class/corlib/System.Runtime.InteropServices/ExtensibleClassFactory.cs

   1 //
   2 // System.Runtime.InteropServices.ExtensibleClassFactory.cs
   3 //
   4 // Author:
   5 //   Andreas Nahr (ClassDevelopment@A-SoftTech.com)
   6 //   Jonathan Chambers (joncham@gmail.com)
   7 //
   8
   9 //
  10 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  11 // Copyright (C) 2006 Jonathan Chambers
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining
  14 // a copy of this software and associated documentation files (the
  15 // "Software"), to deal in the Software without restriction, including
  16 // without limitation the rights to use, copy, modify, merge, publish,
  17 // distribute, sublicense, and/or sell copies of the Software, and to
  18 // permit persons to whom the Software is furnished to do so, subject to
  19 // the following conditions:
  20 //
  21 // The above copyright notice and this permission notice shall be
  22 // included in all copies or substantial portions of the Software.
  23 //
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  31 //
  32
  33 using System.Diagnostics;
  34 using System.Collections;
  35 using System.Reflection;
  36
  37 namespace System.Runtime.InteropServices
  38 {
  39         [ComVisible (true)]
  40         public sealed class ExtensibleClassFactory
  41         {
  42                 static Hashtable hashtable;
  43
  44                 static ExtensibleClassFactory ()
  45                 {
  46                         hashtable = new Hashtable ();
  47                 }
  48
  49                 private ExtensibleClassFactory ()
  50                 {
  51                 }
  52
  53                 internal static ObjectCreationDelegate GetObjectCreationCallback (Type t)
  54                 {
  55                         return hashtable[t] as ObjectCreationDelegate;
  56                 }
  57
  58                 public static void RegisterObjectCreationCallback (ObjectCreationDelegate callback) {
  59                         int i = 1;
  60                         StackTrace trace = new StackTrace (false);
  61                         while (i < trace.FrameCount) {
  62                                 StackFrame frame = trace.GetFrame (i);
  63                                 MethodBase m = frame.GetMethod ();
  64                                 if (m.MemberType == MemberTypes.Constructor && m.IsStatic) {
  65                                         hashtable.Add (m.DeclaringType, callback);
  66                                         return;
  67                                 }
  68                                 i++;
  69                         }
  70                         throw new System.InvalidOperationException (
  71                                 "RegisterObjectCreationCallback must be called from .cctor of class derived from ComImport type.");
  72                 }
  73         }
  74 }