LibWeb: Add ByteStreamController to ReadableStreamController type

Author: https://github.com/mattco98
Commit: https://github.com/SerenityOS/serenity/commit/f9d6a161e8
Pull-request: https://github.com/SerenityOS/serenity/pull/18297
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibWeb/Streams/AbstractOperations.cpp

@@ -84,7 +84,9 @@ WebIDL::ExceptionOr<JS::NonnullGCPtr<WebIDL::Promise>> readable_stream_cancel(Re
     (void)reader;
 
     // 7. Let sourceCancelPromise be ! stream.[[controller]].[[CancelSteps]](reason).
-    auto source_cancel_promise = MUST(stream.controller()->cancel_steps(reason));
+    auto source_cancel_promise = TRY(stream.controller()->visit([&](auto const& controller) {
+        return controller->cancel_steps(reason);
+    }));
 
     // 8. Return the result of reacting to sourceCancelPromise with a fulfillment step that returns undefined.
     auto react_result = WebIDL::react_to_promise(*source_cancel_promise,
@@ -319,7 +321,7 @@ WebIDL::ExceptionOr<void> readable_stream_reader_generic_release(ReadableStreamG
     WebIDL::mark_promise_as_handled(*reader.closed_promise_capability());
 
     // 7. Perform ! stream.[[controller]].[[ReleaseSteps]]().
-    stream->controller()->release_steps();
+    TRY(stream->controller()->visit([](auto const& controller) { return controller->release_steps(); }));
 
     // 8. Set stream.[[reader]] to undefined.
     stream->set_reader({});
@@ -345,7 +347,7 @@ void readable_stream_default_reader_error_read_requests(ReadableStreamDefaultRea
 }
 
 // https://streams.spec.whatwg.org/#readable-stream-default-reader-read
-void readable_stream_default_reader_read(ReadableStreamDefaultReader& reader, ReadRequest& read_request)
+WebIDL::ExceptionOr<void> readable_stream_default_reader_read(ReadableStreamDefaultReader& reader, ReadRequest& read_request)
 {
     // 1. Let stream be reader.[[stream]].
     auto stream = reader.stream();
@@ -370,8 +372,12 @@ void readable_stream_default_reader_read(ReadableStreamDefaultReader& reader, Re
         VERIFY(stream->is_readable());
 
         // 2. Perform ! stream.[[controller]].[[PullSteps]](readRequest).
-        MUST(stream->controller()->pull_steps(read_request));
+        TRY(stream->controller()->visit([&](auto const& controller) {
+            return controller->pull_steps(read_request);
+        }));
     }
+
+    return {};
 }
 
 // https://streams.spec.whatwg.org/#abstract-opdef-readablestreamdefaultreaderrelease
@@ -635,7 +641,7 @@ WebIDL::ExceptionOr<void> set_up_readable_stream_default_controller(ReadableStre
     auto& realm = stream.realm();
 
     // 1. Assert: stream.[[controller]] is undefined.
-    VERIFY(!stream.controller());
+    VERIFY(!stream.controller().has_value());
 
     // 2. Set controller.[[stream]] to stream.
     controller.set_stream(stream);
@@ -660,7 +666,7 @@ WebIDL::ExceptionOr<void> set_up_readable_stream_default_controller(ReadableStre
     controller.set_cancel_algorithm(move(cancel_algorithm));
 
     // 8. Set stream.[[controller]] to controller.
-    stream.set_controller(controller);
+    stream.set_controller(ReadableStreamController { controller });
 
     // 9. Let startResult be the result of performing startAlgorithm. (This might throw an exception.)
     auto start_result = TRY(start_algorithm());

Userland/Libraries/LibWeb/Streams/AbstractOperations.h

@@ -38,7 +38,7 @@ void readable_stream_reader_generic_initialize(ReadableStreamGenericReaderMixin&
 WebIDL::ExceptionOr<void> readable_stream_reader_generic_release(ReadableStreamGenericReaderMixin&);
 
 void readable_stream_default_reader_error_read_requests(ReadableStreamDefaultReader&, JS::Value error);
-void readable_stream_default_reader_read(ReadableStreamDefaultReader&, ReadRequest&);
+WebIDL::ExceptionOr<void> readable_stream_default_reader_read(ReadableStreamDefaultReader&, ReadRequest&);
 WebIDL::ExceptionOr<void> readable_stream_default_reader_release(ReadableStreamDefaultReader&);
 WebIDL::ExceptionOr<void> set_up_readable_stream_default_reader(ReadableStreamDefaultReader&, ReadableStream&);
 void readable_stream_default_controller_close(ReadableStreamDefaultController&);

Userland/Libraries/LibWeb/Streams/ReadableStream.cpp

@@ -7,6 +7,7 @@
 #include <LibJS/Runtime/PromiseCapability.h>
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/Streams/AbstractOperations.h>
+#include <LibWeb/Streams/ReadableByteStreamController.h>
 #include <LibWeb/Streams/ReadableStream.h>
 #include <LibWeb/Streams/ReadableStreamDefaultController.h>
 #include <LibWeb/Streams/ReadableStreamDefaultReader.h>
@@ -107,7 +108,7 @@ JS::ThrowCompletionOr<void> ReadableStream::initialize(JS::Realm& realm)
 void ReadableStream::visit_edges(Cell::Visitor& visitor)
 {
     Base::visit_edges(visitor);
-    visitor.visit(m_controller);
+    m_controller->visit([&](auto& controller) { visitor.visit(controller); });
     visitor.visit(m_stored_error);
     visitor.visit(m_reader);
 }

Userland/Libraries/LibWeb/Streams/ReadableStream.h

@@ -17,9 +17,8 @@ namespace Web::Streams {
 // https://streams.spec.whatwg.org/#typedefdef-readablestreamreader
 using ReadableStreamReader = JS::GCPtr<ReadableStreamDefaultReader>;
 
-// FIXME: Variant<DefaultController, ByteStreamController>
 // https://streams.spec.whatwg.org/#typedefdef-readablestreamcontroller
-using ReadableStreamController = JS::GCPtr<ReadableStreamDefaultController>;
+using ReadableStreamController = Variant<JS::NonnullGCPtr<ReadableStreamDefaultController>, JS::NonnullGCPtr<ReadableByteStreamController>>;
 
 // https://streams.spec.whatwg.org/#readablestream
 class ReadableStream final : public Bindings::PlatformObject {
@@ -40,8 +39,8 @@ public:
     WebIDL::ExceptionOr<JS::GCPtr<JS::Object>> cancel(JS::Value view);
     WebIDL::ExceptionOr<ReadableStreamReader> get_reader();
 
-    ReadableStreamController controller() { return m_controller; }
-    void set_controller(ReadableStreamController value) { m_controller = value; }
+    Optional<ReadableStreamController>& controller() { return m_controller; }
+    void set_controller(Optional<ReadableStreamController> value) { m_controller = move(value); }
 
     JS::Value stored_error() const { return m_stored_error; }
     void set_stored_error(JS::Value value) { m_stored_error = value; }
@@ -68,7 +67,7 @@ private:
 
     // https://streams.spec.whatwg.org/#readablestream-controller
     // A ReadableStreamDefaultController or ReadableByteStreamController created with the ability to control the state and queue of this stream
-    ReadableStreamController m_controller;
+    Optional<ReadableStreamController> m_controller;
 
     // https://streams.spec.whatwg.org/#readablestream-detached
     // A boolean flag set to true when the stream is transferred

Userland/Libraries/LibWeb/Streams/ReadableStreamDefaultController.cpp

@@ -118,9 +118,10 @@ WebIDL::ExceptionOr<void> ReadableStreamDefaultController::pull_steps(Web::Strea
 }
 
 // https://streams.spec.whatwg.org/#abstract-opdef-readablestreamdefaultcontroller-releasesteps
-void ReadableStreamDefaultController::release_steps()
+WebIDL::ExceptionOr<void> ReadableStreamDefaultController::release_steps()
 {
     // 1. Return.
+    return {};
 }
 
 JS::ThrowCompletionOr<void> ReadableStreamDefaultController::initialize(JS::Realm& realm)

Userland/Libraries/LibWeb/Streams/ReadableStreamDefaultController.h

@@ -65,7 +65,7 @@ public:
 
     WebIDL::ExceptionOr<JS::GCPtr<WebIDL::Promise>> cancel_steps(JS::Value reason);
     WebIDL::ExceptionOr<void> pull_steps(ReadRequest&);
-    void release_steps();
+    WebIDL::ExceptionOr<void> release_steps();
 
 private:
     virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;

Userland/Libraries/LibWeb/Streams/ReadableStreamDefaultReader.cpp

@@ -102,7 +102,7 @@ WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::Promise>> ReadableStreamDefaultReader::
     auto read_request = adopt_ref(*new DefaultReaderReadRequest(realm, promise_capability));
 
     // 4. Perform ! ReadableStreamDefaultReaderRead(this, readRequest).
-    readable_stream_default_reader_read(*this, read_request);
+    TRY(readable_stream_default_reader_read(*this, read_request));
 
     // 5. Return promise.
     return JS::NonnullGCPtr { verify_cast<JS::Promise>(*promise_capability->promise()) };