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 1282 2008-11-13 09:31:33Z LarsPson $

    17 */

    18 

    19 #ifndef _PAGER_H_

    20 #define _PAGER_H_

    21 

    22 /*

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

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

    25 */

    26 typedef unsigned int Pgno;

    27 

    28 /*

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

    30 */

    31 typedef struct Pager Pager;

    32 

    33 /*

    34 ** Handle type for pages.

    35 */

    36 typedef struct PgHdr DbPage;

    37 

    38 /*

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

    40 **

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

    42 */

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

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

    45 

    46 /*

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

    48 */

    49 #define PAGER_LOCKINGMODE_QUERY      -1

    50 #define PAGER_LOCKINGMODE_NORMAL      0

    51 #define PAGER_LOCKINGMODE_EXCLUSIVE   1

    52 

    53 /*

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

    55 ** routines:

    56 */

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

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

    59 void sqlite3PagerSetDestructor(Pager*, void(*)(DbPage*,int));

    60 void sqlite3PagerSetReiniter(Pager*, void(*)(DbPage*,int));

    61 int sqlite3PagerSetPagesize(Pager*, u16*);

    62 int sqlite3PagerMaxPageCount(Pager*, int);

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

    64 void sqlite3PagerSetCachesize(Pager*, int);

    65 int sqlite3PagerClose(Pager *pPager);

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

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

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

    69 int sqlite3PagerRef(DbPage*);

    70 int sqlite3PagerUnref(DbPage*);

    71 int sqlite3PagerWrite(DbPage*);

    72 int sqlite3PagerOverwrite(Pager *pPager, Pgno pgno, void*);

    73 int sqlite3PagerPagecount(Pager*);

    74 int sqlite3PagerTruncate(Pager*,Pgno);

    75 int sqlite3PagerBegin(DbPage*, int exFlag);

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

    77 int sqlite3PagerCommitPhaseTwo(Pager*);

    78 int sqlite3PagerRollback(Pager*);

    79 int sqlite3PagerIsreadonly(Pager*);

    80 int sqlite3PagerStmtBegin(Pager*);

    81 int sqlite3PagerStmtCommit(Pager*);

    82 int sqlite3PagerStmtRollback(Pager*);

    83 void sqlite3PagerDontRollback(DbPage*);

    84 void sqlite3PagerDontWrite(DbPage*);

    85 int sqlite3PagerRefcount(Pager*);

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

    87 const char *sqlite3PagerFilename(Pager*);

    88 const sqlite3_vfs *sqlite3PagerVfs(Pager*);

    89 sqlite3_file *sqlite3PagerFile(Pager*);

    90 const char *sqlite3PagerDirname(Pager*);

    91 const char *sqlite3PagerJournalname(Pager*);

    92 int sqlite3PagerNosync(Pager*);

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

    94 void *sqlite3PagerGetData(DbPage *); 

    95 void *sqlite3PagerGetExtra(DbPage *); 

    96 int sqlite3PagerLockingMode(Pager *, int);

    97 void *sqlite3PagerTempSpace(Pager*);

    98 

    99 #if defined(SQLITE_ENABLE_MEMORY_MANAGEMENT) && !defined(SQLITE_OMIT_DISKIO)

   100   int sqlite3PagerReleaseMemory(int);

   101 #endif

   102 

   103 #ifdef SQLITE_HAS_CODEC

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

   105 #endif

   106 

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

   108   Pgno sqlite3PagerPagenumber(DbPage*);

   109   int sqlite3PagerIswriteable(DbPage*);

   110 #endif

   111 

   112 #ifdef SQLITE_TEST

   113   int *sqlite3PagerStats(Pager*);

   114   void sqlite3PagerRefdump(Pager*);

   115   int pager3_refinfo_enable;

   116 #endif

   117 

   118 #ifdef SQLITE_TEST

   119 void disable_simulated_io_errors(void);

   120 void enable_simulated_io_errors(void);

   121 #else

   122 # define disable_simulated_io_errors()

   123 # define enable_simulated_io_errors()

   124 #endif

   125 

   126 #endif /* _PAGER_H_ */