rollingfileappender.cs

精通SQL Server2005项目开发

					{
						System.IO.File.Delete(fileToDelete);
					}
					LogLog.Debug("RollingFileAppender: Deleted file [" + fileName + "]");
				}
				catch(Exception deleteEx)
				{
					if (fileToDelete == fileName)
					{
						// Unable to move or delete the file
						ErrorHandler.Error("Exception while deleting file [" + fileToDelete + "]", deleteEx, ErrorCode.GenericFailure);
					}
					else
					{
						// Moved the file, but the delete failed. File is probably locked.
						// The file should automatically be deleted when the lock is released.
						LogLog.Debug("RollingFileAppender: Exception while deleting temp file [" + fileToDelete + "]", deleteEx);
					}
				}
			}
		}
  
		/// <summary>
		/// Implements file roll base on file size.
		/// </summary>
		/// <remarks>
		/// <para>
		/// If the maximum number of size based backups is reached
		/// (<c>curSizeRollBackups == maxSizeRollBackups</c>) then the oldest
		/// file is deleted -- its index determined by the sign of countDirection.
		/// If <c>countDirection</c> &lt; 0, then files
		/// {<c>File.1</c>, ..., <c>File.curSizeRollBackups -1</c>}
		/// are renamed to {<c>File.2</c>, ...,
		/// <c>File.curSizeRollBackups</c>}. Moreover, <c>File</c> is
		/// renamed <c>File.1</c> and closed.
		/// </para>
		/// <para>
		/// A new file is created to receive further log output.
		/// </para>
		/// <para>
		/// If <c>maxSizeRollBackups</c> is equal to zero, then the
		/// <c>File</c> is truncated with no backup files created.
		/// </para>
		/// <para>
		/// If <c>maxSizeRollBackups</c> &lt; 0, then <c>File</c> is
		/// renamed if needed and no files are deleted.
		/// </para>
		/// </remarks>
		protected void RollOverSize() 
		{
			this.CloseFile(); // keep windows happy.
	
			LogLog.Debug("RollingFileAppender: rolling over count ["+((CountingQuietTextWriter)QuietWriter).Count+"]");
			LogLog.Debug("RollingFileAppender: maxSizeRollBackups ["+m_maxSizeRollBackups+"]");
			LogLog.Debug("RollingFileAppender: curSizeRollBackups ["+m_curSizeRollBackups+"]");
			LogLog.Debug("RollingFileAppender: countDirection ["+m_countDirection+"]");

			RollOverRenameFiles(File);
	
			if (!m_staticLogFileName && m_countDirection >= 0) 
			{
				m_curSizeRollBackups++;
			}

			// This will also close the file. This is OK since multiple close operations are safe.
			SafeOpenFile(m_baseFileName, false);
		}

		/// <summary>
		/// Implements file roll.
		/// </summary>
		/// <param name="baseFileName">the base name to rename</param>
		/// <remarks>
		/// <para>
		/// If the maximum number of size based backups is reached
		/// (<c>curSizeRollBackups == maxSizeRollBackups</c>) then the oldest
		/// file is deleted -- its index determined by the sign of countDirection.
		/// If <c>countDirection</c> &lt; 0, then files
		/// {<c>File.1</c>, ..., <c>File.curSizeRollBackups -1</c>}
		/// are renamed to {<c>File.2</c>, ...,
		/// <c>File.curSizeRollBackups</c>}. 
		/// </para>
		/// <para>
		/// If <c>maxSizeRollBackups</c> is equal to zero, then the
		/// <c>File</c> is truncated with no backup files created.
		/// </para>
		/// <para>
		/// If <c>maxSizeRollBackups</c> &lt; 0, then <c>File</c> is
		/// renamed if needed and no files are deleted.
		/// </para>
		/// <para>
		/// This is called by <see cref="RollOverSize"/> to rename the files.
		/// </para>
		/// </remarks>
		protected void RollOverRenameFiles(string baseFileName) 
		{
			// If maxBackups <= 0, then there is no file renaming to be done.
			if (m_maxSizeRollBackups != 0) 
			{
				if (m_countDirection < 0) 
				{
					// Delete the oldest file, to keep Windows happy.
					if (m_curSizeRollBackups == m_maxSizeRollBackups) 
					{
						DeleteFile(baseFileName + '.' + m_maxSizeRollBackups);
						m_curSizeRollBackups--;
					}
	
					// Map {(maxBackupIndex - 1), ..., 2, 1} to {maxBackupIndex, ..., 3, 2}
					for (int i = m_curSizeRollBackups; i >= 1; i--) 
					{
						RollFile((baseFileName + "." + i), (baseFileName + '.' + (i + 1)));
					}
	
					m_curSizeRollBackups++;

					// Rename fileName to fileName.1
					RollFile(baseFileName, baseFileName + ".1");
				} 
				else 
				{
					//countDirection >= 0
					if (m_curSizeRollBackups >= m_maxSizeRollBackups && m_maxSizeRollBackups > 0) 
					{
						//delete the first and keep counting up.
						int oldestFileIndex = m_curSizeRollBackups - m_maxSizeRollBackups;

						// If static then there is 1 file without a number, therefore 1 less archive
						if (m_staticLogFileName)
						{
							oldestFileIndex++;
						}

						// If using a static log file then the base for the numbered sequence is the baseFileName passed in
						// If not using a static log file then the baseFileName will already have a numbered postfix which
						// we must remove, however it may have a date postfix which we must keep!
						string archiveFileBaseName = baseFileName;
						if (!m_staticLogFileName)
						{
							int lastDotIndex = archiveFileBaseName.LastIndexOf(".");
							if (lastDotIndex >= 0) 
							{
								archiveFileBaseName = archiveFileBaseName.Substring(0, lastDotIndex);
							}
						}

						// Delete the archive file
						DeleteFile(archiveFileBaseName + '.' + oldestFileIndex);
					}
	
					if (m_staticLogFileName) 
					{
						m_curSizeRollBackups++;
						RollFile(baseFileName, baseFileName + '.' + m_curSizeRollBackups);
					}
				}
			}
		}

		#endregion

		#region NextCheckDate

		/// <summary>
		/// Get the start time of the next window for the current rollpoint
		/// </summary>
		/// <param name="currentDateTime">the current date</param>
		/// <param name="rollPoint">the type of roll point we are working with</param>
		/// <returns>the start time for the next roll point an interval after the currentDateTime date</returns>
		/// <remarks>
		/// <para>
		/// Returns the date of the next roll point after the currentDateTime date passed to the method.
		/// </para>
		/// <para>
		/// The basic strategy is to subtract the time parts that are less significant
		/// than the rollpoint from the current time. This should roll the time back to
		/// the start of the time window for the current rollpoint. Then we add 1 window
		/// worth of time and get the start time of the next window for the rollpoint.
		/// </para>
		/// </remarks>
		protected DateTime NextCheckDate(DateTime currentDateTime, RollPoint rollPoint) 
		{
			// Local variable to work on (this does not look very efficient)
			DateTime current = currentDateTime;

			// Do slightly different things depending on what the type of roll point we want.
			switch(rollPoint) 
			{
				case RollPoint.TopOfMinute:
					current = current.AddMilliseconds(-current.Millisecond);
					current = current.AddSeconds(-current.Second);
					current = current.AddMinutes(1);
					break;

				case RollPoint.TopOfHour:
					current = current.AddMilliseconds(-current.Millisecond);
					current = current.AddSeconds(-current.Second);
					current = current.AddMinutes(-current.Minute);
					current = current.AddHours(1);
					break;

				case RollPoint.HalfDay:
					current = current.AddMilliseconds(-current.Millisecond);
					current = current.AddSeconds(-current.Second);
					current = current.AddMinutes(-current.Minute);

					if (current.Hour < 12) 
					{
						current = current.AddHours(12 - current.Hour);
					} 
					else 
					{
						current = current.AddHours(-current.Hour);
						current = current.AddDays(1);
					}
					break;

				case RollPoint.TopOfDay:
					current = current.AddMilliseconds(-current.Millisecond);
					current = current.AddSeconds(-current.Second);
					current = current.AddMinutes(-current.Minute);
					current = current.AddHours(-current.Hour);
					current = current.AddDays(1);
					break;

				case RollPoint.TopOfWeek:
					current = current.AddMilliseconds(-current.Millisecond);
					current = current.AddSeconds(-current.Second);
					current = current.AddMinutes(-current.Minute);
					current = current.AddHours(-current.Hour);
					current = current.AddDays(7 - (int)current.DayOfWeek);
					break;

				case RollPoint.TopOfMonth:
					current = current.AddMilliseconds(-current.Millisecond);
					current = current.AddSeconds(-current.Second);
					current = current.AddMinutes(-current.Minute);
					current = current.AddHours(-current.Hour);
					current = current.AddDays(1 - current.Day); /* first day of month is 1 not 0 */
					current = current.AddMonths(1);
					break;
			}	  
			return current;
		}

		#endregion

		#region Private Instance Fields

		/// <summary>
		/// This object supplies the current date/time.  Allows test code to plug in
		/// a method to control this class when testing date/time based rolling.
		/// </summary>
		private IDateTime m_dateTime = null;

		/// <summary>
		/// The date pattern. By default, the pattern is set to <c>".yyyy-MM-dd"</c> 
		/// meaning daily rollover.
		/// </summary>
		private string m_datePattern = ".yyyy-MM-dd";
  
		/// <summary>
		/// The actual formatted filename that is currently being written to
		/// or will be the file transferred to on roll over
		/// (based on staticLogFileName).
		/// </summary>
		private string m_scheduledFilename = null;
  
		/// <summary>
		/// The timestamp when we shall next recompute the filename.
		/// </summary>
		private DateTime m_nextCheck = DateTime.MaxValue;
  
		/// <summary>
		/// Holds date of last roll over
		/// </summary>
		private DateTime m_now;
  
		/// <summary>
		/// The type of rolling done
		/// </summary>
		private RollPoint m_rollPoint;
  
		/// <summary>
		/// The default maximum file size is 10MB
		/// </summary>
		private long m_maxFileSize = 10*1024*1024;
  
		/// <summary>
		/// There is zero backup files by default
		/// </summary>
		private int m_maxSizeRollBackups  = 0;

		/// <summary>
		/// How many sized based backups have been made so far
		/// </summary>
		private int m_curSizeRollBackups = 0;
  
		/// <summary>
		/// The rolling file count direction. 
		/// </summary>
		private int m_countDirection = -1;
  
		/// <summary>
		/// The rolling mode used in this appender.
		/// </summary>
		private RollingMode m_rollingStyle = RollingMode.Composite;

		/// <summary>
		/// Cache flag set if we are rolling by date.
		/// </summary>
		private bool m_rollDate = true;

		/// <summary>
		/// Cache flag set if we are rolling by size.
		/// </summary>
		private bool m_rollSize = true;
  
		/// <summary>
		/// Value indicating whether to always log to the same file.
		/// </summary>
		private bool m_staticLogFileName = true;
  
		/// <summary>
		/// FileName provided in configuration.  Used for rolling properly
		/// </summary>
		private string m_baseFileName;
  
		#endregion Private Instance Fields

		#region Static Members

		/// <summary>
		/// The 1st of January 1970 in UTC
		/// </summary>
		private static readonly DateTime s_date1970 = new DateTime(1970, 1, 1);

		#endregion

		#region DateTime

		/// <summary>
		/// This interface is used to supply Date/Time information to the <see cref="RollingFileAppender"/>.
		/// </summary>
		/// <remarks>
		/// This interface is used to supply Date/Time information to the <see cref="RollingFileAppender"/>.
		/// Used primarily to allow test classes to plug themselves in so they can
		/// supply test date/times.
		/// </remarks>
		public interface IDateTime
		{
			/// <summary>
			/// Gets the <i>current</i> time.
			/// </summary>
			/// <value>The <i>current</i> time.</value>
			/// <remarks>
			/// <para>
			/// Gets the <i>current</i> time.
			/// </para>
			/// </remarks>
			DateTime Now { get; }
		}

		/// <summary>
		/// Default implementation of <see cref="IDateTime"/> that returns the current time.
		/// </summary>
		private class DefaultDateTime : IDateTime
		{
			/// <summary>
			/// Gets the <b>current</b> time.
			/// </summary>
			/// <value>The <b>current</b> time.</value>
			/// <remarks>
			/// <para>
			/// Gets the <b>current</b> time.
			/// </para>
			/// </remarks>
			public DateTime Now
			{
				get { return DateTime.Now; }
			}
		}

		#endregion DateTime
	}
}