Add base-class checks to FILELOADER* check macros. Refs #7263

Also added runtime checks to the subscribe method. This allows it to static
cast at runtime when checking rather than a more expensive dynamic cast.

Code/Mantid/Framework/API/inc/MantidAPI/FileLoaderRegistry.h

 #ifndef MANTID_API_FILELOADERREGISTRY_H_
 #define MANTID_API_FILELOADERREGISTRY_H_
 
-#include "MantidAPI/DllConfig.h"
 #include "MantidAPI/AlgorithmFactory.h"
+#include "MantidAPI/IFileLoader.h"
+#include "MantidAPI/IHDFFileLoader.h"
 #include "MantidKernel/SingletonHolder.h"
 
+#include <boost/type_traits/is_base_of.hpp>
+
 #include <map>
 #include <string>
 #include <vector>
@@ -70,6 +73,7 @@ namespace Mantid
       template<typename Type>
       void subscribe(LoaderFormat format)
       {
+        SubscriptionValidator<Type>::check(format);
         const auto nameVersion = AlgorithmFactory::Instance().subscribe<Type>();
         // If the factory didn't throw then the name is valid
         m_names[format].insert(nameVersion);
@@ -89,6 +93,33 @@ namespace Mantid
       /// Destructor
       ~FileLoaderRegistryImpl();
 
+      /// Helper for subscribe to check base class
+      template <typename T>
+      struct SubscriptionValidator
+      {
+        static void check(LoaderFormat format)
+        {
+          switch(format)
+          {
+          case HDF:
+            if(!boost::is_base_of<IHDFFileLoader,T>::value)
+            {
+              throw std::runtime_error(std::string("FileLoaderRegistryImpl::subscribe - Class '") + typeid(T).name() +
+                                       "' registered as HDF loader but it does not inherit from Mantid::API::IHDFFileLoader");
+            }
+            break;
+          case NonHDF:
+            if(!boost::is_base_of<IFileLoader,T>::value)
+            {
+              throw std::runtime_error(std::string("FileLoaderRegistryImpl::subscribe - Class '") + typeid(T).name() +
+                "' registered as Non-HDF loader but it does not inherit from Mantid::API::IFileLoader");
+            }
+          break;
+            default: throw std::runtime_error("Invalid LoaderFormat given");
+          }
+        }
+      };
+
       /// The list of names. The index pointed to by LoaderFormat defines a set for that format
       std::vector<std::multimap<std::string,int> > m_names;
       /// Total number of names registered

Code/Mantid/Framework/API/inc/MantidAPI/IHDFFileLoader.h

 #ifndef MANTID_API_IHDFFILELOADER_H_
 #define MANTID_API_IHDFFILELOADER_H_
 
-#include "MantidAPI/IFileLoader.h"
-#include "MantidKernel/FileDescriptor.h"
+#include "MantidAPI/Algorithm.h"
 #include "MantidKernel/HDFDescriptor.h"
 
 namespace Mantid

Code/Mantid/Framework/API/inc/MantidAPI/RegisterFileLoader.h

@@ -3,6 +3,9 @@
 
 #include "MantidAPI/FileLoaderRegistry.h"
 
+#include <boost/static_assert.hpp>
+#include <boost/type_traits/is_base_of.hpp>
+
 /**
  * DECLARE_FILELOADER_ALGORITHM should be used in place of the standard
  * DECLARE_ALGORITHM macro when writing a file loading algorithm that
@@ -13,6 +16,9 @@
 #define DECLARE_FILELOADER_ALGORITHM(classname) \
   namespace \
   {\
+    typedef boost::is_base_of<Mantid::API::IFileLoader,classname> base_checker;\
+    BOOST_STATIC_ASSERT_MSG(base_checker::value,\
+                            #classname" must inherit from Mantid::API::IFileLoader to be used with DECLARE_FILELOADER_ALGORITHM");\
     Mantid::Kernel::RegistrationHelper \
       reg_loader_##classname((Mantid::API::\
         FileLoaderRegistry::Instance().subscribe<classname>(Mantid::API::FileLoaderRegistryImpl::NonHDF), 0));\
@@ -28,6 +34,9 @@
 #define DECLARE_HDF_FILELOADER_ALGORITHM(classname) \
   namespace \
   {\
+    typedef boost::is_base_of<Mantid::API::IHDFFileLoader,classname> base_checker;\
+    BOOST_STATIC_ASSERT_MSG(base_checker::value,\
+                            #classname" must inherit from Mantid::API::IHDFFileLoader to be used with DECLARE_HDF_FILELOADER_ALGORITHM");\
     Mantid::Kernel::RegistrationHelper \
       reg_hdf_loader_##classname((Mantid::API::\
         FileLoaderRegistry::Instance().subscribe<classname>(Mantid::API::FileLoaderRegistryImpl::HDF), 0)); \