/*

** 2001 September 15

**

** 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 that the sqlite page cache

** subsystem.  The page cache subsystem reads and writes a file a page

** at a time and provides a journal for rollback.

**

** @(#) $Id: pager.h,v 1.51 2006/08/08 13:51:43 drh Exp $

*/

#ifndef _PAGER_H_

#define _PAGER_H_

/*

** The default size of a database page.

*/

#ifndef SQLITE_DEFAULT_PAGE_SIZE

# define SQLITE_DEFAULT_PAGE_SIZE 1024

#endif

/* Maximum page size.  The upper bound on this value is 32768.  This a limit

** imposed by necessity of storing the value in a 2-byte unsigned integer

** and the fact that the page size must be a power of 2.

**

** This value is used to initialize certain arrays on the stack at

** various places in the code.  On embedded machines where stack space

** is limited and the flexibility of having large pages is not needed,

** it makes good sense to reduce the maximum page size to something more

** reasonable, like 1024.

*/

#ifndef SQLITE_MAX_PAGE_SIZE

# define SQLITE_MAX_PAGE_SIZE 32768

#endif

/*

** Maximum number of pages in one database.

*/

#define SQLITE_MAX_PAGE 1073741823

/*

** The type used to represent a page number.  The first page in a file

** is called page 1.  0 is used to represent "not a page".

*/

typedef unsigned int Pgno;

/*

** Each open file is managed by a separate instance of the "Pager" structure.

*/

typedef struct Pager Pager;

/*

** Allowed values for the flags parameter to sqlite3pager_open().

**

** NOTE: This values must match the corresponding BTREE_ values in btree.h.

*/

#define PAGER_OMIT_JOURNAL  0x0001    /* Do not use a rollback journal */

#define PAGER_NO_READLOCK   0x0002    /* Omit readlocks on readonly files */

/*

** See source code comments for a detailed description of the following

** routines:

*/

int sqlite3pager_open(Pager **ppPager, const char *zFilename,

                     int nExtra, int flags);

void sqlite3pager_set_busyhandler(Pager*, BusyHandler *pBusyHandler);

void sqlite3pager_set_destructor(Pager*, void(*)(void*,int));

void sqlite3pager_set_reiniter(Pager*, void(*)(void*,int));

int sqlite3pager_set_pagesize(Pager*, int);

void sqlite3pager_read_fileheader(Pager*, int, unsigned char*);

void sqlite3pager_set_cachesize(Pager*, int);

int sqlite3pager_close(Pager *pPager);

int sqlite3pager_get(Pager *pPager, Pgno pgno, void **ppPage);

void *sqlite3pager_lookup(Pager *pPager, Pgno pgno);

int sqlite3pager_ref(void*);

int sqlite3pager_unref(void*);

Pgno sqlite3pager_pagenumber(void*);

int sqlite3pager_write(void*);

int sqlite3pager_iswriteable(void*);

int sqlite3pager_overwrite(Pager *pPager, Pgno pgno, void*);

int sqlite3pager_pagecount(Pager*);

int sqlite3pager_truncate(Pager*,Pgno);

int sqlite3pager_begin(void*, int exFlag);

int sqlite3pager_commit(Pager*);

int sqlite3pager_sync(Pager*,const char *zMaster, Pgno);

int sqlite3pager_rollback(Pager*);

int sqlite3pager_isreadonly(Pager*);

int sqlite3pager_stmt_begin(Pager*);

int sqlite3pager_stmt_commit(Pager*);

int sqlite3pager_stmt_rollback(Pager*);

void sqlite3pager_dont_rollback(void*);

void sqlite3pager_dont_write(Pager*, Pgno);

int sqlite3pager_refcount(Pager*);

int *sqlite3pager_stats(Pager*);

void sqlite3pager_set_safety_level(Pager*,int,int);

const char *sqlite3pager_filename(Pager*);

const char *sqlite3pager_dirname(Pager*);

const char *sqlite3pager_journalname(Pager*);

int sqlite3pager_nosync(Pager*);

int sqlite3pager_rename(Pager*, const char *zNewName);

void sqlite3pager_set_codec(Pager*,void*(*)(void*,void*,Pgno,int),void*);

int sqlite3pager_movepage(Pager*,void*,Pgno);

int sqlite3pager_reset(Pager*);

int sqlite3pager_release_memory(int);

#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)

int sqlite3pager_lockstate(Pager*);

#endif

#ifdef SQLITE_TEST

void sqlite3pager_refdump(Pager*);

int pager3_refinfo_enable;

#endif

#endif /* _PAGER_H_ */