Make directory iterators become end iterator on error

	* src/filesystem/dir.cc (open_dir): Return same value for errors
	whether ignored or not.
	(_Dir::advance(error_code*, directory_options)): Return false on
	error.
	(directory_iterator(const path&, directory_options, error_code*)):
	Create end iterator on error (LWG 2723).
	(recursive_directory_iterator(const path&, directory_options,
	error_code*)): Likewise.
	* testsuite/experimental/filesystem/iterators/directory_iterator.cc:
	Update expected behaviour on error.
	* testsuite/experimental/filesystem/iterators/
	recursive_directory_iterator.cc: Likewise.

From-SVN: r241486

libstdc++-v3/ChangeLog

 2016-10-24  Jonathan Wakely  <jwakely@redhat.com>
 
+	* src/filesystem/dir.cc (open_dir): Return same value for errors
+	whether ignored or not.
+	(_Dir::advance(error_code*, directory_options)): Return false on
+	error.
+	(directory_iterator(const path&, directory_options, error_code*)):
+	Create end iterator on error (LWG 2723).
+	(recursive_directory_iterator(const path&, directory_options,
+	error_code*)): Likewise.
+	* testsuite/experimental/filesystem/iterators/directory_iterator.cc:
+	Update expected behaviour on error.
+	* testsuite/experimental/filesystem/iterators/
+	recursive_directory_iterator.cc: Likewise.
+
 	* src/filesystem/ops.cc (close_fd): Remove.
 	(do_copy_file): Just use close(3) instead of close_fd, to prevent
 	retrying on error.

libstdc++-v3/src/filesystem/dir.cc

@@ -79,8 +79,7 @@ namespace
       return (obj & bits) != Bitmask::none;
     }
 
-  // Returns {dirp, p} on success, {nullptr, p} on error.
-  // If an ignored EACCES error occurs returns {}.
+  // Returns {dirp, p} on success, {} on error (whether ignored or not).
   inline fs::_Dir
   open_dir(const fs::path& p, fs::directory_options options,
 	   std::error_code* ec)
@@ -102,7 +101,7 @@ namespace
             std::error_code(err, std::generic_category())));
 
     ec->assign(err, std::generic_category());
-    return {nullptr, p};
+    return {};
   }
 
   inline fs::file_type
@@ -169,7 +168,7 @@ fs::_Dir::advance(error_code* ec, directory_options options)
 	      "directory iterator cannot advance",
 	      std::error_code(err, std::generic_category())));
       ec->assign(err, std::generic_category());
-      return true;
+      return false;
     }
   else
     {
@@ -191,12 +190,6 @@ directory_iterator(const path& p, directory_options options, error_code* ec)
       if (sp->advance(ec, options))
 	_M_dir.swap(sp);
     }
-  else if (!dir.path.empty())
-    {
-      // An error occurred, we need a non-empty shared_ptr so that *this will
-      // not compare equal to the end iterator.
-      _M_dir.reset(static_cast<fs::_Dir*>(nullptr));
-    }
 }
 
 const fs::directory_entry&
@@ -270,10 +263,6 @@ recursive_directory_iterator(const path& p, directory_options options,
 	      std::error_code(err, std::generic_category())));
 
       ec->assign(err, std::generic_category());
-
-      // An error occurred, we need a non-empty shared_ptr so that *this will
-      // not compare equal to the end iterator.
-      _M_dirs.reset(static_cast<_Dir_stack*>(nullptr));
     }
 }
 

libstdc++-v3/testsuite/experimental/filesystem/iterators/directory_iterator.cc

@@ -34,7 +34,7 @@ test01()
   const auto p = __gnu_test::nonexistent_path();
   fs::directory_iterator iter(p, ec);
   VERIFY( ec );
-  VERIFY( iter != fs::directory_iterator() );
+  VERIFY( iter == fs::directory_iterator() );
 
   // Test empty directory.
   create_directory(p, fs::current_path(), ec);
@@ -58,7 +58,7 @@ test01()
   VERIFY( !ec );
   iter = fs::directory_iterator(p, ec);
   VERIFY( ec );
-  VERIFY( iter != fs::directory_iterator() );
+  VERIFY( iter == fs::directory_iterator() );
 
   // Test inaccessible directory, skipping permission denied.
   const auto opts = fs::directory_options::skip_permission_denied;

libstdc++-v3/testsuite/experimental/filesystem/iterators/recursive_directory_iterator.cc

@@ -34,7 +34,7 @@ test01()
   const auto p = __gnu_test::nonexistent_path();
   fs::recursive_directory_iterator iter(p, ec);
   VERIFY( ec );
-  VERIFY( iter != fs::recursive_directory_iterator() );
+  VERIFY( iter == fs::recursive_directory_iterator() );
 
   // Test empty directory.
   create_directory(p, fs::current_path(), ec);
@@ -60,7 +60,7 @@ test01()
   VERIFY( !ec );
   iter = fs::recursive_directory_iterator(p, ec);
   VERIFY( ec );
-  VERIFY( iter != fs::recursive_directory_iterator() );
+  VERIFY( iter == fs::recursive_directory_iterator() );
 
   // Test inaccessible directory, skipping permission denied.
   const auto opts = fs::directory_options::skip_permission_denied;