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 ReadableStreamDataConsumerHandle.

[hiroshige, 2016/09/30 06:35:14]

nit: ReadableStreamBytesConsumer?

[yhirano, 2016/09/30 09:01:02]

Done.

+    // 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