mono/tests/bug-10127.cs

   1 using System;
   2 using System.Threading;
   3 using System.Collections.Generic;
   4 using System.Runtime.InteropServices;
   5
   6 namespace WeakReferenceTest
   7 {
   8         public static class Cache {
   9                 static GCHandle[] table = new GCHandle[1024 * 1024];
  10
  11                 public static T Probe<T>(int hc) where T : class
  12                 {
  13                         int index = hc & (table.Length - 1);
  14                         lock (table)
  15                         {
  16                                 var wr = table[index];
  17                                 if (!wr.IsAllocated)
  18                                         return null;
  19                                 return wr.Target as T;
  20                         }
  21                 }
  22
  23                 public static T Add<T>(T obj, int hc) where T : class
  24                 {
  25                         int index = hc & (table.Length - 1);
  26                         lock (table)
  27                         {
  28                                 table[index] = GCHandle.Alloc (obj, GCHandleType.Weak);
  29                         }
  30                         return obj;
  31                 }
  32
  33         }
  34
  35         public class Tester {
  36                 public static readonly int seed = unchecked(DateTime.Now.Ticks.GetHashCode());
  37
  38                 Random rand = new Random(seed);
  39
  40                 bool alive;
  41                 Thread thread;
  42
  43                 public void Start()
  44                 {
  45                         alive = true;
  46                         thread = new Thread(new ThreadStart(Work));
  47                         thread.Start();
  48                 }
  49
  50                 void Work()
  51                 {
  52                         do {
  53
  54                                 var item = rand.Next ();
  55                                 var probed = Cache.Probe<object>(item.GetHashCode());
  56
  57                                 if (probed == null) {
  58                                         Cache.Add<object>(item, item.GetHashCode());
  59                                 }
  60
  61                                 if (rand.NextDouble() <= 0.1) {
  62                                         GC.Collect();
  63                                 }
  64
  65                         } while (alive);
  66                 }
  67
  68                 public void Stop ()
  69                 {
  70                         alive = false;
  71                 }
  72
  73         }
  74
  75         static class RandHelper {
  76                 public static string RandString(this Random rand, int len)
  77                 {
  78                         char[] table = new char[len];
  79                         for (int idx = 0; idx < len; idx++) {
  80                                 table[idx] = (char) ('a' + idx);
  81                         }
  82                         return new string(table, 0, len);
  83                 }
  84         }
  85
  86         class MainClass
  87         {
  88                 public static void Main (string[] args)
  89                 {
  90                         Console.WriteLine("Starting cache testers");
  91                         Console.WriteLine("Thread seed: " + Tester.seed);
  92                         List<Tester> testers = new List<Tester>();
  93                         for (int count = 0; count < 10; count++) {
  94                                 testers.Add(new Tester());
  95                         }
  96
  97                         foreach (var tester in testers) {
  98                                 tester.Start();
  99                         }
 100
 101                         for (int i = 0; i < 4; ++i)
 102                         {
 103                                 Thread.Sleep(TimeSpan.FromSeconds(1));
 104                         }
 105
 106                         foreach (var tester in testers)
 107                         {
 108                                 tester.Stop ();
 109                         }
 110                 }
 111         }
 112 }