ydb/contrib/deprecated/galloc/commandlineflags.h

// Copyright (c) 2005, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// ---
// This file is a compatibility layer that defines Google's version of
// command line flags that are used for configuration.
//
// We put flags into their own namespace.  It is purposefully
// named in an opaque way that people should have trouble typing
// directly.  The idea is that DEFINE puts the flag in the weird
// namespace, and DECLARE imports the flag from there into the
// current namespace.  The net result is to force people to use
// DECLARE to get access to a flag, rather than saying
//   extern bool FLAGS_logtostderr;
// or some such instead.  We want this so we can put extra
// functionality (like sanity-checking) in DECLARE if we want,
// and make sure it is picked up everywhere.
//
// We also put the type of the variable in the namespace, so that
// people can't DECLARE_int32 something that they DEFINE_bool'd
// elsewhere.
#ifndef BASE_COMMANDLINEFLAGS_H__
#define BASE_COMMANDLINEFLAGS_H__

#include <string>

#include "basictypes.h"

#define DECLARE_VARIABLE(type, name)                                          \
  namespace FLAG__namespace_do_not_use_directly_use_DECLARE_##type##_instead {  \
  extern type FLAGS_##name;                                                   \
  }                                                                           \
  using FLAG__namespace_do_not_use_directly_use_DECLARE_##type##_instead::FLAGS_##name

#define DEFINE_VARIABLE(type, name, value, meaning) \
  namespace FLAG__namespace_do_not_use_directly_use_DECLARE_##type##_instead {  \
  type FLAGS_##name(value);                                                   \
  char FLAGS_no##name;                                                        \
  }                                                                           \
  using FLAG__namespace_do_not_use_directly_use_DECLARE_##type##_instead::FLAGS_##name

// bool specialization
#define DECLARE_bool(name) \
  DECLARE_VARIABLE(bool, name)
#define DEFINE_bool(name, value, meaning) \
  DEFINE_VARIABLE(bool, name, value, meaning)

// int32 specialization
#define DECLARE_int32(name) \
  DECLARE_VARIABLE(int32, name)
#define DEFINE_int32(name, value, meaning) \
  DEFINE_VARIABLE(int32, name, value, meaning)

// int64 specialization
#define DECLARE_int64(name) \
  DECLARE_VARIABLE(int64, name)
#define DEFINE_int64(name, value, meaning) \
  DEFINE_VARIABLE(int64, name, value, meaning)

#define DECLARE_uint64(name) \
  DECLARE_VARIABLE(uint64, name)
#define DEFINE_uint64(name, value, meaning) \
  DEFINE_VARIABLE(uint64, name, value, meaning)

// double specialization
#define DECLARE_double(name) \
  DECLARE_VARIABLE(double, name)
#define DEFINE_double(name, value, meaning) \
  DEFINE_VARIABLE(double, name, value, meaning)

// Special case for string, because we have to specify the namespace
// std::string, which doesn't play nicely with our FLAG__namespace hackery.
#define DECLARE_string(name)                                          \
  namespace FLAG__namespace_do_not_use_directly_use_DECLARE_string_instead {  \
  extern std::string FLAGS_##name;                                                   \
  }                                                                           \
  using FLAG__namespace_do_not_use_directly_use_DECLARE_string_instead::FLAGS_##name
#define DEFINE_string(name, value, meaning) \
  namespace FLAG__namespace_do_not_use_directly_use_DECLARE_string_instead {  \
  std::string FLAGS_##name(value);                                                   \
  char FLAGS_no##name;                                                        \
  }                                                                           \
  using FLAG__namespace_do_not_use_directly_use_DECLARE_string_instead::FLAGS_##name

#endif  // BASE_COMMANDLINEFLAGS_H__