PowerToys/src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Apps/Utils/ShellLinkHelper.cs

// Copyright (c) Microsoft Corporation
// The Microsoft Corporation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using System.Runtime.InteropServices;
using System.Runtime.InteropServices.ComTypes;
using System.Text;

namespace Microsoft.CmdPal.Ext.Apps.Utils;

public class ShellLinkHelper : IShellLinkHelper
{
    [Flags]
    private enum SLGP_FLAGS
    {
        SLGP_SHORTPATH = 0x1,
        SLGP_UNCPRIORITY = 0x2,
        SLGP_RAWPATH = 0x4,
    }

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1307:Accessible fields should begin with upper-case letter", Justification = "Matching COM")]
    private struct WIN32_FIND_DATAW
    {
        public uint dwFileAttributes;
        public long ftCreationTime;
        public long ftLastAccessTime;
        public long ftLastWriteTime;
        public uint nFileSizeHigh;
        public uint nFileSizeLow;
        public uint dwReserved0;
        public uint dwReserved1;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
        public string cFileName;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 14)]
        public string cAlternateFileName;
    }

    [Flags]
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Naming", "CA1707:Identifiers should not contain underscores", Justification = "Implements COM Interface")]
    public enum SLR_FLAGS
    {
        SLR_NO_UI = 0x1,
        SLR_ANY_MATCH = 0x2,
        SLR_UPDATE = 0x4,
        SLR_NOUPDATE = 0x8,
        SLR_NOSEARCH = 0x10,
        SLR_NOTRACK = 0x20,
        SLR_NOLINKINFO = 0x40,
        SLR_INVOKE_MSI = 0x80,
    }

    // Reference : http://www.pinvoke.net/default.aspx/Interfaces.IShellLinkW

    // The IShellLink interface allows Shell links to be created, modified, and resolved
    [ComImport]
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    [Guid("000214F9-0000-0000-C000-000000000046")]
    private interface IShellLinkW
    {
        /// <summary>Retrieves the path and file name of a Shell link object</summary>
        void GetPath([Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder pszFile, int cchMaxPath, ref WIN32_FIND_DATAW pfd, SLGP_FLAGS fFlags);

        /// <summary>Retrieves the list of item identifiers for a Shell link object</summary>
        void GetIDList(out nint ppidl);

        /// <summary>Sets the pointer to an item identifier list (PIDL) for a Shell link object.</summary>
        void SetIDList(nint pidl);

        /// <summary>Retrieves the description string for a Shell link object</summary>
        void GetDescription([Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder pszName, int cchMaxName);

        /// <summary>Sets the description for a Shell link object. The description can be any application-defined string</summary>
        void SetDescription([MarshalAs(UnmanagedType.LPWStr)] string pszName);

        /// <summary>Retrieves the name of the working directory for a Shell link object</summary>
        void GetWorkingDirectory([Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder pszDir, int cchMaxPath);

        /// <summary>Sets the name of the working directory for a Shell link object</summary>
        void SetWorkingDirectory([MarshalAs(UnmanagedType.LPWStr)] string pszDir);

        /// <summary>Retrieves the command-line arguments associated with a Shell link object</summary>
        void GetArguments([Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder pszArgs, int cchMaxPath);

        /// <summary>Sets the command-line arguments for a Shell link object</summary>
        void SetArguments([MarshalAs(UnmanagedType.LPWStr)] string pszArgs);

        /// <summary>Retrieves the hot key for a Shell link object</summary>
        void GetHotkey(out short pwHotkey);

        /// <summary>Sets a hot key for a Shell link object</summary>
        void SetHotkey(short wHotkey);

        /// <summary>Retrieves the show command for a Shell link object</summary>
        void GetShowCmd(out int piShowCmd);

        /// <summary>Sets the show command for a Shell link object. The show command sets the initial show state of the window.</summary>
        void SetShowCmd(int iShowCmd);

        /// <summary>Retrieves the location (path and index) of the icon for a Shell link object</summary>
        void GetIconLocation([Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder pszIconPath, int cchIconPath, out int piIcon);

        /// <summary>Sets the location (path and index) of the icon for a Shell link object</summary>
        void SetIconLocation([MarshalAs(UnmanagedType.LPWStr)] string pszIconPath, int iIcon);

        /// <summary>Sets the relative path to the Shell link object</summary>
        void SetRelativePath([MarshalAs(UnmanagedType.LPWStr)] string pszPathRel, int dwReserved);

        /// <summary>Attempts to find the target of a Shell link, even if it has been moved or renamed</summary>
        void Resolve(ref nint hwnd, SLR_FLAGS fFlags);

        /// <summary>Sets the path and file name of a Shell link object</summary>
        void SetPath([MarshalAs(UnmanagedType.LPWStr)] string pszFile);
    }

    [ComImport]
    [Guid("00021401-0000-0000-C000-000000000046")]
    private class ShellLink
    {
    }

    // Contains the description of the app
    public string Description { get; set; } = string.Empty;

    // Contains the arguments to the app
    public string Arguments { get; set; } = string.Empty;

    public bool HasArguments { get; set; }

    // Retrieve the target path using Shell Link
    public string RetrieveTargetPath(string path)
    {
        var link = new ShellLink();
        const int STGM_READ = 0;

        try
        {
            ((IPersistFile)link).Load(path, STGM_READ);
        }
        catch (System.IO.FileNotFoundException)
        {
            // Log.Exception("Path could not be retrieved", ex, GetType(), path);
            return string.Empty;
        }

        var hwnd = default(nint);
        ((IShellLinkW)link).Resolve(ref hwnd, 0);

        const int MAX_PATH = 260;
        var buffer = new StringBuilder(MAX_PATH);

        var data = default(WIN32_FIND_DATAW);
        ((IShellLinkW)link).GetPath(buffer, buffer.Capacity, ref data, SLGP_FLAGS.SLGP_SHORTPATH);
        var target = buffer.ToString();

        // To set the app description
        if (!string.IsNullOrEmpty(target))
        {
            buffer = new StringBuilder(MAX_PATH);
            try
            {
                ((IShellLinkW)link).GetDescription(buffer, MAX_PATH);
                Description = buffer.ToString();
            }
            catch (Exception)
            {
                // Log.Exception($"Failed to fetch description for {target}, {e.Message}", e, GetType());
                Description = string.Empty;
            }

            var argumentBuffer = new StringBuilder(MAX_PATH);
            ((IShellLinkW)link).GetArguments(argumentBuffer, argumentBuffer.Capacity);
            Arguments = argumentBuffer.ToString();

            // Set variable to true if the program takes in any arguments
            if (argumentBuffer.Length != 0)
            {
                HasArguments = true;
            }
        }

        // To release unmanaged memory
        Marshal.ReleaseComObject(link);

        return target;
    }
}