Merge branch 'master' into appveyor

src/net/Qml.Net.Tests/Internal/ObjectTaggerTests.cs

@@ -0,0 +1,90 @@
+using Qml.Net.Internal;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using Xunit;
+using FluentAssertions;
+using System.Threading;
+
+namespace Qml.Net.Tests.Internal
+{
+    public class ObjectTaggerTests : BaseTests
+    {
+        private static void SetMaxIdTo(UInt64 maxId)
+        {
+            var fieldInfo = typeof(ObjectId)
+                                .GetField("MaxId", BindingFlags.NonPublic | BindingFlags.Static);
+            fieldInfo.SetValue(null, maxId);
+        }
+
+        private static void Reset()
+        {
+            var methodInfo = typeof(ObjectId)
+                                .GetMethod("Reset", BindingFlags.NonPublic | BindingFlags.Static);
+            methodInfo.Invoke(null, new object[0]);
+        }
+
+        public ObjectTaggerTests()
+        {
+            Reset();
+        }
+
+        public override void Dispose()
+        {
+            Reset();
+            base.Dispose();
+        }
+
+        [Fact]
+        void Can_detect_id_overflow()
+        {
+            SetMaxIdTo(10);
+            List<object> handledObjects = new List<object>();
+            for(int i=0; i < 9; i++)
+            {
+                var obj = new object();
+                obj.GetOrCreateTag();
+                handledObjects.Add(obj);
+            }
+            var lastObj = new object();
+            Assert.Throws<Exception>(() => { lastObj.GetOrCreateTag(); });
+        }
+
+        [Fact]
+        void Can_handle_id_overflow_by_filling_spots()
+        {
+            SetMaxIdTo(10);
+            List<object> handledObjects = new List<object>();
+            for (int i = 0; i < 9; i++)
+            {
+                var obj = new object();
+                obj.GetOrCreateTag();
+                handledObjects.Add(obj);
+            }
+            //Ids are all used
+            handledObjects.Clear();
+            GC.Collect(2, GCCollectionMode.Forced, true);
+            Thread.Sleep(100);
+            //the next one is the already prepared next id
+            var obj10 = new object();
+            var tag10 = obj10.GetOrCreateTag();
+            tag10.Should().Be(10ul);
+            //the next after that will overflow
+            var obj1 = new object();
+            var tag1 = obj1.GetOrCreateTag();
+            tag1.Should().Be(1ul);
+        }
+
+        [Fact]
+        void Can_deliver_same_tag_for_same_instance()
+        {
+            var obj = new object();
+            var tag1 = obj.GetOrCreateTag();
+            var tag2 = obj.GetOrCreateTag();
+
+            tag1.Should().Be(tag2);
+        }
+    }
+}

src/net/Qml.Net/Internal/ObjectTagger.cs

@@ -32,6 +32,17 @@ namespace Qml.Net.Internal
 
         #region Id management
 
+        //set in unit tests
+        private static UInt64 MaxId = UInt64.MaxValue - 1;
+
+        //used in unit tests
+        private static void Reset()
+        {
+            MaxId = UInt64.MaxValue - 1;
+            NextId = 1;
+            UsedIds.Clear();
+        }
+
         private static UInt64 NextId = 1;
         private static HashSet<UInt64> UsedIds = new HashSet<UInt64>();
 
@@ -48,7 +59,7 @@ namespace Qml.Net.Internal
             bool firstPass = true;
             while (UsedIds.Contains(nextId))
             {
-                if(nextId == UInt64.MaxValue)
+                if(nextId >= MaxId)
                 {
                     if(!firstPass)
                     {
@@ -75,6 +86,11 @@ namespace Qml.Net.Internal
             FreeId(Id);
         }
 
+        ~ObjectId()
+        {
+            FreeId(Id);
+        }
+
         #endregion
     }