// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
using System.Diagnostics;
using System.IO;
using System.Net.Sockets;
using System.Runtime.InteropServices;
using Microsoft.Win32.SafeHandles;
 
namespace System.IO.Ports
{
    internal sealed class SafeSerialDeviceHandle : SafeHandleMinusOneIsInvalid
    {
        public SafeSerialDeviceHandle() : base(ownsHandle: true)
        {
        }
 
        internal static SafeSerialDeviceHandle Open(string portName)
        {
            Debug.Assert(portName != null);
            SafeSerialDeviceHandle handle = Interop.Serial.SerialPortOpen(portName);
 
            if (handle.IsInvalid)
            {
                handle.Dispose();
 
                // exception type is matching Windows
                throw new UnauthorizedAccessException(
                    SR.Format(SR.UnauthorizedAccess_IODenied_Port, portName),
                    Interop.GetIOException(Interop.Sys.GetLastErrorInfo()));
            }
 
            return handle;
        }
 
        protected override bool ReleaseHandle()
        {
            Interop.Serial.Shutdown(handle, SocketShutdown.Both);
            int result = Interop.Serial.SerialPortClose(handle);
 
            Debug.Assert(result == 0, $"Close failed with result {result} and error {Interop.Sys.GetLastErrorInfo()}");
 
            return result == 0;
        }
    }
}