ClientSponsor.cs

using System.Collections;
using System.Runtime.InteropServices;
using System.Security;
using System.Security.Permissions;

namespace System.Runtime.Remoting.Lifetime
{
    [SecurityCritical]
    [ComVisible(true)]
    [SecurityPermission(SecurityAction.InheritanceDemand, Flags = SecurityPermissionFlag.Infrastructure)]
    public class ClientSponsor : MarshalByRefObject, ISponsor
    {
        private Hashtable sponsorTable = new Hashtable(10);

        private TimeSpan m_renewalTime = TimeSpan.FromMinutes(2.0);

        public TimeSpan RenewalTime
        {
            get
            {
                return m_renewalTime;
            }
            set
            {
                m_renewalTime = value;
            }
        }

        public ClientSponsor()
        {
        }

        public ClientSponsor(TimeSpan renewalTime)
        {
            m_renewalTime = renewalTime;
        }

        [SecurityCritical]
        public bool Register(MarshalByRefObject obj)
        {
            ILease lease = (ILease)obj.GetLifetimeService();
            if (lease == null)
            {
                return false;
            }
            lease.Register(this);
            lock (sponsorTable)
            {
                sponsorTable[obj] = lease;
            }
            return true;
        }

        [SecurityCritical]
        public void Unregister(MarshalByRefObject obj)
        {
            ILease lease = null;
            lock (sponsorTable)
            {
                lease = (ILease)sponsorTable[obj];
            }
            lease?.Unregister(this);
        }

        [SecurityCritical]
        public TimeSpan Renewal(ILease lease)
        {
            return m_renewalTime;
        }

        [SecurityCritical]
        public void Close()
        {
            lock (sponsorTable)
            {
                IDictionaryEnumerator enumerator = sponsorTable.GetEnumerator();
                while (enumerator.MoveNext())
                {
                    ((ILease)enumerator.Value).Unregister(this);
                }
                sponsorTable.Clear();
            }
        }

        [SecurityCritical]
        public override object InitializeLifetimeService()
        {
            return null;
        }

        [SecuritySafeCritical]
        ~ClientSponsor()
        {
        }
    }
}