ceph/src/common/dout.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) 2004-2010 Sage Weil <sage@newdream.net>
   7  * Copyright (C) 2010 Dreamhost
   8  *
   9  * This is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License version 2.1, as published by the Free Software
  12  * Foundation.  See file COPYING.
  13  *
  14  */
  15
  16 #ifndef CEPH_DOUT_H
  17 #define CEPH_DOUT_H
  18
  19 #include <type_traits>
  20
  21 #include "global/global_context.h"
  22 #include "common/config.h"
  23 #include "common/likely.h"
  24 #include "common/Clock.h"
  25 #include "log/Log.h"
  26
  27 extern void dout_emergency(const char * const str);
  28 extern void dout_emergency(const std::string &str);
  29
  30 // intentionally conflict with endl
  31 class _bad_endl_use_dendl_t { public: _bad_endl_use_dendl_t(int) {} };
  32 static const _bad_endl_use_dendl_t endl = 0;
  33 inline std::ostream& operator<<(std::ostream& out, _bad_endl_use_dendl_t) {
  34   assert(0 && "you are using the wrong endl.. use std::endl or dendl");
  35   return out;
  36 }
  37
  38 class DoutPrefixProvider {
  39 public:
  40   virtual string gen_prefix() const = 0;
  41   virtual CephContext *get_cct() const = 0;
  42   virtual unsigned get_subsys() const = 0;
  43   virtual ~DoutPrefixProvider() {}
  44 };
  45
  46 // generic macros
  47 #define dout_prefix *_dout
  48
  49 #define dout_impl(cct, sub, v)                                          \
  50   do {                                                                  \
  51   if (cct->_conf->subsys.should_gather(sub, v)) {                       \
  52     if (0) {                                                            \
  53       char __array[((v >= -1) && (v <= 200)) ? 0 : -1] __attribute__((unused)); \
  54     }                                                                   \
  55     static size_t _log_exp_length = 80;                                 \
  56     ceph::logging::Entry *_dout_e = cct->_log->create_entry(v, sub, &_log_exp_length);  \
  57     ostream _dout_os(&_dout_e->m_streambuf);                            \
  58     static_assert(std::is_convertible<decltype(&*cct),                  \
  59                                       CephContext* >::value,            \
  60                   "provided cct must be compatible with CephContext*"); \
  61     auto _dout_cct = cct;                                               \
  62     std::ostream* _dout = &_dout_os;
  63
  64 #define lsubdout(cct, sub, v)  dout_impl(cct, ceph_subsys_##sub, v) dout_prefix
  65 #define ldout(cct, v)  dout_impl(cct, dout_subsys, v) dout_prefix
  66 #define lderr(cct) dout_impl(cct, ceph_subsys_, -1) dout_prefix
  67
  68 #define ldpp_dout(dpp, v) if (dpp) dout_impl(dpp->get_cct(), dpp->get_subsys(), v) (*_dout << dpp->gen_prefix())
  69
  70 #define lgeneric_subdout(cct, sub, v) dout_impl(cct, ceph_subsys_##sub, v) *_dout
  71 #define lgeneric_dout(cct, v) dout_impl(cct, ceph_subsys_, v) *_dout
  72 #define lgeneric_derr(cct) dout_impl(cct, ceph_subsys_, -1) *_dout
  73
  74 #define ldlog_p1(cct, sub, lvl)                 \
  75   (cct->_conf->subsys.should_gather((sub), (lvl)))
  76
  77 // NOTE: depend on magic value in _ASSERT_H so that we detect when
  78 // /usr/include/assert.h clobbers our fancier version.
  79 #define dendl_impl std::flush;                          \
  80   _ASSERT_H->_log->submit_entry(_dout_e);               \
  81     }                                           \
  82   } while (0)
  83
  84 #define dendl dendl_impl
  85
  86 #endif