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

/*---
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---*/

#ifndef __LLADD_LOGGING_LOGENTRY_H
#define __LLADD_LOGGING_LOGENTRY_H

#include <stasis/common.h>

BEGIN_C_DECLS

/**
   @file

   Structs and memory managment routines for 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;
  pageid_t page;
  int64_t  arg_size;
  /* Implicit members:
     args;     @ ((byte*)ule) + sizeof(UpdateLogEntry)
  */
} 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;

typedef struct __raw_log_entry CLRLogEntry;
/**
   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);

LogEntry * allocPrepareLogEntry(lsn_t prevLSN, int xid, lsn_t recLSN);
/**
   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 op, pageid_t page,
			       const byte * arg, unsigned int arg_size);

/**
   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 * e);
/**
   @param e a log entry returned from one of the alloc???LogEntry functions.
 */
void freeLogEntry(const LogEntry * e);
/**
   @return the length, in bytes, of e.
*/
lsn_t sizeofLogEntry(const LogEntry * e);
/**
   @todo Remove explicit casts from getUpdateArgs calls (so we don't accidentally strip the const).
   @return the operation's arguments.
*/
const void * getUpdateArgs(const LogEntry * e);

/**
	@return a copy of the log entry that this CLR compensated.
 */
static inline const LogEntry * getCLRCompensated(const CLRLogEntry * e) {
	return (const LogEntry*)(
			((const struct __raw_log_entry*)e)+1
			);
}

lsn_t getPrepareRecLSN(const LogEntry *e);

END_C_DECLS

#endif /* __LOGENTRY_H */