public void AtomicWrite_ReplacingExistingReadOnlyFile_Throws()
{
var path = BaseDir.CreateFile("test.txt");
SafeFile.SetReadOnly(path);
Should.Throw <UnauthorizedAccessException>(() =>
SafeFile.AtomicWrite(path, tmpPath => tmpPath.ToNPath().CreateFile()));
}
public void AtomicWrite_WithEmptyAction_ShouldDoNothing()
{
var path = BaseDir.CreateFile("test.txt");
SafeFile.AtomicWrite(path, tmpPath => { });
path.FileExists().ShouldBeTrue();
(path + SafeFile.TmpExtension).ToNPath().FileExists().ShouldBeFalse();
(path + SafeFile.BakExtension).ToNPath().FileExists().ShouldBeFalse();
}
public void AtomicWrite_WithExistingReadOnlyTempAndBakFiles_OverwritesFilesAndOperatesNormally()
{
var path = BaseDir.Combine("test.txt").WriteAllText("test");
var temp = (path + SafeFile.TmpExtension).ToNPath().CreateFile();
var backup = (path + SafeFile.BakExtension).ToNPath().CreateFile();
SafeFile.SetReadOnly(temp);
SafeFile.SetReadOnly(backup);
SafeFile.AtomicWrite(path, tmpPath => tmpPath.ToNPath().WriteAllText("new"));
temp.FileExists().ShouldBeFalse();
backup.FileExists().ShouldBeFalse();
path.ReadAllText().ShouldBe("new");
}
static bool OverwriteFileIfChanged(FormatItem formatItem, IEnumerable <string> lines, EndOfLine eol)
{
// write to a buffer so we can do an exact comparison vs the file already on disk. let's avoid generating io writes if
// there is no actual change. but we need to have the raw bytes so that differences in encoding and EOL's are not masked.
var newFileBuffer = new MemoryStream();
WriteLines(newFileBuffer, lines, formatItem.EditorConfig.Charset, eol);
var newFileBytes = newFileBuffer.GetBuffer();
var newFileLength = (int)newFileBuffer.Length; // not newFileBytes.Length!
var match = new FileInfo(formatItem.Path).Length == newFileLength; // do cheap length check first
if (match)
{
var oldFileBytes = File.ReadAllBytes(formatItem.Path);
// must do the byte compare vs disk
for (var i = 0; i < newFileLength; ++i)
{
if (newFileBytes[i] != oldFileBytes[i])
{
match = false;
break;
}
}
}
// ok we have to write it
if (!match)
{
// TODO: copy the permission bits over ($mode & 0777) to the new file
// TODO: backup under ./Temp/Format (subfolders? replace folder names with _?) configurable via a new FormatContext.BackupRoot
SafeFile.AtomicWrite(formatItem.Path, writePath =>
{
using (var writeFile = File.OpenWrite(writePath))
writeFile.Write(newFileBytes, 0, newFileLength);
});
}
return(!match);
}