1/* 2** 2001 September 15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the sqlite page cache 13** subsystem. The page cache subsystem reads and writes a file a page 14** at a time and provides a journal for rollback. 15*/ 16 17#ifndef _PAGER_H_ 18#define _PAGER_H_ 19 20/* 21** Default maximum size for persistent journal files. A negative 22** value means no limit. This value may be overridden using the 23** sqlite3PagerJournalSizeLimit() API. See also "PRAGMA journal_size_limit". 24*/ 25#ifndef SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT 26 #define SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT -1 27#endif 28 29/* 30** The type used to represent a page number. The first page in a file 31** is called page 1. 0 is used to represent "not a page". 32*/ 33typedef u32 Pgno; 34 35/* 36** Each open file is managed by a separate instance of the "Pager" structure. 37*/ 38typedef struct Pager Pager; 39 40/* 41** Handle type for pages. 42*/ 43typedef struct PgHdr DbPage; 44 45/* 46** Page number PAGER_MJ_PGNO is never used in an SQLite database (it is 47** reserved for working around a windows/posix incompatibility). It is 48** used in the journal to signify that the remainder of the journal file 49** is devoted to storing a master journal name - there are no more pages to 50** roll back. See comments for function writeMasterJournal() in pager.c 51** for details. 52*/ 53#define PAGER_MJ_PGNO(x) ((Pgno)((PENDING_BYTE/((x)->pageSize))+1)) 54 55/* 56** Allowed values for the flags parameter to sqlite3PagerOpen(). 57** 58** NOTE: These values must match the corresponding BTREE_ values in btree.h. 59*/ 60#define PAGER_OMIT_JOURNAL 0x0001 /* Do not use a rollback journal */ 61#define PAGER_NO_READLOCK 0x0002 /* Omit readlocks on readonly files */ 62#define PAGER_MEMORY 0x0004 /* In-memory database */ 63 64/* 65** Valid values for the second argument to sqlite3PagerLockingMode(). 66*/ 67#define PAGER_LOCKINGMODE_QUERY -1 68#define PAGER_LOCKINGMODE_NORMAL 0 69#define PAGER_LOCKINGMODE_EXCLUSIVE 1 70 71/* 72** Numeric constants that encode the journalmode. 73*/ 74#define PAGER_JOURNALMODE_QUERY (-1) /* Query the value of journalmode */ 75#define PAGER_JOURNALMODE_DELETE 0 /* Commit by deleting journal file */ 76#define PAGER_JOURNALMODE_PERSIST 1 /* Commit by zeroing journal header */ 77#define PAGER_JOURNALMODE_OFF 2 /* Journal omitted. */ 78#define PAGER_JOURNALMODE_TRUNCATE 3 /* Commit by truncating journal */ 79#define PAGER_JOURNALMODE_MEMORY 4 /* In-memory journal file */ 80#define PAGER_JOURNALMODE_WAL 5 /* Use write-ahead logging */ 81 82/* 83** The remainder of this file contains the declarations of the functions 84** that make up the Pager sub-system API. See source code comments for 85** a detailed description of each routine. 86*/ 87 88/* Open and close a Pager connection. */ 89int sqlite3PagerOpen( 90 sqlite3_vfs*, 91 Pager **ppPager, 92 const char*, 93 int, 94 int, 95 int, 96 void(*)(DbPage*) 97); 98int sqlite3PagerClose(Pager *pPager); 99int sqlite3PagerReadFileheader(Pager*, int, unsigned char*); 100 101/* Functions used to configure a Pager object. */ 102void sqlite3PagerSetBusyhandler(Pager*, int(*)(void *), void *); 103int sqlite3PagerSetPagesize(Pager*, u32*, int); 104int sqlite3PagerMaxPageCount(Pager*, int); 105void sqlite3PagerSetCachesize(Pager*, int); 106void sqlite3PagerSetSafetyLevel(Pager*,int,int,int); 107int sqlite3PagerLockingMode(Pager *, int); 108int sqlite3PagerSetJournalMode(Pager *, int); 109int sqlite3PagerGetJournalMode(Pager*); 110int sqlite3PagerOkToChangeJournalMode(Pager*); 111i64 sqlite3PagerJournalSizeLimit(Pager *, i64); 112sqlite3_backup **sqlite3PagerBackupPtr(Pager*); 113 114/* Functions used to obtain and release page references. */ 115int sqlite3PagerAcquire(Pager *pPager, Pgno pgno, DbPage **ppPage, int clrFlag); 116#define sqlite3PagerGet(A,B,C) sqlite3PagerAcquire(A,B,C,0) 117DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno); 118void sqlite3PagerRef(DbPage*); 119void sqlite3PagerUnref(DbPage*); 120 121/* Operations on page references. */ 122int sqlite3PagerWrite(DbPage*); 123void sqlite3PagerDontWrite(DbPage*); 124int sqlite3PagerMovepage(Pager*,DbPage*,Pgno,int); 125int sqlite3PagerPageRefcount(DbPage*); 126void *sqlite3PagerGetData(DbPage *); 127void *sqlite3PagerGetExtra(DbPage *); 128 129/* Functions used to manage pager transactions and savepoints. */ 130void sqlite3PagerPagecount(Pager*, int*); 131int sqlite3PagerBegin(Pager*, int exFlag, int); 132int sqlite3PagerCommitPhaseOne(Pager*,const char *zMaster, int); 133int sqlite3PagerExclusiveLock(Pager*); 134int sqlite3PagerSync(Pager *pPager); 135int sqlite3PagerCommitPhaseTwo(Pager*); 136int sqlite3PagerRollback(Pager*); 137int sqlite3PagerOpenSavepoint(Pager *pPager, int n); 138int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint); 139int sqlite3PagerSharedLock(Pager *pPager); 140 141int sqlite3PagerCheckpoint(Pager *pPager, int, int*, int*); 142int sqlite3PagerWalSupported(Pager *pPager); 143int sqlite3PagerWalCallback(Pager *pPager); 144int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen); 145int sqlite3PagerCloseWal(Pager *pPager); 146 147/* Functions used to query pager state and configuration. */ 148u8 sqlite3PagerIsreadonly(Pager*); 149int sqlite3PagerRefcount(Pager*); 150int sqlite3PagerMemUsed(Pager*); 151const char *sqlite3PagerFilename(Pager*); 152const sqlite3_vfs *sqlite3PagerVfs(Pager*); 153sqlite3_file *sqlite3PagerFile(Pager*); 154const char *sqlite3PagerJournalname(Pager*); 155int sqlite3PagerNosync(Pager*); 156void *sqlite3PagerTempSpace(Pager*); 157int sqlite3PagerIsMemdb(Pager*); 158 159/* Functions used to truncate the database file. */ 160void sqlite3PagerTruncateImage(Pager*,Pgno); 161 162#if defined(SQLITE_HAS_CODEC) && !defined(SQLITE_OMIT_WAL) 163void *sqlite3PagerCodec(DbPage *); 164#endif 165 166/* Functions to support testing and debugging. */ 167#if !defined(NDEBUG) || defined(SQLITE_TEST) 168 Pgno sqlite3PagerPagenumber(DbPage*); 169 int sqlite3PagerIswriteable(DbPage*); 170#endif 171#ifdef SQLITE_TEST 172 int *sqlite3PagerStats(Pager*); 173 void sqlite3PagerRefdump(Pager*); 174 void disable_simulated_io_errors(void); 175 void enable_simulated_io_errors(void); 176#else 177# define disable_simulated_io_errors() 178# define enable_simulated_io_errors() 179#endif 180 181#endif /* _PAGER_H_ */ 182