LibWeb: Add ReadableStreamDefaultController

Userland/Libraries/LibWeb/Streams/ReadableStreamDefaultController.h

@@ -0,0 +1,120 @@
+/*
+ * Copyright (c) 2023, Matthew Olsson <mattco@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Forward.h>
+#include <AK/Optional.h>
+#include <AK/SinglyLinkedList.h>
+#include <LibJS/Forward.h>
+#include <LibWeb/Bindings/PlatformObject.h>
+#include <LibWeb/Forward.h>
+#include <LibWeb/Streams/AbstractOperations.h>
+#include <LibWeb/WebIDL/Promise.h>
+
+namespace Web::Streams {
+
+// https://streams.spec.whatwg.org/#readablestreamdefaultcontroller
+class ReadableStreamDefaultController : public Bindings::PlatformObject {
+    WEB_PLATFORM_OBJECT(ReadableStreamDefaultController, Bindings::PlatformObject);
+
+public:
+    explicit ReadableStreamDefaultController(JS::Realm&);
+    virtual ~ReadableStreamDefaultController() override = default;
+
+    Optional<float> desired_size();
+
+    WebIDL::ExceptionOr<void> close();
+    WebIDL::ExceptionOr<void> enqueue(JS::Value chunk);
+    void error(JS::Value error);
+
+    auto& cancel_algorithm() { return m_cancel_algorithm; }
+    void set_cancel_algorithm(Optional<CancelAlgorithm> value) { m_cancel_algorithm = move(value); }
+
+    bool close_requested() const { return m_close_requested; }
+    void set_close_requested(bool value) { m_close_requested = value; }
+
+    bool pull_again() const { return m_pull_again; }
+    void set_pull_again(bool value) { m_pull_again = value; }
+
+    auto& pull_algorithm() { return m_pull_algorithm; }
+    void set_pull_algorithm(Optional<PullAlgorithm> value) { m_pull_algorithm = move(value); }
+
+    bool pulling() const { return m_pulling; }
+    void set_pulling(bool value) { m_pulling = value; }
+
+    SinglyLinkedList<ValueWithSize>& queue() { return m_queue; }
+
+    double queue_total_size() const { return m_queue_total_size; }
+    void set_queue_total_size(double value) { m_queue_total_size = value; }
+
+    bool started() const { return m_started; }
+    void set_started(bool value) { m_started = value; }
+
+    size_t strategy_hwm() const { return m_strategy_hwm; }
+    void set_strategy_hwm(size_t value) { m_strategy_hwm = value; }
+
+    auto& strategy_size_algorithm() { return m_strategy_size_algorithm; }
+    void set_strategy_size_algorithm(Optional<SizeAlgorithm> value) { m_strategy_size_algorithm = move(value); }
+
+    JS::GCPtr<ReadableStream> stream() { return m_stream; }
+    void set_stream(JS::GCPtr<ReadableStream> value) { m_stream = value; }
+
+    WebIDL::ExceptionOr<JS::GCPtr<WebIDL::Promise>> cancel_steps(JS::Value reason);
+    WebIDL::ExceptionOr<void> pull_steps(ReadRequest&);
+    void release_steps();
+
+private:
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
+
+    virtual void visit_edges(Cell::Visitor&) override;
+
+    // https://streams.spec.whatwg.org/#readablestreamdefaultcontroller-cancelalgorithm
+    // A promise-returning algorithm, taking one argument (the cancel reason), which communicates a requested cancelation to the underlying source
+    Optional<CancelAlgorithm> m_cancel_algorithm;
+
+    // https://streams.spec.whatwg.org/#readablestreamdefaultcontroller-closerequested
+    // A boolean flag indicating whether the stream has been closed by its underlying source, but still has chunks in its internal queue that have not yet been read
+    bool m_close_requested { false };
+
+    // https://streams.spec.whatwg.org/#readablestreamdefaultcontroller-pullagain
+    // A boolean flag set to true if the stream’s mechanisms requested a call to the underlying source's pull algorithm to pull more data, but the pull could not yet be done since a previous call is still executing
+    bool m_pull_again { false };
+
+    // https://streams.spec.whatwg.org/#readablestreamdefaultcontroller-pullalgorithm
+    // A promise-returning algorithm that pulls data from the underlying source
+    Optional<PullAlgorithm> m_pull_algorithm;
+
+    // https://streams.spec.whatwg.org/#readablestreamdefaultcontroller-pulling
+    // A boolean flag set to true while the underlying source's pull algorithm is executing and the returned promise has not yet fulfilled, used to prevent reentrant calls
+    bool m_pulling { false };
+
+    // https://streams.spec.whatwg.org/#readablestreamdefaultcontroller-queue
+    // A list representing the stream’s internal queue of chunks
+    SinglyLinkedList<ValueWithSize> m_queue;
+
+    // https://streams.spec.whatwg.org/#readablestreamdefaultcontroller-queuetotalsize
+    // The total size of all the chunks stored in [[queue]]
+    double m_queue_total_size { 0 };
+
+    // https://streams.spec.whatwg.org/#readablestreamdefaultcontroller-started
+    // A boolean flag indicating whether the underlying source has finished starting
+    bool m_started { false };
+
+    // https://streams.spec.whatwg.org/#readablestreamdefaultcontroller-strategyhwm
+    // A number supplied to the constructor as part of the stream’s queuing strategy, indicating the point at which the stream will apply backpressure to its underlying source
+    size_t m_strategy_hwm { 0 };
+
+    // https://streams.spec.whatwg.org/#readablestreamdefaultcontroller-strategysizealgorithm
+    // An algorithm to calculate the size of enqueued chunks, as part of the stream’s queuing strategy
+    Optional<SizeAlgorithm> m_strategy_size_algorithm;
+
+    // https://streams.spec.whatwg.org/#readablestreamdefaultcontroller-stream
+    // The ReadableStream instance controlled
+    JS::GCPtr<ReadableStream> m_stream;
+};
+
+}