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 ** @(#) $Id: pager.h,v 1.85 2008/09/29 11:49:48 danielk1977 Exp $

    17 */

    18 

    19 #ifndef _PAGER_H_

    20 #define _PAGER_H_

    21 

    22 /*

    23 ** If defined as non-zero, auto-vacuum is enabled by default. Otherwise

    24 ** it must be turned on for each database using "PRAGMA auto_vacuum = 1".

    25 */

    26 #ifndef SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT

    27   #define SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT -1

    28 #endif

    29 

    30 /*

    31 ** The type used to represent a page number.  The first page in a file

    32 ** is called page 1.  0 is used to represent "not a page".

    33 */

    34 typedef u32 Pgno;

    35 

    36 /*

    37 ** Each open file is managed by a separate instance of the "Pager" structure.

    38 */

    39 typedef struct Pager Pager;

    40 

    41 /*

    42 ** Handle type for pages.

    43 */

    44 typedef struct PgHdr DbPage;

    45 

    46 /*

    47 ** Allowed values for the flags parameter to sqlite3PagerOpen().

    48 **

    49 ** NOTE: This values must match the corresponding BTREE_ values in btree.h.

    50 */

    51 #define PAGER_OMIT_JOURNAL  0x0001    /* Do not use a rollback journal */

    52 #define PAGER_NO_READLOCK   0x0002    /* Omit readlocks on readonly files */

    53 

    54 /*

    55 ** Valid values for the second argument to sqlite3PagerLockingMode().

    56 */

    57 #define PAGER_LOCKINGMODE_QUERY      -1

    58 #define PAGER_LOCKINGMODE_NORMAL      0

    59 #define PAGER_LOCKINGMODE_EXCLUSIVE   1

    60 

    61 /*

    62 ** Valid values for the second argument to sqlite3PagerJournalMode().

    63 */

    64 #define PAGER_JOURNALMODE_QUERY      -1

    65 #define PAGER_JOURNALMODE_DELETE      0   /* Commit by deleting journal file */

    66 #define PAGER_JOURNALMODE_PERSIST     1   /* Commit by zeroing journal header */

    67 #define PAGER_JOURNALMODE_OFF         2   /* Journal omitted.  */

    68 #define PAGER_JOURNALMODE_TRUNCATE    3   /* Commit by truncating journal */

    69 

    70 /*

    71 ** See source code comments for a detailed description of the following

    72 ** routines:

    73 */

    74 int sqlite3PagerOpen(sqlite3_vfs *, Pager **ppPager, const char*, int,int,int);

    75 void sqlite3PagerSetBusyhandler(Pager*, BusyHandler *pBusyHandler);

    76 void sqlite3PagerSetReiniter(Pager*, void(*)(DbPage*));

    77 int sqlite3PagerSetPagesize(Pager*, u16*);

    78 int sqlite3PagerMaxPageCount(Pager*, int);

    79 int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);

    80 void sqlite3PagerSetCachesize(Pager*, int);

    81 int sqlite3PagerClose(Pager *pPager);

    82 int sqlite3PagerAcquire(Pager *pPager, Pgno pgno, DbPage **ppPage, int clrFlag);

    83 #define sqlite3PagerGet(A,B,C) sqlite3PagerAcquire(A,B,C,0)

    84 DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno);

    85 int sqlite3PagerPageRefcount(DbPage*);

    86 int sqlite3PagerRef(DbPage*);

    87 int sqlite3PagerUnref(DbPage*);

    88 int sqlite3PagerWrite(DbPage*);

    89 int sqlite3PagerPagecount(Pager*, int*);

    90 int sqlite3PagerTruncate(Pager*,Pgno);

    91 int sqlite3PagerBegin(DbPage*, int exFlag);

    92 int sqlite3PagerCommitPhaseOne(Pager*,const char *zMaster, Pgno, int);

    93 int sqlite3PagerCommitPhaseTwo(Pager*);

    94 int sqlite3PagerRollback(Pager*);

    95 int sqlite3PagerIsreadonly(Pager*);

    96 int sqlite3PagerStmtBegin(Pager*);

    97 int sqlite3PagerStmtCommit(Pager*);

    98 int sqlite3PagerStmtRollback(Pager*);

    99 void sqlite3PagerDontRollback(DbPage*);

   100 int sqlite3PagerDontWrite(DbPage*);

   101 int sqlite3PagerRefcount(Pager*);

   102 void sqlite3PagerSetSafetyLevel(Pager*,int,int);

   103 const char *sqlite3PagerFilename(Pager*);

   104 const sqlite3_vfs *sqlite3PagerVfs(Pager*);

   105 sqlite3_file *sqlite3PagerFile(Pager*);

   106 const char *sqlite3PagerDirname(Pager*);

   107 const char *sqlite3PagerJournalname(Pager*);

   108 int sqlite3PagerNosync(Pager*);

   109 int sqlite3PagerMovepage(Pager*,DbPage*,Pgno,int);

   110 void *sqlite3PagerGetData(DbPage *); 

   111 void *sqlite3PagerGetExtra(DbPage *); 

   112 int sqlite3PagerLockingMode(Pager *, int);

   113 int sqlite3PagerJournalMode(Pager *, int);

   114 i64 sqlite3PagerJournalSizeLimit(Pager *, i64);

   115 void *sqlite3PagerTempSpace(Pager*);

   116 int sqlite3PagerSync(Pager *pPager);

   117 

   118 #ifdef SQLITE_HAS_CODEC

   119   void sqlite3PagerSetCodec(Pager*,void*(*)(void*,void*,Pgno,int),void*);

   120 #endif

   121 

   122 #if !defined(NDEBUG) || defined(SQLITE_TEST)

   123   Pgno sqlite3PagerPagenumber(DbPage*);

   124   int sqlite3PagerIswriteable(DbPage*);

   125 #endif

   126 

   127 #ifdef SQLITE_TEST

   128   int *sqlite3PagerStats(Pager*);

   129   void sqlite3PagerRefdump(Pager*);

   130   int sqlite3PagerIsMemdb(Pager*);

   131 #endif

   132 

   133 #ifdef SQLITE_TEST

   134 void disable_simulated_io_errors(void);

   135 void enable_simulated_io_errors(void);

   136 #else

   137 # define disable_simulated_io_errors()

   138 # define enable_simulated_io_errors()

   139 #endif

   140 

   141 #endif /* _PAGER_H_ */