Implement BlobBytesConsumer

third_party/WebKit/Source/modules/fetch/BlobBytesConsumer.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 BlobBytesConsumer_h
+#define BlobBytesConsumer_h
+
+#include "core/dom/ContextLifecycleObserver.h"
+#include "core/loader/ThreadableLoaderClient.h"
+#include "modules/ModulesExport.h"
+#include "modules/fetch/BytesConsumer.h"
+#include "platform/heap/Handle.h"
+#include "wtf/PassRefPtr.h"
+#include "wtf/RefPtr.h"
+#include <memory>
+
+namespace blink {
+
+class BlobDataHandle;
+class EncodedFormData;
+class ExecutionContext;
+class ThreadableLoader;
+class WebDataConsumerHandle;
+
+// A BlobBytesConsumer is created from a blob handle and it will
+// return a valid handle from drainAsBlobDataHandle as much as possible.
+class MODULES_EXPORT BlobBytesConsumer final : public BytesConsumer, public ContextLifecycleObserver, public BytesConsumer::Client, public ThreadableLoaderClient {
+    USING_GARBAGE_COLLECTED_MIXIN(BlobBytesConsumer);
+    USING_PRE_FINALIZER(BlobBytesConsumer, cancel);
+public:
+    // |handle| can be null. In that case this consumer gets closed.
+    BlobBytesConsumer(ExecutionContext*, PassRefPtr<BlobDataHandle> /* handle */);
+    ~BlobBytesConsumer() override;
+
+    // BytesConsumer implementation
+    Result beginRead(const char** buffer, size_t* available) override;
+    Result endRead(size_t readSize) override;
+    PassRefPtr<BlobDataHandle> drainAsBlobDataHandle(BlobSizePolicy) override;
+    PassRefPtr<EncodedFormData> drainAsFormData() 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 "BlobBytesConsumer"; }
+
+    // ContextLifecycleObserver implementation
+    void contextDestroyed() override;
+
+    // BytesConsumer::Client implementation
+    void onStateChange() override;
+
+    // ThreadableLoaderClient implementation
+    void didReceiveResponse(unsigned long identifier, const ResourceResponse&, std::unique_ptr<WebDataConsumerHandle>) override;
+    void didFinishLoading(unsigned long identifier, double finishTime) override;
+    void didFail(const ResourceError&) override;
+    void didFailRedirectCheck() override;
+
+    DECLARE_TRACE();
+
+    static BlobBytesConsumer* createForTesting(ExecutionContext*, PassRefPtr<BlobDataHandle>, ThreadableLoader*);
+
+private:
+    BlobBytesConsumer(ExecutionContext*, PassRefPtr<BlobDataHandle>, ThreadableLoader*);
+    ThreadableLoader* createLoader();
+    void didFailInternal();
+    bool isClean() const { return m_blobDataHandle.get(); }
+    void close();
+    void error();
+    void clear();
+
+    KURL m_blobURL;
+    RefPtr<BlobDataHandle> m_blobDataHandle;
+    Member<BytesConsumer> m_body;
+    Member<BytesConsumer::Client> m_client;
+    Member<ThreadableLoader> m_loader;
+
+    PublicState m_state = PublicState::ReadableOrWaiting;
+    // These two booleans are meaningful only when m_state is ReadableOrWaiting.
+    bool m_hasSeenEndOfData = false;
+    bool m_hasFinishedLoading = false;
+};
+
+} // namespace blink
+
+#endif // BlobBytesConsumer_h