merge(3p/glog): Vendor glog from commit 'afe04691'

third_party/glog/src/base/commandlineflags.h

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+// 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__