Simplify auto_load_expand_dir_vars and remove substitute_path_component

This simplifies auto_load_expand_dir_vars to first split the string,
then do any needed substitutions.  This was suggested by Simon, and is
much simpler than the current approach.

Then this patch also removes substitute_path_component, as it is no
longer called.  This is nice because it helps with the long term goal
of removing utils.h.

Regression tested on x86-64 Fedora 36.

1 files changed, 21 insertions, 12 deletions

diff --git a/gdb/auto-load.c b/gdb/auto-load.c
index 5267cb4..9d6fabe 100644
--- a/gdb/auto-load.c
+++ b/gdb/auto-load.c
@@ -173,24 +173,33 @@ static std::string auto_load_safe_path = AUTO_LOAD_SAFE_PATH;
    counterpart.  */
 static std::vector<gdb::unique_xmalloc_ptr<char>> auto_load_safe_path_vec;
 
-/* Expand $datadir and $debugdir in STRING according to the rules of
-   substitute_path_component.  */
+/* Expand $datadir and $debugdir in STRING.  */
 
 static std::vector<gdb::unique_xmalloc_ptr<char>>
 auto_load_expand_dir_vars (const char *string)
 {
-  char *s = xstrdup (string);
-  substitute_path_component (&s, "$datadir", gdb_datadir.c_str ());
-  substitute_path_component (&s, "$debugdir", debug_file_directory.c_str ());
+  std::vector<gdb::unique_xmalloc_ptr<char>> result
+    = dirnames_to_char_ptr_vec (string);
 
-  if (debug_auto_load && strcmp (s, string) != 0)
-    auto_load_debug_printf ("Expanded $-variables to \"%s\".", s);
-
-  std::vector<gdb::unique_xmalloc_ptr<char>> dir_vec
-    = dirnames_to_char_ptr_vec (s);
-  xfree(s);
+  for (auto &elt : result)
+    {
+      if (strcmp (elt.get (), "$datadir") == 0)
+	{
+	  elt = make_unique_xstrdup (gdb_datadir.c_str ());
+	  if (debug_auto_load)
+	    auto_load_debug_printf ("Expanded $datadir to \"%s\".",
+				    gdb_datadir.c_str ());
+	}
+      else if (strcmp (elt.get (), "$debugdir") == 0)
+	{
+	  elt = make_unique_xstrdup (debug_file_directory.c_str ());
+	  if (debug_auto_load)
+	    auto_load_debug_printf ("Expanded $debugdir to \"%s\".",
+				    debug_file_directory.c_str ());
+	}
+    }
 
-  return dir_vec;
+  return result;
 }
 
 /* Update auto_load_safe_path_vec from current AUTO_LOAD_SAFE_PATH.  */