ACE/ace/Log_Msg_Backend.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file    Log_Msg_Backend.h
   6  *
   7  *  @author Douglas C. Schmidt <d.schmidt@vanderbilt.edu>
   8  */
   9 //=============================================================================
  10
  11
  12 #ifndef ACE_LOG_MSG_BACKEND_H
  13 #define ACE_LOG_MSG_BACKEND_H
  14 #include /**/ "ace/pre.h"
  15
  16 #include /**/ "ace/ACE_export.h"
  17
  18 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  19 # pragma once
  20 #endif /* ACE_LACKS_PRAGMA_ONCE */
  21
  22 #include "ace/os_include/sys/os_types.h"
  23
  24 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
  25
  26 class ACE_Log_Record;
  27
  28 /**
  29  * @class ACE_Log_Msg_Backend
  30  *
  31  * @brief Defines the interface for ACE_Log_Msg back end processing.
  32  *
  33  * The ACE_Log_Msg class uses ACE_Log_Msg_Backend as the target interface
  34  * for back end log record procesing. In addition to the classes ACE
  35  * derives from this (ACE_Log_Msg_NT_Event_Log, ACE_Log_Msg_UNIX_Syslog, and
  36  * ACE_Log_Msg_IPC) users can derive classes from ACE_Log_Msg_Backend for
  37  * use as a custom logger back end.
  38  */
  39 class ACE_Export ACE_Log_Msg_Backend
  40 {
  41 public:
  42   /// No-op virtual destructor.
  43   virtual ~ACE_Log_Msg_Backend ();
  44
  45   /**
  46    * Open the back end object. Perform any actions needed to prepare
  47    * the object for later logging operations.
  48    *
  49    * @param logger_key  The character string passed to ACE_Log_Msg::open().
  50    *                    If the @c LOGGER logging destination is not being
  51    *                    used, any string can be passed through to the back end.
  52    *
  53    * @retval 0 for success.
  54    * @retval -1 for failure.
  55    */
  56   virtual int open (const ACE_TCHAR *logger_key) = 0;
  57
  58   /**
  59    * Reset the backend.  If ACE_Log_Msg is reopened during execution, this
  60    * hook will be called. This method should perform any needed cleanup
  61    * activity (similar to close()) because this object won't be reopened
  62    * if the new open call does not specify use of this back end being reset.
  63    *
  64    * @retval Currently ignored, but to be safe, return 0 for success;
  65    *         -1 for failure.
  66    */
  67   virtual int reset () = 0;
  68
  69   /// Close the backend completely.
  70   virtual int close () = 0;
  71
  72   /**
  73    * Process a log record.
  74    *
  75    * @param log_record   The ACE_Log_Record to process.
  76    *
  77    * @retval -1 for failure; else it is customarily the number of bytes
  78    *         processed, but can also be 0 to signify success.
  79    */
  80   virtual ssize_t log (ACE_Log_Record &log_record) = 0;
  81 };
  82
  83 ACE_END_VERSIONED_NAMESPACE_DECL
  84
  85 #include /**/ "ace/post.h"
  86 #endif /* ACE_LOG_MSG_BACKEND_H */