Copyright 2013 -> 2014

[folly.git] / folly / Portability.h

diff --git a/folly/Portability.h b/folly/Portability.h
index 14b7c5b081c5178e67f542761597b19796018a4b..b227ba0da9ecf2f9018b7481bb67f870ab584c9a 100644 (file)
--- a/folly/Portability.h
+++ b/folly/Portability.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 Facebook, Inc.
+ * Copyright 2014 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,47 +17,117 @@
 #ifndef FOLLY_PORTABILITY_H_
 #define FOLLY_PORTABILITY_H_
 
+#ifndef FOLLY_NO_CONFIG
 #include "folly-config.h"
+#endif
+
+#if FOLLY_HAVE_FEATURES_H
+#include <features.h>
+#endif
 
-#ifdef FOLLY_HAVE_SCHED_H
+#include "CPortability.h"
+
+#if FOLLY_HAVE_SCHED_H
  #include <sched.h>
  #ifndef FOLLY_HAVE_PTHREAD_YIELD
   #define pthread_yield sched_yield
  #endif
 #endif
 
-// Define macro wrappers for C++11's "final" and "override" keywords, which
-// are supported in gcc 4.7 but not gcc 4.6.
-//
-// TODO(tudorb/agallagher): Autotoolize this.
-#undef FOLLY_FINAL
-#undef FOLLY_OVERRIDE
 
-#if defined(__clang__)
-#  define FOLLY_FINAL final
-#  define FOLLY_OVERRIDE override
-#elif defined(__GNUC__)
-# include <features.h>
-# if __GNUC_PREREQ(4,7)
+// MaxAlign: max_align_t isn't supported by gcc
+#ifdef __GNUC__
+struct MaxAlign { char c; } __attribute__((aligned));
+#else /* !__GNUC__ */
+# error Cannot define MaxAlign on this platform
+#endif
+
+
+// noreturn
+#if defined(__clang__) || defined(__GNUC__)
+# define FOLLY_NORETURN __attribute__((noreturn))
+#else
+# define FOLLY_NORETURN
+#endif
+
+
+// portable version check
+#ifndef __GNUC_PREREQ
+# if defined __GNUC__ && defined __GNUC_MINOR__
+#  define __GNUC_PREREQ(maj, min) ((__GNUC__ << 16) + __GNUC_MINOR__ >= \
+                                   ((maj) << 16) + (min))
+# else
+#  define __GNUC_PREREQ(maj, min) 0
+# endif
+#endif
+
+
+/* Define macro wrappers for C++11's "final" and "override" keywords, which
+ * are supported in gcc 4.7 but not gcc 4.6. */
+#if !defined(FOLLY_FINAL) && !defined(FOLLY_OVERRIDE)
+# if defined(__clang__) || __GNUC_PREREQ(4, 7)
 #  define FOLLY_FINAL final
 #  define FOLLY_OVERRIDE override
+# else
+#  define FOLLY_FINAL /**/
+#  define FOLLY_OVERRIDE /**/
 # endif
 #endif
 
-#ifndef FOLLY_FINAL
-# define FOLLY_FINAL
+
+// Define to 1 if you have the `preadv' and `pwritev' functions, respectively
+#if !defined(FOLLY_HAVE_PREADV) && !defined(FOLLY_HAVE_PWRITEV)
+# if defined(__GLIBC_PREREQ)
+#  if __GLIBC_PREREQ(2, 10)
+#   define FOLLY_HAVE_PREADV 1
+#   define FOLLY_HAVE_PWRITEV 1
+#  endif
+# endif
 #endif
 
-#ifndef FOLLY_OVERRIDE
-# define FOLLY_OVERRIDE
+// It turns out that GNU libstdc++ and LLVM libc++ differ on how they implement
+// the 'std' namespace; the latter uses inline namepsaces. Wrap this decision
+// up in a macro to make forward-declarations easier.
+#if FOLLY_USE_LIBCPP
+#define FOLLY_NAMESPACE_STD_BEGIN     _LIBCPP_BEGIN_NAMESPACE_STD
+#define FOLLY_NAMESPACE_STD_END       _LIBCPP_END_NAMESPACE_STD
+#else
+#define FOLLY_NAMESPACE_STD_BEGIN     namespace std {
+#define FOLLY_NAMESPACE_STD_END       }
 #endif
 
+// Some platforms lack clock_gettime(2) and clock_getres(2). Inject our own
+// versions of these into the global namespace.
+#if FOLLY_HAVE_CLOCK_GETTIME
+#include <time.h>
+#else
+#include "folly/detail/Clock.h"
+#endif
 
-// MaxAlign: max_align_t isn't supported by gcc
-#ifdef __GNUC__
-struct MaxAlign { char c; } __attribute__((aligned));
-#else /* !__GNUC__ */
-# error Cannot define MaxAlign on this platform
+// Provide our own std::__throw_* wrappers for platforms that don't have them
+#if FOLLY_HAVE_BITS_FUNCTEXCEPT_H
+#include <bits/functexcept.h>
+#else
+#include "folly/detail/FunctionalExcept.h"
+#endif
+
+#if defined(__cplusplus)
+// Unfortunately, boost::has_trivial_copy<T> is broken in libc++ due to its
+// usage of __has_trivial_copy(), so we can't use it as a
+// least-common-denominator for C++11 implementations that don't support
+// std::is_trivially_copyable<T>.
+//
+//      http://stackoverflow.com/questions/12754886/has-trivial-copy-behaves-differently-in-clang-and-gcc-whos-right
+//
+// As a result, use std::is_trivially_copyable() where it exists, and fall back
+// to Boost otherwise.
+#if FOLLY_HAVE_STD__IS_TRIVIALLY_COPYABLE
+#include <type_traits>
+#define FOLLY_IS_TRIVIALLY_COPYABLE(T)      (std::is_trivially_copyable<T>::value)
+#else
+#include <boost/type_traits.hpp>
+#define FOLLY_IS_TRIVIALLY_COPYABLE(T)      (boost::has_trivial_copy<T>::value)
 #endif
+#endif // __cplusplus
 
 #endif // FOLLY_PORTABILITY_H_