Make SpaceNav disposable, remove lock

SpaceNav.cs

@@ -3,13 +3,12 @@ using System.Runtime.InteropServices;
 
 namespace spnavwrapper
 {
-	public sealed class SpaceNav
+	public sealed class SpaceNav : IDisposable
 	{
 		double _sensitivity = 1.0;
 		int _threshold = 5;
 
-		static SpaceNav instance = null;
-		static readonly object padlock = new object();
+		static SpaceNav instance;
 
 		const int SPNAV_EVENT_MOTION = 1;
 		const int SPNAV_EVENT_BUTTON = 2;
@@ -53,7 +52,7 @@ namespace spnavwrapper
 		[DllImport(DLL_NAME)]
 		static extern int spnav_sensitivity(double sens);
 		[DllImport(DLL_NAME)]
-        static extern int spnav_deadzone(int threshold);
+		static extern int spnav_deadzone(int threshold);
 
 		SpaceNav()
 		{
@@ -61,107 +60,110 @@ namespace spnavwrapper
 			spnav_open(SPNAV_VENDOR_ID, SPNAV_PRODUCT_ID);
 		}
 
-		~SpaceNav()
-		{
-			// TODO : handle retcode
-			spnav_close();
-		}
-
 		public static SpaceNav Instance
 		{
 			get
 			{
-				lock (padlock)
+				if (instance == null)
 				{
-					if (instance == null)
-					{
-						instance = new SpaceNav();
-					}
-					return instance;
+					instance = new SpaceNav();
 				}
+				return instance;
 			}
 		}
 
 		public void CloseDevice()
 		{
-			lock (padlock)
-			{
-				spnav_close();
-				instance = null;
-			}
+			spnav_close();
+			instance = null;
 		}
 
 		public SpaceNavEvent WaitEvent()
 		{
-			lock (padlock)
+			SpNavEvent sev = new SpNavEvent();
+			spnav_wait_event(ref sev);
+			switch (sev.type)
 			{
-				SpNavEvent sev = new SpNavEvent();
-				spnav_wait_event(ref sev);
-				switch (sev.type)
-				{
-					case SPNAV_EVENT_BUTTON:
-						return new SpaceNavButtonEvent(Convert.ToBoolean(sev.button.press), sev.button.bnum);
-					case SPNAV_EVENT_MOTION:
-						var ev = sev.motion;
-						return new SpaceNavMotionEvent(ev.x, ev.y, ev.z, ev.rx, ev.ry, ev.rz);
-					default:
-						return null;
-				}
+				case SPNAV_EVENT_BUTTON:
+					return new SpaceNavButtonEvent(Convert.ToBoolean(sev.button.press), sev.button.bnum);
+				case SPNAV_EVENT_MOTION:
+					var ev = sev.motion;
+					return new SpaceNavMotionEvent(ev.x, ev.y, ev.z, ev.rx, ev.ry, ev.rz);
+				default:
+					return null;
 			}
 		}
 
 		public SpaceNavEvent WaitEvent(int milliseconds)
 		{
-			lock (padlock)
+			SpNavEvent sev = new SpNavEvent();
+			int ev_type = spnav_wait_event_timeout(ref sev, milliseconds);
+			switch (ev_type)
 			{
-				SpNavEvent sev = new SpNavEvent();
-				int ev_type = spnav_wait_event_timeout(ref sev, milliseconds);
-				switch (ev_type)
-				{
-					case SPNAV_EVENT_BUTTON:
-						return new SpaceNavButtonEvent(Convert.ToBoolean(sev.button.press), sev.button.bnum);
-					case SPNAV_EVENT_MOTION:
-						var ev = sev.motion;
-						return new SpaceNavMotionEvent(ev.x, ev.y, ev.z, ev.rx, ev.ry, ev.rz);
-					default:
-						return null;
-				}
+				case SPNAV_EVENT_BUTTON:
+					return new SpaceNavButtonEvent(Convert.ToBoolean(sev.button.press), sev.button.bnum);
+				case SPNAV_EVENT_MOTION:
+					var ev = sev.motion;
+					return new SpaceNavMotionEvent(ev.x, ev.y, ev.z, ev.rx, ev.ry, ev.rz);
+				default:
+					return null;
 			}
 		}
 
 		public double Sensitivity
-        {
-            get
+		{
+			get
 			{
 				return _sensitivity;
 			}
 
 			set
 			{
-				lock (padlock)
-				{
-					// TODO : handle retcode
-					spnav_sensitivity(value);
-					_sensitivity = value;
-				}
+				// TODO : handle retcode
+				spnav_sensitivity(value);
+				_sensitivity = value;
 			}
 		}
 
 		public int Threshold
-        {
+		{
 			get
 			{
 				return _threshold;
 			}
-            set
+			set
 			{
-				lock (padlock)
-				{
-					// TODO : handle retcode
-					spnav_deadzone(value);
-					_threshold = value;
-				}
+				// TODO : handle retcode
+				spnav_deadzone(value);
+				_threshold = value;
 			}
-        }
+		}
+
+		#region IDisposable Support
+		private bool disposedValue = false; // To detect redundant calls
+
+		void Dispose(bool disposing)
+		{
+			if (!disposedValue)
+			{
+				// Free unmanaged resources
+				spnav_close();
+				disposedValue = true;
+			}
+		}
+
+		~SpaceNav()
+		{
+			// Do not change this code. Put cleanup code in Dispose(bool disposing) above.
+			Dispose(false);
+		}
+
+		// This code added to correctly implement the disposable pattern.
+		public void Dispose()
+		{
+			Dispose(true);
+			GC.SuppressFinalize(this);
+		}
+		#endregion
 	}
 }