LibWeb: Add ReadableStreamBYOBReader interface

Userland/Libraries/LibWeb/CMakeLists.txt

@@ -475,6 +475,7 @@ set(SOURCES
     Streams/AbstractOperations.cpp
     Streams/ReadableByteStreamController.cpp
     Streams/ReadableStream.cpp
+    Streams/ReadableStreamBYOBReader.cpp
     Streams/ReadableStreamBYOBRequest.cpp
     Streams/ReadableStreamDefaultController.cpp
     Streams/ReadableStreamDefaultReader.cpp

Userland/Libraries/LibWeb/Forward.h

@@ -509,6 +509,7 @@ class Selection;
 namespace Web::Streams {
 class ReadableByteStreamController;
 class ReadableStream;
+class ReadableStreamBYOBReader;
 class ReadableStreamBYOBRequest;
 class ReadableStreamDefaultController;
 class ReadableStreamDefaultReader;

Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.cpp

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2023, Matthew Olsson <mattco@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Runtime/PromiseCapability.h>
+#include <LibWeb/Streams/ReadableStream.h>
+#include <LibWeb/Streams/ReadableStreamBYOBReader.h>
+
+namespace Web::Streams {
+
+ReadableStreamBYOBReader::ReadableStreamBYOBReader(JS::Realm& realm)
+    : Bindings::PlatformObject(realm)
+    , ReadableStreamGenericReaderMixin(realm)
+{
+}
+
+void ReadableStreamBYOBReader::visit_edges(Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    ReadableStreamGenericReaderMixin::visit_edges(visitor);
+}
+
+}

Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2023, Matthew Olsson <mattco@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Forward.h>
+#include <AK/Function.h>
+#include <LibJS/Forward.h>
+#include <LibWeb/Bindings/PlatformObject.h>
+#include <LibWeb/Forward.h>
+#include <LibWeb/Streams/ReadableStreamGenericReader.h>
+
+namespace Web::Streams {
+
+// https://streams.spec.whatwg.org/#read-into-request
+class ReadIntoRequest : public RefCounted<ReadIntoRequest> {
+public:
+    virtual ~ReadIntoRequest() = default;
+
+    // An algorithm taking a chunk, called when a chunk is available for reading
+    virtual void on_chunk(JS::Value chunk) = 0;
+
+    // An algorithm taking a chunk or undefined, called when no chunks are available because the stream is closed
+    virtual void on_close(JS::Value chunk_or_undefined) = 0;
+
+    // An algorithm taking a JavaScript value, called when no chunks are available because the stream is errored
+    virtual void on_error(JS::Value error) = 0;
+};
+
+// https://streams.spec.whatwg.org/#readablestreambyobreader
+class ReadableStreamBYOBReader final
+    : public Bindings::PlatformObject
+    , public ReadableStreamGenericReaderMixin {
+    WEB_PLATFORM_OBJECT(ReadableStreamBYOBReader, Bindings::PlatformObject);
+
+public:
+    virtual ~ReadableStreamBYOBReader() override = default;
+
+    Vector<NonnullRefPtr<ReadIntoRequest>>& read_into_requests() { return m_read_into_requests; }
+
+private:
+    explicit ReadableStreamBYOBReader(JS::Realm&);
+
+    virtual void visit_edges(Cell::Visitor&) override;
+
+    // https://streams.spec.whatwg.org/#readablestreambyobreader-readintorequests
+    // A list of read-into requests, used when a consumer requests chunks sooner than they are available
+    Vector<NonnullRefPtr<ReadIntoRequest>> m_read_into_requests;
+};
+
+}

Userland/Libraries/LibWeb/Streams/ReadableStreamBYOBReader.idl

@@ -0,0 +1,11 @@
+#import <Streams/ReadableStreamGenericReader.idl>
+
+[Exposed=*]
+interface ReadableStreamBYOBReader {
+    // FIXME: Implement
+    // constructor(ReadableStream stream);
+
+    // Promise<ReadableStreamReadResult> read(ArrayBufferView view);
+    // undefined releaseLock();
+};
+ReadableStreamBYOBReader includes ReadableStreamGenericReader;

Userland/Libraries/LibWeb/idl_files.cmake

@@ -184,6 +184,7 @@ libweb_js_bindings(RequestIdleCallback/IdleDeadline)
 libweb_js_bindings(ResizeObserver/ResizeObserver)
 libweb_js_bindings(Streams/ReadableByteStreamController)
 libweb_js_bindings(Streams/ReadableStream)
+libweb_js_bindings(Streams/ReadableStreamBYOBReader)
 libweb_js_bindings(Streams/ReadableStreamBYOBRequest)
 libweb_js_bindings(Streams/ReadableStreamDefaultController)
 libweb_js_bindings(Streams/ReadableStreamDefaultReader)