Vanara/Windows.Shell/ShellLink.cs

using System;
using System.Drawing;
using System.IO;
using System.Runtime.InteropServices;
using System.Runtime.InteropServices.ComTypes;
using System.Security.AccessControl;
using System.Security.Permissions;
using System.Text;
using System.Windows.Forms;
using Vanara.Extensions;
using Vanara.PInvoke;
using static Vanara.PInvoke.Macros;
using static Vanara.PInvoke.Ole32;
using static Vanara.PInvoke.Kernel32;
using static Vanara.PInvoke.Shell32;
// ReSharper disable UnusedParameter.Global
// ReSharper disable MemberCanBePrivate.Global
// ReSharper disable UnusedMember.Global
// ReSharper disable SuspiciousTypeConversion.Global
// ReSharper disable InconsistentNaming

namespace Vanara.Windows.Shell
{
	/// <summary>Flags determining how the links with missing targets are resolved.</summary>
	[Flags]
	public enum LinkResolution : uint
	{
		/// <summary>No flags set.</summary>
		None = 0,

		/// <summary>
		/// Do not display a dialog box if the link cannot be resolved. When NoUI is set, a time-out value that specifies
		/// the maximum amount of time to be spent resolving the link can be specified in milliseconds. The function
		/// returns if the link cannot be resolved within the time-out duration. If the timeout is not set, the time-out
		/// duration will be set to the default value of 3,000 milliseconds (3 seconds).
		/// </summary>
		NoUI = 0x1,

		/// <summary>Allow any match during resolution. Has no effect on ME/2000 or above, use the other flags instead.</summary>
		AnyMatch = 0x2,

		/// <summary>
		/// If the link object has changed, update its path and list of identifiers. If UPDATE is set, you do not need to
		/// call IPersistFile::IsDirty to determine whether or not the link object has changed.
		/// </summary>
		Update = 0x4,

		/// <summary>Do not update the link information.</summary>
		NoUpdate = 0x8,

		/// <summary>Do not execute the search heuristics.</summary>
		NoSearch = 0x10,

		/// <summary>Do not use distributed link tracking.</summary>
		NoTrack = 0x20,

		/// <summary>
		/// Disable distributed link tracking. By default, distributed link tracking tracks removable media across
		/// multiple devices based on the volume name. It also uses the UNC path to track remote file systems whose drive
		/// letter has changed. Setting NoLinkInfo disables both types of tracking.
		/// </summary>
		NoLinkInfo = 0x40,

		/// <summary>Call the Microsoft Windows Installer.</summary>
		InvokeMSI = 0x80,

		/// <summary>Windows XP and later. Assume same as NoUI but intended for applications without a hWnd.</summary>
		NoUIWithMsgPump = 0x101,

		/// <summary>
		/// Windows 7 and later. Offer the option to delete the shortcut when this method is unable to resolve it, even
		/// if the shortcut is not a shortcut to a file.
		/// </summary>
		OfferDeleteWithoutFile = 0x200,

		/// <summary>
		/// Windows 7 and later. Report as dirty if the target is a known folder and the known folder was redirected.
		/// This only works if the original target path was a file system path or ID list and not an aliased known folder
		/// ID list.
		/// </summary>
		KnownFolder = 0x400,

		/// <summary>
		/// Windows 7 and later. Resolve the computer name in UNC targets that point to a local computer. This value is
		/// used with SLDFKEEPLOCALIDLISTFORUNCTARGET.
		/// </summary>
		MachineInLocalTarget = 0x800,

		/// <summary>Windows 7 and later. Update the computer GUID and user SID if necessary.</summary>
		UpdateMachineAndSid = 0x1000,

		/// <summary>?? Assuming this does not update the Object ID</summary>
		NoObjectID = 0x2000
	}

	/// <summary>Represents a Shell Shortcut (.lnk) file.</summary>
	public sealed class ShellLink : ShellItem
	{
		internal IShellLinkW link;
		private ShellItem target;

		/// <summary>Initializes a new instance of the <see cref="ShellLink"/> class, which acts as a wrapper for a .lnk file.</summary>
		/// <param name="linkFile">The shortcut file (.lnk) to load.</param>
		/// <param name="window">
		/// The window that the Shell will use as the parent for a dialog box. The Shell displays the dialog box if it needs to prompt the user for more
		/// information while resolving a Shell link.
		/// </param>
		/// <param name="resolveFlags">The resolve flags.</param>
		/// <param name="timeOut">The time out.</param>
		/// <exception cref="System.ArgumentNullException">linkFile</exception>
		public ShellLink(string linkFile, LinkResolution resolveFlags = LinkResolution.NoUI, IWin32Window window = null, TimeSpan timeOut = default) : base(linkFile)
		{
			LoadAndResolve(linkFile, (SLR_FLAGS)resolveFlags, ShellFolder.IWin2Ptr(window), (ushort)timeOut.TotalMilliseconds);
		}

		internal ShellLink(IShellItem iItem) : base(iItem)
		{
			LoadAndResolve(iItem.GetDisplayName(SIGDN.SIGDN_FILESYSPATH), SLR_FLAGS.SLR_NO_UI);
		}

		private ShellLink() { }

		/*public string AppUserModelID
		{
			get
			{
				using (PropVariant pv = new PropVariant())
				{
					VerifySucceeded(PropertyStore.GetValue(AppUserModelIDKey, pv));

					if (pv.Value == null)
						return "Null";
					else
						return pv.Value;
				}
			}
			set
			{
				using (PropVariant pv = new PropVariant(value))
				{
					VerifySucceeded(PropertyStore.SetValue(AppUserModelIDKey, pv));
					VerifySucceeded(PropertyStore.Commit());
				}
			}
		}*/

		/// <summary>Gets/sets any command line arguments associated with the link</summary>
		public string Arguments
		{
			get => GetStringValue(link.GetArguments, MAX_PATH);
			set { link.SetArguments(value); Save(); }
		}

		/// <summary>Gets/sets the description of the link</summary>
		public string Description
		{
			get => GetStringValue(link.GetDescription, ComCtl32.INFOTIPSIZE);
			set { link.SetDescription(value); Save(); }
		}

		/// <summary>Gets the full path of the link file.</summary>
		/// <value>The full path of the link file.</value>
		public string FullPath => GetPath(SLGP.SLGP_RAWPATH);

		/// <summary>Gets/sets the HotKey to start the shortcut (if any).</summary>
		public Keys HotKey
		{
			get { var hk = link.GetHotKey(); return (Keys)MAKELONG(LOBYTE(hk), HIBYTE(hk)); }
			set { link.SetHotKey(MAKEWORD((byte)LOWORD((uint)value), (byte)HIWORD((uint)value))); Save(); }
		}

		/// <summary>Gets the index of this icon within the icon path's resources.</summary>
		public IconLocation IconLocation
		{
			get
			{
				var iconPath = new StringBuilder(MAX_PATH, MAX_PATH);
				link.GetIconLocation(iconPath, iconPath.Capacity, out var iconIndex);
				return new IconLocation(iconPath.ToString(), iconIndex);
			}
			set { link.SetIconLocation(value.ModuleFileName, value.ResourceId); Save(); }
		}

		/// <summary>Get or sets the list of item identifiers for a Shell link.</summary>
		public PIDL IDList
		{
			get => link.GetIDList();
			set { link.SetIDList(value); Save(); }
		}

		/// <summary>Gets/sets the relative path to the link's target</summary>
		public string RelativeTargetPath
		{
			get => GetPath(SLGP.SLGP_RELATIVEPRIORITY);
			set { link.SetRelativePath(value, 0); Save(); }
		}

		/// <summary>Gets or sets a value indicating whether the target is run with Administrator rights.</summary>
		/// <value><c>true</c> if run as Administrator; otherwise, <c>false</c>.</value>
		public bool RunAsAdministrator
		{
			get => ((IShellLinkDataList)link).GetFlags().IsFlagSet(SHELL_LINK_DATA_FLAGS.SLDF_RUNAS_USER);
			set
			{
				var dl = (IShellLinkDataList)link;
				dl.SetFlags(dl.GetFlags().SetFlags(SHELL_LINK_DATA_FLAGS.SLDF_RUNAS_USER, value));
				Save();
			}
		}

		/// <summary>Gets/sets the short (8.3 format) path to the link's target</summary>
		public string ShortTargetPath => GetPath(SLGP.SLGP_SHORTPATH);

		/// <summary>Gets or sets the show command for a Shell link object.</summary>
		/// <value>The show command for a Shell link object.</value>
		public FormWindowState ShowState
		{
			get => (FormWindowState)link.GetShowCmd() - 1;
			set { link.SetShowCmd((ShowWindowCommand)value + 1); Save(); }
		}

		/// <summary>Gets or sets the target with a <see cref="ShellItem"/> instance.</summary>
		public ShellItem Target
		{
			get => target ?? (target = new ShellItem(link.GetIDList()));
			set => link.SetIDList(value.PIDL);
		}

		/// <summary>Gets/sets the fully qualified path to the link's target</summary>
		public string TargetPath
		{
			get => GetPath(SLGP.SLGP_UNCPRIORITY);
			set { link.SetPath(value); Save(); }
		}

		/// <summary>Gets/sets the Working Directory for the Link</summary>
		public string WorkingDirectory
		{
			get => GetStringValue(link.GetWorkingDirectory, MAX_PATH);
			set { link.SetWorkingDirectory(value); Save(); }
		}

		/// <summary>Creates or overwrites a new link file.</summary>
		/// <param name="linkFilename">The link filename.</param>
		/// <param name="targetFilename">The full path to the target file.</param>
		/// <param name="description">The description of the link.</param>
		/// <param name="workingDirectory">The working directory for the execution of the target.</param>
		/// <param name="arguments">The arguments for the target's execution.</param>
		/// <returns>An instance of a <see cref="ShellLink"/> representing the values supplied.</returns>
		public static ShellLink Create(string linkFilename, string targetFilename, string description = null, string workingDirectory = null, string arguments = null)
		{
			if (File.Exists(linkFilename)) throw new InvalidOperationException("File already exists.");
			var lnk = new ShellLink
			{
				link = new IShellLinkW(),
				TargetPath = targetFilename,
				Description = description,
				WorkingDirectory = workingDirectory,
				Arguments = arguments
			};
			lnk.SaveAs(linkFilename);
			lnk.Init((IShellItem)lnk.link);
			return lnk;
		}

		/// <summary>Creates or overwrites a new link file.</summary>
		/// <param name="linkFilename">The link filename.</param>
		/// <param name="target">The ShellItem for the target.</param>
		/// <param name="description">The description of the link.</param>
		/// <param name="workingDirectory">The working directory for the execution of the target.</param>
		/// <param name="arguments">The arguments for the target's execution.</param>
		/// <returns>An instance of a <see cref="ShellLink"/> representing the values supplied.</returns>
		public static ShellLink Create(string linkFilename, ShellItem target, string description = null, string workingDirectory = null, string arguments = null)
		{
			if (File.Exists(linkFilename)) throw new InvalidOperationException("File already exists.");
			var lnk = new ShellLink
			{
				link = new IShellLinkW(),
				Target = target,
				Description = description,
				WorkingDirectory = workingDirectory,
				Arguments = arguments
			};
			lnk.SaveAs(linkFilename);
			lnk.Init((IShellItem)lnk.link);
			return lnk;
		}

		/// <summary>
		/// Copies an existing file to a new file, allowing the overwriting of an existing file.
		/// </summary>
		/// <param name="destShellLink">The name of the new file to copy to.</param>
		/// <param name="overwrite"><c>true</c> to allow an existing file to be overwritten; otherwise <c>false</c>.</param>
		/// <returns>A new file, or an overwrite of an existing file if overwrite is true. If the file exists and overwrite is false, an IOException is thrown.</returns>
		public ShellLink CopyTo(string destShellLink, bool overwrite = false)
		{
			File.Copy(FullPath, destShellLink, overwrite);
			return new ShellLink(destShellLink);
		}

		/// <summary>Dispose the object, releasing the COM ShellLink object</summary>
		public override void Dispose()
		{
			if (link != null) { Marshal.ReleaseComObject(link); link = null; }
			//Release(link);
			base.Dispose();
		}

		/// <summary>Determines whether the specified <see cref="System.Object"/>, is equal to this instance.</summary>
		/// <param name="obj">The <see cref="System.Object"/> to compare with this instance.</param>
		/// <returns>
		/// <c>true</c> if the specified <see cref="System.Object"/> is equal to this instance; otherwise, <c>false</c>.
		/// </returns>
		public override bool Equals(object obj)
		{
			var link2 = obj as ShellLink;
			if (link2 != null)
				return string.Equals(link2.ToString(), ToString(), StringComparison.InvariantCultureIgnoreCase);
			return base.Equals(obj);
		}

		/// <summary>
		/// Gets a FileSecurity object that encapsulates the specified type of access control list (ACL) entries for the file described by the current FileInfo object.
		/// </summary>
		/// <param name="includeSections">One of the AccessControlSections values that specifies which group of access control entries to retrieve.</param>
		/// <returns>A FileSecurity object that encapsulates the access control rules for the current file.</returns>
		public FileSecurity GetAccessControl(AccessControlSections includeSections = AccessControlSections.Access | AccessControlSections.Group | AccessControlSections.Owner) =>
			File.GetAccessControl(FullPath, includeSections);

		/// <summary>Returns a hash code for this instance.</summary>
		/// <returns>
		/// A hash code for this instance, suitable for use in hashing algorithms and data structures like a hash table.
		/// </returns>
		public override int GetHashCode() => ToString().GetHashCode();

		/// <summary>Gets the icon for this link file.</summary>
		/// <param name="large">if set to <c>true</c> retrieve the large icon; other retrieve the small icon.</param>
		/// <returns>The icon.</returns>
		public Icon GetIcon(bool large)
		{
			var loc = IconLocation;
			if (loc.IsValid) return loc.Icon;

			// If there are no details set for the icon, then we must use the shell to get the icon for the target
			var sfi = new ShellFileInfo(TargetPath);
			return large ? sfi.LargeIcon : sfi.SmallIcon;
		}

		/// <summary>
		/// Applies access control list (ACL) entries described by a FileSecurity object to the file described by the current FileInfo object.
		/// </summary>
		/// <param name="fileSecurity">A FileSecurity object that describes an access control list (ACL) entry to apply to the current file.</param>
		public void SetAccessControl(FileSecurity fileSecurity)
		{
			File.SetAccessControl(FullPath, fileSecurity);
		}

		/*/// <summary>Returns a <see cref="System.String"/> that represents this instance.</summary>
		/// <returns>A <see cref="System.String"/> that represents this instance.</returns>
		// Path and title should be case insensitive. Shell treats arguments as case sensitive because apps can handle
		// those differently.
		public override string ToString() =>
			$"{(Properties.GetProperty<string>(PROPERTYKEY.System.Title) ?? "").ToUpperInvariant()} {FullPath.ToUpperInvariant()} {Arguments}";*/

		private static string GetStringValue(Action<StringBuilder, int> method, int buffSize)
		{
			var ret = new StringBuilder(buffSize, buffSize);
			method(ret, ret.Capacity);
			return ret.ToString();
		}

		private string GetPath(SLGP value)
		{
			var target = new StringBuilder(MAX_PATH, MAX_PATH);
			var fd = new WIN32_FIND_DATA();
			link.GetPath(target, target.Capacity, fd, value);
			return target.ToString();
		}

		private void LoadAndResolve(string linkFile, SLR_FLAGS resolveFlags, HWND hWin = default, ushort timeOut = 0)
		{
			if (string.IsNullOrEmpty(linkFile)) throw new ArgumentNullException(nameof(linkFile));
			var fullPath = Path.GetFullPath(linkFile);
			if (!File.Exists(fullPath)) throw new FileNotFoundException("Link file not found.", linkFile);

			link = new IShellLinkW();

			if (resolveFlags.IsFlagSet(SLR_FLAGS.SLR_NO_UI) && timeOut != 0)
				resolveFlags = (SLR_FLAGS)MAKELONG((ushort)resolveFlags, timeOut);

			new FileIOPermission(FileIOPermissionAccess.Read, fullPath).Demand();
			((IPersistFile)link).Load(fullPath, 0); //STGM_DIRECT)
			link.Resolve(hWin, resolveFlags);
		}

		/// <summary>Saves the shortcut to ShortCutFile.</summary>
		private void Save()
		{
			if (File.Exists(FullPath))
				((IPersistFile)link).Save(null, true);
			else if (FullPath != null)
				SaveAs(FullPath);
		}

		/// <summary>Saves the shortcut to the specified file</summary>
		/// <param name="linkFile">The shortcut file (.lnk)</param>
		private void SaveAs(string linkFile)
		{
			((IPersistFile)link).Save(linkFile, true);
		}
	}
}