mono/tests/sgen-bridge-gchandle.cs

   1 using System;
   2 using System.Collections;
   3 using System.Threading;
   4 using System.Runtime.InteropServices;
   5
   6
   7 public class Bridge {
   8         public int __test;
   9         public string id;
  10
  11         ~Bridge () {
  12                 try {Console.WriteLine ("bridge {0} gone", id);} catch (Exception) {}
  13         }
  14 }
  15
  16
  17 /*
  18 Test scenario:
  19         Alloc a bridge and create a gc handle to it
  20         Get it collected.
  21         Create another one and see it steal the handle of the previous one.
  22
  23
  24 */
  25 class Driver {
  26         public static GCHandle weak_track_handle;
  27         public static GCHandle weak_track_handle2;
  28
  29         static void CreateFirstBridge () {
  30                 Bridge b = new Bridge() {
  31                         __test = 0,
  32                         id = "first",
  33                 };
  34                 weak_track_handle = GCHandle.Alloc (b, GCHandleType.WeakTrackResurrection);
  35         }
  36
  37         static void CreateSecondBridge () {
  38                 Bridge b = new Bridge() {
  39                         __test = 1,
  40                         id = "second",
  41                 };
  42                 weak_track_handle2 = GCHandle.Alloc (b, GCHandleType.WeakTrackResurrection);
  43         }
  44
  45         static void DumpHandle (GCHandle h, string name) {
  46                 Console.WriteLine ("{0}:{1:X} alloc:{2} hasValue:{2}", name, (IntPtr)h, h.IsAllocated, h.Target == null);
  47         }
  48
  49         static int Main () {
  50                 var t = new Thread (CreateFirstBridge);
  51                 t.Start ();
  52                 t.Join ();
  53
  54                 GC.Collect ();
  55                 GC.WaitForPendingFinalizers ();
  56                 Console.WriteLine ("GC DONE");
  57
  58                 DumpHandle (weak_track_handle, "weak-track1");
  59
  60                 t = new Thread (CreateSecondBridge);
  61                 t.Start ();
  62                 t.Join ();
  63
  64                 GC.Collect ();
  65                 GC.WaitForPendingFinalizers ();
  66                 Console.WriteLine ("GC DONE");
  67                 DumpHandle (weak_track_handle, "weak-track1");
  68                 DumpHandle (weak_track_handle2, "weak-track2");
  69                 Console.WriteLine ("DONE");
  70
  71                 if ((IntPtr)weak_track_handle == (IntPtr)weak_track_handle2) {
  72                         Console.WriteLine ("FIRST HANDLE GOT DEALLOCATED!");
  73                         return 1;
  74                 }
  75
  76                 return 0;
  77         }
  78 }