Sort folders after files. Closes: #843.

src/libaudcore/adder.cc

@@ -308,6 +308,7 @@ static void add_folder (const char * filename, Playlist::FilterFunc filter,
 
     String error;
     Index<String> files = VFSFile::read_folder (filename, error);
+    Index<String> folders;
 
     if (error)
         aud_ui_show_error (str_printf (_("Error reading %s:\n%s"), filename, (const char *) error));
@@ -327,7 +328,7 @@ static void add_folder (const char * filename, Playlist::FilterFunc filter,
     // sort file list in natural order (must come after add_cuesheets)
     files.sort (str_compare_encoded);
 
-    for (const char * file : files)
+    for (const String & file : files)
     {
         if (filter && ! filter (file, user))
         {
@@ -340,16 +341,20 @@ static void add_folder (const char * filename, Playlist::FilterFunc filter,
          VFSFileTest (VFS_IS_REGULAR | VFS_IS_SYMLINK | VFS_IS_DIR), error);
 
         if (error)
-            AUDERR ("%s: %s\n", file, (const char *) error);
+            AUDERR ("%s: %s\n", (const char *) file, (const char *) error);
 
         if (mode & VFS_IS_SYMLINK)
             continue;
 
         if (mode & VFS_IS_REGULAR)
-            add_file ({String (file)}, filter, user, result, true);
+            add_file ({file}, filter, user, result, true);
         else if ((mode & VFS_IS_DIR) && aud_get_bool (nullptr, "recurse_folders"))
-            add_folder (file, filter, user, result, false);
+            folders.append (file);
     }
+
+    // add folders after files
+    for (const String & folder : folders)
+        add_folder (folder, filter, user, result, false);
 }
 
 static void add_generic (PlaylistAddItem && item, Playlist::FilterFunc filter,

src/libaudcore/playlist-utils.cc

@@ -37,6 +37,19 @@ static const char * get_basename (const char * filename)
     return slash ? slash + 1 : filename;
 }
 
+static int filename_compare_path (const char * a, const char * b)
+{
+    int dirlen_a = get_basename (a) - a;
+    int dirlen_b = get_basename (b) - b;
+
+    // if one folder is a subfolder of the other, sort it last
+    if (dirlen_a != dirlen_b && memcmp (a, b, aud::min (dirlen_a, dirlen_b)) == 0)
+        return dirlen_a - dirlen_b;
+
+    // in all other cases, compare the entire paths
+    return str_compare_encoded (a, b);
+}
+
 static int filename_compare_basename (const char * a, const char * b)
 {
     return str_compare_encoded (get_basename (a), get_basename (b));
@@ -88,7 +101,7 @@ static int tuple_compare_comment (const Tuple & a, const Tuple & b)
     { return tuple_compare_string (a, b, Tuple::Comment); }
 
 static const Playlist::StringCompareFunc filename_comparisons[] = {
-    str_compare_encoded,  // path
+    filename_compare_path,  // path
     filename_compare_basename,  // filename
     nullptr,  // title
     nullptr,  // album