/// <summary>Construct a <see cref="FileSink"/>.</summary>
/// <param name="path">Path to the file.</param>
/// <param name="textFormatter">Formatter used to convert log events to text.</param>
/// <param name="fileSizeLimitBytes">The approximate maximum size, in bytes, to which a log file will be allowed to grow.
/// For unrestricted growth, pass null. The default is 1 GB. To avoid writing partial events, the last event within the limit
/// will be written in full even if it exceeds the limit.</param>
/// <param name="encoding">Character encoding used to write the text file. The default is UTF-8 without BOM.</param>
/// <param name="buffered">Indicates if flushing to the output file can be buffered or not. The default
/// is false.</param>
/// <returns>Configuration object allowing method chaining.</returns>
/// <remarks>The file will be written using the UTF-8 character set.</remarks>
/// <exception cref="IOException"></exception>
public FileSink(string path, ITextFormatter textFormatter, long?fileSizeLimitBytes, Encoding encoding = null, bool buffered = false)
{
if (path == null)
{
throw new ArgumentNullException(nameof(path));
}
if (textFormatter == null)
{
throw new ArgumentNullException(nameof(textFormatter));
}
if (fileSizeLimitBytes.HasValue && fileSizeLimitBytes < 0)
{
throw new ArgumentException("Negative value provided; file size limit must be non-negative");
}
_textFormatter = textFormatter;
_fileSizeLimitBytes = fileSizeLimitBytes;
_buffered = buffered;
var directory = Path.GetDirectoryName(path);
if (!string.IsNullOrWhiteSpace(directory) && !Directory.Exists(directory))
{
Directory.CreateDirectory(directory);
}
Stream outputStream = _underlyingStream = System.IO.File.Open(path, FileMode.Append, FileAccess.Write, FileShare.Read);
if (_fileSizeLimitBytes != null)
{
outputStream = _countingStreamWrapper = new WriteCountingStream(_underlyingStream);
}
_output = new StreamWriter(outputStream, encoding ?? new UTF8Encoding(encoderShouldEmitUTF8Identifier: false));
}
// This overload should be used internally; the overload above maintains compatibility with the earlier public API.
internal FileSink(
string path,
ITextFormatter textFormatter,
long?fileSizeLimitBytes,
Encoding encoding,
bool buffered,
FileLifecycleHooks hooks)
{
if (path == null)
{
throw new ArgumentNullException(nameof(path));
}
if (fileSizeLimitBytes.HasValue && fileSizeLimitBytes < 0)
{
throw new ArgumentException("Negative value provided; file size limit must be non-negative.");
}
_textFormatter = textFormatter ?? throw new ArgumentNullException(nameof(textFormatter));
_fileSizeLimitBytes = fileSizeLimitBytes;
_buffered = buffered;
var directory = Path.GetDirectoryName(path);
if (!string.IsNullOrWhiteSpace(directory) && !Directory.Exists(directory))
{
Directory.CreateDirectory(directory);
}
Stream outputStream = _underlyingStream = System.IO.File.Open(path, FileMode.Append, FileAccess.Write, FileShare.Read);
if (_fileSizeLimitBytes != null)
{
outputStream = _countingStreamWrapper = new WriteCountingStream(_underlyingStream);
}
// Parameter reassignment.
encoding = encoding ?? new UTF8Encoding(encoderShouldEmitUTF8Identifier: false);
if (hooks != null)
{
outputStream = hooks.OnFileOpened(outputStream, encoding) ??
throw new InvalidOperationException($"The file lifecycle hook `{nameof(FileLifecycleHooks.OnFileOpened)}(...)` returned `null`.");
}
_output = new StreamWriter(outputStream, encoding);
}