[glom] Add and use find_if_exists(container, callable).

[Murray Cumming <murrayc src gnome org>]

commit 77a19b321373481677d8e15c37906f688cf6c5c8
Author: Murray Cumming <murrayc murrayc com>
Date:   Tue Jan 5 15:19:38 2016 +0100

    Add and use find_if_exists(container, callable).
    
    To replace lengthy use of
    std::find_if(container.begin(), container.end(), callable) != container.end().
    
    It looks like something like this will be in the standard C++ library
    at some point, but I don't want to wait.

 glom/import_csv/file_encodings.cc        |    2 +-
 glom/libglom/algorithms_utils.h          |    8 ++++++++
 tests/test_document_load_and_change.cc   |   14 ++++++--------
 tests/test_document_load_translations.cc |   27 +++++++++++----------------
 4 files changed, 26 insertions(+), 25 deletions(-)
---
diff --git a/glom/import_csv/file_encodings.cc b/glom/import_csv/file_encodings.cc
index 7ddcca1..db9bfa5 100644
--- a/glom/import_csv/file_encodings.cc
+++ b/glom/import_csv/file_encodings.cc
@@ -21,7 +21,7 @@
 //#include "config.h" //For ISO_CODES_PREFIX.
 
 #include <glom/import_csv/file_encodings.h>
-#include <libglom/algorithm_utils.h>
+#include <libglom/algorithms_utils.h>
 #include <glibmm/i18n.h>
 
 namespace Glom
diff --git a/glom/libglom/algorithms_utils.h b/glom/libglom/algorithms_utils.h
index dbe81a2..a0237c4 100644
--- a/glom/libglom/algorithms_utils.h
+++ b/glom/libglom/algorithms_utils.h
@@ -37,6 +37,14 @@ find_exists(const T_container& container, const T_element& element)
   return std::find(std::begin(container), end, element) != end;
 }
 
+template<typename T_container, typename T_callable>
+bool
+find_if_exists(const T_container& container, const T_callable& callable)
+{
+  const auto end = std::end(container);
+  return std::find_if(std::begin(container), end, callable) != end;
+}
+
 
 template<typename T_container, typename T_element>
 typename T_container::iterator
diff --git a/tests/test_document_load_and_change.cc b/tests/test_document_load_and_change.cc
index 639c5cf..bc6f69b 100644
--- a/tests/test_document_load_and_change.cc
+++ b/tests/test_document_load_and_change.cc
@@ -47,14 +47,12 @@ static bool field_is_on_a_layout(Glom::Document& document, const Glib::ustring&
 
 static bool groups_contain_named(const Glom::Document::type_list_groups& container, const Glib::ustring& 
name)
 {
-  Glom::Document::type_list_groups::const_iterator iter =
-    Utils::find_if(container,
-      [&name] (const Glom::GroupInfo& info)
-      {
-        return info.get_name() == name;
-      }
-    );
-  return iter != container.end();
+  return Glom::Utils::find_if_exists(container,
+    [&name] (const Glom::GroupInfo& info)
+    {
+      return info.get_name() == name;
+    }
+  );
 }
 
 int main()
diff --git a/tests/test_document_load_translations.cc b/tests/test_document_load_translations.cc
index b40332d..875bd26 100644
--- a/tests/test_document_load_translations.cc
+++ b/tests/test_document_load_translations.cc
@@ -59,22 +59,17 @@ typename T_Container::value_type get_titled(const T_Container& container, const
 template<typename T_TypeToFind>
 bool contains_item_type(const Glom::Document::type_list_translatables& container)
 {
-  Glom::Document::type_list_translatables::const_iterator iter =
-    Utils::find_if(container,
-      [] (const Glom::Document::type_list_translatables::value_type& element)
-      {
-        std::shared_ptr<Glom::TranslatableItem> item = element.first;
-        std::shared_ptr<T_TypeToFind> derived = std::dynamic_pointer_cast<T_TypeToFind>(item);
-        if(derived)
-          return true;
-        else
-          return false;
-      }
-    );
-  if(iter != container.end())
-    return true;
-
-  return false;
+  return Glom::Utils::find_if_exists(container,
+    [] (const Glom::Document::type_list_translatables::value_type& element)
+    {
+      std::shared_ptr<Glom::TranslatableItem> item = element.first;
+      std::shared_ptr<T_TypeToFind> derived = std::dynamic_pointer_cast<T_TypeToFind>(item);
+      if(derived)
+        return true;
+      else
+        return false;
+    }
+  );
 }
 
 static std::shared_ptr<const Glom::LayoutItem_Field> get_field_on_layout(const Glom::Document& document, 
const Glib::ustring& layout_table_name, const Glib::ustring& table_name, const Glib::ustring& field_name)