mcs/class/corlib/System.Runtime.InteropServices/GCHandle.cs

   1 using System;
   2 using System.Runtime.CompilerServices;
   3 using System.Runtime.InteropServices;
   4 namespace System.Runtime.InteropServices
   5 {
   6         /// <summary>
   7         /// Summary description for GCHandle.
   8         /// </summary>
   9         public struct GCHandle
  10         {
  11                 // fields
  12                 private IntPtr handle;
  13                 private GCHandleType handleType;
  14
  15                 // Constructors
  16                 private GCHandle(object obj)
  17                         : this(obj, GCHandleType.Normal)
  18                 {}
  19
  20                 private GCHandle(object value, GCHandleType type)
  21                 {
  22                         handle = IntPtr.Zero;
  23                         handleType = type;
  24                 }
  25
  26                 // Properties
  27
  28                 public bool IsAllocated
  29                 {
  30                         get
  31                         {
  32                                 return (handle != IntPtr.Zero);
  33                         }
  34                 }
  35
  36                 public object Target
  37                 {
  38                         get
  39                         {
  40                                 return GetTarget(handle);
  41                         }
  42                         set
  43                         {
  44                                 SetTarget(handle,value);
  45                         }
  46                 }
  47
  48                 // Methods
  49                 public IntPtr AddrOfPinnedObject()
  50                 {
  51                         if(this.handleType == System.Runtime.InteropServices.GCHandleType.Pinned)
  52                         {
  53                                 throw new InvalidOperationException("The handle is not of Pinned type");
  54                         }
  55                         return GetAddrOfPinnedObject();
  56                 }
  57
  58                 public static System.Runtime.InteropServices.GCHandle Alloc(object value)
  59                 {
  60                         return new GCHandle(value);
  61                 }
  62
  63                 public static System.Runtime.InteropServices.GCHandle Alloc(object value, GCHandleType type)
  64                 {
  65                         return new GCHandle(value,type);
  66                 }
  67
  68                 public void Free()
  69                 {
  70                         FreeHandle(handle);
  71                         handle = IntPtr.Zero;
  72                 }
  73                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  74                 public extern static explicit operator IntPtr(GCHandle value);
  75                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  76                 public extern static explicit operator GCHandle(IntPtr value);
  77
  78                 //TODO: Private Native Functions
  79                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  80                 private extern object GetTarget(IntPtr pointer);
  81
  82                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  83                 private extern void SetTarget(IntPtr pointer,object obj);
  84
  85                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  86                 private extern void FreeHandle(IntPtr pointer);
  87
  88                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  89                 private extern IntPtr GetAddrOfPinnedObject();
  90         }
  91 }