[gcc r8-10392] libstdc++: Fix path::generic_string allocator handling (PR 94242)

Jonathan Wakely redi@gcc.gnu.org
Fri Aug 7 11:43:01 GMT 2020


https://gcc.gnu.org/g:39a5a04daa09c711caeb6aaff12f1d03406fe29f

commit r8-10392-g39a5a04daa09c711caeb6aaff12f1d03406fe29f
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Sat Mar 21 21:51:07 2020 +0000

    libstdc++: Fix path::generic_string allocator handling (PR 94242)
    
    It's not possible to construct a path::string_type from an allocator of
    a different type. Create the correct specialization of basic_string, and
    adjust path::_S_str_convert to use a basic_string_view so that it is
    independent of the allocator type.
    
            PR libstdc++/94242
            * include/bits/fs_path.h (path::_S_str_convert): Replace first
            parameter with basic_string_view so that strings with different
            allocators can be accepted.
            (path::generic_string<C,T,A>()): Use basic_string object that uses the
            right allocator type.
            * testsuite/27_io/filesystem/path/generic/94242.cc: New test.
            * testsuite/27_io/filesystem/path/generic/generic_string.cc: Improve
            test coverage.
    
    (cherry picked from commit 9fc985118d9f5014afc1caf32a411ee5803fba61)

Diff:
---
 libstdc++-v3/include/bits/fs_path.h                | 11 +++--
 .../27_io/filesystem/path/generic/94242.cc         | 53 ++++++++++++++++++++++
 .../filesystem/path/generic/generic_string.cc      | 35 ++++++++++++++
 3 files changed, 95 insertions(+), 4 deletions(-)

diff --git a/libstdc++-v3/include/bits/fs_path.h b/libstdc++-v3/include/bits/fs_path.h
index 7ae68f623d1..f121d82c032 100644
--- a/libstdc++-v3/include/bits/fs_path.h
+++ b/libstdc++-v3/include/bits/fs_path.h
@@ -477,7 +477,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
 
     template<typename _CharT, typename _Traits, typename _Allocator>
       static basic_string<_CharT, _Traits, _Allocator>
-      _S_str_convert(const string_type&, const _Allocator& __a);
+      _S_str_convert(basic_string_view<value_type>, const _Allocator&);
 
     static bool _S_is_dir_sep(value_type __ch)
     {
@@ -873,7 +873,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
 
   template<typename _CharT, typename _Traits, typename _Allocator>
     std::basic_string<_CharT, _Traits, _Allocator>
-    path::_S_str_convert(const string_type& __str, const _Allocator& __a)
+    path::_S_str_convert(basic_string_view<value_type> __str,
+			 const _Allocator& __a)
     {
       if (__str.size() == 0)
 	return std::basic_string<_CharT, _Traits, _Allocator>(__a);
@@ -971,7 +972,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
 #else
       const value_type __slash = '/';
 #endif
-      string_type __str(__a);
+      using _Alloc2 = typename allocator_traits<_Allocator>::template
+	rebind_alloc<value_type>;
+      basic_string<value_type, char_traits<value_type>, _Alloc2> __str(__a);
 
       if (_M_type == _Type::_Root_dir)
 	__str.assign(1, __slash);
@@ -983,7 +986,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
 	    {
 	      if (__add_slash)
 		__str += __slash;
-	      __str += __elem._M_pathname;
+	      __str += basic_string_view<value_type>(__elem._M_pathname);
 	      __add_slash = __elem._M_type == _Type::_Filename;
 	    }
 	}
diff --git a/libstdc++-v3/testsuite/27_io/filesystem/path/generic/94242.cc b/libstdc++-v3/testsuite/27_io/filesystem/path/generic/94242.cc
new file mode 100644
index 00000000000..4bb32f83867
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/filesystem/path/generic/94242.cc
@@ -0,0 +1,53 @@
+// { dg-options "-std=gnu++17 -lstdc++fs" }
+// { dg-do run { target c++17 } }
+// { dg-require-filesystem-ts "" }
+
+// Copyright (C) 2020 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// C++17 30.10.7.4.7 path generic format observers [fs.path.generic.obs]
+
+#include <filesystem>
+#include <testsuite_allocator.h>
+
+using std::filesystem::path;
+using __gnu_test::SimpleAllocator;
+
+void
+test01()
+{
+  path p = "//foo//bar//.";
+  using C = path::value_type;
+  auto g = p.generic_string<C, std::char_traits<C>, SimpleAllocator<C>>();
+  VERIFY( g == path("/foo/bar/.").c_str() );
+}
+
+void
+test02()
+{
+  path p = "//foo//bar//.";
+  using C = char16_t;
+  auto g = p.generic_string<C, std::char_traits<C>, SimpleAllocator<C>>();
+  VERIFY( g == u"/foo/bar/." );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+}
diff --git a/libstdc++-v3/testsuite/27_io/filesystem/path/generic/generic_string.cc b/libstdc++-v3/testsuite/27_io/filesystem/path/generic/generic_string.cc
index 16335443c76..c813987ca42 100644
--- a/libstdc++-v3/testsuite/27_io/filesystem/path/generic/generic_string.cc
+++ b/libstdc++-v3/testsuite/27_io/filesystem/path/generic/generic_string.cc
@@ -22,6 +22,7 @@
 // C++17 30.10.7.4.7 path generic format observers [fs.path.generic.obs]
 
 #include <filesystem>
+#include <testsuite_fs.h>
 #include <testsuite_hooks.h>
 
 using std::filesystem::path;
@@ -35,11 +36,15 @@ test01()
 #ifdef __CYGWIN__
   VERIFY( path("//a").generic_string() == "//a" );
   VERIFY( path("//a/").generic_string() == "//a/" );
+  VERIFY( path("//a//").generic_string() == "//a/" );
   VERIFY( path("//a/b").generic_string() == "//a/b" );
+  VERIFY( path("//a//b").generic_string() == "//a/b" );
 #else
   VERIFY( path("//a").generic_string() == "/a" );
   VERIFY( path("//a/").generic_string() == "/a/" );
+  VERIFY( path("//a//").generic_string() == "/a/" );
   VERIFY( path("//a/b").generic_string() == "/a/b" );
+  VERIFY( path("//a//b").generic_string() == "/a/b" );
 #endif
   VERIFY( path("/a//b").generic_string() == "/a/b" );
   VERIFY( path("/a//b/").generic_string() == "/a/b/" );
@@ -47,8 +52,38 @@ test01()
   VERIFY( path("/a//b//.").generic_string() == "/a/b/." );
 }
 
+void
+test02()
+{
+  if constexpr (path::preferred_separator == L'\\')
+  {
+    // PR libstdc++/93244
+    VERIFY( path("C:\\foo\\bar").generic_string() == "C:/foo/bar" );
+    VERIFY( path("C://foo//bar").generic_string() == "C:/foo/bar" );
+  }
+}
+
+void
+test03()
+{
+  for (path p : { "a///b//c", "/a//b//c", "a:b//c" })
+  {
+    // A path constructed from the generic format string should compare equal
+    // to the original, because they represent the same path.
+    // For GCC 8 this only works for some paths, because LWG 2936 is not
+    // implemented on the branch, so e.g. "/" and "//" compare not equal
+    VERIFY( path(p.generic_string()) == p );
+    VERIFY( path(p.generic_wstring()) == p );
+    VERIFY( path(p.generic_u8string()) == p );
+    VERIFY( path(p.generic_u16string()) == p );
+    VERIFY( path(p.generic_u32string()) == p );
+  }
+}
+
 int
 main()
 {
   test01();
+  test02();
+  test03();
 }


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