src/comm/AcceptLimiter.h

   1 #ifndef _SQUID_SRC_COMM_ACCEPT_LIMITER_H
   2 #define _SQUID_SRC_COMM_ACCEPT_LIMITER_H
   3
   4 #include "Array.h"
   5
   6 namespace Comm
   7 {
   8
   9 class TcpAcceptor;
  10
  11 /**
  12  * FIFO Queue holding listener socket handlers which have been activated
  13  * ready to dupe their FD and accept() a new client connection.
  14  * But when doing so there were not enough FD available to handle the
  15  * new connection. These handlers are awaiting some FD to become free.
  16  *
  17  * defer - used only by Comm layer ConnAcceptor adding themselves when FD are limited.
  18  * removeDead - used only by Comm layer ConnAcceptor to remove themselves when dying.
  19  * kick - used by Comm layer when FD are closed.
  20  */
  21 class AcceptLimiter
  22 {
  23
  24 public:
  25     /** retrieve the global instance of the queue. */
  26     static AcceptLimiter &Instance();
  27
  28     /** delay accepting a new client connection. */
  29     void defer(Comm::TcpAcceptor *afd);
  30
  31     /** remove all records of an acceptor. Only to be called by the ConnAcceptor::swanSong() */
  32     void removeDead(const Comm::TcpAcceptor *afd);
  33
  34     /** try to accept and begin processing any delayed client connections. */
  35     void kick();
  36
  37 private:
  38     static AcceptLimiter Instance_;
  39
  40     /** FIFO queue */
  41     Vector<Comm::TcpAcceptor*> deferred;
  42 };
  43
  44 }; // namepace Comm
  45
  46 #endif /* _SQUID_SRC_COMM_ACCEPT_LIMITER_H */