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
  40 namespace System
  41 {
  42         // This is a private class that is used as a generic wrapper class
  43         // for COM objects that have no specific wrapper class.
  44         //
  45         // It has no public methods, it's functionality is exposed trough
  46         // System.Runtime.InteropServices.Marshal class and can be casted to
  47         // any interface that is implemented by the wrapped COM object.
  48         //
  49         // This class is referenced in .NET Framework SDK Documentation so
  50         // many times that obj.GetType().FullName == "System.__ComObject" and
  51         // Type.GetType("System.__ComObject") may be used.
  52
  53         internal class __ComObject : MarshalByRefObject
  54         {
  55 #pragma warning disable 169
  56                 #region Sync with object-internals.h
  57                 IntPtr iunknown;
  58                 IntPtr hash_table;
  59                 #endregion
  60 #pragma warning restore 169
  61
  62                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  63                 internal static extern __ComObject CreateRCW (Type t);
  64
  65                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  66                 private extern void ReleaseInterfaces ();
  67
  68                 ~__ComObject ()
  69                 {
  70                         ReleaseInterfaces ();
  71                 }
  72
  73                 public __ComObject ()
  74                 {
  75                         Initialize (GetType ());
  76                 }
  77
  78                 internal __ComObject (Type t) {
  79                         Initialize (t);
  80                 }
  81
  82                 internal __ComObject (IntPtr pItf)
  83                 {
  84                         Guid iid = IID_IUnknown;
  85                         int hr = Marshal.QueryInterface (pItf, ref iid, out iunknown);
  86                         Marshal.ThrowExceptionForHR (hr);
  87                 }
  88
  89                 internal void Initialize (Type t)
  90                 {
  91                         // Guard multiple invocation.
  92                         if (iunknown != IntPtr.Zero)
  93                                 return;
  94
  95                         ObjectCreationDelegate ocd = ExtensibleClassFactory.GetObjectCreationCallback (t);
  96                         if (ocd != null) {
  97                                 iunknown = ocd (IntPtr.Zero);
  98                                 if (iunknown == IntPtr.Zero)
  99                                         throw new COMException (string.Format("ObjectCreationDelegate for type {0} failed to return a valid COM object", t));
 100                         }
 101                         else {
 102                                 int hr = CoCreateInstance (GetCLSID (t), IntPtr.Zero, 0x1 | 0x4 | 0x10, IID_IUnknown, out iunknown);
 103                                 Marshal.ThrowExceptionForHR (hr);
 104                         }
 105                 }
 106
 107                 private static Guid GetCLSID (Type t)
 108                 {
 109                         if (t.IsImport)
 110                                 return t.GUID;
 111
 112                         // look at supertypes
 113                         Type super = t.BaseType;
 114                         while (super != typeof (object)) {
 115                                 if (super.IsImport)
 116                                         return super.GUID;
 117                                 super = super.BaseType;
 118                         }
 119                         throw new COMException ("Could not find base COM type for type " + t.ToString());
 120                 }
 121
 122                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 123                 internal extern IntPtr GetInterfaceInternal (Type t, bool throwException);
 124
 125                 internal IntPtr GetInterface (Type t, bool throwException) {
 126                         CheckIUnknown ();
 127                         return GetInterfaceInternal (t, throwException);
 128                 }
 129
 130                 internal IntPtr GetInterface(Type t)
 131                 {
 132                         return GetInterface (t, true);
 133                 }
 134
 135                 private void CheckIUnknown ()
 136                 {
 137                         if (iunknown == IntPtr.Zero)
 138                                 throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 139                 }
 140
 141                 internal IntPtr IUnknown
 142                 {
 143                         get
 144                         {
 145                                 if (iunknown == IntPtr.Zero)
 146                                         throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 147                                 return iunknown;
 148                         }
 149                 }
 150
 151                 internal IntPtr IDispatch
 152                 {
 153                         get
 154                         {
 155                                 IntPtr pUnk = GetInterface (typeof (IDispatch));
 156                                 if (pUnk == IntPtr.Zero)
 157                                         throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 158                                 return pUnk;
 159                         }
 160                 }
 161
 162                 internal static Guid IID_IUnknown
 163                 {
 164                         get
 165                         {
 166                                 return new Guid("00000000-0000-0000-C000-000000000046");
 167                         }
 168                 }
 169
 170                 internal static Guid IID_IDispatch
 171                 {
 172                         get
 173                         {
 174                                 return new Guid ("00020400-0000-0000-C000-000000000046");
 175                         }
 176                 }
 177
 178                 public override bool Equals (object obj)
 179                 {
 180                         CheckIUnknown ();
 181                         if (obj == null)
 182                                 return false;
 183
 184                         __ComObject co = obj as __ComObject;
 185                         if ((object)co == null)
 186                                 return false;
 187                         return (iunknown == co.IUnknown);
 188                 }
 189
 190                 public override int GetHashCode ()
 191                 {
 192                         CheckIUnknown ();
 193                         // not what MS seems to do,
 194                         // but IUnknown is identity in COM
 195                         return iunknown.ToInt32 ();
 196                 }
 197
 198                 [DllImport ("ole32.dll", CallingConvention = CallingConvention.StdCall, ExactSpelling = true, PreserveSig = true)]
 199                 static extern int CoCreateInstance (
 200                    [In, MarshalAs (UnmanagedType.LPStruct)] Guid rclsid,
 201                    IntPtr pUnkOuter,
 202                    uint dwClsContext,
 203                   [In, MarshalAs (UnmanagedType.LPStruct)] Guid riid,
 204                         out IntPtr pUnk);
 205         }
 206 }