mcs/class/corlib/System/__ComObject.cs

   1 //
   2 // System.__ComObject
   3 //
   4 // Authors:
   5 //   Sebastien Pouliot <sebastien@ximian.com>
   6 //   Kornél Pál <http://www.kornelpal.hu/>
   7 //   Jonathan Chambers <joncham@gmail.com>
   8 //
   9 // Copyright (C) 2004 Novell (http://www.novell.com)
  10 // Copyright (C) 2005 Kornél Pál
  11 // Copyright (C) 2006 Jonathan Chambers
  12 //
  13
  14 //
  15 // Permission is hereby granted, free of charge, to any person obtaining
  16 // a copy of this software and associated documentation files (the
  17 // "Software"), to deal in the Software without restriction, including
  18 // without limitation the rights to use, copy, modify, merge, publish,
  19 // distribute, sublicense, and/or sell copies of the Software, and to
  20 // permit persons to whom the Software is furnished to do so, subject to
  21 // the following conditions:
  22 //
  23 // The above copyright notice and this permission notice shall be
  24 // included in all copies or substantial portions of the Software.
  25 //
  26 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  27 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  28 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  29 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  30 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  31 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  32 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  33 //
  34
  35 using Mono.Interop;
  36 using System.Collections;
  37 using System.Runtime.InteropServices;
  38 using System.Runtime.CompilerServices;
  39 using System.Threading;
  40
  41 namespace System
  42 {
  43         // This is a private class that is used as a generic wrapper class
  44         // for COM objects that have no specific wrapper class.
  45         //
  46         // It has no public methods, it's functionality is exposed trough
  47         // System.Runtime.InteropServices.Marshal class and can be casted to
  48         // any interface that is implemented by the wrapped COM object.
  49         //
  50         // This class is referenced in .NET Framework SDK Documentation so
  51         // many times that obj.GetType().FullName == "System.__ComObject" and
  52         // Type.GetType("System.__ComObject") may be used.
  53
  54         internal class __ComObject : MarshalByRefObject
  55         {
  56 #pragma warning disable 169
  57                 #region Sync with object-internals.h
  58                 IntPtr iunknown;
  59                 IntPtr hash_table;
  60                 SynchronizationContext synchronization_context;
  61                 #endregion
  62 #pragma warning restore 169
  63
  64                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  65                 internal static extern __ComObject CreateRCW (Type t);
  66
  67                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  68                 private extern void ReleaseInterfaces ();
  69
  70                 ~__ComObject ()
  71                 {
  72                         if (synchronization_context != null)
  73                                 synchronization_context.Post ((state) => ReleaseInterfaces (), this);
  74                         else
  75                                 ReleaseInterfaces ();
  76                 }
  77
  78                 public __ComObject ()
  79                 {
  80                         Initialize (GetType ());
  81                 }
  82
  83                 internal __ComObject (Type t) {
  84                         Initialize (t);
  85                 }
  86
  87                 internal __ComObject (IntPtr pItf)
  88                 {
  89                         InitializeApartmentDetails ();
  90                         Guid iid = IID_IUnknown;
  91                         int hr = Marshal.QueryInterface (pItf, ref iid, out iunknown);
  92                         Marshal.ThrowExceptionForHR (hr);
  93                 }
  94
  95                 internal void Initialize (Type t)
  96                 {
  97                         InitializeApartmentDetails ();
  98                         // Guard multiple invocation.
  99                         if (iunknown != IntPtr.Zero)
 100                                 return;
 101
 102                         ObjectCreationDelegate ocd = ExtensibleClassFactory.GetObjectCreationCallback (t);
 103                         if (ocd != null) {
 104                                 iunknown = ocd (IntPtr.Zero);
 105                                 if (iunknown == IntPtr.Zero)
 106                                         throw new COMException (string.Format("ObjectCreationDelegate for type {0} failed to return a valid COM object", t));
 107                         }
 108                         else {
 109                                 int hr = CoCreateInstance (GetCLSID (t), IntPtr.Zero, 0x1 | 0x4 | 0x10, IID_IUnknown, out iunknown);
 110                                 Marshal.ThrowExceptionForHR (hr);
 111                         }
 112                 }
 113
 114                 private void InitializeApartmentDetails ()
 115                 {
 116                         // Only synchronization_context if thread is STA.
 117                         if (Thread.CurrentThread.GetApartmentState() != ApartmentState.STA)
 118                                 return;
 119
 120                         synchronization_context = SynchronizationContext.Current;
 121
 122                         // Check whether the current context is a plain SynchronizationContext object
 123                         // and handle this as if no context was set at all.
 124                         if (synchronization_context != null &&
 125                                 synchronization_context.GetType () == typeof(SynchronizationContext))
 126                                 synchronization_context = null;
 127                 }
 128
 129                 private static Guid GetCLSID (Type t)
 130                 {
 131                         if (t.IsImport)
 132                                 return t.GUID;
 133
 134                         // look at supertypes
 135                         Type super = t.BaseType;
 136                         while (super != typeof (object)) {
 137                                 if (super.IsImport)
 138                                         return super.GUID;
 139                                 super = super.BaseType;
 140                         }
 141                         throw new COMException ("Could not find base COM type for type " + t.ToString());
 142                 }
 143
 144                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 145                 internal extern IntPtr GetInterfaceInternal (Type t, bool throwException);
 146
 147                 internal IntPtr GetInterface (Type t, bool throwException) {
 148                         CheckIUnknown ();
 149                         return GetInterfaceInternal (t, throwException);
 150                 }
 151
 152                 internal IntPtr GetInterface(Type t)
 153                 {
 154                         return GetInterface (t, true);
 155                 }
 156
 157                 private void CheckIUnknown ()
 158                 {
 159                         if (iunknown == IntPtr.Zero)
 160                                 throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 161                 }
 162
 163                 internal IntPtr IUnknown
 164                 {
 165                         get
 166                         {
 167                                 if (iunknown == IntPtr.Zero)
 168                                         throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 169                                 return iunknown;
 170                         }
 171                 }
 172
 173                 internal IntPtr IDispatch
 174                 {
 175                         get
 176                         {
 177                                 IntPtr pUnk = GetInterface (typeof (IDispatch));
 178                                 if (pUnk == IntPtr.Zero)
 179                                         throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 180                                 return pUnk;
 181                         }
 182                 }
 183
 184                 internal static Guid IID_IUnknown
 185                 {
 186                         get
 187                         {
 188                                 return new Guid("00000000-0000-0000-C000-000000000046");
 189                         }
 190                 }
 191
 192                 internal static Guid IID_IDispatch
 193                 {
 194                         get
 195                         {
 196                                 return new Guid ("00020400-0000-0000-C000-000000000046");
 197                         }
 198                 }
 199
 200                 public override bool Equals (object obj)
 201                 {
 202                         CheckIUnknown ();
 203                         if (obj == null)
 204                                 return false;
 205
 206                         __ComObject co = obj as __ComObject;
 207                         if ((object)co == null)
 208                                 return false;
 209                         return (iunknown == co.IUnknown);
 210                 }
 211
 212                 public override int GetHashCode ()
 213                 {
 214                         CheckIUnknown ();
 215                         // not what MS seems to do,
 216                         // but IUnknown is identity in COM
 217                         return iunknown.ToInt32 ();
 218                 }
 219
 220                 [DllImport ("ole32.dll", CallingConvention = CallingConvention.StdCall, ExactSpelling = true, PreserveSig = true)]
 221                 static extern int CoCreateInstance (
 222                    [In, MarshalAs (UnmanagedType.LPStruct)] Guid rclsid,
 223                    IntPtr pUnkOuter,
 224                    uint dwClsContext,
 225                   [In, MarshalAs (UnmanagedType.LPStruct)] Guid riid,
 226                         out IntPtr pUnk);
 227         }
 228 }