Make WebURLLoader capable of retaining received buffers.

content/child/shared_memory_received_data_factory.h

+// Copyright 2015 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 CONTENT_CHILD_SHARED_MEMORY_RECEIVED_DATA_FACTORY_H_
+#define CONTENT_CHILD_SHARED_MEMORY_RECEIVED_DATA_FACTORY_H_
+
+#include <vector>
+
+#include "base/memory/linked_ptr.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/shared_memory.h"
+#include "content/common/content_export.h"
+#include "content/public/child/request_peer.h"
+
+namespace IPC {
+class Sender;
+}  // namespace IPC
+
+namespace content {
+
+class CONTENT_EXPORT SharedMemoryReceivedDataFactory final
+    : public base::RefCounted<SharedMemoryReceivedDataFactory> {
+ public:
+  SharedMemoryReceivedDataFactory(IPC::Sender* message_sender,
+                                  int request_id,
+                                  linked_ptr<base::SharedMemory> memory);
+
+  scoped_ptr<RequestPeer::ReceivedData> Create(int offset,
+                                               int length,
+                                               int encoded_length);
+
+  // Stops this factory. After calling this function, releasing issued data
+  // won't send ack signal to the browser process.
+  void Stop();
+
+ private:
+  // Here TicketId is uint32_t, but a factory may issue more data by reusing id.
+  using TicketId = uint32_t;
+
+  class SharedMemoryReceivedData;
+  // Called by SharedMemoryReceivedData.
+  void Reclaim(TicketId id);
+
+  class TicketComparator;
+  friend class base::RefCounted<SharedMemoryReceivedDataFactory>;
+  ~SharedMemoryReceivedDataFactory();
+
+  void SendAck(size_t count);
+
+  TicketId id_;
+  TicketId oldest_;
+  std::vector<TicketId> released_tickets_;
+  // We assume that |message_sender_| is valid until |Stop| is called.
+  IPC::Sender* message_sender_;
+  int request_id_;
+  bool is_stopped_;
+  // Just to keep the payload alive while issued data is alive.
+  linked_ptr<base::SharedMemory> memory_;
+
+  DISALLOW_COPY_AND_ASSIGN(SharedMemoryReceivedDataFactory);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_CHILD_SHARED_MEMORY_RECEIVED_DATA_FACTORY_H_