/// <summary>
/// Ensure we have the data.
/// Does not throw for nonexistence.
/// </summary>
private void EnsurePopulated()
{
if (_dataIsGood == null)
{
_dataIsGood = false;
_filename = FileUtilities.AttemptToShortenPath(_filename); // This is no-op unless the path actually is too long
_data = new NativeMethodsShared.WIN32_FILE_ATTRIBUTE_DATA();
// THIS COPIED FROM THE BCL:
//
// For floppy drives, normally the OS will pop up a dialog saying
// there is no disk in drive A:, please insert one. We don't want that.
// SetErrorMode will let us disable this, but we should set the error
// mode back, since this may have wide-ranging effects.
int oldMode = NativeMethodsShared.SetErrorMode(1 /* ErrorModes.SEM_FAILCRITICALERRORS */);
bool success = false;
_fileOrDirectoryExists = true;
try
{
success = NativeMethodsShared.GetFileAttributesEx(_filename, 0, ref _data);
if (!success)
{
int error = Marshal.GetLastWin32Error();
// File not found is the most common case, for example we're copying
// somewhere without a file yet. Don't do something like FileInfo.Exists to
// get a nice error, or we're doing IO again! Don't even format our own string:
// that turns out to be unacceptably expensive here as well. Set a flag for this particular case.
//
// Also, when not under debugger (!) it will give error == 3 for path too long. Make that consistently throw instead.
if ((error == 2 /* ERROR_FILE_NOT_FOUND */ || error == 3 /* ERROR_PATH_NOT_FOUND */) &&
_filename.Length <= NativeMethodsShared.MAX_PATH)
{
_fileOrDirectoryExists = false;
return;
}
// Throw nice message as far as we can. At this point IO is OK.
var length = new FileInfo(_filename).Length;
// Otherwise this will give at least something
NativeMethodsShared.ThrowExceptionForErrorCode(error);
ErrorUtilities.ThrowInternalErrorUnreachable();
}
}
finally
{
NativeMethodsShared.SetErrorMode(oldMode);
}
_dataIsGood = true;
}
}
/// <summary>
/// Constructor gets the data for the filename.
/// On Win32 it uses native means. Otherwise,
/// uses standard .NET FileInfo/DirInfo
/// </summary>
public FileDirInfo(string filename)
{
Exists = false;
// If file/directory does not exist, return 12 midnight 1/1/1601.
LastWriteTimeUtc = new DateTime(1601, 1, 1);
_filename = FileUtilities.AttemptToShortenPath(filename); // This is no-op unless the path actually is too long
int oldMode = 0;
if (NativeMethodsShared.IsWindows)
{
// THIS COPIED FROM THE BCL:
//
// For floppy drives, normally the OS will pop up a dialog saying
// there is no disk in drive A:, please insert one. We don't want that.
// SetErrorMode will let us disable this, but we should set the error
// mode back, since this may have wide-ranging effects.
oldMode = NativeMethodsShared.SetErrorMode(1 /* ErrorModes.SEM_FAILCRITICALERRORS */);
}
try
{
if (NativeMethodsShared.IsWindows)
{
var data = new NativeMethodsShared.WIN32_FILE_ATTRIBUTE_DATA();
bool success = NativeMethodsShared.GetFileAttributesEx(_filename, 0, ref data);
if (!success)
{
int error = Marshal.GetLastWin32Error();
// File not found is the most common case, for example we're copying
// somewhere without a file yet. Don't do something like FileInfo.Exists to
// get a nice error, or we're doing IO again! Don't even format our own string:
// that turns out to be unacceptably expensive here as well. Set a flag for this particular case.
//
// Also, when not under debugger (!) it will give error == 3 for path too long. Make that consistently throw instead.
if ((error == 2 /* ERROR_FILE_NOT_FOUND */ || error == 3 /* ERROR_PATH_NOT_FOUND */) &&
_filename.Length <= NativeMethodsShared.MAX_PATH)
{
Exists = false;
return;
}
// Throw nice message as far as we can. At this point IO is OK.
Length = new FileInfo(_filename).Length;
// Otherwise this will give at least something
NativeMethodsShared.ThrowExceptionForErrorCode(error);
ErrorUtilities.ThrowInternalErrorUnreachable();
}
Exists = true;
IsDirectory = (data.fileAttributes & NativeMethodsShared.FILE_ATTRIBUTE_DIRECTORY) != 0;
IsReadOnly = !IsDirectory &&
(data.fileAttributes & NativeMethodsShared.FILE_ATTRIBUTE_READONLY) != 0;
LastWriteTimeUtc =
DateTime.FromFileTimeUtc(((long)data.ftLastWriteTimeHigh << 0x20) | data.ftLastWriteTimeLow);
Length = IsDirectory ? 0 : (((long)data.fileSizeHigh << 0x20) | data.fileSizeLow);
}
else
{
// Check if we have a directory
IsDirectory = Directory.Exists(_filename);
Exists = IsDirectory;
// If not exists, see if this is a file
if (!Exists)
{
Exists = File.Exists(_filename);
}
if (IsDirectory)
{
// Use DirectoryInfo to get the last write date
var directoryInfo = new DirectoryInfo(_filename);
IsReadOnly = false;
LastWriteTimeUtc = directoryInfo.LastWriteTimeUtc;
}
else if (Exists)
{
// Use FileInfo to get readonly and last write date
var fileInfo = new FileInfo(_filename);
IsReadOnly = fileInfo.IsReadOnly;
LastWriteTimeUtc = fileInfo.LastWriteTimeUtc;
Length = fileInfo.Length;
}
}
}
catch (Exception ex)
{
// Save the exception thrown and assume the file does not exist
_exceptionThrown = ex;
Exists = false;
}
finally
{
// Reset the error mode on Windows
if (NativeMethodsShared.IsWindows)
{
NativeMethodsShared.SetErrorMode(oldMode);
}
}
}
/// <summary>
/// Use in case the state is known to have changed exogenously.
/// </summary>
internal void Reset()
{
_data = new NativeMethodsShared.WIN32_FILE_ATTRIBUTE_DATA();
_dataIsGood = null;
}
