UnityDragAndDropHook.cs

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using System;
using System.Collections.Generic;
using System.Text;
using AOT;
 
namespace B83.Win32;
 
public static class UnityDragAndDropHook
{
    public delegate void DroppedFilesEvent(List<string> aPathNames, POINT aDropPoint);
 
    private static uint threadId;
 
    private static IntPtr mainWindow = IntPtr.Zero;
 
    private static IntPtr m_Hook;
 
    private static string m_ClassName = "UnityWndClass";
 
    public static event DroppedFilesEvent OnDroppedFiles;
 
    [MonoPInvokeCallback(typeof(EnumThreadDelegate))]
    private static bool EnumCallback(IntPtr W, IntPtr _)
    {
        if (Window.IsWindowVisible(W) && (mainWindow == IntPtr.Zero || (m_ClassName != null && Window.GetClassName(W) == m_ClassName)))
        {
            mainWindow = W;
        }
        return true;
    }
 
    public static void InstallHook()
    {
        threadId = WinAPI.GetCurrentThreadId();
        if (threadId != 0)
        {
            Window.EnumThreadWindows(threadId, EnumCallback, IntPtr.Zero);
        }
        IntPtr moduleHandle = WinAPI.GetModuleHandle(null);
        m_Hook = WinAPI.SetWindowsHookEx(HookType.WH_GETMESSAGE, Callback, moduleHandle, threadId);
        WinAPI.DragAcceptFiles(mainWindow, fAccept: true);
    }
 
    public static void UninstallHook()
    {
        WinAPI.UnhookWindowsHookEx(m_Hook);
        WinAPI.DragAcceptFiles(mainWindow, fAccept: false);
        m_Hook = IntPtr.Zero;
    }
 
    [MonoPInvokeCallback(typeof(HookProc))]
    private static IntPtr Callback(int code, IntPtr wParam, ref MSG lParam)
    {
        if (code == 0 && lParam.message == WM.DROPFILES)
        {
            WinAPI.DragQueryPoint(lParam.wParam, out var pos);
            uint num = WinAPI.DragQueryFile(lParam.wParam, uint.MaxValue, null, 0u);
            StringBuilder stringBuilder = new StringBuilder(1024);
            List<string> list = new List<string>();
            for (uint num2 = 0u; num2 < num; num2++)
            {
                int num3 = (int)WinAPI.DragQueryFile(lParam.wParam, num2, stringBuilder, 1024u);
                list.Add(stringBuilder.ToString(0, num3));
                stringBuilder.Length = 0;
            }
            WinAPI.DragFinish(lParam.wParam);
            if (UnityDragAndDropHook.OnDroppedFiles != null)
            {
                UnityDragAndDropHook.OnDroppedFiles(list, pos);
            }
        }
        return WinAPI.CallNextHookEx(m_Hook, code, wParam, ref lParam);
    }
}