[glom] Add and use copy_with_cloned_items().

[Murray Cumming <murrayc src gnome org>]

commit a89b442fcdea0e9f26e8db28679a3de625b10305
Author: Murray Cumming <murrayc murrayc com>
Date:   Wed Feb 10 15:53:32 2016 +0100

    Add and use copy_with_cloned_items().

 glom/libglom/data_structure/layout/layoutgroup.cc |   12 ++----------
 glom/libglom/report_builder.cc                    |    7 ++-----
 glom/libglom/sharedptr.h                          |   16 ++++++++++++++++
 3 files changed, 20 insertions(+), 15 deletions(-)
---
diff --git a/glom/libglom/data_structure/layout/layoutgroup.cc 
b/glom/libglom/data_structure/layout/layoutgroup.cc
index 2407a98..78a8b47 100644
--- a/glom/libglom/data_structure/layout/layoutgroup.cc
+++ b/glom/libglom/data_structure/layout/layoutgroup.cc
@@ -40,11 +40,7 @@ LayoutGroup::LayoutGroup(const LayoutGroup& src)
   m_border_width(src.m_border_width)
 {
   //Deep copy of the items map:
-  for(const auto& item : src.m_list_items)
-  {
-    if(item)
-      m_list_items.emplace_back( glom_sharedptr_clone(item) );
-  }
+  m_list_items = copy_with_cloned_items(src.m_list_items);
 }
 
 LayoutGroup::~LayoutGroup()
@@ -77,11 +73,7 @@ LayoutGroup& LayoutGroup::operator=(const LayoutGroup& src)
     //Deep copy of the items map:
     remove_all_items();
 
-    for(const auto& item : src.m_list_items)
-    {
-      if(item)
-        m_list_items.emplace_back( glom_sharedptr_clone(item) );
-    }
+    m_list_items = copy_with_cloned_items(src.m_list_items);
   }
 
   return *this;
diff --git a/glom/libglom/report_builder.cc b/glom/libglom/report_builder.cc
index 2baa2f5..42af551 100644
--- a/glom/libglom/report_builder.cc
+++ b/glom/libglom/report_builder.cc
@@ -272,11 +272,8 @@ bool ReportBuilder::report_build_groupby(const FoundSet& found_set_parent, xmlpp
         {
           auto nodeSecondaryFields = nodeGroupBy->add_child_element("secondary_fields");
 
-          type_vecLayoutItems itemsToGet;
-          for(const auto& item : group_by->get_secondary_fields()->m_list_items)
-          {
-            itemsToGet.emplace_back( glom_sharedptr_clone(item) );
-          }
+          type_vecLayoutItems itemsToGet =
+            copy_with_cloned_items(group_by->get_secondary_fields()->m_list_items);
 
           if(!itemsToGet.empty())
           {
diff --git a/glom/libglom/sharedptr.h b/glom/libglom/sharedptr.h
index 29b688e..0f00408 100644
--- a/glom/libglom/sharedptr.h
+++ b/glom/libglom/sharedptr.h
@@ -54,6 +54,22 @@ std::shared_ptr<T_obj> glom_sharedptr_clone(const std::shared_ptr<const T_obj>&
     return std::shared_ptr<T_obj>();
 }
 
+template <class T_container>
+decltype(auto) copy_with_cloned_items(T_container src)
+{
+  T_container result;
+  result.reserve(src.size());
+
+  for (const auto& item : src) {
+    if(!item)
+      continue;
+
+    result.emplace_back(glom_sharedptr_clone(item));
+  }
+
+  return result;
+}
+
 } //namespace Glom
 
 #endif //GLOM_SHAREDPTR_H