Implement SafeResourceVariableHandle as a wrapper for TFE_ResourceVariable

src/TensorFlowNET.Core/Variables/SafeResourceVariableHandle.cs

@@ -0,0 +1,40 @@
+/*****************************************************************************
+   Copyright 2018 The TensorFlow.NET Authors. All Rights Reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+******************************************************************************/
+
+using System;
+using Tensorflow.Util;
+
+namespace Tensorflow.Variables
+{
+    public sealed class SafeResourceVariableHandle : SafeTensorflowHandle
+    {
+        private SafeResourceVariableHandle()
+        {
+        }
+
+        public SafeResourceVariableHandle(IntPtr handle)
+            : base(handle)
+        {
+        }
+
+        protected override bool ReleaseHandle()
+        {
+            c_api.TFE_DeleteResourceVariable(handle);
+            SetHandle(IntPtr.Zero);
+            return true;
+        }
+    }
+}

src/TensorFlowNET.Core/Variables/c_api.variable.cs

@@ -1,22 +1,21 @@
 using System;
-using System.Collections.Generic;
 using System.Runtime.InteropServices;
-using System.Text;
+using Tensorflow.Variables;
 
 namespace Tensorflow
 {
     public partial class c_api
     {
         [DllImport(TensorFlowLibName)]
-        public static extern IntPtr TFE_NewResourceVariable();
+        public static extern SafeResourceVariableHandle TFE_NewResourceVariable();
 
         [DllImport(TensorFlowLibName)]
         public static extern void TFE_DeleteResourceVariable(IntPtr variable);
 
         [DllImport(TensorFlowLibName)]
-        public static extern void TFE_SetResourceVariableHandle(IntPtr variable, IntPtr tensor);
+        public static extern void TFE_SetResourceVariableHandle(SafeResourceVariableHandle variable, IntPtr tensor);
 
         [DllImport(TensorFlowLibName)]
-        public static extern void TFE_SetResourceVariableName(IntPtr variable, string name);
+        public static extern void TFE_SetResourceVariableName(SafeResourceVariableHandle variable, string name);
     }
 }