// System.IO.MonoIO.cs: static interface to native filesystem.
//
// Author:
//   Dan Lewis (dihlewis@yahoo.co.uk)
//   Dick Porter (dick@ximian.com)
//
// (C) 2002
// Copyright 2011 Xamarin Inc (http://www.xamarin.com).
//

//
// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Threading;
using Microsoft.Win32.SafeHandles;
#if MOBILE
using System.IO.IsolatedStorage;
#endif

namespace System.IO
{
	unsafe static class MonoIO {
		public const int FileAlreadyExistsHResult = unchecked ((int) 0x80070000) | (int)MonoIOError.ERROR_FILE_EXISTS;

		public const FileAttributes
			InvalidFileAttributes = (FileAttributes)(-1);

		public static readonly IntPtr
			InvalidHandle = (IntPtr)(-1L);

		static bool dump_handles = Environment.GetEnvironmentVariable ("MONO_DUMP_HANDLES_ON_ERROR_TOO_MANY_OPEN_FILES") != null;

		// error methods
		public static Exception GetException (MonoIOError error)
		{
			/* This overload is currently only called from
			 * File.MoveFile(), Directory.Move() and
			 * Directory.GetCurrentDirectory() -
			 * everywhere else supplies a path to format
			 * with the error text.
			 */
			switch(error) {
			case MonoIOError.ERROR_ACCESS_DENIED:
				return new UnauthorizedAccessException ("Access to the path is denied.");
			case MonoIOError.ERROR_FILE_EXISTS:
				string message = "Cannot create a file that already exist.";
				return new IOException (message, FileAlreadyExistsHResult);
			default:
				/* Add more mappings here if other
				 * errors trigger the named but empty
				 * path bug (see bug 82141.) For
				 * everything else, fall through to
				 * the other overload
				 */
				return GetException (String.Empty, error);
			}
		}

		public static Exception GetException (string path,
						      MonoIOError error)
		{
			string message;

			switch (error) {
			// FIXME: add more exception mappings here
			case MonoIOError.ERROR_FILE_NOT_FOUND:
				message = String.Format ("Could not find file \"{0}\"", path);
				return new FileNotFoundException (message, path);

			case MonoIOError.ERROR_TOO_MANY_OPEN_FILES:
				if (dump_handles)
					DumpHandles ();
				return new IOException ("Too many open files", unchecked((int)0x80070000) | (int)error);
				
			case MonoIOError.ERROR_PATH_NOT_FOUND:
				message = String.Format ("Could not find a part of the path \"{0}\"", path);
				return new DirectoryNotFoundException (message);

			case MonoIOError.ERROR_ACCESS_DENIED:
				message = String.Format ("Access to the path \"{0}\" is denied.", path);
				return new UnauthorizedAccessException (message);

			case MonoIOError.ERROR_INVALID_HANDLE:
				message = String.Format ("Invalid handle to path \"{0}\"", path);
				return new IOException (message, unchecked((int)0x80070000) | (int)error);
			case MonoIOError.ERROR_INVALID_DRIVE:
				message = String.Format ("Could not find the drive  '{0}'. The drive might not be ready or might not be mapped.", path);
#if !MOBILE
				return new DriveNotFoundException (message);
#else
				return new IOException (message, unchecked((int)0x80070000) | (int)error);
#endif
			case MonoIOError.ERROR_FILE_EXISTS:
				message = String.Format ("Could not create file \"{0}\". File already exists.", path);
				return new IOException (message, unchecked((int)0x80070000) | (int)error);

			case MonoIOError.ERROR_FILENAME_EXCED_RANGE:
				message = String.Format ("Path is too long. Path: {0}", path); 
				return new PathTooLongException (message);

			case MonoIOError.ERROR_INVALID_PARAMETER:
				message = String.Format ("Invalid parameter");
				return new IOException (message, unchecked((int)0x80070000) | (int)error);

			case MonoIOError.ERROR_WRITE_FAULT:
				message = String.Format ("Write fault on path {0}", path);
				return new IOException (message, unchecked((int)0x80070000) | (int)error);

			case MonoIOError.ERROR_SHARING_VIOLATION:
				message = String.Format ("Sharing violation on path {0}", path);
				return new IOException (message, unchecked((int)0x80070000) | (int)error);
				
			case MonoIOError.ERROR_LOCK_VIOLATION:
				message = String.Format ("Lock violation on path {0}", path);
				return new IOException (message, unchecked((int)0x80070000) | (int)error);
			
			case MonoIOError.ERROR_HANDLE_DISK_FULL:
				message = String.Format ("Disk full. Path {0}", path);
				return new IOException (message, unchecked((int)0x80070000) | (int)error);
			
			case MonoIOError.ERROR_DIR_NOT_EMPTY:
				message = String.Format ("Directory {0} is not empty", path);
				return new IOException (message, unchecked((int)0x80070000) | (int)error);

			case MonoIOError.ERROR_ENCRYPTION_FAILED:
				return new IOException ("Encryption failed", unchecked((int)0x80070000) | (int)error);

			case MonoIOError.ERROR_CANNOT_MAKE:
				message = String.Format ("Path {0} is a directory", path);
				return new IOException (message, unchecked((int)0x80070000) | (int)error);
				
			case MonoIOError.ERROR_NOT_SAME_DEVICE:
				message = "Source and destination are not on the same device";
				return new IOException (message, unchecked((int)0x80070000) | (int)error);

			case MonoIOError.ERROR_DIRECTORY:
				message = "The directory name is invalid";
				return new IOException (message, unchecked((int)0x80070000) | (int)error);
				
			default:
				message = String.Format ("Win32 IO returned {0}. Path: {1}", error, path);
				return new IOException (message, unchecked((int)0x80070000) | (int)error);
			}
		}

		// directory methods

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private unsafe extern static bool CreateDirectory (char* path, out MonoIOError error);

		public static bool CreateDirectory (string path, out MonoIOError error)
		{
			unsafe {
				fixed (char* pathChars = path) {
					return CreateDirectory (pathChars, out error);
				}
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private unsafe extern static bool RemoveDirectory (char* path, out MonoIOError error);

		public static bool RemoveDirectory (string path, out MonoIOError error)
		{
			unsafe {
				fixed (char* pathChars = path) {
					return RemoveDirectory (pathChars, out error);
				}
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		public extern static string GetCurrentDirectory (out MonoIOError error);

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private unsafe extern static bool SetCurrentDirectory (char* path, out MonoIOError error);

		public static bool SetCurrentDirectory (string path, out MonoIOError error)
		{
			unsafe {
				fixed (char* pathChars = path) {
					return SetCurrentDirectory (pathChars, out error);
				}
			}
		}

		// file methods

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private unsafe extern static bool MoveFile (char* path, char* dest,
							    out MonoIOError error);

		public static bool MoveFile (string path, string dest,
					     out MonoIOError error)
		{
			unsafe {
				fixed (char* pathChars = path, destChars = dest) {
					return MoveFile (pathChars, destChars, out error);
				}
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private unsafe extern static bool CopyFile (char* path, char* dest,
							    bool overwrite,
							    out MonoIOError error);

		public static bool CopyFile (string path, string dest,
					     bool overwrite,
					     out MonoIOError error)
		{
			unsafe {
				fixed (char* pathChars = path, destChars = dest) {
					return CopyFile (pathChars, destChars, overwrite, out error);
				}
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private unsafe extern static bool DeleteFile (char* path,
							      out MonoIOError error);

		public static bool DeleteFile (string path,
					       out MonoIOError error)
		{
			unsafe {
				fixed (char* pathChars = path) {
					return DeleteFile (pathChars, out error);
				}
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private unsafe extern static bool ReplaceFile (char* sourceFileName,
							       char* destinationFileName,
							       char* destinationBackupFileName,
							       bool ignoreMetadataErrors,
							       out MonoIOError error);

		public static bool ReplaceFile (string sourceFileName,
						string destinationFileName,
						string destinationBackupFileName,
						bool ignoreMetadataErrors,
						out MonoIOError error)
		{
			unsafe {
				fixed (char* sourceFileNameChars = sourceFileName,
				       destinationFileNameChars = destinationFileName,
				       destinationBackupFileNameChars = destinationBackupFileName) {
					return ReplaceFile (sourceFileNameChars, destinationFileNameChars, destinationBackupFileNameChars, ignoreMetadataErrors, out error);
				}
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private unsafe extern static FileAttributes GetFileAttributes (char* path, out MonoIOError error);

		public static FileAttributes GetFileAttributes (string path, out MonoIOError error)
		{
			unsafe {
				fixed (char* pathChars = path) {
					return GetFileAttributes (pathChars, out error);
				}
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private extern static bool SetFileAttributes (char* path, FileAttributes attrs, out MonoIOError error);

		public static bool SetFileAttributes (string path, FileAttributes attrs, out MonoIOError error)
		{
			unsafe {
				fixed (char* pathChars = path) {
					return SetFileAttributes (pathChars, attrs, out error);
				}
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private extern static MonoFileType GetFileType (IntPtr handle, out MonoIOError error);

		public static MonoFileType GetFileType (SafeHandle safeHandle, out MonoIOError error)
		{
			bool release = false;
			try {
				safeHandle.DangerousAddRef (ref release);
				return GetFileType (safeHandle.DangerousGetHandle (), out error);
			} finally {
				if (release)
					safeHandle.DangerousRelease ();
			}
		}

		//
		// Find file methods
		//

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private unsafe extern static IntPtr FindFirstFile (char* pathWithPattern, out string fileName, out int fileAttr, out int error);

		public static IntPtr FindFirstFile (string pathWithPattern, out string fileName, out int fileAttr, out int error)
		{
			unsafe {
				fixed (char* pathWithPatternChars = pathWithPattern) {
					return FindFirstFile (pathWithPatternChars, out fileName, out fileAttr, out error);
				}
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		public extern static bool FindNextFile (IntPtr hnd, out string fileName, out int fileAttr, out int error);

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		public extern static bool FindCloseFile (IntPtr hnd);

		public static bool Exists (string path, out MonoIOError error)
		{
			FileAttributes attrs = GetFileAttributes (path,
								  out error);
			if (attrs == InvalidFileAttributes)
				return false;

			return true;
		}

		public static bool ExistsFile (string path,
					       out MonoIOError error)
		{
			FileAttributes attrs = GetFileAttributes (path,
								  out error);
			if (attrs == InvalidFileAttributes)
				return false;

			if ((attrs & FileAttributes.Directory) != 0)
				return false;

			return true;
		}

		public static bool ExistsDirectory (string path,
						    out MonoIOError error)
		{
			FileAttributes attrs = GetFileAttributes (path,
								  out error);
								  
			// Actually, we are looking for a directory, not a file
			if (error == MonoIOError.ERROR_FILE_NOT_FOUND)
				error = MonoIOError.ERROR_PATH_NOT_FOUND;
				
			if (attrs == InvalidFileAttributes)
				return false;

			if ((attrs & FileAttributes.Directory) == 0)
				return false;

			return true;
		}

		public static bool ExistsSymlink (string path,
						  out MonoIOError error)
		{
			FileAttributes attrs = GetFileAttributes (path,
								  out error);
			if (attrs == InvalidFileAttributes)
				return false;
			
			if ((attrs & FileAttributes.ReparsePoint) == 0)
				return false;

			return true;
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private unsafe extern static bool GetFileStat (char* path,
							       out MonoIOStat stat,
							       out MonoIOError error);

		public static bool GetFileStat (string path,
						out MonoIOStat stat,
						out MonoIOError error)
		{
			unsafe {
				fixed (char* pathChars = path) {
					return GetFileStat (pathChars, out stat, out error);
				}
			}
		}

		// handle methods

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private unsafe extern static IntPtr Open (char* filename,
							  FileMode mode,
							  FileAccess access,
							  FileShare share,
							  FileOptions options,
							  out MonoIOError error);

		public static IntPtr Open (string filename,
					   FileMode mode,
					   FileAccess access,
					   FileShare share,
					   FileOptions options,
					   out MonoIOError error)
		{
			unsafe {
				fixed (char* filenameChars = filename) {
					return Open (filenameChars, mode, access, share, options, out error);
				}
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private extern static bool Cancel_internal (IntPtr handle, out MonoIOError error);

		internal static bool Cancel (SafeHandle safeHandle, out MonoIOError error)
		{
			bool release = false;
			try {
				safeHandle.DangerousAddRef (ref release);
				return Cancel_internal (safeHandle.DangerousGetHandle (), out error);
			} finally {
				if (release)
					safeHandle.DangerousRelease ();
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		public extern static bool Close (IntPtr handle,
						 out MonoIOError error);
		
		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private extern static int Read (IntPtr handle, byte [] dest,
					       int dest_offset, int count,
					       out MonoIOError error);

		public static int Read (SafeHandle safeHandle, byte [] dest,
					       int dest_offset, int count,
					       out MonoIOError error)
		{
			bool release = false;
			try {
				safeHandle.DangerousAddRef (ref release);
				return Read (safeHandle.DangerousGetHandle (), dest, dest_offset, count, out error);
			} finally {
				if (release)
					safeHandle.DangerousRelease ();
			}
		}
		
		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private extern static int Write (IntPtr handle, [In] byte [] src,
						int src_offset, int count,
						out MonoIOError error);

		public static int Write (SafeHandle safeHandle, byte [] src,
						int src_offset, int count,
						out MonoIOError error)
		{
			bool release = false;
			try {
				safeHandle.DangerousAddRef (ref release);
				return Write (safeHandle.DangerousGetHandle (), src, src_offset, count, out error);
			} finally {
				if (release)
					safeHandle.DangerousRelease ();
			}
		}
		
		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private extern static long Seek (IntPtr handle, long offset,
						SeekOrigin origin,
						out MonoIOError error);

		public static long Seek (SafeHandle safeHandle, long offset,
						SeekOrigin origin,
						out MonoIOError error)
		{
			bool release = false;
			try {
				safeHandle.DangerousAddRef (ref release);
				return Seek (safeHandle.DangerousGetHandle (), offset, origin, out error);
			} finally {
				if (release)
					safeHandle.DangerousRelease ();
			}
		}
		
		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private extern static bool Flush (IntPtr handle,
						 out MonoIOError error);

		public static bool Flush (SafeHandle safeHandle,
						 out MonoIOError error)
		{
			bool release = false;
			try {
				safeHandle.DangerousAddRef (ref release);
				return Flush (safeHandle.DangerousGetHandle (), out error);
			} finally {
				if (release)
					safeHandle.DangerousRelease ();
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private extern static long GetLength (IntPtr handle,
						     out MonoIOError error);

		public static long GetLength (SafeHandle safeHandle,
						     out MonoIOError error)
		{
			bool release = false;
			try {
				safeHandle.DangerousAddRef (ref release);
				return GetLength (safeHandle.DangerousGetHandle (), out error);
			} finally {
				if (release)
					safeHandle.DangerousRelease ();
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private extern static bool SetLength (IntPtr handle,
						     long length,
						     out MonoIOError error);

		public static bool SetLength (SafeHandle safeHandle,
						     long length,
						     out MonoIOError error)
		{
			bool release = false;
			try {
				safeHandle.DangerousAddRef (ref release);
				return SetLength (safeHandle.DangerousGetHandle (), length, out error);
			} finally {
				if (release)
					safeHandle.DangerousRelease ();
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private extern static bool SetFileTime (IntPtr handle,
						       long creation_time,
						       long last_access_time,
						       long last_write_time,
						       out MonoIOError error);

		public static bool SetFileTime (SafeHandle safeHandle,
						       long creation_time,
						       long last_access_time,
						       long last_write_time,
						       out MonoIOError error)
		{
			bool release = false;
			try {
				safeHandle.DangerousAddRef (ref release);
				return SetFileTime (safeHandle.DangerousGetHandle (), creation_time, last_access_time, last_write_time, out error);
			} finally {
				if (release)
					safeHandle.DangerousRelease ();
			}
		}

		public static bool SetFileTime (string path,
						long creation_time,
						long last_access_time,
						long last_write_time,
						out MonoIOError error)
		{
			return SetFileTime (path,
				0,
				creation_time,
				last_access_time,
				last_write_time,
				DateTime.MinValue,
				out error);
		}

		public static bool SetCreationTime (string path,
						DateTime dateTime,
						out MonoIOError error)
		{
			return SetFileTime (path, 1, -1, -1, -1, dateTime, out error);
		}

		public static bool SetLastAccessTime (string path,
						DateTime dateTime,
						out MonoIOError error)
		{
			return SetFileTime (path, 2, -1, -1, -1, dateTime, out error);
		}

		public static bool SetLastWriteTime (string path,
						DateTime dateTime,
						out MonoIOError error)
		{
			return SetFileTime (path, 3, -1, -1, -1, dateTime, out error);
		}

		public static bool SetFileTime (string path,
						int type,
						long creation_time,
						long last_access_time,
						long last_write_time,
						DateTime dateTime,
						out MonoIOError error)
		{
			IntPtr handle;
			bool result;

			handle = Open (path, FileMode.Open,
				       FileAccess.ReadWrite,
				       FileShare.ReadWrite, FileOptions.None, out error);
			if (handle == MonoIO.InvalidHandle)
				return false;

			switch (type) {
			case 1:
				creation_time = dateTime.ToFileTime ();
				break;
			case 2:
				last_access_time = dateTime.ToFileTime ();
				break;
			case 3:
				last_write_time = dateTime.ToFileTime ();
				break;
			}

			result = SetFileTime (new SafeFileHandle(handle, false), creation_time,
					      last_access_time,
					      last_write_time, out error);

			MonoIOError ignore_error;
			Close (handle, out ignore_error);
			
			return result;
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private extern static void Lock (IntPtr handle,
						long position, long length,
						out MonoIOError error);

		public static void Lock (SafeHandle safeHandle,
						long position, long length,
						out MonoIOError error)
		{
			bool release = false;
			try {
				safeHandle.DangerousAddRef (ref release);
				Lock (safeHandle.DangerousGetHandle (), position, length, out error);
			} finally {
				if (release)
					safeHandle.DangerousRelease ();
			}
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		private extern static void Unlock (IntPtr handle,
						  long position, long length,
						  out MonoIOError error);

		public static void Unlock (SafeHandle safeHandle,
						  long position, long length,
						  out MonoIOError error)
		{
			bool release = false;
			try {
				safeHandle.DangerousAddRef (ref release);
				Unlock (safeHandle.DangerousGetHandle (), position, length, out error);
			} finally {
				if (release)
					safeHandle.DangerousRelease ();
			}
		}

		// console handles

		public extern static IntPtr ConsoleOutput {
			[MethodImplAttribute (MethodImplOptions.InternalCall)]
			get;
		}

		public extern static IntPtr ConsoleInput {
			[MethodImplAttribute (MethodImplOptions.InternalCall)]
			get;
		}

		public extern static IntPtr ConsoleError {
			[MethodImplAttribute (MethodImplOptions.InternalCall)]
			get;
		}

		// pipe handles

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		public extern static bool CreatePipe (out IntPtr read_handle, out IntPtr write_handle, out MonoIOError error);

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		public extern static bool DuplicateHandle (IntPtr source_process_handle, IntPtr source_handle,
			IntPtr target_process_handle, out IntPtr target_handle, int access, int inherit, int options, out MonoIOError error);

		// path characters

		public extern static char VolumeSeparatorChar {
			[MethodImplAttribute (MethodImplOptions.InternalCall)]
			get;
		}

		public extern static char DirectorySeparatorChar {
			[MethodImplAttribute (MethodImplOptions.InternalCall)]
			get;
		}

		public extern static char AltDirectorySeparatorChar {
			[MethodImplAttribute (MethodImplOptions.InternalCall)]
			get;
		}

		public extern static char PathSeparator {
			[MethodImplAttribute (MethodImplOptions.InternalCall)]
			get;
		}

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		extern static void DumpHandles ();
	}
}