NLog.Targets.FileTarget.RefreshArchiveFilePatternToWatch C# (CSharp) Method

        private void RefreshArchiveFilePatternToWatch()
        {
#if !SILVERLIGHT && !__IOS__ && !__ANDROID__
            if (this.fileAppenderCache != null)
            {
                bool mustWatchArchiving = IsArchivingEnabled() && ConcurrentWrites && KeepFileOpen;
                if (mustWatchArchiving)
                {
                    var nullEvent = LogEventInfo.CreateNullEvent();
                    string fileNamePattern = GetArchiveFileNamePattern(GetFullFileName(nullEvent), nullEvent);
                    if (!string.IsNullOrEmpty(fileNamePattern))
                    {
                        fileNamePattern = Path.Combine(Path.GetDirectoryName(fileNamePattern),
                            ReplaceFileNamePattern(fileNamePattern, "*"));
                        //fileNamePattern is absolute
                        this.fileAppenderCache.ArchiveFilePatternToWatch = fileNamePattern;

                        if ((EnableArchiveFileCompression) && (this.appenderInvalidatorThread == null))
                        {
                            // EnableArchiveFileCompression creates a new file for the archive, instead of just moving the log file.
                            // The log file is deleted instead of moved. This process may be holding a lock to that file which will
                            // avoid the file from being deleted. Therefore we must periodically close appenders for files that 
                            // were archived so that the file can be deleted.

                            this.appenderInvalidatorThread = new Thread(() =>
                            {
                                while (true)
                                {
                                    try
                                    {
                                        if (this.stopAppenderInvalidatorThreadWaitHandle.WaitOne(200))
                                            break;

                                        lock (SyncRoot)
                                        {
                                            this.fileAppenderCache.InvalidateAppendersForInvalidFiles();
                                        }
                                    }
                                    catch (Exception ex)
                                    {
                                        InternalLogger.Debug(ex, "Exception in FileTarget appender-invalidator thread.");
                                    }
                                }
                            });
                            this.appenderInvalidatorThread.IsBackground = true;
                            this.appenderInvalidatorThread.Start();
                        }
                    }
                }
                else
                {
                    this.fileAppenderCache.ArchiveFilePatternToWatch = null;

                    this.StopAppenderInvalidatorThread();
                }
            }
#endif
        }