[c++/m] Add Source referringDataArray method

Adds the referringDataArray method to the Source
entity on c++ and matlab side and introduces a
corresponding test.

Author: mpsonntag

+nix/Source.m

@@ -53,5 +53,10 @@
             retObj = nix.Utils.fetchObj('Source::parentSource', ...
                 obj.nix_handle, @nix.Source);
         end
+
+        function retObj = referring_data_arrays(obj)
+            retObj = nix.Utils.fetchObjList('Source::referringDataArrays', ...
+                obj.nix_handle, @nix.DataArray);
+        end
     end;
 end

nix_mx.cc

@@ -244,7 +244,8 @@ void mexFunction(int            nlhs,
             .reg("setDefinition", SETTER(const std::string&, nix::Source, definition))
             .reg("setNoneDefinition", SETTER(const boost::none_t, nix::Source, definition))
             .reg("parentSource", GETTER(nix::Source, nix::Source, parentSource))
-            .reg("sourceCount", GETTER(nix::ndsize_t, nix::Source, sourceCount));
+            .reg("sourceCount", GETTER(nix::ndsize_t, nix::Source, sourceCount))
+            .reg("referringDataArrays", GETTER(std::vector<nix::DataArray>, nix::Source, referringDataArrays));
 
         classdef<nix::Tag>("Tag", methods)
             .desc(&nixtag::describe)

tests/TestSource.m

@@ -21,6 +21,7 @@
     funcs{end+1} = @test_parent_source;
     funcs{end+1} = @test_set_metadata;
     funcs{end+1} = @test_open_metadata;
+    funcs{end+1} = @test_referring_data_arrays;
 end
 
 %% Test: fetch sources
@@ -206,3 +207,22 @@
     assert(strcmp(s3.parent_source.name, sourceName2));
     assert(strcmp(s2.parent_source.name, sourceName1));
 end
+
+%% Test: Referring data arrays
+function [] = test_referring_data_arrays( varargin )
+    fileName = fullfile(pwd, 'tests', 'testRW.h5');
+    f = nix.File(fileName, nix.FileMode.Overwrite);
+    b = f.create_block('testBlock', 'nixBlock');
+    s = b.create_source('testSource', 'nixSource');
+
+    assert(isempty(s.referring_data_arrays));
+
+    d1 = b.create_data_array('testDataArray1', 'nixDataArray', nix.DataType.Double, [1 2]);
+    d1.add_source(s);
+    assert(~isempty(s.referring_data_arrays));
+    assert(strcmp(s.referring_data_arrays{1}.name, d1.name));
+
+    d2 = b.create_data_array('testDataArray2', 'nixDataArray', nix.DataType.Double, [1 2]);
+    d2.add_source(s);
+    assert(size(s.referring_data_arrays, 1) == 2);
+end