Native Client Visual Studio Add-in

visual_studio/NativeClientVSAddIn/UnitTests/ComMessageFilter.cs

+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using EnvDTE;
+using EnvDTE80;
+using System.Runtime.InteropServices;
+
+namespace UnitTests
+{
+    /// <summary>
+    /// This class receives messages from the COM calls to Visual Studio
+    /// and auto-retries them if they fail because VS is busy
+    /// </summary>
+    public class ComMessageFilter : IOleMessageFilter
+    {
+        // Start the filter.
+        // Note that this registers the filter only for the current thread
+        public static void Register()
+        {
+            IOleMessageFilter newFilter = new ComMessageFilter(); 
+            IOleMessageFilter oldFilter = null; 
+            CoRegisterMessageFilter(newFilter, out oldFilter);
+        }
+
+        // Done with the filter, close it.
+        // Note that this revokes the filter only for the current thread
+        public static void Revoke()
+        {
+            IOleMessageFilter oldFilter = null; 
+            CoRegisterMessageFilter(null, out oldFilter);
+        }
+
+        // Handle incoming thread requests.
+        int IOleMessageFilter.HandleInComingCall(int dwCallType, 
+          System.IntPtr hTaskCaller, int dwTickCount, System.IntPtr 
+          lpInterfaceInfo) 
+        {
+            //Return the flag SERVERCALL_ISHANDLED.
+            return 0;
+        }
+
+        // Thread call was rejected, so try again.
+        int IOleMessageFilter.RetryRejectedCall(System.IntPtr 
+          hTaskCallee, int dwTickCount, int dwRejectType)
+        {
+            if (dwRejectType == 2)
+            // flag = SERVERCALL_RETRYLATER.
+            {
+                // Retry the thread call immediately if return >=0 & 
+                // <100.
+                return 99;
+            }
+            // Too busy; cancel call.
+            return -1;
+        }
+
+        int IOleMessageFilter.MessagePending(System.IntPtr hTaskCallee, 
+          int dwTickCount, int dwPendingType)
+        {
+            //Return the flag PENDINGMSG_WAITDEFPROCESS.
+            return 2;
+        }
+
+        // Implement the IOleMessageFilter interface.
+        [DllImport("Ole32.dll")]
+        private static extern int 
+          CoRegisterMessageFilter(IOleMessageFilter newFilter, out 
+          IOleMessageFilter oldFilter);
+    }
+
+    [ComImport(), Guid("00000016-0000-0000-C000-000000000046"), 
+    InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)]
+    interface IOleMessageFilter 
+    {
+        [PreserveSig]
+        int HandleInComingCall( 
+            int dwCallType, 
+            IntPtr hTaskCaller, 
+            int dwTickCount, 
+            IntPtr lpInterfaceInfo);
+
+        [PreserveSig]
+        int RetryRejectedCall( 
+            IntPtr hTaskCallee, 
+            int dwTickCount,
+            int dwRejectType);
+
+        [PreserveSig]
+        int MessagePending( 
+            IntPtr hTaskCallee, 
+            int dwTickCount,
+            int dwPendingType);
+    }
+}