Change BodyStreamBuffer to be FetchDataConsumerHandle-based and enable backpressure in Fetch API

Source/modules/fetch/BodyStreamBuffer.h

Index: Source/modules/fetch/BodyStreamBuffer.h
diff --git a/Source/modules/fetch/BodyStreamBuffer.h b/Source/modules/fetch/BodyStreamBuffer.h
index cdb47baab116261c68167786d96f4c924f8e15d1..30922d7eb3ba07188b3ed6541692eb6acf5b0002 100644
--- a/Source/modules/fetch/BodyStreamBuffer.h
+++ b/Source/modules/fetch/BodyStreamBuffer.h
@@ -7,6 +7,9 @@
 
 #include "core/dom/DOMException.h"
 #include "modules/ModulesExport.h"
+#include "modules/fetch/DataConsumerHandleUtil.h"
+#include "modules/fetch/FetchDataConsumerHandle.h"
+#include "modules/fetch/FetchDataLoader.h"
 #include "platform/blob/BlobData.h"
 #include "platform/heap/Heap.h"
 #include "public/platform/WebDataConsumerHandle.h"
@@ -58,14 +61,6 @@ public:
     void error(DOMException*);
     void cancel() { m_canceller->cancel(); }
 
-    // This function registers an observer so it fails and returns false when an
-    // observer was already registered.
-    bool readAllAndCreateBlobHandle(const String& contentType, BlobHandleCreatorClient*);
-
-    // This function registers an observer so it fails and returns false when an
-    // observer was already registered.
-    bool startTee(BodyStreamBuffer* out1, BodyStreamBuffer* out2);
-
     // When an observer was registered this function fails and returns false.
     bool registerObserver(Observer*);
     void unregisterObserver();
@@ -85,6 +80,167 @@ private:
     Member<Canceller> m_canceller;
 };
 
+/*
+// #define createDebugHandleAlways(handle) FetchDebugDataConsumerHandle::create(handle, __FILE__, __LINE__)
+#define createDebugHandleAlways(handle) (handle)
+#define createDebugHandle(handle) (handle)
+
+class FetchDebugDataConsumerHandle : public FetchDataConsumerHandle {
+public:
+    static PassOwnPtr<FetchDataConsumerHandle> create(PassOwnPtr<FetchDataConsumerHandle> handle, const char* file, int line) { return adoptPtr(new FetchDebugDataConsumerHandle(handle, file, line)); }
+private:
+    FetchDebugDataConsumerHandle(PassOwnPtr<FetchDataConsumerHandle> handle, const char *file, int line)
+        : m_handle(handle)
+        , m_name(m_handle->debugName()) { }
+
+    class ReaderImpl final : public FetchDataConsumerHandle::Reader {
+    public:
+        ReaderImpl(FetchDebugDataConsumerHandle* handle, PassOwnPtr<FetchDataConsumerHandle::Reader> reader) : m_handle(handle), m_name(handle->debugName()), m_reader(reader), m_isInTwoPhaseRead(false) { }
+        ~ReaderImpl()
+        {
+            ASSERT(!m_isInTwoPhaseRead);
+            print("dtor\n", (long long)currentThread(), this);
+        }
+        Result read(void* data, size_t size, Flags flags, size_t* readSize) override
+        {
+            ASSERT(!m_isInTwoPhaseRead);
+            print("read(%lld)\n", (long long)size);
+            Result result = m_reader->read(data, size, flags, readSize);
+            print("read(%lld) -> %d (%lld)\n", (long long)size, result, (long long)*readSize);
+            return result;
+        }
+
+        Result beginRead(const void** buffer, Flags flags, size_t* available) override
+        {
+            ASSERT(!m_isInTwoPhaseRead);
+            print("beginRead()\n");
+            Result result = m_reader->beginRead(buffer, flags, available);
+            print("beginRead() -> %d (%lld)\n", result, (long long)*available);
+            if (result == Ok)
+                m_isInTwoPhaseRead = true;
+            return result;
+        }
+        Result endRead(size_t readSize) override
+        {
+            ASSERT(m_isInTwoPhaseRead);
+            m_isInTwoPhaseRead = false;
+            print("endRead(%lld)\n", (long long)readSize);
+            Result result = m_reader->endRead(readSize);
+            print("endRead(%lld) -> %d\n", (long long)readSize, result);
+            return result;
+        }
+        PassRefPtr<BlobDataHandle> drainAsBlobDataHandle() override
+        {
+            print("drainAsBlobDataHandle()\n");
+            RefPtr<BlobDataHandle> blobDataHandle = m_reader->drainAsBlobDataHandle();
+            print("drainAsBlobDataHandle() -> %p\n", blobDataHandle.get());
+            return blobDataHandle.release();
+        }
+        void print(const char* format, ...)
+        {
+            fprintf(stderr, "[Thread:%lld] [Handle:%p (%s)] [Reader:%p] [TargetReader:%p]: ",
+                (long long)currentThread(),
+                m_handle,
+                m_name.c_str(),
+                this,
+                m_reader.get());
+
+            va_list args;
+            va_start(args, format);
+            vfprintf(stderr, format, args);
+            va_end(args);
+        }
+    private:
+        FetchDebugDataConsumerHandle* m_handle; // debugging only
+        std::string m_name;
+        OwnPtr<FetchDataConsumerHandle::Reader> m_reader;
+        bool m_isInTwoPhaseRead;
+    };
+    class ClientWrapper : public Client {
+    public:
+        ClientWrapper(FetchDebugDataConsumerHandle* handle, Client* client) : m_handle(handle), m_name(handle->debugName()), m_reader(nullptr), m_client(client) { }
+        void didGetReadable() override
+        {
+            print("didGetReadable\n");
+            if (m_client)
+                m_client->didGetReadable();
+            print("didGetReadable done\n");
+        }
+        void setReader(Reader* reader) { m_reader = reader; }
+
+        void print(const char* format, ...)
+        {
+            fprintf(stderr, "[Thread:%lld] [Handle:%p (%s)] [Reader:%p] [Client:%p] [TargetClient:%p]: ",
+                (long long)currentThread(),
+                m_handle,
+                m_name.c_str(),
+                m_reader,
+                this,
+                m_client);
+
+            va_list args;
+            va_start(args, format);
+            vfprintf(stderr, format, args);
+            va_end(args);
+        }
+    private:
+        FetchDebugDataConsumerHandle* m_handle; // debugging only
+        std::string m_name;
+        Reader* m_reader; // logging only
+
+        Client* m_client;
+    };
+    Reader* obtainReaderInternal(Client* client) override
+    {
+        print("obtainReaderInternal(Client=%p)\n", client);
+        ClientWrapper* clientWrapper = new ClientWrapper(this, client);
+        Reader* reader = new ReaderImpl(this, m_handle->obtainReader(clientWrapper)); // FIXME: Leaking
+        clientWrapper->setReader(reader);
+        print("obtainReaderInternal(Client=%p) -> %p\n", client, reader);
+        return reader;
+    }
+    void print(const char* format, ...)
+    {
+        fprintf(stderr, "[Thread:%lld] [Handle:%p (%s)]: ",
+            (long long)currentThread(),
+            this,
+            debugName());
+
+        va_list args;
+        va_start(args, format);
+        vfprintf(stderr, format, args);
+        va_end(args);
+    }
+
+    const char* debugName() const override { return m_name.c_str(); }
+
+    OwnPtr<FetchDataConsumerHandle> m_handle;
+    std::string m_name;
+};
+*/
+
+class MODULES_EXPORT BodyStreamBuffer2 final : public GarbageCollectedFinalized<BodyStreamBuffer2> {
+public:
+    static BodyStreamBuffer2* create(PassOwnPtr<FetchDataConsumerHandle> handle) { return new BodyStreamBuffer2(handle); }
+    static BodyStreamBuffer2* createEmpty() { return BodyStreamBuffer2::create(createFetchDataConsumerHandleFromWebHandle(createDoneDataConsumerHandle())); }
+
+    FetchDataConsumerHandle* handle() const { return m_handle.get(); }
+    PassOwnPtr<FetchDataConsumerHandle> releaseHandle() { return m_handle.release(); }
+
+    void registerLoader(FetchDataLoader* loader) { ASSERT(!m_fetchDataLoader); m_fetchDataLoader = loader; }
+    void unregisterLoader() { m_fetchDataLoader.clear(); }
+    DEFINE_INLINE_TRACE()
+    {
+        visitor->trace(m_fetchDataLoader);
+    }
+
+private:
+    explicit BodyStreamBuffer2(PassOwnPtr<FetchDataConsumerHandle> handle) : m_handle(handle) { }
+
+    OwnPtr<FetchDataConsumerHandle> m_handle;
+    Member<FetchDataLoader> m_fetchDataLoader;
+};
+
 } // namespace blink
 
 #endif // BodyStreamBuffer_h