mcs/class/referencesource/mscorlib/system/sharedstatics.cs

   1 // ==++==
   2 //
   3 //   Copyright (c) Microsoft Corporation.  All rights reserved.
   4 //
   5 // ==--==
   6 /*=============================================================================
   7 **
   8 ** Class: SharedStatics
   9 **
  10 **
  11 ** Purpose: Container for statics that are shared across AppDomains.
  12 **
  13 **
  14 =============================================================================*/
  15
  16 namespace System {
  17
  18     using System.Threading;
  19     using System.Runtime.Remoting;
  20     using System.Security;
  21     using System.Security.Util;
  22     using System.Runtime.CompilerServices;
  23     using System.Runtime.ConstrainedExecution;
  24     using System.Diagnostics.Contracts;
  25 #if FEATURE_CAS_POLICY || FEATURE_LEGACYNETCFCRYPTO || MONO
  26     using StringMaker = System.Security.Util.Tokenizer.StringMaker;
  27 #endif // FEATURE_CAS_POLICY
  28
  29     internal sealed class SharedStatics
  30     {
  31 #if MONO
  32         // TODO: We are using only GetSharedStringMaker for now which is
  33         // ok to be AppDomain static
  34         static readonly SharedStatics _sharedStatics = new SharedStatics();
  35
  36         private SharedStatics()
  37         {
  38         }
  39 #else
  40         // this is declared static but is actually forced to be the same object
  41         // for each AppDomain at AppDomain create time.
  42         private static SharedStatics _sharedStatics;
  43
  44         // Note: Do not add any code in this ctor because it is not called
  45         // when we set up _sharedStatics via AppDomain::SetupSharedStatics
  46         private SharedStatics()
  47         {
  48             BCLDebug.Assert(false, "SharedStatics..ctor() is never called.");
  49         }
  50 #endif
  51
  52         private volatile String _Remoting_Identity_IDGuid;
  53         public static String Remoting_Identity_IDGuid
  54         {
  55             [System.Security.SecuritySafeCritical]  // auto-generated
  56             get
  57             {
  58                 if (_sharedStatics._Remoting_Identity_IDGuid == null)
  59                 {
  60                     bool tookLock = false;
  61                     RuntimeHelpers.PrepareConstrainedRegions();
  62                     try {
  63                         Monitor.Enter(_sharedStatics, ref tookLock);
  64
  65                         if (_sharedStatics._Remoting_Identity_IDGuid == null)
  66                         {
  67                             _sharedStatics._Remoting_Identity_IDGuid = Guid.NewGuid().ToString().Replace('-', '_');
  68                         }
  69                     }
  70                     finally {
  71                         if (tookLock)
  72                             Monitor.Exit(_sharedStatics);
  73                     }
  74                 }
  75
  76                 Contract.Assert(_sharedStatics._Remoting_Identity_IDGuid != null,
  77                                 "_sharedStatics._Remoting_Identity_IDGuid != null");
  78                 return _sharedStatics._Remoting_Identity_IDGuid;
  79             }
  80         }
  81
  82 #if FEATURE_CAS_POLICY || FEATURE_LEGACYNETCFCRYPTO || MONO
  83         private StringMaker _maker;
  84         [System.Security.SecuritySafeCritical]  // auto-generated
  85         static public StringMaker GetSharedStringMaker()
  86         {
  87             StringMaker maker = null;
  88
  89             bool tookLock = false;
  90             RuntimeHelpers.PrepareConstrainedRegions();
  91             try {
  92                 Monitor.Enter(_sharedStatics, ref tookLock);
  93
  94                 if (_sharedStatics._maker != null)
  95                 {
  96                     maker = _sharedStatics._maker;
  97                     _sharedStatics._maker = null;
  98                 }
  99             }
 100             finally {
 101                 if (tookLock)
 102                     Monitor.Exit(_sharedStatics);
 103             }
 104
 105             if (maker == null)
 106             {
 107                 maker = new StringMaker();
 108             }
 109
 110             return maker;
 111         }
 112
 113         [System.Security.SecuritySafeCritical]  // auto-generated
 114         static public void ReleaseSharedStringMaker(ref StringMaker maker)
 115         {
 116             // save this stringmaker so someone else can use it
 117             bool tookLock = false;
 118             RuntimeHelpers.PrepareConstrainedRegions();
 119             try
 120             {
 121                 Monitor.Enter(_sharedStatics, ref tookLock);
 122
 123                 _sharedStatics._maker = maker;
 124                 maker = null;
 125             }
 126             finally {
 127                 if (tookLock)
 128                     Monitor.Exit(_sharedStatics);
 129             }
 130         }
 131 #endif // FEATURE_CAS_POLICY
 132
 133         // Note this may not need to be process-wide.
 134         private int _Remoting_Identity_IDSeqNum;
 135         internal static int Remoting_Identity_GetNextSeqNum()
 136         {
 137             return Interlocked.Increment(ref _sharedStatics._Remoting_Identity_IDSeqNum);
 138         }
 139
 140
 141         // This is the total amount of memory currently "reserved" via
 142         // all MemoryFailPoints allocated within the process.
 143         // Stored as a long because we need to use Interlocked.Add.
 144         private long _memFailPointReservedMemory;
 145
 146         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
 147         internal static long AddMemoryFailPointReservation(long size)
 148         {
 149             // Size can legitimately be negative - see Dispose.
 150             return Interlocked.Add(ref _sharedStatics._memFailPointReservedMemory, (long) size);
 151         }
 152
 153         internal static ulong MemoryFailPointReservedMemory {
 154             get {
 155                 Contract.Assert(Volatile.Read(ref _sharedStatics._memFailPointReservedMemory) >= 0, "Process-wide MemoryFailPoint reserved memory was negative!");
 156                 return (ulong) Volatile.Read(ref _sharedStatics._memFailPointReservedMemory);
 157             }
 158         }
 159     }
 160 }