reader: Use xmlFirstElementChild and xmlNextElementSibling rather than xml::advance_to_next_sibling_element

The xml::advance_to_next_sibling_element is redundant with the
xmlNextElementSibling API of libxml.  Similarly, xmlFirstElementChild
is redundant with using xml::advance_to_next_sibling_element on the
xmlNode::children data member.  Let's use the libxml API instead.

	* include/abg-libxml-utils.h (advance_to_next_sibling_element):
	Remove the declaration of this function.
	* src/abg-libxml-utils.cc (go_to_next_sibling_element_or_stay)
	(advance_to_next_sibling_element): Remove definitions of these functions.
	* src/abg-reader.cc (read_translation_unit_from_input)
	(read_elf_needed_from_input, read_corpus_group_from_input): Use xmlNextElementSibling instead
	of xml::advance_to_next_sibling_element.
	(read_corpus_from_input): Likewise.  Also, use
	xmlFirstElementChild instead of
	xml::advance_to_next_sibling_element on the xmlNode::children data
	member.
	(read_corpus_group_from_input): use xmlFirstElementChild instead
	of xml::advance_to_next_sibling_element on the xmlNode::children
	data member.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>

include/abg-libxml-utils.h

@@ -81,9 +81,6 @@ int get_xml_node_depth(xmlNodePtr);
 #define CHAR_STR(xml_char_str) \
   reinterpret_cast<char*>(xml_char_str.get())
 
-xmlNodePtr
-advance_to_next_sibling_element(xmlNodePtr node);
-
 void
 escape_xml_string(const std::string& str,
 		  std::string& escaped);

src/abg-libxml-utils.cc

@@ -413,45 +413,5 @@ unescape_xml_comment(const std::string& str)
   return result;
 }
 
-/// Maybe get the next sibling element node of an XML node, or stay to
-/// the same.
-///
-/// If there is no next sibling xml element node, the function returns
-/// the initial node.
-///
-/// @param node the initial node to consider.
-///
-/// @return the next sibling node or the initial node @p node.
-static xmlNodePtr
-go_to_next_sibling_element_or_stay(xmlNodePtr node)
-{
-  xmlNodePtr n;
-  for (n = node; n; n = n->next)
-    {
-      if (n->type == XML_ELEMENT_NODE)
-	break;
-    }
-  return n ? n : node;
-}
-
-/// Get the next sibling element node of an XML node.
-///
-/// If there is no next sibling xml element node, the function returns nil.
-///
-/// @param node the XML node to consider.
-///
-/// @return the next sibling element node or nil.
-xmlNodePtr
-advance_to_next_sibling_element(xmlNodePtr node)
-{
-  if (!node)
-    return 0;
-
-  xmlNodePtr n = go_to_next_sibling_element_or_stay(node->next);
-  if (n == 0 || n->type != XML_ELEMENT_NODE)
-    return 0;
-  return n;
-}
-
 }//end namespace xml
 }//end namespace abigail

src/abg-reader.cc

@@ -1518,7 +1518,7 @@ read_translation_unit_from_input(read_context&	ctxt)
       // from a local invocation of xmlTextReaderExpand.  So let's set
       // ctxt.get_corpus_node to the next child element node of the
       // corpus that needs to be processed.
-      node = xml::advance_to_next_sibling_element(node);
+      node = xmlNextElementSibling(node);
       ctxt.set_corpus_node(node);
     }
 
@@ -1718,7 +1718,7 @@ read_elf_needed_from_input(read_context&	ctxt,
   if (node)
     {
       result = build_needed(node, needed);
-      node = xml::advance_to_next_sibling_element(node);
+      node = xmlNextElementSibling(node);
       ctxt.set_corpus_node(node);
     }
 
@@ -1930,7 +1930,7 @@ read_corpus_from_input(read_context& ctxt)
   // the corpus element that *needs* to be processed.
   if (node->children)
     {
-      xmlNodePtr n = xml::advance_to_next_sibling_element(node->children);
+      xmlNodePtr n = xmlFirstElementChild(node);
       ctxt.set_corpus_node(n);
     }
 
@@ -1996,12 +1996,12 @@ read_corpus_from_input(read_context& ctxt)
   else
     {
       node = ctxt.get_corpus_node();
-      node = xml::advance_to_next_sibling_element(node);
+      node = xmlNextElementSibling(node);
       if (!node)
 	{
 	  node = ctxt.get_corpus_node();
 	  if (node)
-	    node = xml::advance_to_next_sibling_element(node->parent);
+	    node = xmlNextElementSibling(node->parent);
 	}
       ctxt.set_corpus_node(node);
     }
@@ -2055,7 +2055,7 @@ read_corpus_group_from_input(read_context& ctxt)
     return nil;
 
   //node = xml::get_first_element_sibling_if_text(node->children);
-  node = xml::advance_to_next_sibling_element(node->children);
+  node = xmlFirstElementChild(node);
   ctxt.set_corpus_node(node);
 
   corpus_sptr corp;