Test that RW-mode in group-based mode still works

Also simplify control flow in JSONIOHandler to work more similar to RW
mode

Author: franzpoeschel

src/IO/JSON/JSONIOHandlerImpl.cpp

@@ -123,25 +123,17 @@ namespace openPMD
                     "[JSON] Could not create directory." );
             }
 
-            associateWithFile(
-                writable,
-                shared_name
-            );
-            this->m_dirty
-                .emplace( shared_name );
-            // make sure to overwrite!
-            this->m_jsonVals[shared_name] =
-                std::make_shared< nlohmann::json >( );
-
-            // start off with already written contents if available
-            // @todo Do the same in READ_WRITE mode in ::openFile()?
-            auto const & fullName = fullPath(name);
-            if( m_handler->m_backendAccess == Access::APPEND
-                && auxiliary::file_exists(fullName))
+            associateWithFile( writable, shared_name );
+            this->m_dirty.emplace( shared_name );
+
+            if( m_handler->m_backendAccess != Access::APPEND )
             {
-                std::ifstream handle(fullName);
-                handle >> *this->m_jsonVals[shared_name];
+                // make sure to overwrite!
+                this->m_jsonVals[ shared_name ] =
+                    std::make_shared< nlohmann::json >();
             }
+            // else: the JSON value is not available in m_jsonVals and will be
+            // read from the file later on before overwriting
 
             writable->written = true;
             writable->abstractFilePosition =

test/SerialIOTest.cpp

@@ -4855,3 +4855,103 @@ TEST_CASE( "append_mode_filebased", "[serial]" )
         append_mode_filebased( t );
     }
 }
+
+void groupbased_read_write( std::string const & ext )
+{
+    int data = 0;
+    Dataset ds( Datatype::INT, { 1 } );
+    std::string filename = "../samples/groupbased_read_write." + ext;
+
+    {
+        Series write( filename, Access::CREATE );
+        auto E_x = write.iterations[ 0 ].meshes[ "E" ][ "x" ];
+        auto E_y = write.iterations[ 0 ].meshes[ "E" ][ "y" ];
+        E_x.resetDataset( ds );
+        E_y.resetDataset( ds );
+        E_x.storeChunk( shareRaw( &data ), { 0 }, { 1 } );
+        E_y.storeChunk( shareRaw( &data ), { 0 }, { 1 } );
+
+        E_x.setAttribute( "updated_in_run", 0 );
+        E_y.setAttribute( "updated_in_run", 0 );
+    }
+
+    {
+        Series write( filename, Access::READ_WRITE );
+        // create a new iteration
+        auto E_x = write.iterations[ 1 ].meshes[ "E" ][ "x" ];
+        E_x.resetDataset( ds );
+
+        // overwrite old dataset
+        auto E_y = write.iterations[ 0 ].meshes[ "E" ][ "y" ];
+
+        data = 1;
+
+        E_x.storeChunk( shareRaw( &data ), { 0 }, { 1 } );
+        E_y.storeChunk( shareRaw( &data ), { 0 }, { 1 } );
+
+        E_x.setAttribute( "updated_in_run", 1 );
+        E_y.setAttribute( "updated_in_run", 1 );
+    }
+
+    {
+        Series read( filename, Access::READ_ONLY );
+        auto E_x_0_fromRun0 = read.iterations[ 0 ].meshes[ "E" ][ "x" ];
+        auto E_x_1_fromRun1 = read.iterations[ 1 ].meshes[ "E" ][ "x" ];
+        auto E_y_0_fromRun1 = read.iterations[ 0 ].meshes[ "E" ][ "y" ];
+
+        REQUIRE(
+            E_x_0_fromRun0.getAttribute( "updated_in_run" ).get< int >() == 0 );
+        REQUIRE(
+            E_x_1_fromRun1.getAttribute( "updated_in_run" ).get< int >() == 1 );
+        REQUIRE(
+            E_y_0_fromRun1.getAttribute( "updated_in_run" ).get< int >() == 1 );
+
+        auto chunk_E_x_0_fromRun0 =
+            E_x_0_fromRun0.loadChunk< int >( { 0 }, { 1 } );
+        auto chunk_E_x_1_fromRun1 =
+            E_x_1_fromRun1.loadChunk< int >( { 0 }, { 1 } );
+        auto chunk_E_y_0_fromRun1 =
+            E_y_0_fromRun1.loadChunk< int >( { 0 }, { 1 } );
+
+        read.flush();
+
+        REQUIRE( *chunk_E_x_0_fromRun0 == 0 );
+        REQUIRE( *chunk_E_x_1_fromRun1 == 1 );
+        REQUIRE( *chunk_E_y_0_fromRun1 == 1 );
+    }
+
+    // check that truncation works correctly
+    {
+        Series write( filename, Access::CREATE );
+        // create a new iteration
+        auto E_x = write.iterations[ 2 ].meshes[ "E" ][ "x" ];
+        E_x.resetDataset( ds );
+
+        data = 2;
+
+        E_x.storeChunk( shareRaw( &data ), { 0 }, { 1 } );
+        E_x.setAttribute( "updated_in_run", 2 );
+    }
+
+    {
+        Series read( filename, Access::READ_ONLY );
+        REQUIRE( read.iterations.size() == 1 );
+        REQUIRE( read.iterations.count( 2 ) == 1 );
+    }
+}
+
+TEST_CASE( "groupbased_read_write", "[serial]" )
+{
+    constexpr char const * supportsGroupbasedRW[] = { "h5", "json" };
+    for( auto const & t : testedFileExtensions() )
+    {
+        for( auto const supported : supportsGroupbasedRW )
+        {
+            if( t == supported )
+            {
+                groupbased_read_write( t );
+                break;
+            }
+        }
+    }
+}