Cache first entry name & type in HDFDescriptor. Refs #7263

Code/Mantid/Framework/Kernel/inc/MantidKernel/HDFDescriptor.h

@@ -7,6 +7,7 @@
 #include <map>
 #include <set>
 #include <string>
+#include <utility>
 
 namespace Mantid
 {
@@ -72,6 +73,8 @@ namespace Mantid
        */
       inline const std::string & extension() const { return m_extension; }
 
+      /// Returns the name & type of the first entry in the file
+      const std::pair<std::string,std::string> & firstEntryNameType() const;
       /// Query if the given attribute exists on the root node
       bool hasRootAttr(const std::string &name) const;
       /// Query if a path exists
@@ -92,6 +95,8 @@ namespace Mantid
       std::string m_filename;
       /// Extension
       std::string m_extension;
+      /// First entry name/type
+      std::pair<std::string, std::string> m_firstEntryNameType;
       /// Root attributes
       std::set<std::string> m_rootAttrs;
       /// Map of types to full path strings.

Code/Mantid/Framework/Kernel/src/HDFDescriptor.cpp

@@ -98,7 +98,8 @@ namespace Mantid
      * involves simply checking for the signature if a HDF file at the start of the file
      */
     HDFDescriptor::HDFDescriptor(const std::string & filename)
-      : m_filename(), m_extension(), m_rootAttrs(), m_typesToPaths(NULL)
+      : m_filename(), m_extension(), m_firstEntryNameType(),
+        m_rootAttrs(), m_typesToPaths(NULL)
     {
       if(filename.empty())
       {
@@ -125,6 +126,11 @@ namespace Mantid
       delete m_typesToPaths;
     }
 
+    /// Returns the name & type of the first entry in the file
+    const std::pair<std::string,std::string> & HDFDescriptor::firstEntryNameType() const
+    {
+      return m_firstEntryNameType;
+    }
 
     /**
      * @param name The name of an attribute
@@ -193,6 +199,9 @@ namespace Mantid
       {
         m_rootAttrs.insert(attrInfos[i].name);
       }
+      auto entries = file.getEntries();
+      auto entryIter = entries.begin();
+      m_firstEntryNameType = std::make_pair(entryIter->first, entryIter->second);
       m_typesToPaths = file.getTypeMap();
     }
 

Code/Mantid/Framework/Kernel/test/HDFDescriptorTest.h

@@ -105,6 +105,13 @@ public:
     TS_ASSERT_THROWS(HDFDescriptor fd(m_testNonHDFPath), std::invalid_argument);
   }
 
+  void test_firstEntryNameType_Returns_Correct_Details()
+  {
+    auto entryType = m_testHDF5->firstEntryNameType();
+    TS_ASSERT_EQUALS("entry", entryType.first);
+    TS_ASSERT_EQUALS("NXentry", entryType.second);
+  }
+
   void test_hasRootAttr_Returns_True_For_Existing_Attr()
   {
     TS_ASSERT(m_testHDF5->hasRootAttr("file_time"));