LibWeb: Add the WritableStreamDefaultWriter interface

Userland/Libraries/LibWeb/Streams/WritableStreamDefaultWriter.cpp

@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2023, Matthew Olsson <mattco@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Runtime/PromiseCapability.h>
+#include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/Bindings/WritableStreamDefaultWriterPrototype.h>
+#include <LibWeb/Streams/AbstractOperations.h>
+#include <LibWeb/Streams/WritableStream.h>
+#include <LibWeb/Streams/WritableStreamDefaultWriter.h>
+#include <LibWeb/WebIDL/ExceptionOr.h>
+
+namespace Web::Streams {
+
+WebIDL::ExceptionOr<JS::NonnullGCPtr<WritableStreamDefaultWriter>> WritableStreamDefaultWriter::construct_impl(JS::Realm& realm, JS::NonnullGCPtr<WritableStream> stream)
+{
+    auto writer = MUST_OR_THROW_OOM(realm.heap().allocate<WritableStreamDefaultWriter>(realm, realm));
+
+    // 1. Perform ? SetUpWritableStreamDefaultWriter(this, stream).
+    TRY(set_up_writable_stream_default_writer(*writer, stream));
+
+    return writer;
+}
+
+// https://streams.spec.whatwg.org/#default-writer-closed
+JS::GCPtr<JS::Object> WritableStreamDefaultWriter::closed()
+{
+    // 1. Return this.[[closedPromise]].
+    return m_closed_promise->promise();
+}
+
+// https://streams.spec.whatwg.org/#default-writer-desired-size
+WebIDL::ExceptionOr<Optional<double>> WritableStreamDefaultWriter::desired_size() const
+{
+    // 1. If this.[[stream]] is undefined, throw a TypeError exception.
+    if (!m_stream)
+        return WebIDL::SimpleException { WebIDL::SimpleExceptionType::TypeError, "Cannot get desired size of writer that has no locked stream"sv };
+
+    // 2. Return ! WritableStreamDefaultWriterGetDesiredSize(this).
+    return writable_stream_default_writer_get_desired_size(*this);
+}
+
+// https://streams.spec.whatwg.org/#default-writer-ready
+JS::GCPtr<JS::Object> WritableStreamDefaultWriter::ready()
+{
+    // 1. Return this.[[readyPromise]].
+    return m_ready_promise->promise();
+}
+
+WritableStreamDefaultWriter::WritableStreamDefaultWriter(JS::Realm& realm)
+    : Bindings::PlatformObject(realm)
+{
+}
+
+JS::ThrowCompletionOr<void> WritableStreamDefaultWriter::initialize(JS::Realm& realm)
+{
+    MUST_OR_THROW_OOM(Base::initialize(realm));
+    set_prototype(&Bindings::ensure_web_prototype<Bindings::WritableStreamDefaultWriterPrototype>(realm, "WritableStreamDefaultWriter"));
+
+    return {};
+}
+
+void WritableStreamDefaultWriter::visit_edges(Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_closed_promise);
+    visitor.visit(m_ready_promise);
+    visitor.visit(m_stream);
+}
+
+}