KGdev.BI3D.Revit.Addin/KGdev.BI3D.Revit.Addin.MainWindow.External.BrowserConnector/MessageHandler.cs

using System;
using System.ComponentModel;
using System.Diagnostics;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Security;
using System.Windows.Forms;

namespace KGdev.BI3D.Revit.Addin.MainWindow.External.BrowserConnector
{
    public partial class MessageHandler : Form
    {
        public IntPtr BrowserHandle { get; private set; }

        [field: DebuggerBrowsable(DebuggerBrowsableState.Never)]
        public event MessageHandler.MessageReceivedEventHandler MessageReceivedEvent;

        public void Send(string message)
        {
            this.DoSend(message);
        }

        private void DoSend(string message)
        {
            MessageHandler.MessageStruct messageStruct = new MessageHandler.MessageStruct
            {
                Message = message
            };
            int num = Marshal.SizeOf<MessageHandler.MessageStruct>(messageStruct);
            IntPtr intPtr = Marshal.AllocHGlobal(num);
            try
            {
                Marshal.StructureToPtr<MessageHandler.MessageStruct>(messageStruct, intPtr, true);
                MessageHandler.COPYDATASTRUCT copydatastruct =
                    default(MessageHandler.COPYDATASTRUCT);
                copydatastruct.cbData = num;
                copydatastruct.lpData = intPtr;
                MessageHandler
                    .NativeMethod
                    .SendMessage(this.BrowserHandle, 74, base.Handle, ref copydatastruct);
                int lastWin32Error = Marshal.GetLastWin32Error();
            }
            finally
            {
                Marshal.FreeHGlobal(intPtr);
            }
        }

        protected override void WndProc(ref Message m)
        {
            bool flag = m.Msg == 74;
            if (flag)
            {
                MessageHandler.COPYDATASTRUCT copydatastruct = (MessageHandler.COPYDATASTRUCT)
                    m.GetLParam(typeof(MessageHandler.COPYDATASTRUCT));
                bool flag2 =
                    copydatastruct.cbData == Marshal.SizeOf(typeof(MessageHandler.MessageStruct));
                if (flag2)
                {
                    MessageHandler.MessageStruct messageStruct = (MessageHandler.MessageStruct)
                        Marshal.PtrToStructure(
                            copydatastruct.lpData,
                            typeof(MessageHandler.MessageStruct)
                        );
                    bool flag3 = messageStruct.Message.StartsWith("handle:");
                    if (flag3)
                    {
                        this.BrowserHandle = new IntPtr(
                            int.Parse(messageStruct.Message.Replace("handle:", ""))
                        );
                    }
                    else
                    {
                        bool flag4 = messageStruct.Message.StartsWith("close:");
                        if (flag4)
                        {
                            this.BrowserHandle = IntPtr.Zero;
                        }
                        else
                        {
                            bool flag5 = messageStruct.Message.StartsWith("execute:");
                            if (flag5)
                            {
                                string text = messageStruct.Message.Replace("execute:", "");
                                MessageHandler.MessageReceivedEventHandler messageReceivedEvent =
                                    this.MessageReceivedEvent;
                                if (messageReceivedEvent != null)
                                {
                                    messageReceivedEvent(this, new MessageReceivedEventArgs(text));
                                }
                            }
                        }
                    }
                }
            }
            base.WndProc(ref m);
        }

        private const int MESSAGE_MAX_SIZE = 16777216;

        private Timer actionHandler = new Timer { Interval = 300 };

        internal const int WM_COPYDATA = 74;

        public delegate void MessageReceivedEventHandler(object sender, MessageReceivedEventArgs e);

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        internal struct MessageStruct
        {
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16777216)]
            public string Message;
        }

        internal struct COPYDATASTRUCT
        {
            public IntPtr dwData;

            public int cbData;

            public IntPtr lpData;
        }

        [SuppressUnmanagedCodeSecurity]
        internal class NativeMethod
        {
            [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
            public static extern IntPtr SendMessage(
                IntPtr hWnd,
                int Msg,
                IntPtr wParam,
                ref MessageHandler.COPYDATASTRUCT lParam
            );
        }
    }
}