LibWeb: Add the WritableStream interface

2025-07-26 18:37:36 +00:00 · 2023-04-02 15:15:53 -07:00 · 2023-04-02 15:15:53 -07:00 · e93560b769
commit e93560b769
parent 78feba401d
10 changed files with 311 additions and 0 deletions
--- a/Userland/Libraries/LibWeb/Streams/WritableStream.h
+++ b/Userland/Libraries/LibWeb/Streams/WritableStream.h
@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2023, Matthew Olsson <mattco@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Forward.h>
+#include <AK/SinglyLinkedList.h>
+#include <LibJS/Forward.h>
+#include <LibWeb/Bindings/PlatformObject.h>
+#include <LibWeb/Forward.h>
+#include <LibWeb/WebIDL/Promise.h>
+
+namespace Web::Streams {
+
+// https://streams.spec.whatwg.org/#pending-abort-request
+struct PendingAbortRequest {
+    // https://streams.spec.whatwg.org/#pending-abort-request-promise
+    // A promise returned from WritableStreamAbort
+    JS::NonnullGCPtr<WebIDL::Promise> promise;
+
+    // https://streams.spec.whatwg.org/#pending-abort-request-reason
+    // A JavaScript value that was passed as the abort reason to WritableStreamAbort
+    JS::Value reason;
+
+    // https://streams.spec.whatwg.org/#pending-abort-request-was-already-erroring
+    // A boolean indicating whether or not the stream was in the "erroring" state when WritableStreamAbort was called, which impacts the outcome of the abort request
+    bool was_already_erroring;
+};
+
+// https://streams.spec.whatwg.org/#writablestream
+class WritableStream final : public Bindings::PlatformObject {
+    WEB_PLATFORM_OBJECT(WritableStream, Bindings::PlatformObject);
+
+public:
+    enum class State {
+        Writable,
+        Closed,
+        Erroring,
+        Errored,
+    };
+
+    static WebIDL::ExceptionOr<JS::NonnullGCPtr<WritableStream>> construct_impl(JS::Realm& realm, Optional<JS::Handle<JS::Object>> const& underlying_sink);
+
+    virtual ~WritableStream() = default;
+
+    bool locked() const;
+
+    bool backpressure() const { return m_backpressure; }
+    void set_backpressure(bool value) { m_backpressure = value; }
+
+    JS::GCPtr<WebIDL::Promise const> close_request() const { return m_close_request; }
+    void set_close_request(JS::GCPtr<WebIDL::Promise> value) { m_close_request = value; }
+
+    JS::GCPtr<JS::Object> controller() { return m_controller; }
+    void set_controller(JS::GCPtr<JS::Object> value) { m_controller = value; }
+
+    JS::GCPtr<WebIDL::Promise const> in_flight_write_request() const { return m_in_flight_write_request; }
+    void set_in_flight_write_request(JS::GCPtr<WebIDL::Promise> value) { m_in_flight_write_request = value; }
+
+    JS::GCPtr<WebIDL::Promise const> in_flight_close_request() const { return m_in_flight_close_request; }
+    void set_in_flight_close_request(JS::GCPtr<WebIDL::Promise> value) { m_in_flight_close_request = value; }
+
+    Optional<PendingAbortRequest>& pending_abort_request() { return m_pending_abort_request; }
+    void set_pending_abort_request(Optional<PendingAbortRequest>&& value) { m_pending_abort_request = move(value); }
+
+    State state() const { return m_state; }
+    void set_state(State value) { m_state = value; }
+
+    JS::Value stored_error() const { return m_stored_error; }
+    void set_stored_error(JS::Value value) { m_stored_error = value; }
+
+    JS::GCPtr<JS::Object const> writer() const { return m_writer; }
+    void set_writer(JS::GCPtr<JS::Object> value) { m_writer = value; }
+
+    SinglyLinkedList<JS::NonnullGCPtr<WebIDL::Promise>>& write_requests() { return m_write_requests; }
+
+private:
+    explicit WritableStream(JS::Realm&);
+
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
+
+    virtual void visit_edges(Cell::Visitor&) override;
+
+    // https://streams.spec.whatwg.org/#writablestream-backpressure
+    // A boolean indicating the backpressure signal set by the controller
+    bool m_backpressure { false };
+
+    // https://streams.spec.whatwg.org/#writablestream-closerequest
+    // The promise returned from the writer’s close() method
+    JS::GCPtr<WebIDL::Promise> m_close_request;
+
+    // https://streams.spec.whatwg.org/#writablestream-controller
+    // A WritableStreamDefaultController created with the ability to control the state and queue of this stream
+    JS::GCPtr<JS::Object> m_controller;
+
+    // https://streams.spec.whatwg.org/#writablestream-detached
+    // A boolean flag set to true when the stream is transferred
+    bool m_detached { false };
+
+    // https://streams.spec.whatwg.org/#writablestream-inflightwriterequest
+    // A slot set to the promise for the current in-flight write operation while the underlying sink's write algorithm is executing and has not yet fulfilled, used to prevent reentrant calls
+    JS::GCPtr<WebIDL::Promise> m_in_flight_write_request;
+
+    // https://streams.spec.whatwg.org/#writablestream-inflightcloserequest
+    // A slot set to the promise for the current in-flight close operation while the underlying sink's close algorithm is executing and has not yet fulfilled, used to prevent the abort() method from interrupting close
+    JS::GCPtr<WebIDL::Promise> m_in_flight_close_request;
+
+    // https://streams.spec.whatwg.org/#writablestream-pendingabortrequest
+    // A pending abort request
+    Optional<PendingAbortRequest> m_pending_abort_request;
+
+    // https://streams.spec.whatwg.org/#writablestream-state
+    // A string containing the stream’s current state, used internally; one of "writable", "closed", "erroring", or "errored"
+    State m_state { State::Writable };
+
+    // https://streams.spec.whatwg.org/#writablestream-storederror
+    // A value indicating how the stream failed, to be given as a failure reason or exception when trying to operate on the stream while in the "errored" state
+    JS::Value m_stored_error { JS::js_undefined() };
+
+    // https://streams.spec.whatwg.org/#writablestream-writer
+    // A WritableStreamDefaultWriter instance, if the stream is locked to a writer, or undefined if it is not
+    JS::GCPtr<JS::Object> m_writer;
+
+    // https://streams.spec.whatwg.org/#writablestream-writerequests
+    // A list of promises representing the stream’s internal queue of write requests not yet processed by the underlying sink
+    SinglyLinkedList<JS::NonnullGCPtr<WebIDL::Promise>> m_write_requests;
+};
+
+}