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The Labs \ Source Viewer \ SSCLI \ System.Runtime.Remoting.Lifetime \ LifetimeServices

SSCLI
  1. // ==++==
  2. //
  3. //
  4. // Copyright (c) 2006 Microsoft Corporation. All rights reserved.
  5. //
  6. // The use and distribution terms for this software are contained in the file
  7. // named license.txt, which can be found in the root of this distribution.
  8. // By using this software in any fashion, you are agreeing to be bound by the
  9. // terms of this license.
  10. //
  11. // You must not remove this notice, or any other, from this software.
  12. //
  13. //
  14. // ==--==
  15. //+----------------------------------------------------------------------------
  16. //
  17. // Microsoft Windows
  18. // File: LifetimeServices.cs
  19. //
  20. // Contents: Used to obtain a lease
  21. //
  22. // History: 1/5/00 Created
  24. //
  25. //+----------------------------------------------------------------------------
  27. namespace System.Runtime.Remoting.Lifetime
  28. {
  29.    
  30.     using System;
  31.     using System.Threading;
  32.     using System.Security;
  33.     using System.Security.Permissions;
  34.     using System.Runtime.Remoting.Contexts;
  35.     using System.Runtime.Remoting.Messaging;
  36.     using System.Globalization;
  37.    
  38.     // access needs to be restricted
  39.     [SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.Infrastructure)]
  40.     [System.Runtime.InteropServices.ComVisible(true)]
  41.     public sealed class LifetimeServices
  42.     {
  43.         // Set once boolean
  44.         private static bool isLeaseTime = false;
  45.         private static bool isRenewOnCallTime = false;
  46.         private static bool isSponsorshipTimeout = false;
  47.        
  48.         // Default values
  49.         private static TimeSpan m_leaseTime = TimeSpan.FromMinutes(5);
  50.         private static TimeSpan m_renewOnCallTime = TimeSpan.FromMinutes(2);
  51.         private static TimeSpan m_sponsorshipTimeout = TimeSpan.FromMinutes(2);
  52.         private static TimeSpan m_pollTime = TimeSpan.FromMilliseconds(10000);
  53.        
  54.         // Testing values
  55.         //private static TimeSpan m_leaseTime = TimeSpan.FromSeconds(20);
  56.         //private static TimeSpan m_renewOnCallTime = TimeSpan.FromSeconds(20);
  57.         //private static TimeSpan m_sponsorshipTimeout = TimeSpan.FromSeconds(20);
  58.         //private static TimeSpan m_pollTime = TimeSpan.FromMilliseconds(10000);
  59.        
  60.         private static object s_LifetimeSyncObject = null;
  61.        
  62.         private static object LifetimeSyncObject {
  63.             get {
  64.                 if (s_LifetimeSyncObject == null) {
  65.                     object o = new object();
  66.                     Interlocked.CompareExchange(ref s_LifetimeSyncObject, o, null);
  67.                 }
  68.                 return s_LifetimeSyncObject;
  69.             }
  70.         }
  71.        
  72.         // Initial Lease Time span for appdomain
  73.         public static TimeSpan LeaseTime {
  74.             get { return m_leaseTime; }
  75.            
  76.             [SecurityPermissionAttribute(SecurityAction.Demand, Flags = SecurityPermissionFlag.RemotingConfiguration)]
  77.             set {
  78.                 lock (LifetimeSyncObject) {
  79.                     if (isLeaseTime)
  80.                         throw new RemotingException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("Remoting_Lifetime_SetOnce"), "LeaseTime"));
  81.                    
  82.                    
  83.                     m_leaseTime = value;
  84.                     isLeaseTime = true;
  85.                 }
  86.             }
  87.         }
  88.        
  89.        
  90.         // Initial renew on call time span for appdomain
  91.         public static TimeSpan RenewOnCallTime {
  92.            
  93.             get { return m_renewOnCallTime; }
  94.             [SecurityPermissionAttribute(SecurityAction.Demand, Flags = SecurityPermissionFlag.RemotingConfiguration)]
  95.             set {
  96.                 lock (LifetimeSyncObject) {
  97.                     if (isRenewOnCallTime)
  98.                         throw new RemotingException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("Remoting_Lifetime_SetOnce"), "RenewOnCallTime"));
  99.                    
  100.                    
  101.                     m_renewOnCallTime = value;
  102.                     isRenewOnCallTime = true;
  103.                 }
  104.             }
  105.         }
  106.        
  107.        
  108.        
  109.         // Initial sponsorshiptimeout for appdomain
  110.         public static TimeSpan SponsorshipTimeout {
  111.            
  112.             get { return m_sponsorshipTimeout; }
  113.             [SecurityPermissionAttribute(SecurityAction.Demand, Flags = SecurityPermissionFlag.RemotingConfiguration)]
  114.             set {
  115.                 lock (LifetimeSyncObject) {
  116.                     if (isSponsorshipTimeout)
  117.                         throw new RemotingException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("Remoting_Lifetime_SetOnce"), "SponsorshipTimeout"));
  118.                     m_sponsorshipTimeout = value;
  119.                     isSponsorshipTimeout = true;
  120.                 }
  121.             }
  122.         }
  123.        
  124.        
  125.        
  126.         // Initial sponsorshiptimeout for appdomain
  127.         public static TimeSpan LeaseManagerPollTime {
  128.            
  129.             get { return m_pollTime; }
  130.             [SecurityPermissionAttribute(SecurityAction.Demand, Flags = SecurityPermissionFlag.RemotingConfiguration)]
  131.             set {
  132.                 lock (LifetimeSyncObject) {
  133.                     m_pollTime = value;
  134.                     if (LeaseManager.IsInitialized())
  135.                         LeaseManager.GetLeaseManager().ChangePollTime(m_pollTime);
  136.                 }
  137.             }
  138.         }
  139.        
  140.        
  141.        
  142.        
  143.        
  144.         static internal ILease GetLeaseInitial(MarshalByRefObject obj)
  145.         {
  146.             ILease lease = null;
  147.             LeaseManager leaseManager = LeaseManager.GetLeaseManager(LeaseManagerPollTime);
  148.             lease = (ILease)leaseManager.GetLease(obj);
  149.             if (lease == null)
  150.                 lease = CreateLease(obj);
  151.             return lease;
  152.            
  153.         }
  154.        
  155.        
  156.        
  157.         static internal ILease GetLease(MarshalByRefObject obj)
  158.         {
  159.             ILease lease = null;
  160.             LeaseManager leaseManager = LeaseManager.GetLeaseManager(LeaseManagerPollTime);
  161.             lease = (ILease)leaseManager.GetLease(obj);
  162.             return lease;
  163.            
  164.         }
  165.        
  166.        
  167.        
  168.        
  169.         //internal static ILease CreateLease(MarshalByRefObject obj, IMessageSink nextSink)
  170.        
  171.        
  172.         static internal ILease CreateLease(MarshalByRefObject obj)
  173.         {
  174.             return CreateLease(LeaseTime, RenewOnCallTime, SponsorshipTimeout, obj);
  175.            
  176.         }
  177.        
  178.        
  179.        
  180.         static internal ILease CreateLease(TimeSpan leaseTime, TimeSpan renewOnCallTime, TimeSpan sponsorshipTimeout, MarshalByRefObject obj)
  181.         {
  182.             // Will create leaseManager if not already created.
  183.             LeaseManager.GetLeaseManager(LeaseManagerPollTime);
  184.             return (ILease)(new Lease(leaseTime, renewOnCallTime, sponsorshipTimeout, obj));
  185.            
  186.         }
  187.        
  188.     }
  189.    
  190.    
  191.     [Serializable()]
  192.     internal class LeaseLifeTimeServiceProperty : IContextProperty, IContributeObjectSink
  193.     {
  194.        
  195.        
  196.         public string Name {
  197.            
  198.             get { return "LeaseLifeTimeServiceProperty"; }
  199.         }
  200.        
  201.        
  202.        
  203.        
  204.         public bool IsNewContextOK(Context newCtx)
  205.         {
  206.             return true;
  207.            
  208.         }
  209.        
  210.        
  211.        
  212.         public void Freeze(Context newContext)
  213.         {
  214.            
  215.         }
  216.        
  217.        
  218.         // Initiates the creation of a lease
  219.        
  220.         // Creates a sink for invoking a renew on call when an object is created.
  221.        
  222.        
  223.         public IMessageSink GetObjectSink(MarshalByRefObject obj, IMessageSink nextSink)
  224.         {
  225.             bool fServer;
  226.             ServerIdentity identity = (ServerIdentity)MarshalByRefObject.GetIdentity(obj, out fServer);
  227.             BCLDebug.Assert(identity != null, "[LifetimeServices.GetObjectSink] identity != null");
  228.            
  229.             // NOTE: Single Call objects do not have a lease associated with it because they last
  230.             // only for the duration of the call.
  231.             // Singleton objects on the other hand do have leases associated with them and they can
  232.             // be garbage collected.
  233.             if (identity.IsSingleCall()) {
  234.                 BCLDebug.Trace("REMOTE", "LeaseLifeTimeServiceProperty.GetObjectSink, no lease SingleCall", obj, ", NextSink " + nextSink);
  235.                 return nextSink;
  236.             }
  237.            
  238.            
  239.            
  240.             // Create lease. InitializeLifetimeService is a virtual method which can be overridded so that a lease with
  241.             // object specific properties can be created.
  242.             object leaseObj = obj.InitializeLifetimeService();
  243.            
  244.            
  245.             BCLDebug.Trace("REMOTE", "LeaseLifeTimeServiceProperty.GetObjectSink, return from InitializeLifetimeService obj ", obj, ", lease ", leaseObj);
  246.            
  247.            
  248.             // InitializeLifetimeService can return a lease in one of conditions:
  249.             // 1) the lease has a null state which specifies that no lease is to be created.
  250.             // 2) the lease has an initial state which specifies that InitializeLifeTimeService has created a new lease.
  251.             // 3) the lease has another state which indicates that the lease has already been created and registered.
  252.            
  253.            
  254.             if (leaseObj == null) {
  255.                 BCLDebug.Trace("REMOTE", "LeaseLifeTimeServiceProperty.GetObjectSink, no lease ", obj, ", NextSink " + nextSink);
  256.                 return nextSink;
  257.             }
  258.            
  259.             if (!(leaseObj is System.Runtime.Remoting.Lifetime.ILease))
  260.                 throw new RemotingException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("Remoting_Lifetime_ILeaseReturn"), leaseObj));
  261.            
  262.             ILease ilease = (ILease)leaseObj;
  263.            
  264.             if (ilease.InitialLeaseTime.CompareTo(TimeSpan.Zero) <= 0) {
  265.                 // No lease
  266.                 {
  267.                     BCLDebug.Trace("REMOTE", "LeaseLifeTimeServiceProperty.GetObjectSink, no lease because InitialLeaseTime is Zero ", obj);
  268.                     if (ilease is System.Runtime.Remoting.Lifetime.Lease) {
  269.                         ((Lease)ilease).Remove();
  270.                     }
  271.                     return nextSink;
  272.                 }
  273.             }
  274.            
  275.            
  276.             Lease lease = null;
  277.             lock (identity) {
  278.                 if (identity.Lease != null) {
  279.                     // Lease already exists for object, object is being marsalled again
  280.                     BCLDebug.Trace("REMOTE", "LeaseLifeTimeServiceProperty.GetObjectSink, Lease already exists for object ", obj);
  281.                     lease = (Lease)identity.Lease;
  282.                     lease.Renew(lease.InitialLeaseTime);
  283.                     // Reset initial lease time
  284.                 }
  285.                 else {
  286.                     // New lease
  287.                     if (!(ilease is System.Runtime.Remoting.Lifetime.Lease)) {
  288.                         // InitializeLifetimeService created its own ILease object
  289.                         // Need to create a System.Runtime.Remoting.Lease object
  290.                         BCLDebug.Trace("REMOTE", "LeaseLifeTimeServiceProperty.GetObjectSink, New Lease, lease not of type Lease ", obj);
  291.                         lease = (Lease)LifetimeServices.GetLeaseInitial(obj);
  292.                         if (lease.CurrentState == LeaseState.Initial) {
  293.                             lease.InitialLeaseTime = ilease.InitialLeaseTime;
  294.                             lease.RenewOnCallTime = ilease.RenewOnCallTime;
  295.                             lease.SponsorshipTimeout = ilease.SponsorshipTimeout;
  296.                         }
  297.                     }
  298.                     else {
  299.                         // An object of Type Lease was created
  300.                         BCLDebug.Trace("REMOTE", "LeaseLifeTimeServiceProperty.GetObjectSink, New Lease, lease is type Lease ", obj);
  301.                         lease = (Lease)ilease;
  302.                     }
  303.                    
  304.                     // Put lease in active state
  305.                     // Creation phase of lease is over, properties can no longer be set on lease.
  306.                     identity.Lease = lease;
  307.                     // Place lease into identity for object
  308.                     // If the object has been marshaled activate
  309.                     // the lease
  310.                     if (identity.ObjectRef != null) {
  311.                         lease.ActivateLease();
  312.                     }
  313.                 }
  314.             }
  315.            
  316.            
  317.             if (lease.RenewOnCallTime > TimeSpan.Zero) {
  318.                 // RenewOnCall create sink
  319.                 BCLDebug.Trace("REMOTE", "LeaseLifeTimeServiceProperty.GetObjectSink, lease created ", obj);
  320.                 return new LeaseSink(lease, nextSink);
  321.             }
  322.             else {
  323.                 // No RenewOnCall so no sink created
  324.                 BCLDebug.Trace("REMOTE", "LeaseLifeTimeServiceProperty.GetObjectSink, No RenewOnCall so no sink created ", obj);
  325.                 return nextSink;
  326.             }
  327.            
  328.         }
  329.        
  330.     }
  331.    
  332. }

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