaybeSetPendingException(aCx,
+ "WritableStreamDefaultController.write")) {
+ JS::Rooted<JS::Value> error(aCx);
+ JS_GetPendingException(aCx, &error);
+ JS_ClearPendingException(aCx);
+
+ // Step 2.1. Perform !
+ // WritableStreamDefaultControllerErrorIfNeeded(controller,
+ // enqueueResult.[[Value]]).
+ WritableStreamDefaultControllerErrorIfNeeded(aCx, aController, error, aRv);
+
+ // Step 2.2. Return.
+ return;
+ }
+
+ // Step 3. Let stream be controller.[[stream]].
+ RefPtr<WritableStream> stream = aController->Stream();
+
+ // Step 4. If ! WritableStreamCloseQueuedOrInFlight(stream) is false and
+ // stream.[[state]] is "writable",
+ if (!stream->CloseQueuedOrInFlight() &&
+ stream->State() == WritableStream::WriterState::Writable) {
+ // Step 4.1. Let backpressure be
+ // !WritableStreamDefaultControllerGetBackpressure(controller).
+ bool backpressure = aController->GetBackpressure();
+
+ // Step 4.2. Perform ! WritableStreamUpdateBackpressure(stream,
+ // backpressure).
+ stream->UpdateBackpressure(backpressure);
+ }
+
+ // Step 5. Perform
+ // ! WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller).
+ WritableStreamDefaultControllerAdvanceQueueIfNeeded(aCx, aController, aRv);
+}
+
+void WritableStreamDefaultControllerError(
+ JSContext* aCx, WritableStreamDefaultController* aController,
+ JS::Handle<JS::Value> aError, ErrorResult& aRv) {
+ // Step 1. Let stream be controller.[[stream]].
+ RefPtr<WritableStream> stream = aController->Stream();
+
+ // Step 2. Assert: stream.[[state]] is "writable".
+ MOZ_ASSERT(stream->State() == WritableStream::WriterState::Writable);
+
+ // Step 3. Perform
+ // ! WritableStreamDefaultControllerClearAlgorithms(controller).
+ aController->ClearAlgorithms();
+
+ // Step 4.Perform ! WritableStreamStartErroring(stream, error).
+ stream->StartErroring(aCx, aError, aRv);
+}
+
+// https://streams.spec.whatwg.org/#writable-stream-default-controller-error-if-needed
+void WritableStreamDefaultControllerErrorIfNeeded(
+ JSContext* aCx, WritableStreamDefaultController* aController,
+ JS::Handle<JS::Value> aError, ErrorResult& aRv) {
+ // Step 1. If controller.[[stream]].[[state]] is "writable", perform
+ // !WritableStreamDefaultControllerError(controller, error).
+ if (aController->Stream()->State() == WritableStream::WriterState::Writable) {
+ WritableStreamDefaultControllerError(aCx, aController, aError, aRv);
+ }
+}
+
+// https://streams.spec.whatwg.org/#writable-stream-default-controller-get-chunk-size
+double WritableStreamDefaultControllerGetChunkSize(
+ JSContext* aCx, WritableStreamDefaultController* aController,
+ JS::Handle<JS::Value> aChunk, ErrorResult& aRv) {
+ // Step 1. Let returnValue be the result of performing
+ // controller.[[strategySizeAlgorithm]], passing in chunk, and interpreting
+ // the result as a completion record.
+ RefPtr<QueuingStrategySize> sizeAlgorithm(
+ aController->StrategySizeAlgorithm());
+
+ // If !sizeAlgorithm, we return 1, which is inlined from
+ // https://streams.spec.whatwg.org/#make-size-algorithm-from-size-function
+ Optional<JS::Handle<JS::Value>> optionalChunk(aCx, aChunk);
+
+ double chunkSize =
+ sizeAlgorithm
+ ? sizeAlgorithm->Call(
+ optionalChunk, aRv,
+ "WritableStreamDefaultController.[[strategySizeAlgorithm]]",
+ CallbackObject::eRethrowExceptions)
+ : 1.0;
+
+ // Step 2. If returnValue is an abrupt completion,
+ if (aRv.MaybeSetPendingException(
+ aCx, "WritableStreamDefaultController.[[strategySizeAlgorithm]]")) {
+ JS::Rooted<JS::Value> error(aCx);
+ JS_GetPendingException(aCx, &error);
+ JS_ClearPendingException(aCx);
+
+ // Step 2.1. Perform !
+ // WritableStreamDefaultControllerErrorIfNeeded(controller,
+ // returnValue.[[Value]]).
+ WritableStreamDefaultControllerErrorIfNeeded(aCx, aController, error, aRv);
+
+ // Step 2.2. Return 1.
+ return 1.0;
+ }
+
+ // Step 3. Return returnValue.[[Value]].
+ return chunkSize;
+}
+
+} // namespace streams_abstract
+
+} // namespace mozilla::dom