Land Recent QUIC Changes.

net/quic/quic_flow_controller.h

+// Copyright (c) 2014 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 NET_QUIC_QUIC_FLOW_CONTROLLER_H_
+#define NET_QUIC_QUIC_FLOW_CONTROLLER_H_
+
+#include "base/basictypes.h"
+#include "net/base/net_export.h"
+#include "net/quic/quic_protocol.h"
+
+namespace net {
+
+namespace test {
+class QuicFlowControllerPeer;
+}  // namespace test
+
+class QuicConnection;
+
+// QuicFlowController allows a QUIC stream or connection to perform flow
+// control. The stream/connection owns a QuicFlowController which keeps track of
+// bytes sent/received, can tell the owner if it is flow control blocked, and
+// can send WINDOW_UPDATE or BLOCKED frames when needed.
+class NET_EXPORT_PRIVATE QuicFlowController {
+ public:
+  QuicFlowController(QuicStreamId id,
+                     bool is_server,
+                     uint64 send_window_offset,
+                     uint64 receive_window_offset,
+                     uint64 max_receive_window);
+  ~QuicFlowController() {}
+
+  // Called when bytes are received from the peer, and buffered.
+  void AddBytesBuffered(uint64 bytes_buffered);
+
+  // Called when bytes currently buffered locally, are removed from the buffer.
+  void RemoveBytesBuffered(uint64 bytes_buffered);
+
+  // Called when bytes received from the peer are consumed locally.
+  void AddBytesConsumed(uint64 bytes_consumed);
+
+  // Called when bytes are sent to the peer.
+  void AddBytesSent(uint64 bytes_sent);
+
+  // Set a new send window offset.
+  // Returns true if this changes send_window_offset_, and false in the case
+  // where |new_send_window| is <= send_window_offset_.
+  bool UpdateSendWindowOffset(uint64 new_send_window_offset);
+
+  // Returns the current available send window.
+  uint64 SendWindowSize() const;
+
+  // Send a BLOCKED frame on |connection| if appropriate.
+  void MaybeSendBlocked(QuicConnection* connection);
+
+  // Send a WINDOW_UPDATE frame on |connection| if appropriate.
+  void MaybeSendWindowUpdate(QuicConnection* connection);
+
+  // Disable flow control.
+  void Disable();
+
+  // Returns true if flow control is enabled.
+  bool IsEnabled() const;
+
+  // Returns true if flow control send limits have been reached.
+  bool IsBlocked() const;
+
+  // Returns true if flow control receive limits have been violated by the peer.
+  bool FlowControlViolation();
+
+ private:
+  friend class test::QuicFlowControllerPeer;
+
+  // Total received bytes is the sum of bytes buffered, and bytes consumed.
+  uint64 TotalReceivedBytes() const;
+
+  // ID of stream this flow controller belongs to. This can be 0 if this is a
+  // connection level flow controller.
+  QuicStreamId id_;
+
+  // True if flow control is enabled.
+  bool is_enabled_;
+
+  // True if this is owned by a server.
+  bool is_server_;
+
+  // Track number of bytes received from the peer, which have been consumed
+  // locally.
+  uint64 bytes_consumed_;
+
+  // Tracks number of bytes received from the peer, and buffered locally.
+  uint64 bytes_buffered_;
+
+  // Tracks number of bytes sent to the peer.
+  uint64 bytes_sent_;
+
+  // The absolute offset in the outgoing byte stream. If this offset is reached
+  // then we become flow control blocked until we receive a WINDOW_UPDATE.
+  uint64 send_window_offset_;
+
+  // The absolute offset in the incoming byte stream. The peer should never send
+  // us bytes which are beyond this offset.
+  uint64 receive_window_offset_;
+
+  // Largest size the receive window can grow to.
+  uint64 max_receive_window_;
+
+  DISALLOW_COPY_AND_ASSIGN(QuicFlowController);
+};
+
+}  // namespace net
+
+#endif  // NET_QUIC_QUIC_FLOW_CONTROLLER_H_