apt.dat parser: clearer log and exception messages

- the 'apt_dat' variable introduced here will be used in further
  commits;
- use two spaces for indentation, as seen in most of the file.

diff --git a/src/Airports/apt_loader.cxx b/src/Airports/apt_loader.cxx
index 9e6a475884228a25fd99206f89c82afbac7b1493..d99e9355e5c1b5566a04c62c3889b2435ff3f2a8 100644 (file)
--- a/src/Airports/apt_loader.cxx
+++ b/src/Airports/apt_loader.cxx
@@ -88,11 +88,12 @@ public:
 
   void parseAPT(const SGPath &aptdb_file)
   {
-    sg_gzifstream in( aptdb_file.str() );
+    std::string apt_dat = aptdb_file.str();
+    sg_gzifstream in(apt_dat);
 
     if ( !in.is_open() ) {
-        SG_LOG( SG_GENERAL, SG_ALERT, "Cannot open file: " << aptdb_file );
-        throw sg_io_exception("cannot open APT file", aptdb_file);
+      SG_LOG( SG_GENERAL, SG_ALERT, "Cannot open file: " << apt_dat );
+      throw sg_io_exception("cannot open apt.dat file", apt_dat.c_str());
     }
 
     string line;