// Copyright (c) 2008, 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

// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

// 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 "config.h"

#include <string>

#include <string.h>               // for memchr

#include <stdlib.h>               // for getenv

#ifdef HAVE_LIB_GFLAGS

#include <gflags/gflags.h>

#else

#include "glog/logging.h"

#define DECLARE_VARIABLE(type, shorttype, name, tn)                     \

  namespace fL##shorttype {                                             \

    extern GOOGLE_GLOG_DLL_DECL type FLAGS_##name;                      \

  }                                                                     \

  using fL##shorttype::FLAGS_##name

#define DEFINE_VARIABLE(type, shorttype, name, value, meaning, tn)      \

  namespace fL##shorttype {                                             \

    GOOGLE_GLOG_DLL_DECL type FLAGS_##name(value);                      \

    char FLAGS_no##name;                                                \

  }                                                                     \

  using fL##shorttype::FLAGS_##name

// bool specialization

#define DECLARE_bool(name) \

  DECLARE_VARIABLE(bool, B, name, bool)

#define DEFINE_bool(name, value, meaning) \

  DEFINE_VARIABLE(bool, B, name, value, meaning, bool)

// int32 specialization

#define DECLARE_int32(name) \

  DECLARE_VARIABLE(GOOGLE_NAMESPACE::int32, I, name, int32)

#define DEFINE_int32(name, value, meaning) \

  DEFINE_VARIABLE(GOOGLE_NAMESPACE::int32, I, name, value, meaning, int32)

// 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 fLS {                                                       \

    extern GOOGLE_GLOG_DLL_DECL std::string& FLAGS_##name;              \

  }                                                                     \

  using fLS::FLAGS_##name

#define DEFINE_string(name, value, meaning)                             \

  namespace fLS {                                                       \

    std::string FLAGS_##name##_buf(value);                              \

    GOOGLE_GLOG_DLL_DECL std::string& FLAGS_##name = FLAGS_##name##_buf; \

    char FLAGS_no##name;                                                \

  }                                                                     \

  using fLS::FLAGS_##name

#endif  // HAVE_LIB_GFLAGS

// Define GLOG_DEFINE_* using DEFINE_* . By using these macros, we

// have GLOG_* environ variables even if we have gflags installed.

//

// If both an environment variable and a flag are specified, the value

// specified by a flag wins. E.g., if GLOG_v=0 and --v=1, the

// verbosity will be 1, not 0.

#define GLOG_DEFINE_bool(name, value, meaning) \

  DEFINE_bool(name, EnvToBool("GLOG_" #name, value), meaning)

#define GLOG_DEFINE_int32(name, value, meaning) \

  DEFINE_int32(name, EnvToInt("GLOG_" #name, value), meaning)

#define GLOG_DEFINE_string(name, value, meaning) \

  DEFINE_string(name, EnvToString("GLOG_" #name, value), meaning)

// These macros (could be functions, but I don't want to bother with a .cc

// file), make it easier to initialize flags from the environment.

#define EnvToString(envname, dflt)   \

  (!getenv(envname) ? (dflt) : getenv(envname))

#define EnvToBool(envname, dflt)   \

  (!getenv(envname) ? (dflt) : memchr("tTyY1\0", getenv(envname)[0], 6) != NULL)

#define EnvToInt(envname, dflt)  \

  (!getenv(envname) ? (dflt) : strtol(getenv(envname), NULL, 10))

#endif  // BASE_COMMANDLINEFLAGS_H__