gdb: change xml_fetch_another a function_view

The xml_fetch_another is currently a plain function pointer type, with a
`void *` baton parameter.  To improve type-safety, change this to a
function_view.  Any required data is captured by a lambda at the call
site.

gdb/ChangeLog:

	* xml-support.h (xml_fetch_another): Change type to be a
	function_view.
	(xml_process_xincludes): Remove baton parameter.
	(xml_fetch_content_from_file): Change baton parameter to
	dirname.
	* xml-support.c (struct xinclude_parsing_data)
	<xinclude_parsing_data>: Remove baton parameter.
	<fetcher_baton>: Remove.
	(xinclude_start_include): Adjust.
	(xml_process_xincludes): Adjust.
	(xml_fetch_content_from_file): Replace baton parameter with
	dirname.
	* xml-syscall.c (syscall_parse_xml): Remove baton parameter.
	(xml_init_syscalls_info): Use a lambda.
	* xml-tdesc.c (tdesc_parse_xml): Remove baton parameter.
	(file_read_description_xml): Use a lambda.
	(fetch_available_features_from_target): Change baton parameter
	to target_ops.
	(target_read_description_xml): Use a lambda.
	(target_fetch_description_xml): Use a lambda.
	(string_read_description_xml): Update.

Change-Id: I7ba4b8f5e97fc6a952c6c20ccc3be92a06cc2bd2

1 files changed, 7 insertions, 13 deletions

diff --git a/gdb/xml-support.c b/gdb/xml-support.c
index c906b69..8b698e5 100644
--- a/gdb/xml-support.c
+++ b/gdb/xml-support.c
@@ -745,13 +745,12 @@ gdb_xml_parse_attr_enum (struct gdb_xml_parser *parser,
 struct xinclude_parsing_data
 {
   xinclude_parsing_data (std::string &output_,
-			 xml_fetch_another fetcher_, void *fetcher_baton_,
+			 xml_fetch_another fetcher_,
 			 int include_depth_)
     : output (output_),
       skip_depth (0),
       include_depth (include_depth_),
-      fetcher (fetcher_),
-      fetcher_baton (fetcher_baton_)
+      fetcher (fetcher_)
   {}
 
   /* Where the output goes.  */
@@ -770,7 +769,6 @@ struct xinclude_parsing_data
   /* A function to call to obtain additional features, and its
      baton.  */
   xml_fetch_another fetcher;
-  void *fetcher_baton;
 };
 
 static void
@@ -789,14 +787,12 @@ xinclude_start_include (struct gdb_xml_parser *parser,
     gdb_xml_error (parser, _("Maximum XInclude depth (%d) exceeded"),
 		   MAX_XINCLUDE_DEPTH);
 
-  gdb::optional<gdb::char_vector> text
-    = data->fetcher (href, data->fetcher_baton);
+  gdb::optional<gdb::char_vector> text = data->fetcher (href);
   if (!text)
     gdb_xml_error (parser, _("Could not load XML document \"%s\""), href);
 
   if (!xml_process_xincludes (data->output, parser->name (),
 			      text->data (), data->fetcher,
-			      data->fetcher_baton,
 			      data->include_depth + 1))
     gdb_xml_error (parser, _("Parsing \"%s\" failed"), href);
 
@@ -878,10 +874,9 @@ const struct gdb_xml_element xinclude_elements[] = {
 bool
 xml_process_xincludes (std::string &result,
 		       const char *name, const char *text,
-		       xml_fetch_another fetcher, void *fetcher_baton,
-		       int depth)
+		       xml_fetch_another fetcher, int depth)
 {
-  xinclude_parsing_data data (result, fetcher, fetcher_baton, depth);
+  xinclude_parsing_data data (result, fetcher, depth);
 
   gdb_xml_parser parser (name, xinclude_elements, &data);
   parser.set_is_xinclude (true);
@@ -968,12 +963,11 @@ show_debug_xml (struct ui_file *file, int from_tty,
 }
 
 gdb::optional<gdb::char_vector>
-xml_fetch_content_from_file (const char *filename, void *baton)
+xml_fetch_content_from_file (const char *filename, const char *dirname)
 {
-  const char *dirname = (const char *) baton;
   gdb_file_up file;
 
-  if (dirname && *dirname)
+  if (dirname != nullptr && *dirname != '\0')
     {
       char *fullname = concat (dirname, "/", filename, (char *) NULL);