OW_FileAppender.cpp

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#include "OW_config.h"
#include "OW_FileAppender.hpp"
#include "OW_Format.hpp"
#include "OW_Logger.hpp"
#include "OW_LogMessage.hpp"
#include "OW_Mutex.hpp"
#include "OW_MutexLock.hpp"
#include "OW_FileSystem.hpp"

#include <fstream>

namespace OW_NAMESPACE
{

FileAppender::FileAppender(const StringArray& components,
   const StringArray& categories,
   const char* filename,
   const String& pattern,
   UInt64 maxFileSize,
   unsigned int maxBackupIndex,
   bool flushLog)
   : LogAppender(components, categories, pattern)
   , m_filename(filename)
   , m_maxFileSize(maxFileSize)
   , m_maxBackupIndex(maxBackupIndex)
   , m_flushLog(flushLog)
{
   m_log.open(m_filename.c_str(), std::ios::out | std::ios::app);
   if (!m_log)
   {
      OW_THROW(LoggerException, Format("FileAppender: Unable to open file: %1", m_filename).toString().c_str() );
   }
}

FileAppender::~FileAppender()
{
}

namespace
{
   Mutex fileGuard;
}
void
FileAppender::doProcessLogMessage(const String& formattedMessage, const LogMessage& message) const
{
   MutexLock lock(fileGuard);

   // take into account external log rotators, if the file we have open no longer exists, then reopen it.
   if (!FileSystem::exists(m_filename.c_str()))
   {
      m_log.close();
      m_log.open(m_filename.c_str(), std::ios::out | std::ios::app);
   }

   if (!m_log)
   {
      // hmm, not much we can do here.  doProcessLogMessage can't throw.
      return;
   }

   m_log.write(formattedMessage.c_str(), formattedMessage.length());
   m_log << '\n';

   if (m_flushLog)
   {
      m_log.flush();
   }

   // handle log rotation
   if (m_maxFileSize != NO_MAX_LOG_SIZE && m_log.tellp() >= static_cast<std::streampos>(m_maxFileSize * 1024))
   {
      // since we can't throw an exception, or log any errors, it something fails here, we'll just return silently :-(

      // do the roll over
      m_log.close();

      if (m_maxBackupIndex > 0)
      {
         // delete the oldest file first - this may or may not exist, we try anyway.
         FileSystem::removeFile(m_filename + '.' + String(m_maxBackupIndex));

         // increment the numbers on all the files - some may exist or not, but try anyway.
         for (unsigned int i = m_maxBackupIndex - 1; i >= 1; --i)
         {
            FileSystem::renameFile(m_filename + '.' + String(i), m_filename + '.' + String(i + 1));
         }

         if (!FileSystem::renameFile(m_filename, m_filename + ".1"))
         {
            // if we can't rename it, avoid truncating it.
            return;
         }
      }

      // truncate the existing one
      m_log.open(m_filename.c_str(), std::ios_base::out | std::ios_base::trunc);
   }
}

const String FileAppender::STR_DEFAULT_MESSAGE_PATTERN("%d{%a %b %d %H:%M:%S %Y} [%t]: %m");

} // end namespace OW_NAMESPACE

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