/*
** 2010 February 1
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface to the write-ahead logging
** system. Refer to the comments below and the header comment attached to
** the implementation of each function in log.c for further details.
*/
#ifndef _LOG_H_
#define _LOG_H_
#include "sqliteInt.h"
/* Connection to a log file. There is one object of this type for each pager. */
typedef struct Log Log;
/* Open and close a connection to a log file. */
int sqlite3LogOpen(sqlite3_vfs*, const char *zDb, Log **ppLog);
int sqlite3LogClose(Log *pLog, sqlite3_file *pFd, int sync_flags, u8 *zBuf);
/* Used by readers to open (lock) and close (unlock) a snapshot. */
int sqlite3LogOpenSnapshot(Log *pLog, int *);
void sqlite3LogCloseSnapshot(Log *pLog);
/* Read a page from the log, if it is present. */
int sqlite3LogRead(Log *pLog, Pgno pgno, int *pInLog, u8 *pOut);
void sqlite3LogDbsize(Log *pLog, Pgno *pPgno);
/* Obtain or release the WRITER lock. */
int sqlite3LogWriteLock(Log *pLog, int op);
/* Undo any frames written (but not committed) to the log */
int sqlite3LogUndo(Log *pLog, int (*xUndo)(void *, Pgno), void *pUndoCtx);
/* Return true if data has been written but not committed to the log file. */
int sqlite3LogDirty(Log *pLog);
/* Write a frame or frames to the log. */
int sqlite3LogFrames(Log *pLog, int, PgHdr *, Pgno, int, int);
/* Copy pages from the log to the database file */
int sqlite3LogCheckpoint(
Log *pLog, /* Log connection */
sqlite3_file *pFd, /* File descriptor open on db file */
int sync_flags, /* Flags to sync db file with (or 0) */
u8 *zBuf, /* Temporary buffer to use */
int (*xBusyHandler)(void *), /* Pointer to busy-handler function */
void *pBusyHandlerArg /* Argument to pass to xBusyHandler */
);
/* Return the value to pass to a log callback. Or 0 for no callback. */
int sqlite3LogCallback(Log *pLog);
#endif /* _LOG_H_ */