Implement P0430R2 - File system library on non-POSIX systems.

This patch implements P0430R2, who's largest change is adding the path::format
enumeration for supporting path format conversions in path constructors.

However, since libc++'s filesystem only really supports POSIX like systems,
there are no real changes needed. This patch simply adds the format enum
and then ignores it when it's passed to constructors.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@329031 91177308-0d34-0410-b5e6-96231b3b80d8

include/experimental/filesystem

@@ -721,24 +721,31 @@ public:
     typedef _VSTD::string_view __string_view;
     static _LIBCPP_CONSTEXPR value_type preferred_separator = '/';
 
+    enum class _LIBCPP_ENUM_VIS format : unsigned char {
+      auto_format,
+      native_format,
+      generic_format
+    };
+
     // constructors and destructor
     _LIBCPP_INLINE_VISIBILITY path() _NOEXCEPT {}
     _LIBCPP_INLINE_VISIBILITY path(const path& __p)      : __pn_(__p.__pn_) {}
     _LIBCPP_INLINE_VISIBILITY path(path&& __p) _NOEXCEPT : __pn_(_VSTD::move(__p.__pn_)) {}
 
     _LIBCPP_INLINE_VISIBILITY
-    path(string_type&& __s) _NOEXCEPT : __pn_(_VSTD::move(__s)) {}
+    path(string_type&& __s, format = format::auto_format) _NOEXCEPT
+        : __pn_(_VSTD::move(__s)) {}
 
     template <
         class _Source,
         class = _EnableIfPathable<_Source, void>
         >
-    path(const _Source& __src) {
+    path(const _Source& __src, format = format::auto_format) {
         _SourceCVT<_Source>::__append_source(__pn_, __src);
     }
 
     template <class _InputIt>
-    path(_InputIt __first, _InputIt __last) {
+    path(_InputIt __first, _InputIt __last, format = format::auto_format) {
         typedef typename iterator_traits<_InputIt>::value_type _ItVal;
         _PathCVT<_ItVal>::__append_range(__pn_, __first, __last);
     }
@@ -747,9 +754,11 @@ public:
     template <class _Source,
               class = _EnableIfPathable<_Source, void>
              >
-        path(const _Source& __src, const locale& __loc);
+        path(const _Source& __src, const locale& __loc,
+             format = format::auto_format);
     template <class _InputIt>
-        path(_InputIt __first, _InputIt _last, const locale& __loc);
+        path(_InputIt __first, _InputIt _last, const locale& __loc,
+             format = format::auto_format);
 
     _LIBCPP_INLINE_VISIBILITY
     ~path() = default;

test/std/experimental/filesystem/class.path/path.member/path.construct/source.pass.cpp

@@ -29,8 +29,8 @@
 #include "filesystem_test_helper.hpp"
 
 
-template <class CharT>
-void RunTestCase(MultiStringType const& MS) {
+template <class CharT, class ...Args>
+void RunTestCaseImpl(MultiStringType const& MS, Args... args) {
   using namespace fs;
   const char* Expect = MS;
   const CharT* TestPath = MS;
@@ -41,44 +41,52 @@ void RunTestCase(MultiStringType const& MS) {
   // StringTypes
   {
     const std::basic_string<CharT> S(TestPath);
-    path p(S);
+    path p(S, args...);
     assert(p.native() == Expect);
     assert(p.string<CharT>() == TestPath);
     assert(p.string<CharT>() == S);
   }
   {
     const std::basic_string_view<CharT> S(TestPath);
-    path p(S);
+    path p(S, args...);
     assert(p.native() == Expect);
     assert(p.string<CharT>() == TestPath);
     assert(p.string<CharT>() == S);
   }
   // Char* pointers
   {
-    path p(TestPath);
+    path p(TestPath, args...);
     assert(p.native() == Expect);
     assert(p.string<CharT>() == TestPath);
   }
   {
-    path p(TestPath, TestPathEnd);
+    path p(TestPath, TestPathEnd, args...);
     assert(p.native() == Expect);
     assert(p.string<CharT>() == TestPath);
   }
   // Iterators
   {
     using It = input_iterator<const CharT*>;
-    path p(It{TestPath});
+    path p(It{TestPath}, args...);
     assert(p.native() == Expect);
     assert(p.string<CharT>() == TestPath);
   }
   {
     using It = input_iterator<const CharT*>;
-    path p(It{TestPath}, It{TestPathEnd});
+    path p(It{TestPath}, It{TestPathEnd}, args...);
     assert(p.native() == Expect);
     assert(p.string<CharT>() == TestPath);
   }
 }
 
+template <class CharT, class ...Args>
+void RunTestCase(MultiStringType const& MS) {
+  RunTestCaseImpl<CharT>(MS);
+  RunTestCaseImpl<CharT>(MS, fs::path::format::auto_format);
+  RunTestCaseImpl<CharT>(MS, fs::path::format::native_format);
+  RunTestCaseImpl<CharT>(MS, fs::path::format::generic_format);
+}
+
 void test_sfinae() {
   using namespace fs;
   {

test/std/experimental/filesystem/fs.enum/enum.path.format.pass.cpp

@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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>
+
+// class path;
+// enum class format;
+
+#include "filesystem_include.hpp"
+#include <type_traits>
+#include <cassert>
+
+#include "test_macros.h"
+
+int main() {
+  typedef fs::path::format E;
+  static_assert(std::is_enum<E>::value, "");
+
+  // Check that E is a scoped enum by checking for conversions.
+  typedef std::underlying_type<E>::type UT;
+  static_assert(!std::is_convertible<E, UT>::value, "");
+
+  LIBCPP_ONLY(static_assert(std::is_same<UT, unsigned char>::value, "")); // Implementation detail
+
+  static_assert(
+          E::auto_format   != E::native_format &&
+          E::auto_format   != E::generic_format &&
+          E::native_format != E::generic_format,
+        "Expected enumeration values are not unique");
+}

www/cxx1z_status.html

@@ -149,7 +149,7 @@
 	<tr><td><a href="https://wg21.link/P0270R3">P0270R3</a></td><td>CWG</td><td>Removing C dependencies from signal handler wording</td><td>Kona</td><td></td><td></td></tr>
 	<tr><td><a href="https://wg21.link/P0298R3">P0298R3</a></td><td>CWG</td><td>A byte type definition</td><td>Kona</td><td>Complete</td><td>5.0</td></tr>
 	<tr><td><a href="https://wg21.link/P0317R1">P0317R1</a></td><td>LWG</td><td>Directory Entry Caching for Filesystem</td><td>Kona</td><td></td><td></td></tr>
-	<tr><td><a href="https://wg21.link/P0430R2">P0430R2</a></td><td>LWG</td><td>File system library on non-POSIX-like operating systems</td><td>Kona</td><td></td><td></td></tr>
+	<tr><td><a href="https://wg21.link/P0430R2">P0430R2</a></td><td>LWG</td><td>File system library on non-POSIX-like operating systems</td><td>Kona</td><td>Complete</td><td>7.0</td></tr>
 	<tr><td><a href="https://wg21.link/P0433R2">P0433R2</a></td><td>LWG</td><td>Toward a resolution of US7 and US14: Integrating template deduction for class templates into the standard library</td><td>Kona</td><td><i>In progress</i></td><td>7.0</td></tr>
 	<tr><td><a href="https://wg21.link/P0452R1">P0452R1</a></td><td>LWG</td><td>Unifying &lt;numeric&gt; Parallel Algorithms</td><td>Kona</td><td></td><td></td></tr>
 	<tr><td><a href="https://wg21.link/P0467R2">P0467R2</a></td><td>LWG</td><td>Iterator Concerns for Parallel Algorithms</td><td>Kona</td><td></td><td></td></tr>