Add a merely pass-through QuicMultipathSentPacketManager. Protected behind blocked flag FLAGS_quic_…

net/quic/quic_multipath_sent_packet_manager.h

Index: net/quic/quic_multipath_sent_packet_manager.h
diff --git a/net/quic/quic_multipath_sent_packet_manager.h b/net/quic/quic_multipath_sent_packet_manager.h
new file mode 100644
index 0000000000000000000000000000000000000000..8c2e9b95662f77b0ae44fffd238419606ac8521e
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+++ b/net/quic/quic_multipath_sent_packet_manager.h
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+#ifndef NET_QUIC_QUIC_MULTIPATH_SENT_PACKET_MANAGER_H_

[Zhongyi Shi, 2016/07/25 22:30:34]

Could you add chromium license to this new file?

+#define NET_QUIC_QUIC_MULTIPATH_SENT_PACKET_MANAGER_H_
+
+#include <vector>
+
+#include "net/base/net_export.h"
+#include "net/quic/quic_protocol.h"
+#include "net/quic/quic_sent_packet_manager.h"
+#include "net/quic/quic_sent_packet_manager_interface.h"
+
+namespace net {
+
+namespace test {
+class QuicConnectionPeer;
+class QuicMultipathSentPacketManagerPeer;
+}  // namespace test
+
+// A connection level sent packet manager which manages a sent packet manager
+// per path. The main duties of multipath sent packet manager comprise:
+// (1) manages a pending retransmission queue shared among all paths;
+// (2) records mapping of packets transmitted on different paths;
+// (3) consults paths which should timeout on a retransmission timeout.
+// TODO(fayang): Currently above duties are not fully implemented, need to
+// finish them.
+class NET_EXPORT_PRIVATE QuicMultipathSentPacketManager :
+      public QuicSentPacketManagerInterface {
+ public:
+  // Multipath sent packet manager takes ownership of |manager|.
+  explicit QuicMultipathSentPacketManager(
+      QuicSentPacketManagerInterface* manager,
+      QuicConnectionCloseDelegateInterface* delegate);
+  ~QuicMultipathSentPacketManager() override;
+
+  // Start implementation of QuicSentPacketManagerInterface.
+  // Sets all paths from |config|.
+  void SetFromConfig(const QuicConfig& config) override;
+
+  // Resumes connection state on the default path.
+  void ResumeConnectionState(
+      const CachedNetworkParameters& cached_network_params,
+      bool max_bandwidth_resumption) override;
+
+  // Sets number of active streams of all paths.
+  void SetNumOpenStreams(size_t num_streams) override;
+
+  // Sets max pacing rate of the default path.
+  void SetMaxPacingRate(QuicBandwidth max_pacing_rate) override;
+
+  void SetHandshakeConfirmed() override;
+
+  // Directs |ack_frame| to the appropriate path sent packet manager.
+  void OnIncomingAck(const QuicAckFrame& ack_frame,
+                     QuicTime ack_receive_time) override;
+
+  // Returns true if |packet_number| is unacked on path with |path_id|.
+  bool IsUnacked(QuicPathId path_id,
+                 QuicPacketNumber packet_number) const override;
+
+  // Returns true if |packet_number| on |path_id| is unacked and has
+  // retransmittable frames.
+  bool HasRetransmittableFrames(QuicPathId path_id,
+                                QuicPacketNumber packet_number) const override;
+
+  // Requests retransmission of all unacked packets of |retransmission_type| on
+  // the default path.
+  void RetransmitUnackedPackets(TransmissionType retransmission_type) override;
+
+  // Tries to retransmit the oldest pending packet across all paths. The
+  // retransmission is sent on the path that has a TLP timer pending.
+  bool MaybeRetransmitTailLossProbe() override;
+
+  // Removes the retransmittable frames from all unencrypted packets on the
+  // default path to ensure they don't get retransmitted.
+  void NeuterUnencryptedPackets() override;
+
+  // Returns true if there are pending retransmissions.
+  bool HasPendingRetransmissions() const override;
+
+  // Retrieves the next pending retransmission.  Caller must ensure that
+  // there are pending retransmissions prior to calling this function.
+  PendingRetransmission NextPendingRetransmission() override;
+
+  // Returns true if the any path has unacked packets.
+  bool HasUnackedPackets() const override;
+
+  // Returns the smallest packet number of a serialized packet which has not
+  // been acked on |path_id|.
+  QuicPacketNumber GetLeastUnacked(QuicPathId path_id) const override;
+
+  // Called when a packet has been sent to the peer. If this packet is a
+  // retransmission on a different path than the original packet, records the
+  // mapping in |transmissions_map_|. Retransmittable frames are transfered from
+  // original packet to the sent packet.
+  bool OnPacketSent(SerializedPacket* serialized_packet,
+                    QuicPathId original_path_id,
+                    QuicPacketNumber original_packet_number,
+                    QuicTime sent_time,
+                    TransmissionType transmission_type,
+                    HasRetransmittableData has_retransmittable_data) override;
+
+  // Called when the retransmission timer expires.
+  void OnRetransmissionTimeout() override;
+
+  // Returns the earliest time the next packet can be sent. Sets |path_id| to be
+  // the path on which the next packet should be sent.
+  QuicTime::Delta TimeUntilSend(QuicTime now,
+                                HasRetransmittableData retransmittable,
+                                QuicPathId* path_id) override;
+
+  // Returns the earliest retransmission time of all paths.
+  const QuicTime GetRetransmissionTime() const override;
+
+  // Returns the rtt stats of the default path.
+  const RttStats* GetRttStats() const override;
+
+  // Returns the estimated bandwidth on default path calculated by the
+  // congestion algorithm.
+  QuicBandwidth BandwidthEstimate() const override;
+
+  // Returns the sustained bandwidth recorder on the default path.
+  const QuicSustainedBandwidthRecorder* SustainedBandwidthRecorder()
+      const override;
+
+  // Returns the size of the current congestion window on default path in number
+  // of kDefaultTCPMSS-sized segments.
+  QuicPacketCount GetCongestionWindowInTcpMss() const override;
+
+  // Determines the number of packets of length |max_packet_length| which fit in
+  // the congestion windows for all paths, and returns the max number of packets
+  // across all paths.
+  QuicPacketCount EstimateMaxPacketsInFlight(
+      QuicByteCount max_packet_length) const override;
+
+  // Returns the size of the current congestion window size on the default path
+  // in bytes.
+  QuicByteCount GetCongestionWindowInBytes() const override;
+
+  // Returns the size of the slow start congestion window in number of 1460 byte
+  // TCP segments on the default path.
+  QuicPacketCount GetSlowStartThresholdInTcpMss() const override;
+
+  // No longer retransmit data for |stream_id| on all paths and any pending
+  // retransmissions in pending_retransmissions_.
+  void CancelRetransmissionsForStream(QuicStreamId stream_id) override;
+
+  void OnConnectionMigration(QuicPathId path_id,
+                             PeerAddressChangeType type) override;
+
+  bool IsHandshakeConfirmed() const override;
+
+  // Sets debug delegate for all active paths.
+  void SetDebugDelegate(DebugDelegate* debug_delegate) override;
+
+  QuicPacketNumber GetLargestObserved(QuicPathId path_id) const override;
+
+  QuicPacketNumber GetLargestSentPacket(QuicPathId path_id) const override;
+
+  QuicPacketNumber GetLeastPacketAwaitedByPeer(
+      QuicPathId path_id) const override;
+
+  // Sets network change visitor for all active paths.
+  void SetNetworkChangeVisitor(NetworkChangeVisitor* visitor) override;
+
+  // Returns true if the default path is in slow start.
+  bool InSlowStart() const override;
+
+  // These two methods return the consecutive RTO or TLP count of the default
+  // path.
+  size_t GetConsecutiveRtoCount() const override;
+  size_t GetConsecutiveTlpCount() const override;
+
+ private:
+  friend class test::QuicConnectionPeer;
+  friend class test::QuicMultipathSentPacketManagerPeer;
+
+  // State of per path sent packet manager.
+  // TODO(fayang): Need to add a state that path can receive acks but cannot
+  // send data.
+  enum PathSentPacketManagerState {
+    ACTIVE,   // We both send packets and receiving acks on this path.
+    CLOSING,  // We stop sending packets and receiving acks on this path. There
+              // are retransmittable frames in the unacked packets map.
+  };
+
+  // PathSentPacketManagerInfo contains sent packet manager and its state.
+  struct PathSentPacketManagerInfo {
+    PathSentPacketManagerInfo();
+    PathSentPacketManagerInfo(QuicSentPacketManagerInterface* manager,
+                              PathSentPacketManagerState state);
+    PathSentPacketManagerInfo(const PathSentPacketManagerInfo& other);
+
+    QuicSentPacketManagerInterface* manager;
+    PathSentPacketManagerState state;
+  };
+
+  // Returns path sent packet manager if it exists for |path_id|, returns
+  // nullptr otherwise.
+  QuicSentPacketManagerInterface* MaybeGetSentPacketManagerForPath(
+      QuicPathId path_id) const;
+
+  // Returns path sent packet manager if it exists and |path_id| is ACTIVE,
+  // returns nullptr otherwise.
+  QuicSentPacketManagerInterface* MaybeGetSentPacketManagerForActivePath(
+      QuicPathId path_id) const;
+
+  // Returns the path which has the earliest retransmission time.
+  QuicPathId DetermineRetransmissionTimeoutPath() const;
+
+  // Close the connection on unrecoverable path errors.
+  void OnUnrecoverablePathError(QuicPathId path_id);
+
+  // Current path sent packet managers info, index is path id.
+  std::vector<PathSentPacketManagerInfo> path_managers_info_;
+
+  // Does not own this delegate.
+  QuicConnectionCloseDelegateInterface* delegate_;
+
+  DISALLOW_COPY_AND_ASSIGN(QuicMultipathSentPacketManager);
+};
+
+}  // namespace net
+
+#endif  // NET_QUIC_QUIC_MULTIPATH_SENT_PACKET_MANAGER_H_