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 

   Next generation logger api.  

   @todo Was getting some memory over-runs from the fact that I didn't
   know the exact length of a raw log entry.  This seems to be fixed
   now. 
   
   @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 {
  lsn_t    thisUpdateLSN;
  recordid rid; 
  lsn_t    undoNextLSN;
} CLRLogEntry;

typedef struct {
  unsigned int funcID : 8;
  recordid rid;
  unsigned int argSize;
  /*  int invertible; */ /* no longer needed */
  /* 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;
};

/*#define sizeofRawLogEntry (sizeof(lsn_t)*2+sizeof(int)+4)*/

typedef struct {
  lsn_t LSN;
  lsn_t prevLSN;
  int   xid;
  unsigned int type;
  union {
    UpdateLogEntry update;
    CLRLogEntry    clr;
  } contents;
} LogEntry;

/**
   All of these return a pointer to a single malloced region that should be freed. 
*/

/**
   Allocate a log entry that does not contain any extra payload information.  (Eg:  Tbegin, Tcommit, etc.)
 */
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().
*/
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().
*/
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 to
   indicate that the stable copy of the store file reflects the state
   of the database after an operation has successfuly been
   redone/undone.
 */
LogEntry * allocCLRLogEntry   (lsn_t prevLSN, int xid, 
			       lsn_t thisUpdateLSN, recordid rid, lsn_t undoNextLSN);



long sizeofLogEntry(const LogEntry * log);
const byte * getUpdateArgs(const LogEntry * log);
const byte * getUpdatePreImage(const LogEntry * log);

END_C_DECLS

#endif /* __LOGENTRY_H */