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                 #region Sync with object-internals.h
  56                 IntPtr iunknown;
  57                 IntPtr hash_table;
  58                 #endregion
  59
  60                 [ThreadStatic]
  61                 static bool coinitialized;
  62
  63                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  64                 internal static extern __ComObject CreateRCW (Type t);
  65
  66                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  67                 private static extern void AddInterface (__ComObject co, Type t, IntPtr pItf);
  68
  69                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  70                 private static extern IntPtr FindInterface (__ComObject co, Type t);
  71
  72                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  73                 private extern void ReleaseInterfaces ();
  74
  75                 ~__ComObject ()
  76                 {
  77                         ReleaseInterfaces ();
  78                 }
  79
  80                 public __ComObject ()
  81                 {
  82                         // call CoInitialize once per thread
  83                         if (!coinitialized) {
  84                                 CoInitialize (IntPtr.Zero);
  85                                 coinitialized = true;
  86                         }
  87
  88                         Type t = GetType ();
  89                         int hr = CoCreateInstance (GetCLSID (t), IntPtr.Zero, 0x1 | 0x4 | 0x10, IID_IUnknown, out iunknown);
  90                         Marshal.ThrowExceptionForHR (hr);
  91                 }
  92
  93                 internal __ComObject (Type t)
  94                 {
  95                         // call CoInitialize once per thread
  96                         if (!coinitialized) {
  97                                 CoInitialize (IntPtr.Zero);
  98                                 coinitialized = true;
  99                         }
 100
 101                         int hr = CoCreateInstance (GetCLSID (t), IntPtr.Zero, 0x1 | 0x4 | 0x10, IID_IUnknown, out iunknown);
 102                         Marshal.ThrowExceptionForHR (hr);
 103                 }
 104
 105                 internal __ComObject (IntPtr pItf)
 106                 {
 107                         Guid iid = IID_IUnknown;
 108                         int hr = Marshal.QueryInterface (pItf, ref iid, out iunknown);
 109                         Marshal.ThrowExceptionForHR (hr);
 110                 }
 111
 112                 private static Guid GetCLSID (Type t)
 113                 {
 114                         if (t.IsImport)
 115                                 return t.GUID;
 116
 117                         // look at supertypes
 118                         Type super = t.BaseType;
 119                         while (super != typeof (object)) {
 120                                 if (super.IsImport)
 121                                         return super.GUID;
 122                                 super = super.BaseType;
 123                         }
 124                         throw new COMException ("Could not find base COM type for type " + t.ToString());
 125                 }
 126
 127                 internal IntPtr GetInterface(Type t)
 128                 {
 129                         CheckIUnknown ();
 130                         IntPtr pItf = FindInterface (this, t);
 131                         if (pItf != IntPtr.Zero) {
 132                                 return pItf;
 133                         }
 134
 135                         Guid iid = t.GUID;
 136                         IntPtr ppv;
 137                         int hr = Marshal.QueryInterface (iunknown, ref iid, out ppv);
 138                         Marshal.ThrowExceptionForHR (hr);
 139                         AddInterface (this, t, ppv);
 140                         return ppv;
 141                 }
 142
 143                 private void CheckIUnknown ()
 144                 {
 145                         if (iunknown == IntPtr.Zero)
 146                                 throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 147                 }
 148
 149                 internal IntPtr IUnknown
 150                 {
 151                         get
 152                         {
 153                                 if (iunknown == IntPtr.Zero)
 154                                         throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 155                                 return iunknown;
 156                         }
 157                 }
 158
 159                 internal IntPtr IDispatch
 160                 {
 161                         get
 162                         {
 163                                 IntPtr pUnk = GetInterface (typeof (IDispatch));
 164                                 if (pUnk == IntPtr.Zero)
 165                                         throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 166                                 return pUnk;
 167                         }
 168                 }
 169
 170                 internal static Guid IID_IUnknown
 171                 {
 172                         get
 173                         {
 174                                 return new Guid("00000000-0000-0000-C000-000000000046");
 175                         }
 176                 }
 177
 178                 internal static Guid IID_IDispatch
 179                 {
 180                         get
 181                         {
 182                                 return new Guid ("00020400-0000-0000-C000-000000000046");
 183                         }
 184                 }
 185
 186                 public override bool Equals (object obj)
 187                 {
 188                         CheckIUnknown ();
 189                         if (obj == null)
 190                                 return false;
 191
 192                         __ComObject co = obj as __ComObject;
 193                         if ((object)co == null)
 194                                 return false;
 195                         return (iunknown == co.IUnknown);
 196                 }
 197
 198                 public override int GetHashCode ()
 199                 {
 200                         CheckIUnknown ();
 201                         // not what MS seems to do,
 202                         // but IUnknown is identity in COM
 203                         return iunknown.ToInt32 ();
 204                 }
 205
 206                 [DllImport ("ole32.dll", CallingConvention = CallingConvention.StdCall)]
 207                 static extern int CoInitialize (IntPtr pvReserved);
 208
 209                 [DllImport ("ole32.dll", CallingConvention = CallingConvention.StdCall, ExactSpelling = true, PreserveSig = true)]
 210                 static extern int CoCreateInstance (
 211                    [In, MarshalAs (UnmanagedType.LPStruct)] Guid rclsid,
 212                    IntPtr pUnkOuter,
 213                    uint dwClsContext,
 214                   [In, MarshalAs (UnmanagedType.LPStruct)] Guid riid,
 215                         out IntPtr pUnk);
 216         }
 217 }