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Diffstat (limited to '')
| -rw-r--r-- | dom/streams/ReadableStream.cpp | 1521 |
1 files changed, 1521 insertions, 0 deletions
diff --git a/dom/streams/ReadableStream.cpp b/dom/streams/ReadableStream.cpp new file mode 100644 index 0000000000..cc2266cbfb --- /dev/null +++ b/dom/streams/ReadableStream.cpp @@ -0,0 +1,1521 @@ +/* -*- 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 "mozilla/dom/ReadableStream.h" + +#include "ReadIntoRequest.h" +#include "ReadableStreamPipeTo.h" +#include "ReadableStreamTee.h" +#include "StreamUtils.h" +#include "TeeState.h" +#include "js/Array.h" +#include "js/Exception.h" +#include "js/PropertyAndElement.h" +#include "js/TypeDecls.h" +#include "js/Value.h" +#include "js/Iterator.h" +#include "mozilla/AlreadyAddRefed.h" +#include "mozilla/Assertions.h" +#include "mozilla/Attributes.h" +#include "mozilla/CycleCollectedJSContext.h" +#include "mozilla/HoldDropJSObjects.h" +#include "mozilla/StaticPrefs_dom.h" +#include "mozilla/dom/BindingCallContext.h" +#include "mozilla/dom/ByteStreamHelpers.h" +#include "mozilla/dom/QueueWithSizes.h" +#include "mozilla/dom/QueuingStrategyBinding.h" +#include "mozilla/dom/ReadRequest.h" +#include "mozilla/dom/ReadableByteStreamController.h" +#include "mozilla/dom/ReadableStreamBYOBReader.h" +#include "mozilla/dom/ReadableStreamBYOBRequest.h" +#include "mozilla/dom/ReadableStreamBinding.h" +#include "mozilla/dom/ReadableStreamController.h" +#include "mozilla/dom/ReadableStreamDefaultController.h" +#include "mozilla/dom/ReadableStreamDefaultReader.h" +#include "mozilla/dom/RootedDictionary.h" +#include "mozilla/dom/ScriptSettings.h" +#include "mozilla/dom/UnderlyingSourceBinding.h" +#include "mozilla/dom/UnderlyingSourceCallbackHelpers.h" +#include "mozilla/dom/WritableStream.h" +#include "mozilla/dom/WritableStreamDefaultWriter.h" +#include "nsCOMPtr.h" + +#include "mozilla/dom/Promise-inl.h" +#include "nsIGlobalObject.h" +#include "nsISupports.h" + +inline void ImplCycleCollectionTraverse( + nsCycleCollectionTraversalCallback& aCallback, + mozilla::Variant<mozilla::Nothing, + RefPtr<mozilla::dom::ReadableStreamDefaultReader>>& + aReader, + const char* aName, uint32_t aFlags = 0) { + if (aReader.is<RefPtr<mozilla::dom::ReadableStreamDefaultReader>>()) { + ImplCycleCollectionTraverse( + aCallback, + aReader.as<RefPtr<mozilla::dom::ReadableStreamDefaultReader>>(), aName, + aFlags); + } +} + +inline void ImplCycleCollectionUnlink( + mozilla::Variant<mozilla::Nothing, + RefPtr<mozilla::dom::ReadableStreamDefaultReader>>& + aReader) { + aReader = AsVariant(mozilla::Nothing()); +} + +namespace mozilla::dom { + +using namespace streams_abstract; + +// Only needed for refcounted objects. +NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_WITH_JS_MEMBERS( + ReadableStream, (mGlobal, mController, mReader), (mStoredError)) + +NS_IMPL_CYCLE_COLLECTING_ADDREF(ReadableStream) +NS_IMPL_CYCLE_COLLECTING_RELEASE(ReadableStream) +NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ReadableStream) + NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY + NS_INTERFACE_MAP_ENTRY(nsISupports) +NS_INTERFACE_MAP_END + +ReadableStream::ReadableStream(nsIGlobalObject* aGlobal, + HoldDropJSObjectsCaller aHoldDropCaller) + : mGlobal(aGlobal), mReader(nullptr), mHoldDropCaller(aHoldDropCaller) { + if (mHoldDropCaller == HoldDropJSObjectsCaller::Implicit) { + mozilla::HoldJSObjects(this); + } +} + +ReadableStream::ReadableStream(const GlobalObject& aGlobal, + HoldDropJSObjectsCaller aHoldDropCaller) + : mGlobal(do_QueryInterface(aGlobal.GetAsSupports())), + mReader(nullptr), + mHoldDropCaller(aHoldDropCaller) { + if (mHoldDropCaller == HoldDropJSObjectsCaller::Implicit) { + mozilla::HoldJSObjects(this); + } +} + +ReadableStream::~ReadableStream() { + if (mHoldDropCaller == HoldDropJSObjectsCaller::Implicit) { + mozilla::DropJSObjects(this); + } +} + +JSObject* ReadableStream::WrapObject(JSContext* aCx, + JS::Handle<JSObject*> aGivenProto) { + return ReadableStream_Binding::Wrap(aCx, this, aGivenProto); +} + +ReadableStreamDefaultReader* ReadableStream::GetDefaultReader() { + return mReader->AsDefault(); +} + +void ReadableStream::SetReader(ReadableStreamGenericReader* aReader) { + mReader = aReader; +} + +namespace streams_abstract { + +// https://streams.spec.whatwg.org/#readable-stream-has-byob-reader +bool ReadableStreamHasBYOBReader(ReadableStream* aStream) { + // Step 1. Let reader be stream.[[reader]]. + ReadableStreamGenericReader* reader = aStream->GetReader(); + + // Step 2. If reader is undefined, return false. + if (!reader) { + return false; + } + + // Step 3. If reader implements ReadableStreamBYOBReader, return true. + // Step 4. Return false. + return reader->IsBYOB(); +} + +// https://streams.spec.whatwg.org/#readable-stream-has-default-reader +bool ReadableStreamHasDefaultReader(ReadableStream* aStream) { + // Step 1. Let reader be stream.[[reader]]. + ReadableStreamGenericReader* reader = aStream->GetReader(); + + // Step 2. If reader is undefined, return false. + if (!reader) { + return false; + } + + // Step 3. If reader implements ReadableStreamDefaultReader, return true. + // Step 4. Return false. + return reader->IsDefault(); +} + +} // namespace streams_abstract + +// Streams Spec: 4.2.4: https://streams.spec.whatwg.org/#rs-prototype +/* static */ +already_AddRefed<ReadableStream> ReadableStream::Constructor( + const GlobalObject& aGlobal, + const Optional<JS::Handle<JSObject*>>& aUnderlyingSource, + const QueuingStrategy& aStrategy, ErrorResult& aRv) { + // Step 1. + JS::Rooted<JSObject*> underlyingSourceObj( + aGlobal.Context(), + aUnderlyingSource.WasPassed() ? aUnderlyingSource.Value() : nullptr); + + // Step 2. + RootedDictionary<UnderlyingSource> underlyingSourceDict(aGlobal.Context()); + if (underlyingSourceObj) { + JS::Rooted<JS::Value> objValue(aGlobal.Context(), + JS::ObjectValue(*underlyingSourceObj)); + dom::BindingCallContext callCx(aGlobal.Context(), + "ReadableStream.constructor"); + aRv.MightThrowJSException(); + if (!underlyingSourceDict.Init(callCx, objValue)) { + aRv.StealExceptionFromJSContext(aGlobal.Context()); + return nullptr; + } + } + + // Step 3. + RefPtr<ReadableStream> readableStream = + new ReadableStream(aGlobal, HoldDropJSObjectsCaller::Implicit); + + // Step 4. + if (underlyingSourceDict.mType.WasPassed()) { + // Implicit assertion on above check. + MOZ_ASSERT(underlyingSourceDict.mType.Value() == ReadableStreamType::Bytes); + + // Step 4.1 + if (aStrategy.mSize.WasPassed()) { + aRv.ThrowRangeError("Implementation preserved member 'size'"); + return nullptr; + } + + // Step 4.2 + double highWaterMark = ExtractHighWaterMark(aStrategy, 0, aRv); + if (aRv.Failed()) { + return nullptr; + } + + // Step 4.3 + SetUpReadableByteStreamControllerFromUnderlyingSource( + aGlobal.Context(), readableStream, underlyingSourceObj, + underlyingSourceDict, highWaterMark, aRv); + if (aRv.Failed()) { + return nullptr; + } + + return readableStream.forget(); + } + + // Step 5.1 (implicit in above check) + // Step 5.2. Extract callback. + // + // Implementation Note: The specification demands that if the size doesn't + // exist, we instead would provide an algorithm that returns 1. Instead, we + // will teach callers that a missing callback should simply return 1, rather + // than gin up a fake callback here. + // + // This decision may need to be revisited if the default action ever diverges + // within the specification. + RefPtr<QueuingStrategySize> sizeAlgorithm = + aStrategy.mSize.WasPassed() ? &aStrategy.mSize.Value() : nullptr; + + // Step 5.3 + double highWaterMark = ExtractHighWaterMark(aStrategy, 1, aRv); + if (aRv.Failed()) { + return nullptr; + } + + // Step 5.4. + SetupReadableStreamDefaultControllerFromUnderlyingSource( + aGlobal.Context(), readableStream, underlyingSourceObj, + underlyingSourceDict, highWaterMark, sizeAlgorithm, aRv); + if (aRv.Failed()) { + return nullptr; + } + + return readableStream.forget(); +} + +// https://streams.spec.whatwg.org/#readable-stream-from-iterable +class ReadableStreamFromAlgorithms final + : public UnderlyingSourceAlgorithmsWrapper { + public: + NS_DECL_ISUPPORTS_INHERITED + NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_INHERITED( + ReadableStreamFromAlgorithms, UnderlyingSourceAlgorithmsWrapper) + + ReadableStreamFromAlgorithms(nsIGlobalObject* aGlobal, + JS::Handle<JSObject*> aIteratorRecord) + : mGlobal(aGlobal), mIteratorRecordMaybeCrossRealm(aIteratorRecord) { + mozilla::HoldJSObjects(this); + }; + + // Step 3. Let startAlgorithm be an algorithm that returns undefined. + // Note: Provided by UnderlyingSourceAlgorithmsWrapper::StartCallback. + + // Step 4. Let pullAlgorithm be the following steps: + MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> PullCallbackImpl( + JSContext* aCx, ReadableStreamController& aController, + ErrorResult& aRv) override { + aRv.MightThrowJSException(); + + JS::Rooted<JSObject*> iteratorRecord(aCx, mIteratorRecordMaybeCrossRealm); + JSAutoRealm ar(aCx, iteratorRecord); + + // Step 1. Let nextResult be IteratorNext(iteratorRecord). + JS::Rooted<JS::Value> nextResult(aCx); + if (!JS::IteratorNext(aCx, iteratorRecord, &nextResult)) { + // Step 2. If nextResult is an abrupt completion, return a promise + // rejected with nextResult.[[Value]]. + aRv.StealExceptionFromJSContext(aCx); + return nullptr; + } + + // Step 3. Let nextPromise be a promise resolved with nextResult.[[Value]]. + RefPtr<Promise> nextPromise = Promise::CreateInfallible(mGlobal); + nextPromise->MaybeResolve(nextResult); + + // Step 4. Return the result of reacting to nextPromise with the following + // fulfillment steps, given iterResult: + auto result = nextPromise->ThenWithCycleCollectedArgs( + [](JSContext* aCx, JS::Handle<JS::Value> aIterResult, ErrorResult& aRv, + const RefPtr<ReadableStreamDefaultController>& aController) + MOZ_CAN_RUN_SCRIPT_FOR_DEFINITION -> already_AddRefed<Promise> { + aRv.MightThrowJSException(); + + // Step 4.1. If Type(iterResult) is not Object, throw a TypeError. + if (!aIterResult.isObject()) { + aRv.ThrowTypeError("next() returned a non-object value"); + return nullptr; + } + + JS::Rooted<JSObject*> iterResult(aCx, &aIterResult.toObject()); + + // Step 4.2. Let done be ? IteratorComplete(iterResult). + bool done = false; + if (!JS::IteratorComplete(aCx, iterResult, &done)) { + aRv.StealExceptionFromJSContext(aCx); + return nullptr; + } + + // Step 4.3. If done is true: + if (done) { + // Step 4.3.1. Perform ! + // ReadableStreamDefaultControllerClose(stream.[[controller]]). + ReadableStreamDefaultControllerClose(aCx, aController, aRv); + } else { + // Step 4.4. Otherwise: + // Step 4.4.1. Let value be ? IteratorValue(iterResult). + JS::Rooted<JS::Value> value(aCx); + if (!JS::IteratorValue(aCx, iterResult, &value)) { + aRv.StealExceptionFromJSContext(aCx); + return nullptr; + } + + // Step 4.4.2. Perform ! + // ReadableStreamDefaultControllerEnqueue(stream.[[controller]], + // value). + ReadableStreamDefaultControllerEnqueue(aCx, aController, value, + aRv); + } + + return nullptr; + }, + RefPtr(aController.AsDefault())); + if (result.isErr()) { + aRv.Throw(result.unwrapErr()); + return nullptr; + } + return result.unwrap().forget(); + }; + + // Step 5. Let cancelAlgorithm be the following steps, given reason: + MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> CancelCallbackImpl( + JSContext* aCx, const Optional<JS::Handle<JS::Value>>& aReason, + ErrorResult& aRv) override { + aRv.MightThrowJSException(); + + JS::Rooted<JSObject*> iteratorRecord(aCx, mIteratorRecordMaybeCrossRealm); + JSAutoRealm ar(aCx, iteratorRecord); + + // Step 1. Let iterator be iteratorRecord.[[Iterator]]. + JS::Rooted<JS::Value> iterator(aCx); + if (!JS::GetIteratorRecordIterator(aCx, iteratorRecord, &iterator)) { + aRv.StealExceptionFromJSContext(aCx); + return nullptr; + } + + // Step 2. Let returnMethod be GetMethod(iterator, "return"). + JS::Rooted<JS::Value> returnMethod(aCx); + if (!JS::GetReturnMethod(aCx, iterator, &returnMethod)) { + // Step 3. If returnMethod is an abrupt completion, return a promise + // rejected with returnMethod.[[Value]]. + aRv.StealExceptionFromJSContext(aCx); + return nullptr; + } + + // Step 4. If returnMethod.[[Value]] is undefined, return a promise resolved + // with undefined. + if (returnMethod.isUndefined()) { + return Promise::CreateResolvedWithUndefined(mGlobal, aRv); + } + + // Step 5. Let returnResult be Call(returnMethod.[[Value]], iterator, « + // reason »). + JS::Rooted<JS::Value> returnResult(aCx); + if (!JS::Call(aCx, iterator, returnMethod, + JS::HandleValueArray(aReason.Value()), &returnResult)) { + // Step 6. If returnResult is an abrupt completion, return a promise + // rejected with returnResult.[[Value]]. + aRv.StealExceptionFromJSContext(aCx); + return nullptr; + } + + // Step 7. Let returnPromise be a promise resolved with + // returnResult.[[Value]]. + RefPtr<Promise> returnPromise = Promise::CreateInfallible(mGlobal); + returnPromise->MaybeResolve(returnResult); + + // Step 8. Return the result of reacting to returnPromise with the following + // fulfillment steps, given iterResult: + auto result = returnPromise->ThenWithCycleCollectedArgs( + [](JSContext* aCx, JS::Handle<JS::Value> aIterResult, ErrorResult& aRv) + MOZ_CAN_RUN_SCRIPT_FOR_DEFINITION -> already_AddRefed<Promise> { + // Step 8.1. If Type(iterResult) is not Object, throw a TypeError. + if (!aIterResult.isObject()) { + aRv.ThrowTypeError("return() returned a non-object value"); + return nullptr; + } + + // Step 8.2. Return undefined. + return nullptr; + }); + if (result.isErr()) { + aRv.Throw(result.unwrapErr()); + return nullptr; + } + return result.unwrap().forget(); + }; + + protected: + ~ReadableStreamFromAlgorithms() override { mozilla::DropJSObjects(this); }; + + private: + // Virtually const, but are cycle collected + nsCOMPtr<nsIGlobalObject> mGlobal; + JS::Heap<JSObject*> mIteratorRecordMaybeCrossRealm; +}; + +NS_IMPL_CYCLE_COLLECTION_INHERITED_WITH_JS_MEMBERS( + ReadableStreamFromAlgorithms, UnderlyingSourceAlgorithmsWrapper, (mGlobal), + (mIteratorRecordMaybeCrossRealm)) +NS_IMPL_ADDREF_INHERITED(ReadableStreamFromAlgorithms, + UnderlyingSourceAlgorithmsWrapper) +NS_IMPL_RELEASE_INHERITED(ReadableStreamFromAlgorithms, + UnderlyingSourceAlgorithmsWrapper) +NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ReadableStreamFromAlgorithms) +NS_INTERFACE_MAP_END_INHERITING(UnderlyingSourceAlgorithmsWrapper) + +// https://streams.spec.whatwg.org/#readable-stream-from-iterable +static already_AddRefed<ReadableStream> MOZ_CAN_RUN_SCRIPT +ReadableStreamFromIterable(JSContext* aCx, nsIGlobalObject* aGlobal, + JS::Handle<JS::Value> aAsyncIterable, + ErrorResult& aRv) { + aRv.MightThrowJSException(); + + // Step 1. Let stream be undefined. (not required) + // Step 2. Let iteratorRecord be ? GetIterator(asyncIterable, async). + JS::Rooted<JSObject*> iteratorRecord( + aCx, JS::GetIteratorObject(aCx, aAsyncIterable, true)); + if (!iteratorRecord) { + aRv.StealExceptionFromJSContext(aCx); + return nullptr; + } + + // Steps 3-5. are in ReadableStreamFromAlgorithms. + auto algorithms = + MakeRefPtr<ReadableStreamFromAlgorithms>(aGlobal, iteratorRecord); + + // Step 6. Set stream to ! CreateReadableStream(startAlgorithm, pullAlgorithm, + // cancelAlgorithm, 0). + // Step 7. Return stream. + return ReadableStream::CreateAbstract(aCx, aGlobal, algorithms, + mozilla::Some(0.0), nullptr, aRv); +} + +/* static */ +already_AddRefed<ReadableStream> ReadableStream::From( + const GlobalObject& aGlobal, JS::Handle<JS::Value> aAsyncIterable, + ErrorResult& aRv) { + // Step 1. Return ? ReadableStreamFromIterable(asyncIterable). + nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aGlobal.GetAsSupports()); + return ReadableStreamFromIterable(aGlobal.Context(), global, aAsyncIterable, + aRv); +} + +// Dealing with const this ptr is a pain, so just re-implement. +// https://streams.spec.whatwg.org/#is-readable-stream-locked +bool ReadableStream::Locked() const { + // Step 1 + 2. + return mReader; +} + +namespace streams_abstract { +// https://streams.spec.whatwg.org/#initialize-readable-stream +static void InitializeReadableStream(ReadableStream* aStream) { + // Step 1. + aStream->SetState(ReadableStream::ReaderState::Readable); + + // Step 2. + aStream->SetReader(nullptr); + aStream->SetStoredError(JS::UndefinedHandleValue); + + // Step 3. + aStream->SetDisturbed(false); +} +} // namespace streams_abstract + +// https://streams.spec.whatwg.org/#create-readable-stream +MOZ_CAN_RUN_SCRIPT +already_AddRefed<ReadableStream> ReadableStream::CreateAbstract( + JSContext* aCx, nsIGlobalObject* aGlobal, + UnderlyingSourceAlgorithmsBase* aAlgorithms, + mozilla::Maybe<double> aHighWaterMark, QueuingStrategySize* aSizeAlgorithm, + ErrorResult& aRv) { + // Step 1. If highWaterMark was not passed, set it to 1. + double highWaterMark = aHighWaterMark.valueOr(1.0); + + // Step 2. consumers of sizeAlgorithm + // handle null algorithms correctly. + // Step 3. + MOZ_ASSERT(IsNonNegativeNumber(highWaterMark)); + // Step 4. + RefPtr<ReadableStream> stream = + new ReadableStream(aGlobal, HoldDropJSObjectsCaller::Implicit); + + // Step 5. + InitializeReadableStream(stream); + + // Step 6. + RefPtr<ReadableStreamDefaultController> controller = + new ReadableStreamDefaultController(aGlobal); + + // Step 7. + SetUpReadableStreamDefaultController(aCx, stream, controller, aAlgorithms, + highWaterMark, aSizeAlgorithm, aRv); + + // Step 8. + return stream.forget(); +} + +namespace streams_abstract { +// https://streams.spec.whatwg.org/#readable-stream-close +void ReadableStreamClose(JSContext* aCx, ReadableStream* aStream, + ErrorResult& aRv) { + // Step 1. + MOZ_ASSERT(aStream->State() == ReadableStream::ReaderState::Readable); + + // Step 2. + aStream->SetState(ReadableStream::ReaderState::Closed); + + // Step 3. + ReadableStreamGenericReader* reader = aStream->GetReader(); + + // Step 4. + if (!reader) { + return; + } + + // Step 5. + reader->ClosedPromise()->MaybeResolveWithUndefined(); + + // Step 6. + if (reader->IsDefault()) { + // Step 6.1. Let readRequests be reader.[[readRequests]]. + // Move LinkedList out of DefaultReader onto stack to avoid the potential + // for concurrent modification, which could invalidate the iterator. + // + // See https://bugs.chromium.org/p/chromium/issues/detail?id=1045874 as an + // example of the kind of issue that could occur. + LinkedList<RefPtr<ReadRequest>> readRequests = + std::move(reader->AsDefault()->ReadRequests()); + + // Step 6.2. Set reader.[[readRequests]] to an empty list. + // Note: The std::move already cleared this anyway. + reader->AsDefault()->ReadRequests().clear(); + + // Step 6.3. For each readRequest of readRequests, + // Drain the local list and destroy elements along the way. + while (RefPtr<ReadRequest> readRequest = readRequests.popFirst()) { + // Step 6.3.1. Perform readRequest’s close steps. + readRequest->CloseSteps(aCx, aRv); + if (aRv.Failed()) { + return; + } + } + } +} + +// https://streams.spec.whatwg.org/#readable-stream-cancel +already_AddRefed<Promise> ReadableStreamCancel(JSContext* aCx, + ReadableStream* aStream, + JS::Handle<JS::Value> aError, + ErrorResult& aRv) { + // Step 1. + aStream->SetDisturbed(true); + + // Step 2. + if (aStream->State() == ReadableStream::ReaderState::Closed) { + RefPtr<Promise> promise = + Promise::CreateInfallible(aStream->GetParentObject()); + promise->MaybeResolveWithUndefined(); + return promise.forget(); + } + + // Step 3. + if (aStream->State() == ReadableStream::ReaderState::Errored) { + JS::Rooted<JS::Value> storedError(aCx, aStream->StoredError()); + return Promise::CreateRejected(aStream->GetParentObject(), storedError, + aRv); + } + + // Step 4. + ReadableStreamClose(aCx, aStream, aRv); + if (aRv.Failed()) { + return nullptr; + } + + // Step 5. + ReadableStreamGenericReader* reader = aStream->GetReader(); + + // Step 6. + if (reader && reader->IsBYOB()) { + // Step 6.1. Let readIntoRequests be reader.[[readIntoRequests]]. + LinkedList<RefPtr<ReadIntoRequest>> readIntoRequests = + std::move(reader->AsBYOB()->ReadIntoRequests()); + + // Step 6.2. Set reader.[[readIntoRequests]] to an empty list. + // Note: The std::move already cleared this anyway. + reader->AsBYOB()->ReadIntoRequests().clear(); + + // Step 6.3. For each readIntoRequest of readIntoRequests, + while (RefPtr<ReadIntoRequest> readIntoRequest = + readIntoRequests.popFirst()) { + // Step 6.3.1.Perform readIntoRequest’s close steps, given undefined. + readIntoRequest->CloseSteps(aCx, JS::UndefinedHandleValue, aRv); + if (aRv.Failed()) { + return nullptr; + } + } + } + + // Step 7. + RefPtr<ReadableStreamController> controller(aStream->Controller()); + RefPtr<Promise> sourceCancelPromise = + controller->CancelSteps(aCx, aError, aRv); + if (aRv.Failed()) { + return nullptr; + } + + // Step 8. + RefPtr<Promise> promise = + Promise::CreateInfallible(sourceCancelPromise->GetParentObject()); + + // ThenWithCycleCollectedArgs will carry promise, keeping it alive until the + // callback executes. + Result<RefPtr<Promise>, nsresult> returnResult = + sourceCancelPromise->ThenWithCycleCollectedArgs( + [](JSContext*, JS::Handle<JS::Value>, ErrorResult&, + RefPtr<Promise> newPromise) { + newPromise->MaybeResolveWithUndefined(); + return newPromise.forget(); + }, + promise); + + if (returnResult.isErr()) { + aRv.Throw(returnResult.unwrapErr()); + return nullptr; + } + + return returnResult.unwrap().forget(); +} + +} // namespace streams_abstract + +// https://streams.spec.whatwg.org/#rs-cancel +already_AddRefed<Promise> ReadableStream::Cancel(JSContext* aCx, + JS::Handle<JS::Value> aReason, + ErrorResult& aRv) { + // Step 1. If ! IsReadableStreamLocked(this) is true, + // return a promise rejected with a TypeError exception. + if (Locked()) { + aRv.ThrowTypeError("Cannot cancel a stream locked by a reader."); + return nullptr; + } + + // Step 2. Return ! ReadableStreamCancel(this, reason). + RefPtr<ReadableStream> thisRefPtr = this; + return ReadableStreamCancel(aCx, thisRefPtr, aReason, aRv); +} + +namespace streams_abstract { +// https://streams.spec.whatwg.org/#acquire-readable-stream-reader +already_AddRefed<ReadableStreamDefaultReader> +AcquireReadableStreamDefaultReader(ReadableStream* aStream, ErrorResult& aRv) { + // Step 1. + RefPtr<ReadableStreamDefaultReader> reader = + new ReadableStreamDefaultReader(aStream->GetParentObject()); + + // Step 2. + SetUpReadableStreamDefaultReader(reader, aStream, aRv); + if (aRv.Failed()) { + return nullptr; + } + + // Step 3. + return reader.forget(); +} +} // namespace streams_abstract + +// https://streams.spec.whatwg.org/#rs-get-reader +void ReadableStream::GetReader(const ReadableStreamGetReaderOptions& aOptions, + OwningReadableStreamReader& resultReader, + ErrorResult& aRv) { + // Step 1. If options["mode"] does not exist, + // return ? AcquireReadableStreamDefaultReader(this). + if (!aOptions.mMode.WasPassed()) { + RefPtr<ReadableStreamDefaultReader> defaultReader = + AcquireReadableStreamDefaultReader(this, aRv); + if (aRv.Failed()) { + return; + } + resultReader.SetAsReadableStreamDefaultReader() = defaultReader; + return; + } + + // Step 2. Assert: options["mode"] is "byob". + MOZ_ASSERT(aOptions.mMode.Value() == ReadableStreamReaderMode::Byob); + + // Step 3. Return ? AcquireReadableStreamBYOBReader(this). + RefPtr<ReadableStreamBYOBReader> byobReader = + AcquireReadableStreamBYOBReader(this, aRv); + if (aRv.Failed()) { + return; + } + resultReader.SetAsReadableStreamBYOBReader() = byobReader; +} + +namespace streams_abstract { +// https://streams.spec.whatwg.org/#is-readable-stream-locked +bool IsReadableStreamLocked(ReadableStream* aStream) { + // Step 1 + 2. + return aStream->Locked(); +} +} // namespace streams_abstract + +// https://streams.spec.whatwg.org/#rs-pipe-through +MOZ_CAN_RUN_SCRIPT already_AddRefed<ReadableStream> ReadableStream::PipeThrough( + const ReadableWritablePair& aTransform, const StreamPipeOptions& aOptions, + ErrorResult& aRv) { + // Step 1: If ! IsReadableStreamLocked(this) is true, throw a TypeError + // exception. + if (IsReadableStreamLocked(this)) { + aRv.ThrowTypeError("Cannot pipe from a locked stream."); + return nullptr; + } + + // Step 2: If ! IsWritableStreamLocked(transform["writable"]) is true, throw a + // TypeError exception. + if (IsWritableStreamLocked(aTransform.mWritable)) { + aRv.ThrowTypeError("Cannot pipe to a locked stream."); + return nullptr; + } + + // Step 3: Let signal be options["signal"] if it exists, or undefined + // otherwise. + RefPtr<AbortSignal> signal = + aOptions.mSignal.WasPassed() ? &aOptions.mSignal.Value() : nullptr; + + // Step 4: Let promise be ! ReadableStreamPipeTo(this, transform["writable"], + // options["preventClose"], options["preventAbort"], options["preventCancel"], + // signal). + RefPtr<WritableStream> writable = aTransform.mWritable; + RefPtr<Promise> promise = ReadableStreamPipeTo( + this, writable, aOptions.mPreventClose, aOptions.mPreventAbort, + aOptions.mPreventCancel, signal, aRv); + if (aRv.Failed()) { + return nullptr; + } + + // Step 5: Set promise.[[PromiseIsHandled]] to true. + MOZ_ALWAYS_TRUE(promise->SetAnyPromiseIsHandled()); + + // Step 6: Return transform["readable"]. + return do_AddRef(aTransform.mReadable.get()); +}; + +namespace streams_abstract { + +// https://streams.spec.whatwg.org/#readable-stream-get-num-read-requests +double ReadableStreamGetNumReadRequests(ReadableStream* aStream) { + // Step 1. + MOZ_ASSERT(ReadableStreamHasDefaultReader(aStream)); + + // Step 2. + return double(aStream->GetDefaultReader()->ReadRequests().length()); +} + +// https://streams.spec.whatwg.org/#readable-stream-error +void ReadableStreamError(JSContext* aCx, ReadableStream* aStream, + JS::Handle<JS::Value> aValue, ErrorResult& aRv) { + // Step 1. + MOZ_ASSERT(aStream->State() == ReadableStream::ReaderState::Readable); + + // Step 2. + aStream->SetState(ReadableStream::ReaderState::Errored); + + // Step 3. + aStream->SetStoredError(aValue); + + // Step 4. + ReadableStreamGenericReader* reader = aStream->GetReader(); + + // Step 5. + if (!reader) { + return; + } + + // Step 6. + reader->ClosedPromise()->MaybeReject(aValue); + + // Step 7. + reader->ClosedPromise()->SetSettledPromiseIsHandled(); + + // Step 8. + if (reader->IsDefault()) { + // Step 8.1. Perform ! ReadableStreamDefaultReaderErrorReadRequests(reader, + // e). + RefPtr<ReadableStreamDefaultReader> defaultReader = reader->AsDefault(); + ReadableStreamDefaultReaderErrorReadRequests(aCx, defaultReader, aValue, + aRv); + if (aRv.Failed()) { + return; + } + } else { + // Step 9. Otherwise, + // Step 9.1. Assert: reader implements ReadableStreamBYOBReader. + MOZ_ASSERT(reader->IsBYOB()); + + // Step 9.2. Perform ! ReadableStreamBYOBReaderErrorReadIntoRequests(reader, + // e). + RefPtr<ReadableStreamBYOBReader> byobReader = reader->AsBYOB(); + ReadableStreamBYOBReaderErrorReadIntoRequests(aCx, byobReader, aValue, aRv); + if (aRv.Failed()) { + return; + } + } +} + +// https://streams.spec.whatwg.org/#rs-default-controller-close +void ReadableStreamFulfillReadRequest(JSContext* aCx, ReadableStream* aStream, + JS::Handle<JS::Value> aChunk, bool aDone, + ErrorResult& aRv) { + // Step 1. + MOZ_ASSERT(ReadableStreamHasDefaultReader(aStream)); + + // Step 2. + ReadableStreamDefaultReader* reader = aStream->GetDefaultReader(); + + // Step 3. + MOZ_ASSERT(!reader->ReadRequests().isEmpty()); + + // Step 4+5. + RefPtr<ReadRequest> readRequest = reader->ReadRequests().popFirst(); + + // Step 6. + if (aDone) { + readRequest->CloseSteps(aCx, aRv); + if (aRv.Failed()) { + return; + } + } + + // Step 7. + readRequest->ChunkSteps(aCx, aChunk, aRv); +} + +// https://streams.spec.whatwg.org/#readable-stream-add-read-request +void ReadableStreamAddReadRequest(ReadableStream* aStream, + ReadRequest* aReadRequest) { + // Step 1. + MOZ_ASSERT(aStream->GetReader()->IsDefault()); + // Step 2. + MOZ_ASSERT(aStream->State() == ReadableStream::ReaderState::Readable); + // Step 3. + aStream->GetDefaultReader()->ReadRequests().insertBack(aReadRequest); +} + +} // namespace streams_abstract + +// https://streams.spec.whatwg.org/#abstract-opdef-readablestreamdefaulttee +// Step 14, 15 +MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> +ReadableStreamDefaultTeeSourceAlgorithms::CancelCallback( + JSContext* aCx, const Optional<JS::Handle<JS::Value>>& aReason, + ErrorResult& aRv) { + // Step 1. + mTeeState->SetCanceled(mBranch, true); + + // Step 2. + mTeeState->SetReason(mBranch, aReason.Value()); + + // Step 3. + + if (mTeeState->Canceled(OtherTeeBranch(mBranch))) { + // Step 3.1 + + JS::Rooted<JSObject*> compositeReason(aCx, JS::NewArrayObject(aCx, 2)); + if (!compositeReason) { + aRv.StealExceptionFromJSContext(aCx); + return nullptr; + } + + JS::Rooted<JS::Value> reason1(aCx, mTeeState->Reason1()); + if (!JS_SetElement(aCx, compositeReason, 0, reason1)) { + aRv.StealExceptionFromJSContext(aCx); + return nullptr; + } + + JS::Rooted<JS::Value> reason2(aCx, mTeeState->Reason2()); + if (!JS_SetElement(aCx, compositeReason, 1, reason2)) { + aRv.StealExceptionFromJSContext(aCx); + return nullptr; + } + + // Step 3.2 + JS::Rooted<JS::Value> compositeReasonValue( + aCx, JS::ObjectValue(*compositeReason)); + RefPtr<ReadableStream> stream(mTeeState->GetStream()); + RefPtr<Promise> cancelResult = + ReadableStreamCancel(aCx, stream, compositeReasonValue, aRv); + if (aRv.Failed()) { + return nullptr; + } + + // Step 3.3 + mTeeState->CancelPromise()->MaybeResolve(cancelResult); + } + + // Step 4. + return do_AddRef(mTeeState->CancelPromise()); +} + +// https://streams.spec.whatwg.org/#abstract-opdef-readablestreamdefaulttee +MOZ_CAN_RUN_SCRIPT +static void ReadableStreamDefaultTee(JSContext* aCx, ReadableStream* aStream, + bool aCloneForBranch2, + nsTArray<RefPtr<ReadableStream>>& aResult, + ErrorResult& aRv) { + // Step 1. Implicit. + // Step 2. Implicit. + + // Steps 3-12 are contained in the construction of Tee State. + RefPtr<TeeState> teeState = TeeState::Create(aStream, aCloneForBranch2, aRv); + if (aRv.Failed()) { + return; + } + + // Step 13 - 16 + auto branch1Algorithms = MakeRefPtr<ReadableStreamDefaultTeeSourceAlgorithms>( + teeState, TeeBranch::Branch1); + auto branch2Algorithms = MakeRefPtr<ReadableStreamDefaultTeeSourceAlgorithms>( + teeState, TeeBranch::Branch2); + + // Step 17. + nsCOMPtr<nsIGlobalObject> global( + do_AddRef(teeState->GetStream()->GetParentObject())); + teeState->SetBranch1(ReadableStream::CreateAbstract( + aCx, global, branch1Algorithms, mozilla::Nothing(), nullptr, aRv)); + if (aRv.Failed()) { + return; + } + + // Step 18. + teeState->SetBranch2(ReadableStream::CreateAbstract( + aCx, global, branch2Algorithms, mozilla::Nothing(), nullptr, aRv)); + if (aRv.Failed()) { + return; + } + + // Step 19. + teeState->GetReader()->ClosedPromise()->AddCallbacksWithCycleCollectedArgs( + [](JSContext* aCx, JS::Handle<JS::Value> aValue, ErrorResult& aRv, + TeeState* aTeeState) {}, + [](JSContext* aCx, JS::Handle<JS::Value> aReason, ErrorResult& aRv, + TeeState* aTeeState) { + // Step 19.1. + ReadableStreamDefaultControllerError( + aCx, aTeeState->Branch1()->DefaultController(), aReason, aRv); + if (aRv.Failed()) { + return; + } + + // Step 19.2 + ReadableStreamDefaultControllerError( + aCx, aTeeState->Branch2()->DefaultController(), aReason, aRv); + if (aRv.Failed()) { + return; + } + + // Step 19.3 + if (!aTeeState->Canceled1() || !aTeeState->Canceled2()) { + aTeeState->CancelPromise()->MaybeResolveWithUndefined(); + } + }, + RefPtr(teeState)); + + // Step 20. + aResult.AppendElement(teeState->Branch1()); + aResult.AppendElement(teeState->Branch2()); +} + +// https://streams.spec.whatwg.org/#rs-pipe-to +already_AddRefed<Promise> ReadableStream::PipeTo( + WritableStream& aDestination, const StreamPipeOptions& aOptions, + ErrorResult& aRv) { + // Step 1. If !IsReadableStreamLocked(this) is true, return a promise rejected + // with a TypeError exception. + if (IsReadableStreamLocked(this)) { + aRv.ThrowTypeError("Cannot pipe from a locked stream."); + return nullptr; + } + + // Step 2. If !IsWritableStreamLocked(destination) is true, return a promise + // rejected with a TypeError exception. + if (IsWritableStreamLocked(&aDestination)) { + aRv.ThrowTypeError("Cannot pipe to a locked stream."); + return nullptr; + } + + // Step 3. Let signal be options["signal"] if it exists, or undefined + // otherwise. + RefPtr<AbortSignal> signal = + aOptions.mSignal.WasPassed() ? &aOptions.mSignal.Value() : nullptr; + + // Step 4. Return ! ReadableStreamPipeTo(this, destination, + // options["preventClose"], options["preventAbort"], options["preventCancel"], + // signal). + return ReadableStreamPipeTo(this, &aDestination, aOptions.mPreventClose, + aOptions.mPreventAbort, aOptions.mPreventCancel, + signal, aRv); +} + +// https://streams.spec.whatwg.org/#readable-stream-tee +MOZ_CAN_RUN_SCRIPT +static void ReadableStreamTee(JSContext* aCx, ReadableStream* aStream, + bool aCloneForBranch2, + nsTArray<RefPtr<ReadableStream>>& aResult, + ErrorResult& aRv) { + // Step 1. Implicit. + // Step 2. Implicit. + // Step 3. + if (aStream->Controller()->IsByte()) { + ReadableByteStreamTee(aCx, aStream, aResult, aRv); + return; + } + // Step 4. + ReadableStreamDefaultTee(aCx, aStream, aCloneForBranch2, aResult, aRv); +} + +void ReadableStream::Tee(JSContext* aCx, + nsTArray<RefPtr<ReadableStream>>& aResult, + ErrorResult& aRv) { + ReadableStreamTee(aCx, this, false, aResult, aRv); +} + +void ReadableStream::IteratorData::Traverse( + nsCycleCollectionTraversalCallback& cb) { + ReadableStream::IteratorData* tmp = this; + NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mReader); +} +void ReadableStream::IteratorData::Unlink() { + ReadableStream::IteratorData* tmp = this; + NS_IMPL_CYCLE_COLLECTION_UNLINK(mReader); +} + +// https://streams.spec.whatwg.org/#rs-get-iterator +void ReadableStream::InitAsyncIteratorData( + IteratorData& aData, Iterator::IteratorType aType, + const ReadableStreamIteratorOptions& aOptions, ErrorResult& aRv) { + // Step 1. Let reader be ? AcquireReadableStreamDefaultReader(stream). + RefPtr<ReadableStreamDefaultReader> reader = + AcquireReadableStreamDefaultReader(this, aRv); + if (aRv.Failed()) { + return; + } + + // Step 2. Set iterator’s reader to reader. + aData.mReader = reader; + + // Step 3. Let preventCancel be args[0]["preventCancel"]. + // Step 4. Set iterator’s prevent cancel to preventCancel. + aData.mPreventCancel = aOptions.mPreventCancel; +} + +// https://streams.spec.whatwg.org/#rs-asynciterator-prototype-next +// Step 4. +struct IteratorReadRequest : public ReadRequest { + public: + NS_DECL_ISUPPORTS_INHERITED + NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(IteratorReadRequest, ReadRequest) + + RefPtr<Promise> mPromise; + RefPtr<ReadableStreamDefaultReader> mReader; + + explicit IteratorReadRequest(Promise* aPromise, + ReadableStreamDefaultReader* aReader) + : mPromise(aPromise), mReader(aReader) {} + + // chunk steps, given chunk + void ChunkSteps(JSContext* aCx, JS::Handle<JS::Value> aChunk, + ErrorResult& aRv) override { + // Step 1. Resolve promise with chunk. + mPromise->MaybeResolve(aChunk); + } + + // close steps + void CloseSteps(JSContext* aCx, ErrorResult& aRv) override { + // Step 1. Perform ! ReadableStreamDefaultReaderRelease(reader). + ReadableStreamDefaultReaderRelease(aCx, mReader, aRv); + if (aRv.Failed()) { + mPromise->MaybeRejectWithUndefined(); + return; + } + + // Step 2. Resolve promise with end of iteration. + iterator_utils::ResolvePromiseForFinished(mPromise); + } + + // error steps, given e + void ErrorSteps(JSContext* aCx, JS::Handle<JS::Value> aError, + ErrorResult& aRv) override { + // Step 1. Perform ! ReadableStreamDefaultReaderRelease(reader). + ReadableStreamDefaultReaderRelease(aCx, mReader, aRv); + if (aRv.Failed()) { + mPromise->MaybeRejectWithUndefined(); + return; + } + + // Step 2. Reject promise with e. + mPromise->MaybeReject(aError); + } + + protected: + virtual ~IteratorReadRequest() = default; +}; + +NS_IMPL_CYCLE_COLLECTION_INHERITED(IteratorReadRequest, ReadRequest, mPromise, + mReader) + +NS_IMPL_ADDREF_INHERITED(IteratorReadRequest, ReadRequest) +NS_IMPL_RELEASE_INHERITED(IteratorReadRequest, ReadRequest) + +NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(IteratorReadRequest) +NS_INTERFACE_MAP_END_INHERITING(ReadRequest) + +// https://streams.spec.whatwg.org/#rs-asynciterator-prototype-next +already_AddRefed<Promise> ReadableStream::GetNextIterationResult( + Iterator* aIterator, ErrorResult& aRv) { + // Step 1. Let reader be iterator’s reader. + RefPtr<ReadableStreamDefaultReader> reader = aIterator->Data().mReader; + + // Step 2. Assert: reader.[[stream]] is not undefined. + MOZ_ASSERT(reader->GetStream()); + + // Step 3. Let promise be a new promise. + RefPtr<Promise> promise = Promise::CreateInfallible(GetParentObject()); + + // Step 4. Let readRequest be a new read request with the following items: + RefPtr<ReadRequest> request = new IteratorReadRequest(promise, reader); + + // Step 5. Perform ! ReadableStreamDefaultReaderRead(this, readRequest). + AutoJSAPI jsapi; + if (!jsapi.Init(mGlobal)) { + aRv.ThrowUnknownError("Internal error"); + return nullptr; + } + + ReadableStreamDefaultReaderRead(jsapi.cx(), reader, request, aRv); + if (aRv.Failed()) { + return nullptr; + } + + // Step 6. Return promise. + return promise.forget(); +} + +// https://streams.spec.whatwg.org/#rs-asynciterator-prototype-return +already_AddRefed<Promise> ReadableStream::IteratorReturn( + JSContext* aCx, Iterator* aIterator, JS::Handle<JS::Value> aValue, + ErrorResult& aRv) { + // Step 1. Let reader be iterator’s reader. + RefPtr<ReadableStreamDefaultReader> reader = aIterator->Data().mReader; + + // Step 2. Assert: reader.[[stream]] is not undefined. + MOZ_ASSERT(reader->GetStream()); + + // Step 3. Assert: reader.[[readRequests]] is empty, as the async iterator + // machinery guarantees that any previous calls to next() have settled before + // this is called. + MOZ_ASSERT(reader->ReadRequests().isEmpty()); + + // Step 4. If iterator’s prevent cancel is false: + if (!aIterator->Data().mPreventCancel) { + // Step 4.1. Let result be ! ReadableStreamReaderGenericCancel(reader, arg). + RefPtr<ReadableStream> stream(reader->GetStream()); + RefPtr<Promise> result = ReadableStreamCancel(aCx, stream, aValue, aRv); + if (NS_WARN_IF(aRv.Failed())) { + return nullptr; + } + + MOZ_DIAGNOSTIC_ASSERT( + reader->GetStream(), + "We shouldn't have a null stream here (bug 1821169)."); + if (!reader->GetStream()) { + aRv.Throw(NS_ERROR_FAILURE); + return nullptr; + } + + // Step 4.2. Perform ! ReadableStreamDefaultReaderRelease(reader). + ReadableStreamDefaultReaderRelease(aCx, reader, aRv); + if (NS_WARN_IF(aRv.Failed())) { + return nullptr; + } + + // Step 4.3. Return result. + return result.forget(); + } + + // Step 5. Perform ! ReadableStreamDefaultReaderRelease(reader). + ReadableStreamDefaultReaderRelease(aCx, reader, aRv); + if (NS_WARN_IF(aRv.Failed())) { + return nullptr; + } + + // Step 6. Return a promise resolved with undefined. + return Promise::CreateResolvedWithUndefined(GetParentObject(), aRv); +} + +namespace streams_abstract { +// https://streams.spec.whatwg.org/#readable-stream-add-read-into-request +void ReadableStreamAddReadIntoRequest(ReadableStream* aStream, + ReadIntoRequest* aReadIntoRequest) { + // Step 1. Assert: stream.[[reader]] implements ReadableStreamBYOBReader. + MOZ_ASSERT(aStream->GetReader()->IsBYOB()); + + // Step 2. Assert: stream.[[state]] is "readable" or "closed". + MOZ_ASSERT(aStream->State() == ReadableStream::ReaderState::Readable || + aStream->State() == ReadableStream::ReaderState::Closed); + + // Step 3. Append readRequest to stream.[[reader]].[[readIntoRequests]]. + aStream->GetReader()->AsBYOB()->ReadIntoRequests().insertBack( + aReadIntoRequest); +} +} // namespace streams_abstract + +// https://streams.spec.whatwg.org/#abstract-opdef-createreadablebytestream +already_AddRefed<ReadableStream> ReadableStream::CreateByteAbstract( + JSContext* aCx, nsIGlobalObject* aGlobal, + UnderlyingSourceAlgorithmsBase* aAlgorithms, ErrorResult& aRv) { + // Step 1. Let stream be a new ReadableStream. + RefPtr<ReadableStream> stream = + new ReadableStream(aGlobal, HoldDropJSObjectsCaller::Implicit); + + // Step 2. Perform ! InitializeReadableStream(stream). + InitializeReadableStream(stream); + + // Step 3. Let controller be a new ReadableByteStreamController. + RefPtr<ReadableByteStreamController> controller = + new ReadableByteStreamController(aGlobal); + + // Step 4. Perform ? SetUpReadableByteStreamController(stream, controller, + // startAlgorithm, pullAlgorithm, cancelAlgorithm, 0, undefined). + SetUpReadableByteStreamController(aCx, stream, controller, aAlgorithms, 0, + mozilla::Nothing(), aRv); + if (aRv.Failed()) { + return nullptr; + } + + // Return stream. + return stream.forget(); +} + +// https://streams.spec.whatwg.org/#readablestream-set-up +// (except this instead creates a new ReadableStream rather than accepting an +// existing instance) +// _BOUNDARY because `aAlgorithms->StartCallback` (called by +// SetUpReadableStreamDefaultController below) should not be able to run script +// in this case. +MOZ_CAN_RUN_SCRIPT_BOUNDARY already_AddRefed<ReadableStream> +ReadableStream::CreateNative(JSContext* aCx, nsIGlobalObject* aGlobal, + UnderlyingSourceAlgorithmsWrapper& aAlgorithms, + mozilla::Maybe<double> aHighWaterMark, + QueuingStrategySize* aSizeAlgorithm, + ErrorResult& aRv) { + // an optional number highWaterMark (default 1) + double highWaterMark = aHighWaterMark.valueOr(1); + // and if given, highWaterMark must be a non-negative, non-NaN number. + MOZ_ASSERT(IsNonNegativeNumber(highWaterMark)); + + // Step 1: Let startAlgorithm be an algorithm that returns undefined. + // Step 2: Let pullAlgorithmWrapper be an algorithm that runs these steps: + // Step 3: Let cancelAlgorithmWrapper be an algorithm that runs these steps: + // (Done by UnderlyingSourceAlgorithmsWrapper) + + // Step 4: If sizeAlgorithm was not given, then set it to an algorithm that + // returns 1. (Callers will treat nullptr as such, see + // ReadableStream::Constructor for details) + + // Step 5: Perform ! InitializeReadableStream(stream). + RefPtr<ReadableStream> stream = + new ReadableStream(aGlobal, HoldDropJSObjectsCaller::Implicit); + + // Step 6: Let controller be a new ReadableStreamDefaultController. + auto controller = MakeRefPtr<ReadableStreamDefaultController>(aGlobal); + + // Step 7: Perform ! SetUpReadableStreamDefaultController(stream, controller, + // startAlgorithm, pullAlgorithmWrapper, cancelAlgorithmWrapper, + // highWaterMark, sizeAlgorithm). + SetUpReadableStreamDefaultController(aCx, stream, controller, &aAlgorithms, + highWaterMark, aSizeAlgorithm, aRv); + if (aRv.Failed()) { + return nullptr; + } + return stream.forget(); +} + +// https://streams.spec.whatwg.org/#readablestream-set-up-with-byte-reading-support +// _BOUNDARY because `aAlgorithms->StartCallback` (called by +// SetUpReadableByteStreamController below) should not be able to run script in +// this case. +MOZ_CAN_RUN_SCRIPT_BOUNDARY void ReadableStream::SetUpByteNative( + JSContext* aCx, UnderlyingSourceAlgorithmsWrapper& aAlgorithms, + mozilla::Maybe<double> aHighWaterMark, ErrorResult& aRv) { + // an optional number highWaterMark (default 0) + double highWaterMark = aHighWaterMark.valueOr(0); + // and if given, highWaterMark must be a non-negative, non-NaN number. + MOZ_ASSERT(IsNonNegativeNumber(highWaterMark)); + + // Step 1: Let startAlgorithm be an algorithm that returns undefined. + // Step 2: Let pullAlgorithmWrapper be an algorithm that runs these steps: + // Step 3: Let cancelAlgorithmWrapper be an algorithm that runs these steps: + // (Done by UnderlyingSourceAlgorithmsWrapper) + + // Step 4: Perform ! InitializeReadableStream(stream). + // (Covered by constructor) + + // Step 5: Let controller be a new ReadableByteStreamController. + auto controller = MakeRefPtr<ReadableByteStreamController>(GetParentObject()); + + // Step 6: Perform ! SetUpReadableByteStreamController(stream, controller, + // startAlgorithm, pullAlgorithmWrapper, cancelAlgorithmWrapper, + // highWaterMark, undefined). + SetUpReadableByteStreamController(aCx, this, controller, &aAlgorithms, + highWaterMark, Nothing(), aRv); +} + +already_AddRefed<ReadableStream> ReadableStream::CreateByteNative( + JSContext* aCx, nsIGlobalObject* aGlobal, + UnderlyingSourceAlgorithmsWrapper& aAlgorithms, + mozilla::Maybe<double> aHighWaterMark, ErrorResult& aRv) { + RefPtr<ReadableStream> stream = + new ReadableStream(aGlobal, HoldDropJSObjectsCaller::Implicit); + stream->SetUpByteNative(aCx, aAlgorithms, aHighWaterMark, aRv); + if (aRv.Failed()) { + return nullptr; + } + return stream.forget(); +} + +// https://streams.spec.whatwg.org/#readablestream-close +void ReadableStream::CloseNative(JSContext* aCx, ErrorResult& aRv) { + MOZ_ASSERT_IF(mController->GetAlgorithms(), + mController->GetAlgorithms()->IsNative()); + // Step 1: If stream.[[controller]] implements ReadableByteStreamController, + if (mController->IsByte()) { + RefPtr<ReadableByteStreamController> controller = mController->AsByte(); + + // Step 1.1: Perform ! + // ReadableByteStreamControllerClose(stream.[[controller]]). + ReadableByteStreamControllerClose(aCx, controller, aRv); + if (aRv.Failed()) { + return; + } + + // Step 1.2: If stream.[[controller]].[[pendingPullIntos]] is not empty, + // perform ! ReadableByteStreamControllerRespond(stream.[[controller]], 0). + if (!controller->PendingPullIntos().isEmpty()) { + ReadableByteStreamControllerRespond(aCx, controller, 0, aRv); + } + return; + } + + // Step 2: Otherwise, perform ! + // ReadableStreamDefaultControllerClose(stream.[[controller]]). + RefPtr<ReadableStreamDefaultController> controller = mController->AsDefault(); + ReadableStreamDefaultControllerClose(aCx, controller, aRv); +} + +// https://streams.spec.whatwg.org/#readablestream-error +void ReadableStream::ErrorNative(JSContext* aCx, JS::Handle<JS::Value> aError, + ErrorResult& aRv) { + // Step 1: If stream.[[controller]] implements ReadableByteStreamController, + // then perform ! ReadableByteStreamControllerError(stream.[[controller]], e). + if (mController->IsByte()) { + ReadableByteStreamControllerError(mController->AsByte(), aError, aRv); + return; + } + // Step 2: Otherwise, perform ! + // ReadableStreamDefaultControllerError(stream.[[controller]], e). + ReadableStreamDefaultControllerError(aCx, mController->AsDefault(), aError, + aRv); +} + +// https://streams.spec.whatwg.org/#readablestream-current-byob-request-view +static void CurrentBYOBRequestView(JSContext* aCx, + ReadableByteStreamController& aController, + JS::MutableHandle<JSObject*> aRetVal, + ErrorResult& aRv) { + // Step 1. Assert: stream.[[controller]] implements + // ReadableByteStreamController. (implicit) + + // Step 2: Let byobRequest be ! + // ReadableByteStreamControllerGetBYOBRequest(stream.[[controller]]). + RefPtr<ReadableStreamBYOBRequest> byobRequest = + ReadableByteStreamControllerGetBYOBRequest(aCx, &aController, aRv); + // Step 3: If byobRequest is null, then return null. + if (!byobRequest) { + aRetVal.set(nullptr); + return; + } + // Step 4: Return byobRequest.[[view]]. + byobRequest->GetView(aCx, aRetVal); +} + +static bool HasSameBufferView(JSContext* aCx, JS::Handle<JSObject*> aX, + JS::Handle<JSObject*> aY, ErrorResult& aRv) { + bool isShared; + JS::Rooted<JSObject*> viewedBufferX( + aCx, JS_GetArrayBufferViewBuffer(aCx, aX, &isShared)); + if (!viewedBufferX) { + aRv.StealExceptionFromJSContext(aCx); + return false; + } + + JS::Rooted<JSObject*> viewedBufferY( + aCx, JS_GetArrayBufferViewBuffer(aCx, aY, &isShared)); + if (!viewedBufferY) { + aRv.StealExceptionFromJSContext(aCx); + return false; + } + + return viewedBufferX == viewedBufferY; +} + +// https://streams.spec.whatwg.org/#readablestream-enqueue +void ReadableStream::EnqueueNative(JSContext* aCx, JS::Handle<JS::Value> aChunk, + ErrorResult& aRv) { + MOZ_ASSERT(mController->GetAlgorithms()->IsNative()); + + // Step 1: If stream.[[controller]] implements + // ReadableStreamDefaultController, + if (mController->IsDefault()) { + // Step 1.1: Perform ! + // ReadableStreamDefaultControllerEnqueue(stream.[[controller]], chunk). + RefPtr<ReadableStreamDefaultController> controller = + mController->AsDefault(); + ReadableStreamDefaultControllerEnqueue(aCx, controller, aChunk, aRv); + return; + } + + // Step 2.1: Assert: stream.[[controller]] implements + // ReadableByteStreamController. + MOZ_ASSERT(mController->IsByte()); + RefPtr<ReadableByteStreamController> controller = mController->AsByte(); + + // Step 2.2: Assert: chunk is an ArrayBufferView. + MOZ_ASSERT(aChunk.isObject() && + JS_IsArrayBufferViewObject(&aChunk.toObject())); + JS::Rooted<JSObject*> chunk(aCx, &aChunk.toObject()); + + // Step 3: Let byobView be the current BYOB request view for stream. + JS::Rooted<JSObject*> byobView(aCx); + CurrentBYOBRequestView(aCx, *controller, &byobView, aRv); + if (aRv.Failed()) { + return; + } + + // Step 4: If byobView is non-null, and chunk.[[ViewedArrayBuffer]] is + // byobView.[[ViewedArrayBuffer]], then: + if (byobView && HasSameBufferView(aCx, chunk, byobView, aRv)) { + // Step 4.1: Assert: chunk.[[ByteOffset]] is byobView.[[ByteOffset]]. + MOZ_ASSERT(JS_GetArrayBufferViewByteOffset(chunk) == + JS_GetArrayBufferViewByteOffset(byobView)); + // Step 4.2: Assert: chunk.[[ByteLength]] ≤ byobView.[[ByteLength]]. + MOZ_ASSERT(JS_GetArrayBufferViewByteLength(chunk) <= + JS_GetArrayBufferViewByteLength(byobView)); + // Step 4.3: Perform ? + // ReadableByteStreamControllerRespond(stream.[[controller]], + // chunk.[[ByteLength]]). + ReadableByteStreamControllerRespond( + aCx, controller, JS_GetArrayBufferViewByteLength(chunk), aRv); + return; + } + + if (aRv.Failed()) { + return; + } + + // Step 5: Otherwise, perform ? + // ReadableByteStreamControllerEnqueue(stream.[[controller]], chunk). + ReadableByteStreamControllerEnqueue(aCx, controller, chunk, aRv); +} + +// https://streams.spec.whatwg.org/#readablestream-current-byob-request-view +void ReadableStream::GetCurrentBYOBRequestView( + JSContext* aCx, JS::MutableHandle<JSObject*> aView, ErrorResult& aRv) { + aView.set(nullptr); + + // Step 1: Assert: stream.[[controller]] implements + // ReadableByteStreamController. + MOZ_ASSERT(mController->IsByte()); + + // Step 2: Let byobRequest be ! + // ReadableByteStreamControllerGetBYOBRequest(stream.[[controller]]). + RefPtr<ReadableStreamBYOBRequest> byobRequest = + mController->AsByte()->GetByobRequest(aCx, aRv); + + // Step 3: If byobRequest is null, then return null. + if (!byobRequest || aRv.Failed()) { + return; + } + + // Step 4: Return byobRequest.[[view]]. + byobRequest->GetView(aCx, aView); +} + +// https://streams.spec.whatwg.org/#readablestream-get-a-reader +// To get a reader for a ReadableStream stream, return ? +// AcquireReadableStreamDefaultReader(stream). The result will be a +// ReadableStreamDefaultReader. +already_AddRefed<mozilla::dom::ReadableStreamDefaultReader> +ReadableStream::GetReader(ErrorResult& aRv) { + return AcquireReadableStreamDefaultReader(this, aRv); +} + +} // namespace mozilla::dom |