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         [StructLayout (LayoutKind.Sequential)]
  55         internal class __ComObject : MarshalByRefObject
  56         {
  57 #pragma warning disable 169
  58                 #region Sync with object-internals.h
  59                 IntPtr iunknown;
  60                 IntPtr hash_table;
  61                 SynchronizationContext synchronization_context;
  62                 #endregion
  63 #pragma warning restore 169
  64
  65                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  66                 internal static extern __ComObject CreateRCW (Type t);
  67
  68                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  69                 private extern void ReleaseInterfaces ();
  70
  71                 ~__ComObject ()
  72                 {
  73                         if (synchronization_context != null)
  74                                 synchronization_context.Post ((state) => ReleaseInterfaces (), this);
  75                         else
  76                                 ReleaseInterfaces ();
  77                 }
  78
  79                 public __ComObject ()
  80                 {
  81                         Initialize (GetType ());
  82                 }
  83
  84                 internal __ComObject (Type t) {
  85                         Initialize (t);
  86                 }
  87
  88                 internal __ComObject (IntPtr pItf)
  89                 {
  90                         InitializeApartmentDetails ();
  91                         Guid iid = IID_IUnknown;
  92                         int hr = Marshal.QueryInterface (pItf, ref iid, out iunknown);
  93                         Marshal.ThrowExceptionForHR (hr);
  94                 }
  95
  96                 internal void Initialize (Type t)
  97                 {
  98                         InitializeApartmentDetails ();
  99                         // Guard multiple invocation.
 100                         if (iunknown != IntPtr.Zero)
 101                                 return;
 102
 103                         System.Runtime.CompilerServices.RuntimeHelpers.RunClassConstructor (t.TypeHandle);
 104
 105                         ObjectCreationDelegate ocd = ExtensibleClassFactory.GetObjectCreationCallback (t);
 106                         if (ocd != null) {
 107                                 iunknown = ocd (IntPtr.Zero);
 108                                 if (iunknown == IntPtr.Zero)
 109                                         throw new COMException (string.Format("ObjectCreationDelegate for type {0} failed to return a valid COM object", t));
 110                         }
 111                         else {
 112                                 int hr = CoCreateInstance (GetCLSID (t), IntPtr.Zero, 0x1 | 0x4 | 0x10, IID_IUnknown, out iunknown);
 113                                 Marshal.ThrowExceptionForHR (hr);
 114                         }
 115                 }
 116
 117                 private void InitializeApartmentDetails ()
 118                 {
 119                         // Only synchronization_context if thread is STA.
 120                         if (Thread.CurrentThread.GetApartmentState() != ApartmentState.STA)
 121                                 return;
 122
 123                         synchronization_context = SynchronizationContext.Current;
 124
 125                         // Check whether the current context is a plain SynchronizationContext object
 126                         // and handle this as if no context was set at all.
 127                         if (synchronization_context != null &&
 128                                 synchronization_context.GetType () == typeof(SynchronizationContext))
 129                                 synchronization_context = null;
 130                 }
 131
 132                 private static Guid GetCLSID (Type t)
 133                 {
 134                         if (t.IsImport)
 135                                 return t.GUID;
 136
 137                         // look at supertypes
 138                         Type super = t.BaseType;
 139                         while (super != typeof (object)) {
 140                                 if (super.IsImport)
 141                                         return super.GUID;
 142                                 super = super.BaseType;
 143                         }
 144                         throw new COMException ("Could not find base COM type for type " + t.ToString());
 145                 }
 146
 147                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 148                 internal extern IntPtr GetInterfaceInternal (Type t, bool throwException);
 149
 150                 internal IntPtr GetInterface (Type t, bool throwException) {
 151                         CheckIUnknown ();
 152                         return GetInterfaceInternal (t, throwException);
 153                 }
 154
 155                 internal IntPtr GetInterface(Type t)
 156                 {
 157                         return GetInterface (t, true);
 158                 }
 159
 160                 private void CheckIUnknown ()
 161                 {
 162                         if (iunknown == IntPtr.Zero)
 163                                 throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 164                 }
 165
 166                 internal IntPtr IUnknown
 167                 {
 168                         get
 169                         {
 170                                 if (iunknown == IntPtr.Zero)
 171                                         throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 172                                 return iunknown;
 173                         }
 174                 }
 175
 176                 internal IntPtr IDispatch
 177                 {
 178                         get
 179                         {
 180                                 IntPtr pUnk = GetInterface (typeof (IDispatch));
 181                                 if (pUnk == IntPtr.Zero)
 182                                         throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 183                                 return pUnk;
 184                         }
 185                 }
 186
 187                 internal static Guid IID_IUnknown
 188                 {
 189                         get
 190                         {
 191                                 return new Guid("00000000-0000-0000-C000-000000000046");
 192                         }
 193                 }
 194
 195                 internal static Guid IID_IDispatch
 196                 {
 197                         get
 198                         {
 199                                 return new Guid ("00020400-0000-0000-C000-000000000046");
 200                         }
 201                 }
 202
 203                 public override bool Equals (object obj)
 204                 {
 205                         CheckIUnknown ();
 206                         if (obj == null)
 207                                 return false;
 208
 209                         __ComObject co = obj as __ComObject;
 210                         if ((object)co == null)
 211                                 return false;
 212                         return (iunknown == co.IUnknown);
 213                 }
 214
 215                 public override int GetHashCode ()
 216                 {
 217                         CheckIUnknown ();
 218                         // not what MS seems to do,
 219                         // but IUnknown is identity in COM
 220                         return iunknown.ToInt32 ();
 221                 }
 222
 223                 [DllImport ("ole32.dll", CallingConvention = CallingConvention.StdCall, ExactSpelling = true, PreserveSig = true)]
 224                 static extern int CoCreateInstance (
 225                    [In, MarshalAs (UnmanagedType.LPStruct)] Guid rclsid,
 226                    IntPtr pUnkOuter,
 227                    uint dwClsContext,
 228                   [In, MarshalAs (UnmanagedType.LPStruct)] Guid riid,
 229                         out IntPtr pUnk);
 230         }
 231 }