[sql] Import reference version of SQLite 3.17..

third_party/sqlite/sqlite-src-3170000/src/pager.h

+/*
+** 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_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_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);
+#ifdef SQLITE_HAS_CODEC
+void sqlite3PagerAlignReserve(Pager*,Pager*);
+#endif
+int sqlite3PagerMaxPageCount(Pager*, int);
+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*);
+
+/* 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, const char *zMaster);
+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_DIRECT_OVERFLOW_READ
+  int sqlite3PagerUseWal(Pager *pPager, Pgno);
+# endif
+# ifdef SQLITE_ENABLE_SNAPSHOT
+  int sqlite3PagerSnapshotGet(Pager *pPager, sqlite3_snapshot **ppSnapshot);
+  int sqlite3PagerSnapshotOpen(Pager *pPager, sqlite3_snapshot *pSnapshot);
+  int sqlite3PagerSnapshotRecover(Pager *pPager);
+# endif
+#else
+# define sqlite3PagerUseWal(x,y) 0
+#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(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);
+
+#if defined(SQLITE_HAS_CODEC) && !defined(SQLITE_OMIT_WAL)
+void *sqlite3PagerCodec(DbPage *);
+#endif
+
+/* 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 */