From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Wed, 15 Apr 2020 14:50:12 +0000 (-0600)
Subject: Use std::ifstream instead of the detour via std::filebuf.
X-Git-Tag: v9.2.0-rc1~228^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=788156f3656e9e387bb66bff26f8e996a76d1a04;p=dealii.git

Use std::ifstream instead of the detour via std::filebuf.

While there also move an assertion.
---

diff --git a/source/base/parameter_handler.cc b/source/base/parameter_handler.cc
index d25e890220..4fc7deca58 100644
--- a/source/base/parameter_handler.cc
+++ b/source/base/parameter_handler.cc
@@ -513,32 +513,24 @@ ParameterHandler::parse_input(const std::string &filename,
                               const bool         skip_undefined,
                               const bool assert_mandatory_entries_are_found)
 {
-  std::filebuf fb;
-  if (fb.open(filename, std::ios::in))
-    {
-      std::istream is(&fb);
-      std::string file_ending = filename.substr(filename.find_last_of('.') + 1);
-      boost::algorithm::to_lower(file_ending);
-      if (file_ending == "prm")
-        parse_input(is, filename, last_line, skip_undefined);
-      else if (file_ending == "xml")
-        parse_input_from_xml(is, skip_undefined);
-      else if (file_ending == "json")
-        parse_input_from_json(is, skip_undefined);
-      else
-        AssertThrow(
-          false,
-          ExcMessage(
-            "Unknown input file. Supported types are .prm, .xml, and .json."));
-
-      fb.close();
-    }
+  std::ifstream is(filename);
+  AssertThrow(is,
+              ExcMessage("Invalid filename " + filename +
+                         " provided. File does not exist or "
+                         "can not be read from."));
+
+  std::string file_ending = filename.substr(filename.find_last_of('.') + 1);
+  boost::algorithm::to_lower(file_ending);
+  if (file_ending == "prm")
+    parse_input(is, filename, last_line, skip_undefined);
+  else if (file_ending == "xml")
+    parse_input_from_xml(is, skip_undefined);
+  else if (file_ending == "json")
+    parse_input_from_json(is, skip_undefined);
   else
-    {
-      AssertThrow(false,
-                  ExcMessage("Invalid filename " + filename +
-                             " provided. File does not exist."));
-    }
+    AssertThrow(false,
+                ExcMessage("Unknown input file name extension. Supported types "
+                           "are .prm, .xml, and .json."));
 
   if (assert_mandatory_entries_are_found)
     assert_that_entries_have_been_set();