//------------------------------------------------------------------------------
// <copyright file="IPersistStreamInit.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>                                                                
//------------------------------------------------------------------------------
 
namespace System.Messaging.Interop
{
    using System;
    using System.Runtime.InteropServices;
    using Microsoft.Win32.SafeHandles;
 
    internal class MessageQueueHandle : SafeHandleZeroOrMinusOneIsInvalid
    {
 
        public static readonly MessageQueueHandle InvalidHandle = new InvalidMessageQueueHandle();
 
        MessageQueueHandle() : base(true) { }
 
 
        protected override bool ReleaseHandle()
        {
            SafeNativeMethods.MQCloseQueue(this.handle);
 
            return true;
        }
 
        public override bool IsInvalid
        {
            get { return base.IsInvalid || IsClosed; }
        }
 
 
        // A subclass needed to express InvalidHandle. The reason is that CLR notices that 
        // ReleaseHandle requires a call to MQRT.DLL, and throws in the ctor if MQRT.DLL is not available,
        // even though CTOR ITSELF DOES NOT REQUIRE MQRT.DLL. 
        // We address this by defining a NOOP ReleaseHandle
        sealed class InvalidMessageQueueHandle : MessageQueueHandle
        {
 
            protected override bool ReleaseHandle()
            {
                return true;
            }
        }
    }
 
 
    internal class CursorHandle : SafeHandleZeroOrMinusOneIsInvalid
    {
 
        public static readonly CursorHandle NullHandle = new InvalidCursorHandle();
 
        protected CursorHandle() : base(true) { }
 
        protected override bool ReleaseHandle()
        {
            SafeNativeMethods.MQCloseCursor(this.handle);
 
            return true;
        }
 
        public override bool IsInvalid
        {
            get { return base.IsInvalid || IsClosed; }
        }
 
 
        // A subclass needed to express InvalidHandle. The reason is that CLR notices that 
        // ReleaseHandle requires a call to MQRT.DLL, and throws in the ctor if MQRT.DLL is not available,
        // even though CTOR ITSELF DOES NOT REQUIRE MQRT.DLL. 
        // We address this by defining a NOOP ReleaseHandle
        sealed class InvalidCursorHandle : CursorHandle
        {
 
            protected override bool ReleaseHandle()
            {
                return true;
            }
        }
    }
 
 
    internal class LocatorHandle : SafeHandleZeroOrMinusOneIsInvalid
    {
 
        public static readonly LocatorHandle InvalidHandle = new InvalidLocatorHandle();
 
        protected LocatorHandle() : base(true) { }
 
        protected override bool ReleaseHandle()
        {
            SafeNativeMethods.MQLocateEnd(this.handle);
 
            return true;
        }
 
        public override bool IsInvalid
        {
            get { return base.IsInvalid || IsClosed; }
        }
 
 
        // A subclass needed to express InvalidHandle. The reason is that CLR notices that 
        // ReleaseHandle requires a call to MQRT.DLL, and throws in the ctor if MQRT.DLL is not available,
        // even though CTOR ITSELF DOES NOT REQUIRE MQRT.DLL. 
        // We address this by defining a NOOP ReleaseHandle
        sealed class InvalidLocatorHandle : LocatorHandle
        {
 
            protected override bool ReleaseHandle()
            {
                return true;
            }
        }
    }
 
 
 
 
    internal sealed class SecurityContextHandle : SafeHandleZeroOrMinusOneIsInvalid
    {
 
        internal SecurityContextHandle(IntPtr existingHandle)
            : base(true)
        {
            SetHandle(existingHandle);
        }
 
        protected override bool ReleaseHandle()
        {
            SafeNativeMethods.MQFreeSecurityContext(this.handle);
 
            return true;
        }
 
        public override bool IsInvalid
        {
            get { return base.IsInvalid || IsClosed; }
        }
    }
}