QuickLook/QuickLook.Plugin/QuickLook.Plugin.PDFViewer/Plugin.cs

// Copyright © 2017-2025 QL-Win Contributors
//
// 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 PdfiumViewer;
using QuickLook.Common.Helpers;
using QuickLook.Common.Plugin;
using System;
using System.IO;
using System.Reflection;
using System.Runtime.ExceptionServices;
using System.Text;
using System.Windows;
using System.Windows.Threading;

namespace QuickLook.Plugin.PDFViewer;

public class Plugin : IViewer
{
    private ContextObject _context;
    private string _path;
    private PdfViewerControl _pdfControl;
    private PasswordControl _passwordControl;

    public int Priority => 0;

    public void Init()
    {
    }

    public bool CanHandle(string path)
    {
        if (Directory.Exists(path))
            return false;

        if (File.Exists(path) && Path.GetExtension(path).ToLower() == ".pdf")
            return true;

        using (var br = new BinaryReader(new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read)))
        {
            return Encoding.ASCII.GetString(br.ReadBytes(4)) == "%PDF";
        }
    }

    public void Prepare(string path, ContextObject context)
    {
        _context = context;
        _path = path;

        try
        {
            var desiredSize = PdfViewerControl.GetDesiredControlSizeByFirstPage(path);
            context.SetPreferredSizeFit(desiredSize, 0.9);
        }
        catch (PdfException ex) when (ex.Message == "Password required or incorrect password")
        {
            // Fallback to a size to request the password
            context.PreferredSize = new Size { Width = 800, Height = 600 };
        }
    }

    public void View(string path, ContextObject context)
    {
        _pdfControl = new PdfViewerControl();
        context.ViewerContent = _pdfControl;

        Exception exception = null;

        _ = _pdfControl.Dispatcher.BeginInvoke(() =>
        {
            try
            {
                _pdfControl.LoadPdf(path);

                context.Title = $"1 / {_pdfControl.TotalPages}: {Path.GetFileName(path)}";

                _pdfControl.CurrentPageChanged += UpdateWindowCaption;
                context.IsBusy = false;
            }
            catch (PdfException ex) when (ex.Message == "Password required or incorrect password")
            {
                // Fallback to request a password
                _passwordControl = new PasswordControl();
                _passwordControl.PasswordRequested += (string password) =>
                {
                    try
                    {
                        var desiredSize = PdfViewerControl.GetDesiredControlSizeByFirstPage(path, password);
                        context.SetPreferredSizeFit(desiredSize, 0.9); // Actually it is no longer effective here
                        context.ViewerContent = _pdfControl;

                        // Call the viewer window private method using reflection
                        // QuickLook.ViewerWindow.ResizeAndCentreExistingWindow
                        if (Window.GetWindow(_pdfControl) is Window window)
                        {
                            var ResizeAndCentreExistingWindow = window.GetType().GetMethod("ResizeAndCentreExistingWindow",
                                BindingFlags.NonPublic | BindingFlags.Instance);

                            if (ResizeAndCentreExistingWindow != null)
                            {
                                var newRect = (Rect)ResizeAndCentreExistingWindow.Invoke(window, [context.PreferredSize]);

                                window.MoveWindow(newRect.Left, newRect.Top, newRect.Width, newRect.Height);
                            }
                        }

                        context.IsBusy = true;
                        _pdfControl.LoadPdf(path, password);

                        context.Title = $"1 / {_pdfControl.TotalPages}: {Path.GetFileName(path)}";

                        _pdfControl.CurrentPageChanged += UpdateWindowCaption;
                        context.IsBusy = false;
                    }
                    catch (PdfException ex) when (ex.Message == "Password required or incorrect password")
                    {
                        // This password is not accepted
                        return false;
                    }

                    // This password is accepted
                    return true;
                };

                context.ViewerContent = _passwordControl;
                context.Title = $"[PASSWORD PROTECTED] {Path.GetFileName(path)}";
                context.IsBusy = false;
            }
            catch (Exception ex)
            {
                exception = ex;
            }
        }, DispatcherPriority.Loaded).Wait();

        if (exception != null)
            ExceptionDispatchInfo.Capture(exception).Throw();
    }

    public void Cleanup()
    {
        GC.SuppressFinalize(this);

        _pdfControl?.Dispose();
        _pdfControl = null;

        _context = null;
    }

    private void UpdateWindowCaption(object sender, EventArgs e2)
    {
        _context.Title = $"{_pdfControl.CurrentPage + 1} / {_pdfControl.TotalPages}: {Path.GetFileName(_path)}";
    }
}