1 files changed, 77 insertions, 0 deletions
diff --git a/src/System.Private.CoreLib/shared/Internal/IO/File.Windows.cs b/src/System.Private.CoreLib/shared/Internal/IO/File.Windows.cs
new file mode 100644
index 0000000000..0acae3b457
--- /dev/null
+++ b/src/System.Private.CoreLib/shared/Internal/IO/File.Windows.cs
@@ -0,0 +1,77 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Microsoft.Win32;
+using Microsoft.Win32.SafeHandles;
+using System.IO;
+using System.Runtime.InteropServices;
+
+namespace Internal.IO
+{
+    internal static partial class File
+    {
+        internal static bool InternalExists(string fullPath)
+        {
+            Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA data = new Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA();
+            int errorCode = FillAttributeInfo(fullPath, ref data, returnErrorOnNotFound: true);
+
+            return (errorCode == 0) && (data.dwFileAttributes != -1)
+                    && ((data.dwFileAttributes & Interop.Kernel32.FileAttributes.FILE_ATTRIBUTE_DIRECTORY) == 0);
+        }
+
+        /// <summary>
+        /// Returns 0 on success, otherwise a Win32 error code.  Note that
+        /// classes should use -1 as the uninitialized state for dataInitialized.
+        /// </summary>
+        /// <param name="returnErrorOnNotFound">Return the error code for not found errors?</param>
+        internal static int FillAttributeInfo(string path, ref Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA data, bool returnErrorOnNotFound)
+        {
+            int errorCode = Interop.Errors.ERROR_SUCCESS;
+
+            using (DisableMediaInsertionPrompt.Create())
+            {
+                if (!Interop.Kernel32.GetFileAttributesEx(path, Interop.Kernel32.GET_FILEEX_INFO_LEVELS.GetFileExInfoStandard, ref data))
+                {
+                    errorCode = Marshal.GetLastWin32Error();
+                    if (errorCode == Interop.Errors.ERROR_ACCESS_DENIED)
+                    {
+                        // Files that are marked for deletion will not let you GetFileAttributes,
+                        // ERROR_ACCESS_DENIED is given back without filling out the data struct.
+                        // FindFirstFile, however, will. Historically we always gave back attributes
+                        // for marked-for-deletion files.
+
+                        var findData = new Interop.Kernel32.WIN32_FIND_DATA();
+                        using (SafeFindHandle handle = Interop.Kernel32.FindFirstFile(path, ref findData))
+                        {
+                            if (handle.IsInvalid)
+                            {
+                                errorCode = Marshal.GetLastWin32Error();
+                            }
+                            else
+                            {
+                                errorCode = Interop.Errors.ERROR_SUCCESS;
+                                data.PopulateFrom(ref findData);
+                            }
+                        }
+                    }
+                }
+            }
+
+            if (errorCode != Interop.Errors.ERROR_SUCCESS && !returnErrorOnNotFound)
+            {
+                switch (errorCode)
+                {
+                    case Interop.Errors.ERROR_FILE_NOT_FOUND:
+                    case Interop.Errors.ERROR_PATH_NOT_FOUND:
+                    case Interop.Errors.ERROR_NOT_READY: // Removable media not ready
+                        // Return default value for backward compatibility
+                        data.dwFileAttributes = -1;
+                        return Interop.Errors.ERROR_SUCCESS;
+                }
+            }
+
+            return errorCode;
+        }
+    }
+}