2017

[folly.git] / folly / portability / GFlags.h

diff --git a/folly/portability/GFlags.h b/folly/portability/GFlags.h
index 3bbcf1193b10e289b3986b61bc8c7065e6369fb5..48bd125da73655fe1cd5b478c71369f7cf68c26b 100644 (file)
--- a/folly/portability/GFlags.h
+++ b/folly/portability/GFlags.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,30 +16,53 @@
 
 #pragma once
 
-#include <folly/Portability.h>
+#include <folly/portability/Config.h>
+
+#if !FOLLY_HAVE_LIBGFLAGS
+// glog/logging.h is dependent on this implementation detail
+// being defined otherwise it undefines all of this -_-....
+//
+// Also, this is deliberately expanded such that places using
+// it directly break loudly. (C will break louder than C++, but oh well)
+#define DECLARE_VARIABLE() \
+  static_assert(false, "You shouldn't be using GFlags internals.");
+
+#define FOLLY_DECLARE_FLAG(_type, _shortType, _name) \
+  namespace fL##_shortType {                         \
+    extern _type FLAGS_##_name;                      \
+  }                                                  \
+  using fL##_shortType::FLAGS_##_name
+
+#define DECLARE_bool(_name) FOLLY_DECLARE_FLAG(bool, B, _name)
+#define DECLARE_double(_name) FOLLY_DECLARE_FLAG(double, D, _name)
+#define DECLARE_int32(_name) FOLLY_DECLARE_FLAG(int, I, _name)
+#define DECLARE_int64(_name) FOLLY_DECLARE_FLAG(long long, I64, _name)
+#define DECLARE_uint64(_name) FOLLY_DECLARE_FLAG(unsigned long long, U64, _name)
+#define DECLARE_string(_name) FOLLY_DECLARE_FLAG(std::string, S, _name)
+
+#define FOLLY_DEFINE_FLAG(_type, _shortType, _name, _default) \
+  namespace fL##_shortType {                                  \
+    _type FLAGS_##_name = _default;                           \
+  }                                                           \
+  using fL##_shortType::FLAGS_##_name
 
-#if FOLLY_HAVE_LIBGFLAGS
-#include <gflags/gflags.h>
-#else
-#define FOLLY_DECLARE_FLAG(_type, _name) extern _type FLAGS_##_name
-#define DECLARE_bool(_name) FOLLY_DECLARE_FLAG(bool, _name)
-#define DECLARE_double(_name) FOLLY_DECLARE_FLAG(double, _name)
-#define DECLARE_int32(_name) FOLLY_DECLARE_FLAG(int, _name)
-#define DECLARE_int64(_name) FOLLY_DECLARE_FLAG(long long, _name)
-#define DECLARE_uint64(_name) FOLLY_DECLARE_FLAG(unsigned long long, _name)
-#define DECLARE_string(_name) FOLLY_DECLARE_FLAG(std::string, _name)
-
-#define FOLLY_DEFINE_FLAG(_type, _name, _default) _type FLAGS_##_name = _default
 #define DEFINE_bool(_name, _default, _description) \
-  FOLLY_DEFINE_FLAG(bool, _name, _default)
+  FOLLY_DEFINE_FLAG(bool, B, _name, _default)
 #define DEFINE_double(_name, _default, _description) \
-  FOLLY_DEFINE_FLAG(double, _name, _default)
+  FOLLY_DEFINE_FLAG(double, D, _name, _default)
 #define DEFINE_int32(_name, _default, _description) \
-  FOLLY_DEFINE_FLAG(int, _name, _default)
+  FOLLY_DEFINE_FLAG(int, I, _name, _default)
 #define DEFINE_int64(_name, _default, _description) \
-  FOLLY_DEFINE_FLAG(long long, _name, _default)
+  FOLLY_DEFINE_FLAG(long long, I64, _name, _default)
 #define DEFINE_uint64(_name, _default, _description) \
-  FOLLY_DEFINE_FLAG(unsigned long long, _name, _default)
+  FOLLY_DEFINE_FLAG(unsigned long long, U64, _name, _default)
 #define DEFINE_string(_name, _default, _description) \
-  FOLLY_DEFINE_FLAG(std::string, _name, _default)
+  FOLLY_DEFINE_FLAG(std::string, S, _name, _default)
+
+namespace google {
+class FlagSaver {};
+}
+
+#else
+#include <gflags/gflags.h>
 #endif