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, 23 insertions, 15 deletions

diff --git a/gdb/xml-tdesc.c b/gdb/xml-tdesc.c
index 6f108a4..6e21ff4 100644
--- a/gdb/xml-tdesc.c
+++ b/gdb/xml-tdesc.c
@@ -617,8 +617,7 @@ static const struct gdb_xml_element tdesc_elements[] = {
 /* Parse DOCUMENT into a target description and return it.  */
 
 static struct target_desc *
-tdesc_parse_xml (const char *document, xml_fetch_another fetcher,
-		 void *fetcher_baton)
+tdesc_parse_xml (const char *document, xml_fetch_another fetcher)
 {
   struct tdesc_parsing_data data;
 
@@ -627,7 +626,7 @@ tdesc_parse_xml (const char *document, xml_fetch_another fetcher,
 
   if (!xml_process_xincludes (expanded_text,
 			      _("target description"),
-			      document, fetcher, fetcher_baton, 0))
+			      document, fetcher, 0))
     {
       warning (_("Could not load XML target description; ignoring"));
       return NULL;
@@ -673,8 +672,13 @@ file_read_description_xml (const char *filename)
       return NULL;
     }
 
-  return tdesc_parse_xml (tdesc_str->data (), xml_fetch_content_from_file,
-			  (void *) ldirname (filename).c_str ());
+  const std::string dirname = ldirname (filename);
+  auto fetch_another = [&dirname] (const char *name)
+    {
+      return xml_fetch_content_from_file (name, dirname.c_str ());
+    };
+
+  return tdesc_parse_xml (tdesc_str->data (), fetch_another);
 }
 
 /* Read a string representation of available features from the target,
@@ -685,10 +689,8 @@ file_read_description_xml (const char *filename)
    for <xi:include>.  */
 
 static gdb::optional<gdb::char_vector>
-fetch_available_features_from_target (const char *name, void *baton_)
+fetch_available_features_from_target (const char *name, target_ops *ops)
 {
-  struct target_ops *ops = (struct target_ops *) baton_;
-
   /* Read this object as a string.  This ensures that a NUL
      terminator is added.  */
   return target_read_stralloc (ops,
@@ -708,9 +710,12 @@ target_read_description_xml (struct target_ops *ops)
   if (!tdesc_str)
     return NULL;
 
-  return tdesc_parse_xml (tdesc_str->data (),
-			  fetch_available_features_from_target,
-			  ops);
+  auto fetch_another = [ops] (const char *name)
+    {
+      return fetch_available_features_from_target (name, ops);
+    };
+
+  return tdesc_parse_xml (tdesc_str->data (), fetch_another);
 }
 
 /* Fetches an XML target description using OPS,  processing
@@ -737,11 +742,14 @@ target_fetch_description_xml (struct target_ops *ops)
   if (!tdesc_str)
     return {};
 
+  auto fetch_another = [ops] (const char *name)
+    {
+      return fetch_available_features_from_target (name, ops);
+    };
   std::string output;
   if (!xml_process_xincludes (output,
 			      _("target description"),
-			      tdesc_str->data (),
-			      fetch_available_features_from_target, ops, 0))
+			      tdesc_str->data (), fetch_another, 0))
     {
       warning (_("Could not load XML target description; ignoring"));
       return {};
@@ -755,9 +763,9 @@ target_fetch_description_xml (struct target_ops *ops)
 const struct target_desc *
 string_read_description_xml (const char *xml)
 {
-  return tdesc_parse_xml (xml, [] (const char *href, void *baton)
+  return tdesc_parse_xml (xml, [] (const char *href)
     {
       error (_("xincludes are unsupported with this method"));
       return gdb::optional<gdb::char_vector> ();
-    }, nullptr);
+    });
 }