Fix failure to re-create config when it is bad (due to attempt to find a link
authorCarl Hetherington <cth@carlh.net>
Tue, 25 Dec 2018 02:05:06 +0000 (02:05 +0000)
committerCarl Hetherington <cth@carlh.net>
Tue, 25 Dec 2018 02:05:06 +0000 (02:05 +0000)
in the bad file).

Improve config saving with low disk space; don't corrupt an existing file if we can't
save a new one.

src/lib/config.cc

index eb26713..9dd6f63 100644 (file)
@@ -982,13 +982,15 @@ Config::write_config () const
 
        try {
                string const s = doc.write_to_string_formatted ();
-               boost::filesystem::path const cf = config_file ();
-               FILE* f = fopen_boost (cf, "w");
+               boost::filesystem::path tmp (string(config_file().string()).append(".tmp"));
+               FILE* f = fopen_boost (tmp, "w");
                if (!f) {
-                       throw FileError (_("Could not open file for writing"), cf);
+                       throw FileError (_("Could not open file for writing"), tmp);
                }
-               checked_fwrite (s.c_str(), s.length(), f, cf);
+               checked_fwrite (s.c_str(), s.length(), f, tmp);
                fclose (f);
+               boost::filesystem::remove (config_file());
+               boost::filesystem::rename (tmp, config_file());
        } catch (xmlpp::exception& e) {
                string s = e.what ();
                trim (s);
@@ -1008,7 +1010,9 @@ Config::write_cinemas () const
        }
 
        try {
-               doc.write_to_file_formatted (_cinemas_file.string ());
+               doc.write_to_file_formatted (_cinemas_file.string() + ".tmp");
+               boost::filesystem::remove (_cinemas_file);
+               boost::filesystem::rename (_cinemas_file.string() + ".tmp", _cinemas_file);
        } catch (xmlpp::exception& e) {
                string s = e.what ();
                trim (s);
@@ -1233,10 +1237,16 @@ Config::config_file ()
        }
 
        /* See if there's a link */
-       f.read_file (main);
-       optional<string> link = f.optional_string_child("Link");
-       if (link) {
-               return *link;
+       try {
+               f.read_file (main);
+               optional<string> link = f.optional_string_child("Link");
+               if (link) {
+                       return *link;
+               }
+       } catch (xmlpp::exception& e) {
+               /* There as a problem reading the main configuration file,
+                  so there can't be a link.
+               */
        }
 
        return main;