Native Client Visual Studio Add-in

visual_studio/NativeClientVSAddIn/UnitTests/ComMessageFilter.cs

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+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
+  {
+    /// <summary>
+    /// Note this registers the filter only for the current thread.
+    /// </summary>
+    public static void Register()
+    {
+      IOleMessageFilter oldFilter = null;
+      CoRegisterMessageFilter(new ComMessageFilter(), out oldFilter);
+    }
+
+    /// <summary>
+    /// Note this only closes the filter for the current thread.
+    /// </summary>
+    public static void Revoke()
+    {
+      IOleMessageFilter oldFilter = null;
+      CoRegisterMessageFilter(null, out oldFilter);
+    }
+
+    /// <summary>
+    /// Handles calls for the thread
+    /// </summary>
+    /// <param name="dwCallType">Unused</param>
+    /// <param name="hTaskCaller">Unused</param>
+    /// <param name="dwTickCount">Unused</param>
+    /// <param name="lpInterfaceInfo">Unused</param>
+    /// <returns>Code indicating message was handled</returns>
+    int IOleMessageFilter.HandleInComingCall(int dwCallType, System.IntPtr hTaskCaller,
+        int dwTickCount, System.IntPtr lpInterfaceInfo)
+    {
+      return 0;  // SERVERCALL_ISHANDLED.
+    }
+
+    /// <summary>
+    /// Automatically retries the failed call
+    /// </summary>
+    /// <param name="hTaskCallee">Unused</param>
+    /// <param name="dwTickCount">Unused</param>
+    /// <param name="dwRejectType">Unused</param>
+    /// <returns>Code indicating call should be retried</returns>
+    int IOleMessageFilter.RetryRejectedCall(System.IntPtr hTaskCallee,
+        int dwTickCount, int dwRejectType)
+    {
+      if (dwRejectType == 2) // SERVERCALL_RETRYLATER
+      {
+        // Immediate retry
+        return 99;
+      }
+      // Cancel call
+      return -1;
+    }
+
+    /// <summary>
+    /// Handles an incoming message by indicating it should be dispatched always
+    /// </summary>
+    /// <param name="hTaskCallee">Unused</param>
+    /// <param name="dwTickCount">Unused</param>
+    /// <param name="dwPendingType"><Unused/param>
+    /// <returns>Code indicating message should be dispatched</returns>
+    int IOleMessageFilter.MessagePending(System.IntPtr hTaskCallee, 
+        int dwTickCount, int dwPendingType)
+    {
+      return 2; // PENDINGMSG_WAITDEFPROCESS
+    }
+
+    // Implement the IOleMessageFilter interface.
+    [DllImport("Ole32.dll")]
+    private static extern int CoRegisterMessageFilter(
+        IOleMessageFilter newFilter, out IOleMessageFilter oldFilter);
+  }
+
+  /// <summary>
+  /// Interface for IOleMessageFilter
+  /// </summary>
+  [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);
+  }
+}