stasis-aries-wal/lladd/logger/logEntry.h

/*---
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---*/

#ifndef __LLADD_LOGGING_LOGENTRY_H
#define __LLADD_LOGGING_LOGENTRY_H

#include <lladd/common.h>

BEGIN_C_DECLS

/**
   @file structs and memory managment routines for log entries

   @todo Is there a better way to deal with sizeof() and log entries?
   
   @todo Other than some typedefs, is there anything in logEntry that belongs in the API?

   @ingroup LLADD_CORE
   
   $Id$
*/

typedef struct {
  unsigned int funcID : 8;
  recordid rid;
  unsigned int argSize;
  /* Implicit members:
     args;     @ ((byte*)ule) + sizeof(UpdateLogEntry)
     preImage; @ ((byte*)ule) + sizeof(UpdateLogEntry) + ule.argSize */
} UpdateLogEntry;

struct __raw_log_entry {
  lsn_t LSN;
  lsn_t prevLSN;
  int   xid;
  unsigned int type;
};

typedef struct {
  lsn_t LSN;
  lsn_t prevLSN;
  int   xid;
  unsigned int type;
  UpdateLogEntry update;
} LogEntry;

/**
   Allocate a log entry that does not contain any extra payload
   information.  (Eg: Tbegin, Tcommit, etc.)

   @return a LogEntry that should be freed with free().
 */
LogEntry * allocCommonLogEntry(lsn_t prevLSN, int xid, unsigned int type);
/** 
   Allocate a log entry associated with an operation implemention.  This
   is usually called inside of Tupdate().

   @return a LogEntry that should be freed with free().

*/
LogEntry * allocUpdateLogEntry(lsn_t prevLSN, int xid, 
			       unsigned int operation, recordid rid, 
			       const byte * args, unsigned int argSize, 
			       const byte * preImage);
/**
   Alloc a deferred log entry.  This is just like allocUpdateLogEntry(), except 
   the log entry's type will be DEFERLOG instead UPDATELOG.  This is usually
   called inside of Tdefer().

   @return a LogEntry that should be freed with free().

*/
LogEntry * allocDeferredLogEntry(lsn_t prevLSN, int xid, 
				 unsigned int operation, recordid rid, 
				 const byte * args, unsigned int argSize, 
				 const byte * preImage);
/**
   Allocate a CLR entry.  These are written during recovery as log
   entries are undone.  This moves undo operations into the redo
   phase, by recording the inverse of the original operation, and sets
   prevLSN to the prevLSN of old_e.

   @return a LogEntry that should be freed with free().
*/
LogEntry * allocCLRLogEntry(const LogEntry * old_e);
/** 
   @return the length, in bytes, of e.
*/
long sizeofLogEntry(const LogEntry * e);
/**
   @return the operation's arguments.
*/
const byte * getUpdateArgs(const LogEntry * e);
/**
   @return the undo information for operations that use record-based
   phsysical undo.
*/
const byte * getUpdatePreImage(const LogEntry * e);

END_C_DECLS

#endif /* __LOGENTRY_H */