Land recent QUIC changes.

net/quic/quic_packet_generator.h

+// Copyright (c) 2012 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.
+//
+// Responsible for generating packets on behalf of a QuicConnection.
+// Packets are serialized just-in-time.  Control frame are queued.
+// Ack and Feedback frames will requested from the Connection
+// just-in-time.  When a packet needs to be sent, the Generator
+// wills serialized a packet pass it to  QuicConnection::SendOrQueuePacket()
+//
+// The Generator's mode of operation is controlled by two conditions:
+//
+// 1) Is the Delegate writable?
+//
+// If the Delegate is not writable, then no operations will cause
+// a packet to be serialized.  In particular:
+// * SetShouldSendAck will simply record that an ack is to be send.
+// * AddControlFram will enqueue the control frame.
+// * ConsumeData will do nothing.
+//
+// If the Delegate is writable, then the behavior depends on the second
+// condition:
+//
+// 2) Is the Generator in batch mode?
+//
+// If the Generator is NOT in batch mode, then each call to a write
+// operation will serialize one or more packets.  The contents will
+// include any previous queued frames.  If an ack should be sent
+// but has not been sent, then the Delegate will be asked to create
+// an Ack frame which will then be included in the packet.  When
+// the write call completes, the current packet will be serialized
+// and sent to the Delegate, even if it is not full.
+//
+// If the Generator is in batch mode, then each write operation will
+// add data to the "current" packet.  When the current packet becomes
+// full, it will be serialized and sent to the packet.  When batch
+// mode is ended via |FinishBatchOperations|, the current packet
+// will be serialzied, even if it is not full.
+//
+// FEC behavior also depends on batch mode.  In batch mode, FEC packets
+// will be sent after |max_packets_per_group| have been sent, as well
+// as after batch operations are complete.  When not in batch mode,
+// an FEC packet will be sent after each write call completes.
+//
+// TODO(rch): This behavior should probably be tuned.  When not in batch
+// mode we, should probably set a timer so that several independent
+// operations can be grouped into the same FEC group.
+//
+// When an FEC packet is generate, it will be send to the Delegate,
+// even if the Delegate has become unwritable after handling the
+// data packet immediately proceeding the FEC packet.
+
+#ifndef NET_QUIC_QUIC_PACKET_GENERATOR_H_
+#define NET_QUIC_QUIC_PACKET_GENERATOR_H_
+
+#include "net/quic/quic_packet_creator.h"
+
+namespace net {
+
+class NET_EXPORT_PRIVATE QuicPacketGenerator {
+ public:
+  class NET_EXPORT_PRIVATE DelegateInterface {
+   public:
+    virtual ~DelegateInterface() {}
+    virtual bool CanWrite(bool is_retransmission) = 0;
+    virtual QuicAckFrame* CreateAckFrame() = 0;
+    virtual QuicCongestionFeedbackFrame* CreateFeedbackFrame() = 0;
+    // Takes ownership of |packet.packet| and |packet.retransmittable_frames|.
+    virtual bool OnSerializedPacket(const SerializedPacket& packet) = 0;
+  };
+
+  QuicPacketGenerator(DelegateInterface* delegate,
+                      QuicPacketCreator* creator);
+
+  virtual ~QuicPacketGenerator();
+
+  void SetShouldSendAck(bool also_send_feedback);
+  void AddControlFrame(const QuicFrame& frame);
+  QuicConsumedData ConsumeData(QuicStreamId id,
+                               base::StringPiece data,
+                               QuicStreamOffset offset,
+                               bool fin);
+
+  // Disables flushing.
+  void StartBatchOperations();
+  // Enables flushing and flushes queued data.
+  void FinishBatchOperations();
+
+  bool HasQueuedData() const;
+
+ private:
+  // Must be called when the connection is writable
+  // and not blocked by the congestion manager.
+  void SendQueuedData();
+
+  bool HasPendingData() const;
+  bool AddNextPendingFrame();
+  void SerializeAndSendPacket();
+
+  DelegateInterface* delegate_;
+
+  QuicPacketCreator* packet_creator_;
+  QuicFrames queued_control_frames_;
+  bool should_flush_;
+  bool should_send_ack_;
+  scoped_ptr<QuicAckFrame> pending_ack_frame_;
+  scoped_ptr<QuicCongestionFeedbackFrame> pending_feedback_frame_;
+  bool should_send_feedback_;
+};
+
+}  // namespace net
+
+#endif  // NET_QUIC_QUIC_PACKET_GENERATOR_H_