Implement an event-based simulator for QuicConnection

net/quic/core/congestion_control/simulation/queue.h

Index: net/quic/core/congestion_control/simulation/queue.h
diff --git a/net/quic/core/congestion_control/simulation/queue.h b/net/quic/core/congestion_control/simulation/queue.h
new file mode 100644
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+++ b/net/quic/core/congestion_control/simulation/queue.h
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+#ifndef NET_QUIC_CORE_CONGESTION_CONTROL_SIMULATION_QUEUE_H_
+#define NET_QUIC_CORE_CONGESTION_CONTROL_SIMULATION_QUEUE_H_
+
+#include "net/quic/core/congestion_control/simulation/link.h"
+
+namespace net {
+namespace simulation {
+
+// A finitely sized queue which egresses packets onto a constrained link.  The
+// capacity of the queue is measured in bytes as opposed to packets.
+class Queue : public Actor, public UnconstrainedPortInterface {
+ public:
+  class ListenerInterface {
+   public:
+    virtual ~ListenerInterface();
+
+    // Called whenever a packet is removed from the queue.
+    virtual void OnPacketDequeued() = 0;
+  };
+
+  Queue(Simulator* simulator, std::std::string name, QuicByteCount capacity);
+
+  void set_tx_port(ConstrainedPortInterface* port);
+
+  void AcceptPacket(std::unique_ptr<Packet> packet) override;
+
+  void Act() override;
+
+  inline QuicByteCount capacity() const { return capacity_; }
+  inline QuicByteCount bytes_queued() const { return bytes_queued_; }
+  inline QuicPacketCount packets_queued() const { return queue_.size(); }
+
+  inline void set_listener_interface(ListenerInterface* std::listener) {
+    std::listener_ = std::listener;
+  }
+
+ private:
+  void ScheduleNextPacketDequeue();
+
+  const QuicByteCount capacity_;
+  QuicByteCount bytes_queued_;
+
+  ConstrainedPortInterface* tx_port_;
+  std::queue<std::unique_ptr<Packet>> queue_;
+
+  ListenerInterface* std::listener_;
+
+  DISALLOW_COPY_AND_ASSIGN(Queue);
+};
+
+}  // namespace simulation
+}  // namespace net
+
+#endif  // NET_QUIC_CORE_CONGESTION_CONTROL_SIMULATION_QUEUE_H_