Added registry helpers

Author: 0x5bfa

src/Files.App.CsWin32/NativeMethods.txt

@@ -225,3 +225,6 @@ QITIPF_FLAGS
 GetKeyboardState
 MapVirtualKey
 GetKeyboardLayout
+RegOpenKeyExW
+HKEY_CLASSES_ROOT
+RegEnumKeyEx

src/Files.App.Storage/Storables/WindowsStorage/ShellNewItem.cs

@@ -0,0 +1,9 @@
+// Copyright (c) Files Community
+// Licensed under the MIT License.
+
+namespace Files.App.Storage
+{
+	public partial class ShellNewItem
+	{
+	}
+}

src/Files.App.Storage/Storables/WindowsStorage/ShellNewManager.cs

@@ -0,0 +1,46 @@
+// Copyright (c) Files Community
+// Licensed under the MIT License.
+
+using Microsoft.Win32;
+using Windows.Win32;
+using Windows.Win32.Foundation;
+using Windows.Win32.System.Registry;
+
+namespace Files.App.Storage
+{
+	public static partial class ShellNewManager
+	{
+		public static IEnumerable<ShellNewItem> GetItems()
+		{
+			var newMenuItems = new List<ShellNewItem>();
+			string[] extensionsExcluded = [ ".contact", ".library-ms", ".url", ".lnk" ];
+
+			// Get a handle of HKEY_CLASSES_ROOT
+			bool fRes = WindowsStorableHelpers.OpenRegistryKey(HKEY.HKEY_CLASSES_ROOT, string.Empty, REG_SAM_FLAGS.KEY_READ, out HKEY hKey);
+			if (!fRes)
+			{
+				if (!hKey.IsNull) PInvoke.RegCloseKey(hKey);
+				yield break;
+			}
+
+			foreach (string keyName in WindowsStorableHelpers.EnumerateRegistryKeyNames(hKey).Where(x => x.StartsWith('.') &&
+				!extensionsExcluded.Contains(x, StringComparer.OrdinalIgnoreCase)))
+			{
+				fRes = WindowsStorableHelpers.OpenRegistryKey(HKEY.HKEY_CLASSES_ROOT, keyName, REG_SAM_FLAGS.KEY_READ, out HKEY hSubKey);
+				if (!fRes)
+				{
+					if (!hKey.IsNull) PInvoke.RegCloseKey(hKey);
+					if (!hSubKey.IsNull) PInvoke.RegCloseKey(hSubKey);
+					yield break;
+				}
+
+				// TODO: Get an entry
+				yield return new();
+			}
+
+			// TODO: Add .txt if necessary
+
+			if (!hKey.IsNull) PInvoke.RegCloseKey(hKey);
+		}
+	}
+}

src/Files.App.Storage/Storables/WindowsStorage/WindowsStorableHelpers.Registry.cs

@@ -0,0 +1,59 @@
+// Copyright (c) Files Community
+// Licensed under the MIT License.
+
+using Windows.Win32;
+using Windows.Win32.Foundation;
+using Windows.Win32.System.Registry;
+
+namespace Files.App.Storage
+{
+	public unsafe static partial class WindowsStorableHelpers
+	{
+		public static bool OpenRegistryKey(HKEY hRootKey, string subKey, REG_SAM_FLAGS flags, out HKEY hKey)
+		{
+			hKey = default;
+
+			HKEY hResultKey = default;
+			WIN32_ERROR dwResult = default;
+
+			fixed (char* pszSubKey = subKey)
+				dwResult = PInvoke.RegOpenKeyEx(hRootKey, pszSubKey, 0, flags, &hResultKey);
+
+			hKey = hResultKey;
+
+			return dwResult is WIN32_ERROR.ERROR_SUCCESS;
+		}
+
+		public static string[] EnumerateRegistryKeyNames(HKEY hKey)
+		{
+			WIN32_ERROR dwResult = default;
+			uint dwIndex = 0U;
+			char* pszName = stackalloc char[256]; // 255 chars + null terminator
+			uint cchName = 256U;
+			string[] keyNames = [];
+
+			while ((dwResult = PInvoke.RegEnumKeyEx(hKey, dwIndex, pszName, &cchName, null, null, null, null)) is not WIN32_ERROR.ERROR_NO_MORE_ITEMS)
+			{
+				if (dwResult is WIN32_ERROR.ERROR_SUCCESS)
+				{
+					// Double the capacity of the array if necessary
+					if (dwIndex >= keyNames.Length)
+						Array.Resize(ref keyNames, keyNames.Length < 10 ? 10 : keyNames.Length * 2);
+
+					keyNames[dwIndex++] = new string(pszName);
+				}
+				else
+				{
+					// An error occurred, handle it accordingly
+					break;
+				}
+			}
+
+			// Fit the array if necessary
+			if (dwIndex < keyNames.Length)
+				Array.Resize(ref keyNames, (int)dwIndex);
+
+			return keyNames;
+		}
+	}
+}