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using Ionic.Zlib;
using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;
namespace IPA.Logging.Printers
{
/// <summary>
/// A <see cref="LogPrinter"/> abstract class that provides the utilities to write to a GZip file.
/// </summary>
public abstract class GZFilePrinter : LogPrinter, IDisposable
{
[DllImport("Kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
static extern bool CreateHardLink(
string lpFileName,
string lpExistingFileName,
IntPtr lpSecurityAttributes
);
private FileInfo fileInfo;
/// <summary>
/// The <see cref="StreamWriter"/> that writes to the GZip file.
/// </summary>
protected StreamWriter FileWriter;
private GZipStream zstream;
private FileStream fstream;
/// <summary>
/// Gets the <see cref="FileInfo"/> for the file to write to without the .gz extension.
/// </summary>
/// <returns></returns>
protected abstract FileInfo GetFileInfo();
private void InitLog()
{
try
{
if (fileInfo == null)
{ // first init
fileInfo = GetFileInfo();
var ext = fileInfo.Extension;
fileInfo = new FileInfo(fileInfo.FullName + ".gz");
fileInfo.Create().Close();
var symlink = new FileInfo(Path.Combine(fileInfo.DirectoryName ?? throw new InvalidOperationException(), $"latest{ext}.gz"));
if (symlink.Exists) symlink.Delete();
try
{
if (!CreateHardLink(symlink.FullName, fileInfo.FullName, IntPtr.Zero))
{
var error = Marshal.GetLastWin32Error();
Logger.log.Error($"Hardlink creation failed ({error})");
}
}
catch (Exception e)
{
Logger.log.Error("Error creating latest hardlink!");
Logger.log.Error(e);
}
}
}
catch (Exception e)
{
Logger.log.Error("Error initializing log!");
Logger.log.Error(e);
}
}
/// <summary>
/// Called at the start of any print session.
/// </summary>
public sealed override void StartPrint()
{
InitLog();
fstream = fileInfo.Open(FileMode.Append, FileAccess.Write);
zstream = new GZipStream(fstream, CompressionMode.Compress)
{
FlushMode = FlushType.Full
};
FileWriter = new StreamWriter(zstream, new UTF8Encoding(false));
}
/// <summary>
/// Called at the end of any print session.
/// </summary>
public sealed override void EndPrint()
{
FileWriter.Flush();
zstream.Flush();
fstream.Flush();
FileWriter.Close();
zstream.Close();
fstream.Close();
FileWriter.Dispose();
zstream.Dispose();
fstream.Dispose();
}
/// <summary>
/// Disposes the file printer.
/// </summary>
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
/// <summary>
/// Disposes the file printer.
/// </summary>
/// <param name="disposing">does nothing</param>
protected virtual void Dispose(bool disposing)
{
if (disposing)
{
FileWriter.Flush();
zstream.Flush();
fstream.Flush();
FileWriter.Close();
zstream.Close();
fstream.Close();
FileWriter.Dispose();
zstream.Dispose();
fstream.Dispose();
}
}
}
}