From 4d2759eb780358975959535d35b92a0c9d46bd70 Mon Sep 17 00:00:00 2001
From: the_fiddler <the_fiddler@ebc5dd9b-fb1d-0410-b6f8-d24c324e9604>
Date: Fri, 22 Oct 2010 07:41:56 +0000
Subject: [PATCH] * XI2Mouse.cs: * X11Factory.cs: Detect whether XInput2 is not
 supported without   throwing an exception.

---
 Source/OpenTK/Platform/X11/X11Factory.cs | 13 +++----
 Source/OpenTK/Platform/X11/XI2Mouse.cs   | 45 ++++++++++++++++--------
 2 files changed, 35 insertions(+), 23 deletions(-)

diff --git a/Source/OpenTK/Platform/X11/X11Factory.cs b/Source/OpenTK/Platform/X11/X11Factory.cs
index 96dd6162..a5a82c08 100644
--- a/Source/OpenTK/Platform/X11/X11Factory.cs
+++ b/Source/OpenTK/Platform/X11/X11Factory.cs
@@ -85,15 +85,10 @@ namespace OpenTK.Platform.X11
 
         public virtual OpenTK.Input.IMouseDriver CreateMouseDriver()
         {
-            try
-            {
-                // Only supported on xorg 1.7 or higher.
-                return new XI2Mouse(null);
-            }
-            catch (NotSupportedException) { }
-
-            // Should always be supported.
-            return new X11Mouse(null);
+            if (XI2Mouse.IsSupported(IntPtr.Zero))
+                return new XI2Mouse(null); // Requires xorg 1.7 or higher.
+            else
+                return new X11Mouse(null); // Always supported.
         }
 
         #endregion
diff --git a/Source/OpenTK/Platform/X11/XI2Mouse.cs b/Source/OpenTK/Platform/X11/XI2Mouse.cs
index b4026905..c92984fd 100644
--- a/Source/OpenTK/Platform/X11/XI2Mouse.cs
+++ b/Source/OpenTK/Platform/X11/XI2Mouse.cs
@@ -41,7 +41,7 @@ namespace OpenTK.Platform.X11
         Dictionary<int, int> rawids = new Dictionary<int, int>(); // maps raw ids to mouse ids
         int first_mouse;
         readonly X11WindowInfo window;
-        readonly int XIOpCode;
+        static int XIOpCode;
 
         static readonly Functions.EventPredicate PredicateImpl = IsEventValid;
         readonly IntPtr Predicate = Marshal.GetFunctionPointerForDelegate(PredicateImpl);
@@ -65,25 +65,40 @@ namespace OpenTK.Platform.X11
                 }
             }
 
-            using (new XLock(window.Display))
-            {
-                int major, ev, error;
-                if (Functions.XQueryExtension(window.Display, "XInputExtension", out major, out ev, out error) == 0)
-                {
-                    Debug.WriteLine("XInput2 not supported.");
-                    throw new NotSupportedException();
-                }
-                XIOpCode = major;
+            if (!IsSupported(window.Display))
+                throw new NotSupportedException("XInput2 not supported.");
 
-                using (XIEventMask mask = new XIEventMask(1, XIEventMasks.RawButtonPressMask |
+            using (XIEventMask mask = new XIEventMask(1, XIEventMasks.RawButtonPressMask |
                     XIEventMasks.RawButtonReleaseMask | XIEventMasks.RawMotionMask))
-                {
-                    Functions.XISelectEvents(window.Display, window.WindowHandle, mask);
-                }
+            {
+                Functions.XISelectEvents(window.Display, window.WindowHandle, mask);
             }
+
             Debug.WriteLine("Using XI2Mouse.");
         }
 
+        // Checks whether XInput2 is supported on the specified display.
+        // If a display is not specified, the default display is used.
+        internal static bool IsSupported(IntPtr display)
+        {
+            if (display == IntPtr.Zero)
+                display = API.DefaultDisplay;
+
+            using (new XLock(display))
+            {
+                int major, ev, error;
+                if (Functions.XQueryExtension(display, "XInputExtension", out major, out ev, out error) == 0)
+                {
+                    return false;
+                }
+                XIOpCode = major;
+            }
+
+            return true;
+        }
+
+        #region IMouseDriver Members
+
         // Todo: remove this
         public IList<MouseDevice> Mouse { get { throw new NotSupportedException(); } }
 
@@ -105,6 +120,8 @@ namespace OpenTK.Platform.X11
                 return new MouseState();
         }
 
+        #endregion
+
         void ProcessEvents()
         {
             while (true)