QuickLook/QuickLook/NativeMethods/QuickLook.cs

// Copyright © 2017 Paddy Xu
// 
// This file is part of QuickLook program.
// 
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

using System;
using System.Diagnostics;
using System.IO;
using System.Runtime.InteropServices;
using System.Runtime.InteropServices.ComTypes;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace QuickLook.NativeMethods
{
    internal static class QuickLook
    {
        private const int MaxPath = 32767;

        [DllImport("QuickLook.Native32.dll", EntryPoint = "Init",
            CallingConvention = CallingConvention.Cdecl)]
        private static extern void Init_32();

        [DllImport("QuickLook.Native32.dll", EntryPoint = "GetFocusedWindowType",
            CallingConvention = CallingConvention.Cdecl)]
        private static extern FocusedWindowType GetFocusedWindowTypeNative_32();

        [DllImport("QuickLook.Native32.dll", EntryPoint = "GetCurrentSelection",
            CallingConvention = CallingConvention.Cdecl)]
        private static extern void GetCurrentSelectionNative_32([MarshalAs(UnmanagedType.LPWStr)] StringBuilder sb);

        [DllImport("QuickLook.Native64.dll", EntryPoint = "Init",
            CallingConvention = CallingConvention.Cdecl)]
        private static extern void Init_64();

        [DllImport("QuickLook.Native64.dll", EntryPoint = "GetFocusedWindowType",
            CallingConvention = CallingConvention.Cdecl)]
        private static extern FocusedWindowType GetFocusedWindowTypeNative_64();

        [DllImport("QuickLook.Native64.dll", EntryPoint = "GetCurrentSelection",
            CallingConvention = CallingConvention.Cdecl)]
        private static extern void GetCurrentSelectionNative_64([MarshalAs(UnmanagedType.LPWStr)] StringBuilder sb);

        internal static void Init()
        {
            try
            {
                if (App.Is64Bit)
                    Init_64();
                else
                    Init_32();
            }
            catch (Exception e)
            {
                Debug.WriteLine(e);
            }
        }

        internal static FocusedWindowType GetFocusedWindowType()
        {
            try
            {
                return App.Is64Bit ? GetFocusedWindowTypeNative_64() : GetFocusedWindowTypeNative_32();
            }
            catch (Exception e)
            {
                Debug.WriteLine(e);
                return FocusedWindowType.Invalid;
            }
        }

        internal static string GetCurrentSelection()
        {
            StringBuilder sb = new StringBuilder(MaxPath);
            // communicate with COM in a separate STA thread
            var thread = new Thread(() =>
            {
                try
                {
                    if (App.Is64Bit)
                        GetCurrentSelectionNative_64(sb);
                    else
                        GetCurrentSelectionNative_32(sb);
                }
                catch (Exception e)
                {
                    Debug.WriteLine(e);
                }
            });
            thread.SetApartmentState(ApartmentState.STA);
            thread.Start();
            thread.Join();
            return ResolveShortcut(sb?.ToString() ?? string.Empty);
        }

        private static string ResolveShortcut(string path)
        {
            if (string.IsNullOrEmpty(path)) return path;

            if (Path.GetExtension(path).ToLower() != ".lnk") return path;

            var link = new ShellLink();
            ((IPersistFile) link).Load(path, 0);
            var sb = new StringBuilder(MaxPath);
            ((IShellLinkW) link).GetPath(sb, sb.Capacity, out _, 0);

            return sb.Length == 0 ? path : sb.ToString();
        }

        internal enum FocusedWindowType
        {
            Invalid,
            Desktop,
            Explorer,
            Dialog,
            Everything,
            DOpus,
            MultiCommander
        }
    }
}