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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 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, u64*);
+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
+
+#if defined(SQLITE_USE_SEH) && !defined(SQLITE_OMIT_WAL)
+int sqlite3PagerWalSystemErrno(Pager*);
+#endif
+
+#endif /* SQLITE_PAGER_H */