/*** 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 1.44 2005/05/20 20:01:56 drh Exp $*//*** 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 8192#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_stats(Pager*);void sqlite3pager_set_safety_level(Pager*,int);const char *sqlite3pager_filename(Pager*);const char *sqlite3pager_dirname(Pager*);const char *sqlite3pager_journalname(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*);#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)int sqlite3pager_lockstate(Pager*);#endif#ifdef SQLITE_TESTvoid sqlite3pager_refdump(Pager*);int pager3_refinfo_enable;#endif