Managed API: Refactoring and formatting.

Signed-off-by: Christoph M. Wintersteiger <cwinter@microsoft.com>

src/api/dotnet/IDecRefQueue.cs

@@ -0,0 +1,92 @@
+/*++
+Copyright (c) 2012 Microsoft Corporation
+
+Module Name:
+
+    DecRefQueue.cs
+
+Abstract:
+
+    Z3 Managed API: DecRef Queues
+
+Author:
+
+    Christoph Wintersteiger (cwinter) 2012-03-16
+
+Notes:
+    
+--*/
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Threading;
+using System.Diagnostics.Contracts;
+
+namespace Microsoft.Z3
+{    
+    [ContractClass(typeof(DecRefQueueContracts))]
+    internal abstract class IDecRefQueue
+    {
+        #region Object invariant
+
+        [ContractInvariantMethod]
+        private void ObjectInvariant()
+        {
+            Contract.Invariant(this.m_queue != null);
+        }
+        
+        #endregion
+
+        readonly internal protected Object m_lock = new Object();
+        readonly internal protected List<IntPtr> m_queue = new List<IntPtr>();
+        internal const uint m_move_limit = 1024;
+
+        public abstract void IncRef(Context ctx, IntPtr obj);
+        public abstract void DecRef(Context ctx, IntPtr obj);
+
+        public void IncAndClear(Context ctx, IntPtr o)
+        {
+            Contract.Requires(ctx != null);
+
+            IncRef(ctx, o);
+            if (m_queue.Count >= m_move_limit) Clear(ctx);
+        }
+
+        public void Add(IntPtr o)
+        {
+            if (o == IntPtr.Zero) return;
+
+            lock (m_lock)
+            {
+                m_queue.Add(o);
+            }
+        }
+
+        public void Clear(Context ctx)
+        {
+            Contract.Requires(ctx != null);
+
+            lock (m_lock)
+            {
+                foreach (IntPtr o in m_queue)
+                    DecRef(ctx, o);
+                m_queue.Clear();
+            }
+        }
+    }
+
+    [ContractClassFor(typeof(IDecRefQueue))]
+    abstract class DecRefQueueContracts : IDecRefQueue
+    {
+        public override void IncRef(Context ctx, IntPtr obj)
+        {
+            Contract.Requires(ctx != null);
+        }
+
+        public override void DecRef(Context ctx, IntPtr obj)
+        {
+            Contract.Requires(ctx != null);
+        }
+    }
+}