//
// Copyright (c) 2004-2006 Jaroslaw Kowalski <jaak@jkowalski.net>
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// * Neither the name of Jaroslaw Kowalski nor the names of its
// contributors may be used to endorse or promote products derived from this
// software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
// THE POSSIBILITY OF SUCH DAMAGE.
//
#if !NETCF
using System;
using System.Xml;
using System.IO;
using System.Threading;
using System.Text;
using System.Collections;
using System.Collections.Specialized;
using NLog;
using NLog.Config;
using NLog.Internal;
namespace NLog.Internal.FileAppenders
{
/// <summary>
/// Provides a multiprocess-safe atomic file appends while
/// keeping the files open.
/// </summary>
/// <remarks>
/// On Unix you can get all the appends to be atomic, even when multiple
/// processes are trying to write to the same file, because setting the file
/// pointer to the end of the file and appending can be made one operation.
/// On Win32 we need to maintain some synchronization between processes
/// (global named mutex is used for this)
/// </remarks>
internal class MutexMultiProcessFileAppender : BaseFileAppender
{
private Mutex _mutex;
private FileStream _file;
public static readonly IFileAppenderFactory TheFactory = new Factory();
public class Factory : IFileAppenderFactory
{
public BaseFileAppender Open(string fileName, ICreateFileParameters parameters)
{
return new MutexMultiProcessFileAppender(fileName, parameters);
}
}
public MutexMultiProcessFileAppender(string fileName, ICreateFileParameters parameters) : base(fileName, parameters)
{
try
{
_mutex = new Mutex(false, GetMutexName(fileName));
_file = CreateFileStream(true);
}
catch
{
if (_mutex != null)
{
_mutex.Close();
_mutex = null;
}
if (_file != null)
{
_file.Close();
_file = null;
}
throw;
}
}
public override void Write(byte[] bytes)
{
if (_mutex == null)
return;
_mutex.WaitOne();
try
{
_file.Seek(0, SeekOrigin.End);
_file.Write(bytes, 0, bytes.Length);
_file.Flush();
FileTouched();
}
finally
{
_mutex.ReleaseMutex();
}
}
public override void Close()
{
InternalLogger.Trace("Closing '{0}'", FileName);
if (_mutex != null)
{
_mutex.Close();
}
if (_file != null)
{
_file.Close();
}
_mutex = null;
_file = null;
FileTouched();
}
public override void Flush()
{
// do nothing, the stream is always flushed
}
private string GetMutexName(string fileName)
{
string canonicalName = Path.GetFullPath(fileName).ToLower();
canonicalName = canonicalName.Replace('\\', '_');
canonicalName = canonicalName.Replace('/', '_');
canonicalName = canonicalName.Replace(':', '_');
return "filelock-mutex-" + canonicalName;
}
public override bool GetFileInfo(out DateTime lastWriteTime, out long fileLength)
{
#if NET_2_API
return FileInfoHelper.Helper.GetFileInfo(FileName, _file.SafeFileHandle.DangerousGetHandle(), out lastWriteTime, out fileLength);
#else
return FileInfoHelper.Helper.GetFileInfo(FileName, _file.Handle, out lastWriteTime, out fileLength);
#endif
}
}
}
#endif