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Diffstat (limited to 'src/pager.h')
| -rw-r--r-- | src/pager.h | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/src/pager.h b/src/pager.h new file mode 100644 index 0000000..eb13060 --- /dev/null +++ b/src/pager.h @@ -0,0 +1,243 @@ +/* +** 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 SQLITE_PAGER_H +#define SQLITE_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". +*/ +#ifndef SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT + #define SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT -1 +#endif + +/* +** 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_SJ_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 super-journal name - there are no more pages to +** roll back. See comments for function writeSuperJournal() in pager.c +** for details. +*/ +#define PAGER_SJ_PGNO_COMPUTED(x) ((Pgno)((PENDING_BYTE/((x)->pageSize))+1)) +#define PAGER_SJ_PGNO(x) ((x)->lckPgno) + +/* +** 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_MEMORY 0x0002 /* In-memory database */ + +/* +** Valid values for the second argument to sqlite3PagerLockingMode(). +*/ +#define PAGER_LOCKINGMODE_QUERY -1 +#define PAGER_LOCKINGMODE_NORMAL 0 +#define PAGER_LOCKINGMODE_EXCLUSIVE 1 + +/* +** Numeric constants that encode the journalmode. +** +** The numeric values encoded here (other than PAGER_JOURNALMODE_QUERY) +** are exposed in the API via the "PRAGMA journal_mode" command and +** therefore cannot be changed without a compatibility break. +*/ +#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 */ + +/* +** Flags that make up the mask passed to sqlite3PagerGet(). +*/ +#define PAGER_GET_NOCONTENT 0x01 /* Do not load data from disk */ +#define PAGER_GET_READONLY 0x02 /* Read-only page is acceptable */ + +/* +** Flags for sqlite3PagerSetFlags() +** +** Value constraints (enforced via assert()): +** PAGER_FULLFSYNC == SQLITE_FullFSync +** PAGER_CKPT_FULLFSYNC == SQLITE_CkptFullFSync +** PAGER_CACHE_SPILL == SQLITE_CacheSpill +*/ +#define PAGER_SYNCHRONOUS_OFF 0x01 /* PRAGMA synchronous=OFF */ +#define PAGER_SYNCHRONOUS_NORMAL 0x02 /* PRAGMA synchronous=NORMAL */ +#define PAGER_SYNCHRONOUS_FULL 0x03 /* PRAGMA synchronous=FULL */ +#define PAGER_SYNCHRONOUS_EXTRA 0x04 /* PRAGMA synchronous=EXTRA */ +#define PAGER_SYNCHRONOUS_MASK 0x07 /* Mask for four values above */ +#define PAGER_FULLFSYNC 0x08 /* PRAGMA fullfsync=ON */ +#define PAGER_CKPT_FULLFSYNC 0x10 /* PRAGMA checkpoint_fullfsync=ON */ +#define PAGER_CACHESPILL 0x20 /* PRAGMA cache_spill=ON */ +#define PAGER_FLAGS_MASK 0x38 /* All above except SYNCHRONOUS */ + +/* +** 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( + sqlite3_vfs*, + Pager **ppPager, + const char*, + int, + int, + int, + void(*)(DbPage*) +); +int sqlite3PagerClose(Pager *pPager, sqlite3*); +int sqlite3PagerReadFileheader(Pager*, int, unsigned char*); + +/* Functions used to configure a Pager object. */ +void sqlite3PagerSetBusyHandler(Pager*, int(*)(void *), void *); +int sqlite3PagerSetPagesize(Pager*, u32*, int); +Pgno sqlite3PagerMaxPageCount(Pager*, Pgno); +void sqlite3PagerSetCachesize(Pager*, int); +int sqlite3PagerSetSpillsize(Pager*, int); +void sqlite3PagerSetMmapLimit(Pager *, sqlite3_int64); +void sqlite3PagerShrink(Pager*); +void sqlite3PagerSetFlags(Pager*,unsigned); +int sqlite3PagerLockingMode(Pager *, int); +int sqlite3PagerSetJournalMode(Pager *, int); +int sqlite3PagerGetJournalMode(Pager*); +int sqlite3PagerOkToChangeJournalMode(Pager*); +i64 sqlite3PagerJournalSizeLimit(Pager *, i64); +sqlite3_backup **sqlite3PagerBackupPtr(Pager*); +int sqlite3PagerFlush(Pager*); + +/* Functions used to obtain and release page references. */ +int sqlite3PagerGet(Pager *pPager, Pgno pgno, DbPage **ppPage, int clrFlag); +DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno); +void sqlite3PagerRef(DbPage*); +void sqlite3PagerUnref(DbPage*); +void sqlite3PagerUnrefNotNull(DbPage*); +void sqlite3PagerUnrefPageOne(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 *zSuper, int); +int sqlite3PagerExclusiveLock(Pager*); +int sqlite3PagerSync(Pager *pPager, const char *zSuper); +int sqlite3PagerCommitPhaseTwo(Pager*); +int sqlite3PagerRollback(Pager*); +int sqlite3PagerOpenSavepoint(Pager *pPager, int n); +int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint); +int sqlite3PagerSharedLock(Pager *pPager); + +#ifndef SQLITE_OMIT_WAL + int sqlite3PagerCheckpoint(Pager *pPager, sqlite3*, int, int*, int*); + int sqlite3PagerWalSupported(Pager *pPager); + int sqlite3PagerWalCallback(Pager *pPager); + int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen); + int sqlite3PagerCloseWal(Pager *pPager, sqlite3*); +# ifdef SQLITE_ENABLE_SNAPSHOT + int sqlite3PagerSnapshotGet(Pager*, sqlite3_snapshot **ppSnapshot); + int sqlite3PagerSnapshotOpen(Pager*, sqlite3_snapshot *pSnapshot); + int sqlite3PagerSnapshotRecover(Pager *pPager); + int sqlite3PagerSnapshotCheck(Pager *pPager, sqlite3_snapshot *pSnapshot); + void sqlite3PagerSnapshotUnlock(Pager *pPager); +# endif +#endif + +#if !defined(SQLITE_OMIT_WAL) && defined(SQLITE_ENABLE_SETLK_TIMEOUT) + int sqlite3PagerWalWriteLock(Pager*, int); + void sqlite3PagerWalDb(Pager*, sqlite3*); +#else +# define sqlite3PagerWalWriteLock(y,z) SQLITE_OK +# define sqlite3PagerWalDb(x,y) +#endif + +#ifdef SQLITE_DIRECT_OVERFLOW_READ + int sqlite3PagerDirectReadOk(Pager *pPager, Pgno pgno); +#endif + +#ifdef SQLITE_ENABLE_ZIPVFS + int sqlite3PagerWalFramesize(Pager *pPager); +#endif + +/* Functions used to query pager state and configuration. */ +u8 sqlite3PagerIsreadonly(Pager*); +u32 sqlite3PagerDataVersion(Pager*); +#ifdef SQLITE_DEBUG + int sqlite3PagerRefcount(Pager*); +#endif +int sqlite3PagerMemUsed(Pager*); +const char *sqlite3PagerFilename(const Pager*, int); +sqlite3_vfs *sqlite3PagerVfs(Pager*); +sqlite3_file *sqlite3PagerFile(Pager*); +sqlite3_file *sqlite3PagerJrnlFile(Pager*); +const char *sqlite3PagerJournalname(Pager*); +void *sqlite3PagerTempSpace(Pager*); +int sqlite3PagerIsMemdb(Pager*); +void sqlite3PagerCacheStat(Pager *, int, int, int *); +void sqlite3PagerClearCache(Pager*); +int sqlite3SectorSize(sqlite3_file *); + +/* Functions used to truncate the database file. */ +void sqlite3PagerTruncateImage(Pager*,Pgno); + +void sqlite3PagerRekey(DbPage*, Pgno, u16); + +/* Functions to support testing and debugging. */ +#if !defined(NDEBUG) || defined(SQLITE_TEST) + Pgno sqlite3PagerPagenumber(DbPage*); + int sqlite3PagerIswriteable(DbPage*); +#endif +#ifdef SQLITE_TEST + int *sqlite3PagerStats(Pager*); + void sqlite3PagerRefdump(Pager*); + void disable_simulated_io_errors(void); + void enable_simulated_io_errors(void); +#else +# define disable_simulated_io_errors() +# define enable_simulated_io_errors() +#endif + +#endif /* SQLITE_PAGER_H */ |