public override void ActivateOptions()

in src/log4net/Appender/RollingFileAppender.cs [1115:1176]
46 lines of code
10 McCabe index (conditional complexity)

		public override void ActivateOptions() 
		{
			if (m_dateTime == null)
			{
				m_dateTime = new LocalDateTime();
			}

			if (m_rollDate && m_datePattern != null) 
			{
				m_now = m_dateTime.Now;
				m_rollPoint = ComputeCheckPeriod(m_datePattern);

				if (m_rollPoint == RollPoint.InvalidRollPoint)
				{
					throw new ArgumentException("Invalid RollPoint, unable to parse ["+m_datePattern+"]");
				}

				// next line added as this removes the name check in rollOver
				m_nextCheck = NextCheckDate(m_now, m_rollPoint);
			} 
			else 
			{
				if (m_rollDate)
				{
					ErrorHandler.Error("Either DatePattern or rollingStyle options are not set for ["+Name+"].");
				}
			}

			if (SecurityContext == null)
			{
				SecurityContext = SecurityContextProvider.DefaultProvider.CreateSecurityContext(this);
			}

			using(SecurityContext.Impersonate(this))
			{
				// Must convert the FileAppender's m_filePath to an absolute path before we
				// call ExistingInit(). This will be done by the base.ActivateOptions() but
				// we need to duplicate that functionality here first.
				base.File = ConvertToFullPath(base.File.Trim());

				// Store fully qualified base file name
				m_baseFileName = base.File;
			}

#if !NETCF
			// initialize the mutex that is used to lock rolling
			m_mutexForRolling = new Mutex(false, m_baseFileName
				.Replace("\\", "_")
				.Replace(":", "_")
				.Replace("/", "_") + "_rolling"
			);
#endif

			if (m_rollDate && File != null && m_scheduledFilename == null)
			{
                m_scheduledFilename = CombinePath(File, m_now.ToString(m_datePattern, DateTimeFormatInfo.InvariantInfo));
			}

			ExistingInit();
	
			base.ActivateOptions();
		}