Implement ReadableStreamBytesConsumer

third_party/WebKit/Source/modules/fetch/ReadableStreamBytesConsumer.h

+// Copyright 2016 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 ReadableStreamBytesConsumer_h
+#define ReadableStreamBytesConsumer_h
+
+#include "bindings/core/v8/ScriptValue.h"
+#include "core/dom/DOMTypedArray.h"
+#include "modules/ModulesExport.h"
+#include "modules/fetch/BytesConsumer.h"
+#include "platform/heap/Handle.h"
+#include "wtf/Forward.h"
+#include "wtf/RefPtr.h"
+#include <memory>
+
+namespace blink {
+
+class ScriptState;
+
+// This class is a BytesConsumer pulling bytes from ReadableStream
+// implemented with V8 Extras.
+// The stream will be immediately locked by the consumer and will never be
+// released.
+//
+// The ReadableStreamReader handle held in a ReadableStreamDataConsumerHandle
+// is weak. A user must guarantee that the ReadableStreamReader object is kept
+// alive appropriately.
+class MODULES_EXPORT ReadableStreamBytesConsumer final : public BytesConsumer {
+  WTF_MAKE_NONCOPYABLE(ReadableStreamBytesConsumer);
+  USING_PRE_FINALIZER(ReadableStreamBytesConsumer, dispose);
+
+ public:
+  ReadableStreamBytesConsumer(ScriptState*, ScriptValue streamReader);
+  ~ReadableStreamBytesConsumer() override;
+
+  Result beginRead(const char** buffer, size_t* available) override;
+  Result endRead(size_t readSize) override;
+  void setClient(BytesConsumer::Client*) override;
+  void clearClient() override;
+
+  void cancel() override;
+  PublicState getPublicState() const override;
+  Error getError() const override;
+  String debugName() const override { return "ReadableStreamBytesConsumer"; }
+
+  DECLARE_TRACE();
+
+ private:
+  class OnFulfilled;
+  class OnRejected;
+
+  void dispose();
+  void onRead(DOMUint8Array*);
+  void onReadDone();
+  void onRejected();
+  void notify();
+
+  // |m_reader| is a weak persistent. It should be kept alive by someone
+  // outside of ReadableStreamBytesConsumer.
+  // Holding a ScopedPersistent here is safe in terms of cross-world wrapper
+  // leakage because we read only Uint8Array chunks from the reader.
+  ScopedPersistent<v8::Value> m_reader;
+  RefPtr<ScriptState> m_scriptState;
+  Member<BytesConsumer::Client> m_client;
+  Member<DOMUint8Array> m_pendingBuffer;
+  size_t m_pendingOffset = 0;
+  PublicState m_state = PublicState::ReadableOrWaiting;
+  bool m_isReading = false;
+};
+
+}  // namespace blink
+
+#endif  // ReadableStreamBytesConsumer_h