ceph/src/include/counter.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3 /*
   4  * Ceph - scalable distributed file system
   5  *
   6  * Copyright (C) 2017 Red Hat, Inc.
   7  *
   8  * This is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License version 2.1, as published by the Free Software
  11  * Foundation.  See file COPYING.
  12  *
  13  */
  14
  15 #ifndef CEPH_COUNTER_H
  16 #define CEPH_COUNTER_H
  17
  18 template <typename T>
  19 class Counter {
  20 public:
  21   Counter() {
  22     _count()++;
  23     _increments()++;
  24   }
  25   Counter(const Counter &rhs) {
  26     _count()++;
  27     _increments()++;
  28   }
  29   Counter(Counter &&rhs) {}
  30   ~Counter() {
  31     _count()--;
  32   }
  33   static unsigned long count() {
  34     return _count();
  35   }
  36   static unsigned long increments() {
  37     return _increments();
  38   }
  39   static unsigned long decrements() {
  40     return increments()-count();
  41   }
  42
  43 private:
  44   static unsigned long &_count() {
  45     static unsigned long c;
  46     return c;
  47   }
  48   static unsigned long &_increments() {
  49     static unsigned long i;
  50     return i;
  51   }
  52 };
  53
  54 #endif