Add Filesystem TS -- Complete

Add the completed std::experimental::filesystem implementation and tests.
The implementation supports C++11 or newer.

The TS is built as part of 'libc++experimental.a'. Users of the TS need to
manually link this library. Building and testing the TS can be disabled using
the CMake option '-DLIBCXX_ENABLE_FILESYSTEM=OFF'.

Currently 'libc++experimental.a' is not installed by default. To turn on the
installation of the library use '-DLIBCXX_INSTALL_EXPERIMENTAL_LIBRARY=ON'.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@273034 91177308-0d34-0410-b5e6-96231b3b80d8

test/libcxx/experimental/filesystem/class.path/path.req/is_pathable.pass.cpp

@@ -0,0 +1,101 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03
+
+// <experimental/filesystem>
+
+// template <class Tp> struct __is_pathable
+
+// [path.req]
+// In addition to the requirements (5), function template parameters named
+// `Source` shall be one of:
+// * basic_string<_ECharT, _Traits, _Alloc>
+// * InputIterator with a value_type of _ECharT
+// * A character array, which points to a NTCTS after array-to-pointer decay.
+
+
+#include <experimental/filesystem>
+#include <type_traits>
+#include <cassert>
+
+#include "test_macros.h"
+#include "test_iterators.h"
+#include "min_allocator.h"
+
+namespace fs = std::experimental::filesystem;
+
+using fs::__is_pathable;
+
+template <class Tp>
+struct Identity { typedef Tp type; };
+
+template <class Source>
+Identity<Source> CheckSourceType(Source const&);
+
+template <class Tp>
+using GetSourceType = typename decltype(CheckSourceType(std::declval<Tp>()))::type;
+
+template <class Tp, class Exp,
+          class ExpQual = typename std::remove_const<Exp>::type>
+using CheckPass = std::is_same<ExpQual, GetSourceType<Tp>>;
+
+template <class Source>
+using CheckPassSource = std::integral_constant<bool,
+        CheckPass<Source&,        Source>::value &&
+        CheckPass<Source const&,  Source>::value &&
+        CheckPass<Source&&,       Source>::value &&
+        CheckPass<Source const&&, Source>::value
+  >;
+
+template <class CharT>
+struct MakeTestType {
+  using value_type = CharT;
+  using string_type = std::basic_string<CharT>;
+  using string_type2 = std::basic_string<CharT, std::char_traits<CharT>, min_allocator<CharT>>;
+  using cstr_type = CharT* const;
+  using const_cstr_type = const CharT*;
+  using array_type = CharT[25];
+  using const_array_type = const CharT[25];
+  using iter_type = input_iterator<CharT*>;
+  using bad_iter_type = input_iterator<signed char*>;
+
+  template <class TestT>
+  static void AssertPathable() {
+    static_assert(__is_pathable<TestT>::value, "");
+    static_assert(CheckPassSource<TestT>::value, "cannot pass as Source const&");
+    ASSERT_SAME_TYPE(CharT, typename __is_pathable<TestT>::__char_type);
+  }
+
+  template <class TestT>
+  static void AssertNotPathable() {
+    static_assert(!__is_pathable<TestT>::value, "");
+  }
+
+  static void Test() {
+    AssertPathable<string_type>();
+    AssertPathable<string_type2>();
+    AssertPathable<cstr_type>();
+    AssertPathable<const_cstr_type>();
+    AssertPathable<array_type>();
+    AssertPathable<const_array_type>();
+    AssertPathable<iter_type>();
+
+    AssertNotPathable<CharT>();
+    AssertNotPathable<bad_iter_type>();
+    AssertNotPathable<signed char*>();
+  }
+};
+
+int main() {
+  MakeTestType<char>::Test();
+  MakeTestType<wchar_t>::Test();
+  MakeTestType<char16_t>::Test();
+  MakeTestType<char32_t>::Test();
+}

test/libcxx/experimental/filesystem/lit.local.cfg

@@ -0,0 +1,3 @@
+# Disable all of the filesystem tests if the correct feature is not available.
+if 'c++filesystem' not in config.available_features:
+  config.unsupported = True

test/libcxx/experimental/filesystem/version.pass.cpp

@@ -0,0 +1,22 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03
+
+// <experimental/filesystem>
+
+#include <experimental/filesystem>
+
+#ifndef _LIBCPP_VERSION
+#error _LIBCPP_VERSION not defined
+#endif
+
+int main()
+{
+}