project reader: try to simplify code

Align variable names
Remove superfluous loops
Regroup code

Author: iMichka

src/pygccxml/parser/project_reader.py

@@ -321,14 +321,7 @@ def __parse_file_by_file(self, files):
         self.logger.debug(
             "Cache has been flushed in %.1f secs",
             (timeit.default_timer() - start_time))
-        namespaces = []
-        self.logger.debug("Joining namespaces ...")
-        for file_nss in namespaces:
-            namespaces = self._join_top_namespaces(namespaces, file_nss)
-        self.logger.debug("Joining declarations ...")
-        for namespace in namespaces:
-            if isinstance(namespace, pygccxml.declarations.namespace_t):
-                declarations_joiner.join_declarations(namespace)
+        namespaces = self.__join_namespaces_and_declarations(namespaces)
         leaved_classes = self._join_class_hierarchy(namespaces)
         types = self.__declarated_types(namespaces)
         self.logger.debug("Relinking declared types ...")
@@ -354,9 +347,14 @@ def __parse_all_at_once(self, files):
                     '#include "%s" %s' %
                     (header, os.linesep))
         namespaces = self.read_string(''.join(header_content))
-        namespaces = self._join_top_namespaces(namespaces, [])
+        return self.__join_namespaces_and_declarations(namespaces)
+
+    def __join_namespaces_and_declarations(self, namespaces):
         for namespace in namespaces:
             if isinstance(namespace, pygccxml.declarations.namespace_t):
+                self.logger.debug("Joining namespaces ...")
+                namespace = self._join_top_namespaces(namespace)
+                self.logger.debug("Joining declarations ...")
                 declarations_joiner.join_declarations(namespace)
         return namespaces
 
@@ -422,27 +420,27 @@ def read_xml(self, file_configuration):
                 utils.remove_file_no_raise(xml_file_path, self.__config)
 
     @staticmethod
-    def _join_top_namespaces(main_ns_list, other_ns_list):
-        answer = main_ns_list[:]
-        for other_ns in other_ns_list:
+    def _join_top_namespaces(namespaces):
+        answer = namespaces[:]
+        for namespace in namespaces:
             same_name_namespaces = pygccxml.declarations.find_all_declarations(
                 answer,
                 decl_type=pygccxml.declarations.namespace_t,
-                name=other_ns.name,
+                name=namespace.name,
                 parent=None,  # top-level only
                 recursive=False
             )
             if len(same_name_namespaces) == 0:
-                answer.append(other_ns)
+                answer.append(namespace)
             elif len(same_name_namespaces) == 1:
-                same_name_namespaces[0].take_parenting(other_ns)
+                same_name_namespaces[0].take_parenting(namespace)
             else:
                 primary_ns = same_name_namespaces[0]
                 for extra_ns in same_name_namespaces[1:]:
                     primary_ns.take_parenting(extra_ns)
                     answer.remove(extra_ns)
                 # then unify the new other_ns
-                primary_ns.take_parenting(other_ns)
+                primary_ns.take_parenting(namespace)
         return answer
 
     @staticmethod