Eliminate make_cleanup_ui_file_deleteusers/palves/cxx-eliminate-cleanups

And now that ui_file_as_string is in, let's eliminate it.  :-)

Makes ui_file a real C++ hierarchy.  mem_fileopen is replaced with a
new string_file class that is treated as a value class created on the
stack.  This alone eliminates most make_cleanup_ui_file_delete calls,
and, simplifies code a whole lot (diffstat shows almost 1k loc
dropped.)

string_file has a string() method that gives you a direct reference to
the internal std::string.  This is what replaces old (well, new)
ui_file_as_string, which used to alway return a new copy of the same
data the stream had inside..  With direct access via a writable
reference, we can instead move the string out of the string_stream.

Note I needed a tweak on scoped_restore.  That one should probably be
split out to a separate patch.

This exposed the need to make use of gnulib namespace support.
Otherwise, making use of read/write/printf/puts/etc symbol names will
clash on systems where gnulib replaces those functions, due to
'#define foo rpl_foo'.

1 files changed, 3 insertions, 9 deletions

diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index e364bd85685..f6591199ad3 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -7602,17 +7602,11 @@ ada_value_struct_elt (struct value *arg, char *name, int no_err)
 static std::string
 type_as_string (struct type *type)
 {
-  struct ui_file *tmp_stream = mem_fileopen ();
-  struct cleanup *old_chain;
-
-  tmp_stream = mem_fileopen ();
-  old_chain = make_cleanup_ui_file_delete (tmp_stream);
+  string_file tmp_stream;
 
-  type_print (type, "", tmp_stream, -1);
-  std::string str = ui_file_as_string (tmp_stream);
+  type_print (type, "", &tmp_stream, -1);
 
-  do_cleanups (old_chain);
-  return str;
+  return std::move (tmp_stream.string ());
 }
 
 /* Given a type TYPE, look up the type of the component of type named NAME.