Merge OfficeViewer-Native plugin #1662

Repo URL: https://github.com/QL-Win/QuickLook.Plugin.OfficeViewer-Native

QuickLook.Plugin/QuickLook.Plugin.OfficeViewer/PreviewHandlerHost.cs

@@ -0,0 +1,169 @@
+// 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 System;
+using System.ComponentModel;
+using System.Drawing;
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Windows.Forms;
+using Microsoft.Win32;
+
+namespace QuickLook.Plugin.OfficeViewer;
+
+/// <summary>
+/// A Windows Forms host for Preview Handlers.
+/// </summary>
+public class PreviewHandlerHost : Control
+{
+    /// <summary>
+    /// The GUID for the IShellItem interface.
+    /// </summary>
+    internal const string GuidIshellitem = "43826d1e-e718-42ee-bc55-a1e261c37bfe";
+
+    private IPreviewHandler _mCurrentPreviewHandler;
+
+    /// <summary>
+    /// Initialialises a new instance of the PreviewHandlerHost class.
+    /// </summary>
+    public PreviewHandlerHost()
+    {
+        Size = new Size(320, 240);
+    }
+
+    /// <summary>
+    /// Gets the GUID of the current preview handler.
+    /// </summary>
+    [Browsable(false)]
+    [ReadOnly(true)]
+    public Guid CurrentPreviewHandler { get; private set; } = Guid.Empty;
+
+    /// <summary>
+    /// Releases the unmanaged resources used by the PreviewHandlerHost and optionally releases the managed resources.
+    /// </summary>
+    /// <param name="disposing"></param>
+    protected override void Dispose(bool disposing)
+    {
+        UnloadPreviewHandler();
+
+        if (_mCurrentPreviewHandler != null)
+        {
+            Marshal.FinalReleaseComObject(_mCurrentPreviewHandler);
+            _mCurrentPreviewHandler = null;
+            GC.Collect();
+        }
+
+        base.Dispose(disposing);
+    }
+
+    /// <summary>
+    /// Returns the GUID of the preview handler associated with the specified file.
+    /// </summary>
+    /// <param name="filename"></param>
+    /// <returns></returns>
+    public static Guid GetPreviewHandlerGUID(string filename)
+    {
+        // open the registry key corresponding to the file extension
+        var ext = Registry.ClassesRoot.OpenSubKey(Path.GetExtension(filename));
+        if (ext != null)
+        {
+            // open the key that indicates the GUID of the preview handler type
+            var test = ext.OpenSubKey("shellex\\{8895b1c6-b41f-4c1c-a562-0d564250836f}");
+            if (test != null) return new Guid(Convert.ToString(test.GetValue(null)));
+
+            // sometimes preview handlers are declared on key for the class
+            var className = Convert.ToString(ext.GetValue(null));
+            if (className != null)
+            {
+                test = Registry.ClassesRoot.OpenSubKey(
+                    className + "\\shellex\\{8895b1c6-b41f-4c1c-a562-0d564250836f}");
+                if (test != null) return new Guid(Convert.ToString(test.GetValue(null)));
+            }
+        }
+
+        return Guid.Empty;
+    }
+
+    /// <summary>
+    /// Resizes the hosted preview handler when this PreviewHandlerHost is resized.
+    /// </summary>
+    /// <param name="e"></param>
+    protected override void OnResize(EventArgs e)
+    {
+        base.OnResize(e);
+
+        var r = ClientRectangle;
+        _mCurrentPreviewHandler?.SetRect(ref r);
+    }
+
+    /// <summary>
+    /// Opens the specified file using the appropriate preview handler and displays the result in this PreviewHandlerHost.
+    /// </summary>
+    /// <param name="path"></param>
+    /// <returns></returns>
+    public bool Open(string path)
+    {
+        UnloadPreviewHandler();
+
+        if (string.IsNullOrEmpty(path))
+            return false;
+
+        // try to get GUID for the preview handler
+        var guid = GetPreviewHandlerGUID(path);
+
+        if (guid == Guid.Empty)
+            return false;
+
+        CurrentPreviewHandler = guid;
+        var o = Activator.CreateInstance(Type.GetTypeFromCLSID(CurrentPreviewHandler, true));
+
+        var fileInit = o as IInitializeWithFile;
+
+        if (fileInit == null)
+            return false;
+
+        fileInit.Initialize(path, 0);
+        _mCurrentPreviewHandler = o as IPreviewHandler;
+        if (_mCurrentPreviewHandler == null)
+            return false;
+
+        if (IsDisposed)
+            return false;
+
+        // bind the preview handler to the control's bounds and preview the content
+        var r = ClientRectangle;
+        _mCurrentPreviewHandler.SetWindow(Handle, ref r);
+        _mCurrentPreviewHandler.DoPreview();
+
+        return true;
+    }
+
+    /// <summary>
+    /// Unloads the preview handler hosted in this PreviewHandlerHost and closes the file stream.
+    /// </summary>
+    public void UnloadPreviewHandler()
+    {
+        try
+        {
+            _mCurrentPreviewHandler?.Unload();
+        }
+        catch (Exception)
+        {
+            // ignored
+        }
+    }
+}