sqlite3/pager.h

   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 ** @(#) $Id$
  17 */
  18
  19 /*
  20 ** The default size of a database page.
  21 */
  22 #ifndef SQLITE_DEFAULT_PAGE_SIZE
  23 # define SQLITE_DEFAULT_PAGE_SIZE 1024
  24 #endif
  25
  26 /* Maximum page size.  The upper bound on this value is 32768.  This a limit
  27 ** imposed by necessity of storing the value in a 2-byte unsigned integer
  28 ** and the fact that the page size must be a power of 2.
  29 **
  30 ** This value is used to initialize certain arrays on the stack at
  31 ** various places in the code.  On embedded machines where stack space
  32 ** is limited and the flexibility of having large pages is not needed,
  33 ** it makes good sense to reduce the maximum page size to something more
  34 ** reasonable, like 1024.
  35 */
  36 #ifndef SQLITE_MAX_PAGE_SIZE
  37 # define SQLITE_MAX_PAGE_SIZE 8192
  38 #endif
  39
  40 /*
  41 ** Maximum number of pages in one database.
  42 */
  43 #define SQLITE_MAX_PAGE 1073741823
  44
  45 /*
  46 ** The type used to represent a page number.  The first page in a file
  47 ** is called page 1.  0 is used to represent "not a page".
  48 */
  49 typedef unsigned int Pgno;
  50
  51 /*
  52 ** Each open file is managed by a separate instance of the "Pager" structure.
  53 */
  54 typedef struct Pager Pager;
  55
  56 /*
  57 ** Allowed values for the flags parameter to sqlite3pager_open().
  58 **
  59 ** NOTE: This values must match the corresponding BTREE_ values in btree.h.
  60 */
  61 #define PAGER_OMIT_JOURNAL  0x0001    /* Do not use a rollback journal */
  62 #define PAGER_NO_READLOCK   0x0002    /* Omit readlocks on readonly files */
  63
  64
  65 /*
  66 ** See source code comments for a detailed description of the following
  67 ** routines:
  68 */
  69 int sqlite3pager_open(Pager **ppPager, const char *zFilename,
  70                      int nExtra, int flags);
  71 void sqlite3pager_set_busyhandler(Pager*, BusyHandler *pBusyHandler);
  72 void sqlite3pager_set_destructor(Pager*, void(*)(void*,int));
  73 void sqlite3pager_set_reiniter(Pager*, void(*)(void*,int));
  74 int sqlite3pager_set_pagesize(Pager*, int);
  75 void sqlite3pager_read_fileheader(Pager*, int, unsigned char*);
  76 void sqlite3pager_set_cachesize(Pager*, int);
  77 int sqlite3pager_close(Pager *pPager);
  78 int sqlite3pager_get(Pager *pPager, Pgno pgno, void **ppPage);
  79 void *sqlite3pager_lookup(Pager *pPager, Pgno pgno);
  80 int sqlite3pager_ref(void*);
  81 int sqlite3pager_unref(void*);
  82 Pgno sqlite3pager_pagenumber(void*);
  83 int sqlite3pager_write(void*);
  84 int sqlite3pager_iswriteable(void*);
  85 int sqlite3pager_overwrite(Pager *pPager, Pgno pgno, void*);
  86 int sqlite3pager_pagecount(Pager*);
  87 int sqlite3pager_truncate(Pager*,Pgno);
  88 int sqlite3pager_begin(void*, int exFlag);
  89 int sqlite3pager_commit(Pager*);
  90 int sqlite3pager_sync(Pager*,const char *zMaster, Pgno);
  91 int sqlite3pager_rollback(Pager*);
  92 int sqlite3pager_isreadonly(Pager*);
  93 int sqlite3pager_stmt_begin(Pager*);
  94 int sqlite3pager_stmt_commit(Pager*);
  95 int sqlite3pager_stmt_rollback(Pager*);
  96 void sqlite3pager_dont_rollback(void*);
  97 void sqlite3pager_dont_write(Pager*, Pgno);
  98 int *sqlite3pager_stats(Pager*);
  99 void sqlite3pager_set_safety_level(Pager*,int);
 100 const char *sqlite3pager_filename(Pager*);
 101 const char *sqlite3pager_dirname(Pager*);
 102 const char *sqlite3pager_journalname(Pager*);
 103 int sqlite3pager_rename(Pager*, const char *zNewName);
 104 void sqlite3pager_set_codec(Pager*,void(*)(void*,void*,Pgno,int),void*);
 105 int sqlite3pager_movepage(Pager*,void*,Pgno);
 106 int sqlite3pager_reset(Pager*);
 107
 108 #if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
 109 int sqlite3pager_lockstate(Pager*);
 110 #endif
 111
 112 #ifdef SQLITE_TEST
 113 void sqlite3pager_refdump(Pager*);
 114 int pager3_refinfo_enable;
 115 #endif