third_party/blink/renderer/core/streams/readable_stream_byob_reader.h

// Copyright 2020 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be found
// in the LICENSE file.

#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_STREAMS_READABLE_STREAM_BYOB_READER_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_STREAMS_READABLE_STREAM_BYOB_READER_H_

#include "third_party/blink/renderer/bindings/core/v8/script_value.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/streams/readable_stream_generic_reader.h"
#include "third_party/blink/renderer/core/typed_arrays/array_buffer_view_helpers.h"
#include "third_party/blink/renderer/core/typed_arrays/dom_typed_array.h"
#include "third_party/blink/renderer/platform/bindings/script_wrappable.h"
#include "third_party/blink/renderer/platform/wtf/casting.h"

namespace blink {

class ExceptionState;
class ScriptPromise;
class ScriptState;
class StreamPromiseResolver;
class ReadableStream;
class DOMArrayBufferView;

class CORE_EXPORT ReadableStreamBYOBReader
    : public ReadableStreamGenericReader {
  DEFINE_WRAPPERTYPEINFO();

 public:
  static ReadableStreamBYOBReader* Create(ScriptState*,
                                          ReadableStream* stream,
                                          ExceptionState&);

  // https://streams.spec.whatwg.org/#byob-reader-constructor
  ReadableStreamBYOBReader(ScriptState*,
                           ReadableStream* stream,
                           ExceptionState&);
  ~ReadableStreamBYOBReader() override;

  bool IsDefaultReader() const override { return false; }
  bool IsBYOBReader() const override { return true; }

  // https://streams.spec.whatwg.org/#byob-reader-read
  ScriptPromise read(ScriptState*,
                     NotShared<DOMArrayBufferView> view,
                     ExceptionState&);

  // https://streams.spec.whatwg.org/#byob-reader-release-lock
  void releaseLock(ScriptState*, ExceptionState&);

  // https://streams.spec.whatwg.org/#set-up-readable-stream-byob-reader
  static void SetUpBYOBReader(ScriptState*,
                              ReadableStreamBYOBReader* reader,
                              ReadableStream* stream,
                              ExceptionState&);

  void Trace(Visitor*) const override;

 private:
  friend class ReadableByteStreamController;
  friend class ReadableStream;

  class ReadIntoRequest : public GarbageCollected<ReadIntoRequest> {
   public:
    explicit ReadIntoRequest(StreamPromiseResolver* resolver);

    void ChunkSteps(ScriptState*, DOMArrayBufferView* chunk) const;
    void CloseSteps(ScriptState*, DOMArrayBufferView* chunk) const;
    void ErrorSteps(ScriptState*, v8::Local<v8::Value> e) const;

    void Trace(Visitor*) const;

   private:
    friend class ReadableStream;

    Member<StreamPromiseResolver> resolver_;
  };

  // https://streams.spec.whatwg.org/#readable-stream-byob-reader-read
  static void Read(ScriptState*,
                   ReadableStreamBYOBReader*,
                   NotShared<DOMArrayBufferView> view,
                   ReadIntoRequest*,
                   ExceptionState&);

  HeapDeque<Member<ReadIntoRequest>> read_into_requests_;
};

template <>
struct DowncastTraits<ReadableStreamBYOBReader> {
  static bool AllowFrom(const ReadableStreamGenericReader& reader) {
    return reader.IsBYOBReader();
  }
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_STREAMS_READABLE_STREAM_BYOB_READER_H_