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** 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.
#ifndef _PAGER_H_
#define _PAGER_H_
** Default maximum size for persistent journal files. A negative
** value means no limit. This value may be overridden using the
** sqlite3PagerJournalSizeLimit() API. See also "PRAGMA journal_size_limit".
** 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 u32 Pgno;
** Each open file is managed by a separate instance of the "Pager" structure.
typedef struct Pager Pager;
** Handle type for pages.
typedef struct PgHdr DbPage;
** Page number PAGER_MJ_PGNO is never used in an SQLite database (it is
** reserved for working around a windows/posix incompatibility). It is
** used in the journal to signify that the remainder of the journal file
** is devoted to storing a master journal name - there are no more pages to
** roll back. See comments for function writeMasterJournal() in pager.c
** for details.
#define PAGER_MJ_PGNO(x) ((Pgno)((PENDING_BYTE/((x)->pageSize))+1))
** Allowed values for the flags parameter to sqlite3PagerOpen().
** NOTE: These 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 */
#define PAGER_MEMORY 0x0004 /* In-memory database */
** Valid values for the second argument to sqlite3PagerLockingMode().
** Numeric constants that encode the journalmode.
#define PAGER_JOURNALMODE_QUERY (-1) /* Query the value of journalmode */
#define PAGER_JOURNALMODE_DELETE 0 /* Commit by deleting journal file */
#define PAGER_JOURNALMODE_PERSIST 1 /* Commit by zeroing journal header */
#define PAGER_JOURNALMODE_OFF 2 /* Journal omitted. */
#define PAGER_JOURNALMODE_TRUNCATE 3 /* Commit by truncating journal */
#define PAGER_JOURNALMODE_MEMORY 4 /* In-memory journal file */
#define PAGER_JOURNALMODE_WAL 5 /* Use write-ahead logging */
** The remainder of this file contains the declarations of the functions
** that make up the Pager sub-system API. See source code comments for
** a detailed description of each routine.
/* Open and close a Pager connection. */
int sqlite3PagerOpen(
Pager **ppPager,
const char*,
int sqlite3PagerClose(Pager *pPager);
int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);
/* Functions used to configure a Pager object. */
void sqlite3PagerSetBusyhandler(Pager*, int(*)(void *), void *);
int sqlite3PagerSetPagesize(Pager*, u32*, int);
int sqlite3PagerMaxPageCount(Pager*, int);
void sqlite3PagerSetCachesize(Pager*, int);
void sqlite3PagerSetSafetyLevel(Pager*,int,int,int);
int sqlite3PagerLockingMode(Pager *, int);
int sqlite3PagerSetJournalMode(Pager *, int);
int sqlite3PagerGetJournalMode(Pager*);
int sqlite3PagerOkToChangeJournalMode(Pager*);
i64 sqlite3PagerJournalSizeLimit(Pager *, i64);
sqlite3_backup **sqlite3PagerBackupPtr(Pager*);
/* Functions used to obtain and release page references. */
int sqlite3PagerAcquire(Pager *pPager, Pgno pgno, DbPage **ppPage, int clrFlag);
#define sqlite3PagerGet(A,B,C) sqlite3PagerAcquire(A,B,C,0)
DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno);
void sqlite3PagerRef(DbPage*);
void sqlite3PagerUnref(DbPage*);
/* Operations on page references. */
int sqlite3PagerWrite(DbPage*);
void sqlite3PagerDontWrite(DbPage*);
int sqlite3PagerMovepage(Pager*,DbPage*,Pgno,int);
int sqlite3PagerPageRefcount(DbPage*);
void *sqlite3PagerGetData(DbPage *);
void *sqlite3PagerGetExtra(DbPage *);
/* Functions used to manage pager transactions and savepoints. */
void sqlite3PagerPagecount(Pager*, int*);
int sqlite3PagerBegin(Pager*, int exFlag, int);
int sqlite3PagerCommitPhaseOne(Pager*,const char *zMaster, int);
int sqlite3PagerExclusiveLock(Pager*);
int sqlite3PagerSync(Pager *pPager);
int sqlite3PagerCommitPhaseTwo(Pager*);
int sqlite3PagerRollback(Pager*);
int sqlite3PagerOpenSavepoint(Pager *pPager, int n);
int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint);
int sqlite3PagerSharedLock(Pager *pPager);
int sqlite3PagerCheckpoint(Pager *pPager, int, int*, int*);
int sqlite3PagerWalSupported(Pager *pPager);
int sqlite3PagerWalCallback(Pager *pPager);
int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen);
int sqlite3PagerCloseWal(Pager *pPager);
/* Functions used to query pager state and configuration. */
u8 sqlite3PagerIsreadonly(Pager*);
int sqlite3PagerRefcount(Pager*);
int sqlite3PagerMemUsed(Pager*);
const char *sqlite3PagerFilename(Pager*);
const sqlite3_vfs *sqlite3PagerVfs(Pager*);
sqlite3_file *sqlite3PagerFile(Pager*);
const char *sqlite3PagerJournalname(Pager*);
int sqlite3PagerNosync(Pager*);
/* This function is for preload-cache.patch for Chromium: */
int sqlite3PagerLoadall(Pager*);
void *sqlite3PagerTempSpace(Pager*);
int sqlite3PagerIsMemdb(Pager*);
/* Functions used to truncate the database file. */
void sqlite3PagerTruncateImage(Pager*,Pgno);
#if defined(SQLITE_HAS_CODEC) && !defined(SQLITE_OMIT_WAL)
void *sqlite3PagerCodec(DbPage *);
/* Functions to support testing and debugging. */
#if !defined(NDEBUG) || defined(SQLITE_TEST)
Pgno sqlite3PagerPagenumber(DbPage*);
int sqlite3PagerIswriteable(DbPage*);
int *sqlite3PagerStats(Pager*);
void sqlite3PagerRefdump(Pager*);
void disable_simulated_io_errors(void);
void enable_simulated_io_errors(void);
# define disable_simulated_io_errors()
# define enable_simulated_io_errors()
#endif /* _PAGER_H_ */