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lightning-sunbird  0.9+nobinonly
Classes | Defines | Typedefs | Functions | Variables
pager.c File Reference
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

Go to the source code of this file.

Classes

struct  PgHdr
struct  PgHistory
struct  Pager

Defines

#define TRACE1(X)
#define TRACE2(X, Y)
#define TRACE3(X, Y, Z)
#define TRACE4(X, Y, Z, W)
#define TRACE5(X, Y, Z, W, V)
#define PAGERID(p)   ((int)(p->fd))
#define FILEHANDLEID(fd)   ((int)fd)
#define PAGER_UNLOCK   0
#define PAGER_SHARED   1 /* same as SHARED_LOCK */
#define PAGER_RESERVED   2 /* same as RESERVED_LOCK */
#define PAGER_EXCLUSIVE   4 /* same as EXCLUSIVE_LOCK */
#define PAGER_SYNCED   5
#define SQLITE_BUSY_RESERVED_LOCK   0
#define FORCE_ALIGNMENT(X)   (((X)+7)&~7)
#define CODEC1(P, D, N, X)   /* NO-OP */
#define CODEC2(P, D, N, X)   ((char*)D)
#define PGHDR_TO_DATA(P)   ((void*)(&(P)[1]))
#define DATA_TO_PGHDR(D)   (&((PgHdr*)(D))[-1])
#define PGHDR_TO_EXTRA(G, P)   ((void*)&((char*)(&(G)[1]))[(P)->pageSize])
#define PGHDR_TO_HIST(P, PGR)   ((PgHistory*)&((char*)(&(P)[1]))[(PGR)->pageSize+(PGR)->nExtra])
#define TEST_INCR(x)
#define JOURNAL_PG_SZ(pPager)   ((pPager->pageSize) + 8)
#define JOURNAL_HDR_SZ(pPager)   (pPager->sectorSize)
#define MEMDB   pPager->memDb
#define PAGER_SECTOR_SIZE   512
#define PAGER_MJ_PGNO(x)   ((PENDING_BYTE/((x)->pageSize))+1)
#define PAGER_MAX_PGNO   2147483647
#define REFINFO(X)
#define CHECK_PAGE(x)
#define clear_simulated_io_error()
#define disable_simulated_io_errors()
#define enable_simulated_io_errors()
#define page_ref(P)   ((P)->nRef==0?_page_ref(P):(void)(P)->nRef++)

Typedefs

typedef struct PgHdr
typedef struct PgHistory

Functions

static void pager_resize_hash_table (Pager *pPager, int N)
static int read32bits (OsFile *fd, u32 *pRes)
static void put32bits (char *ac, u32 val)
static int write32bits (OsFile *fd, u32 val)
static u32 retrieve32bits (PgHdr *p, int offset)
static int pager_error (Pager *pPager, int rc)
static int readMasterJournal (OsFile *pJrnl, char **pzMaster)
static int seekJournalHdr (Pager *pPager)
static int writeJournalHdr (Pager *pPager)
static int readJournalHdr (Pager *pPager, i64 journalSize, u32 *pNRec, u32 *pDbSize)
static int writeMasterJournal (Pager *pPager, const char *zMaster)
static void page_add_to_stmt_list (PgHdr *pPg)
static void page_remove_from_stmt_list (PgHdr *pPg)
static PgHdrpager_lookup (Pager *pPager, Pgno pgno)
static void pager_reset (Pager *pPager)
static int pager_unwritelock (Pager *pPager)
static u32 pager_cksum (Pager *pPager, const u8 *aData)
static void makeClean (PgHdr *)
static int pager_playback_one_page (Pager *pPager, OsFile *jfd, int useCksum)
static int pager_delmaster (const char *zMaster)
static int pager_reload_cache (Pager *pPager)
static int pager_truncate (Pager *pPager, int nPage)
static int pager_playback (Pager *pPager)
static int pager_stmt_playback (Pager *pPager)
void sqlite3pager_set_cachesize (Pager *pPager, int mxPage)
void sqlite3pager_set_safety_level (Pager *pPager, int level, int full_fsync)
static int sqlite3pager_opentemp (char *zFile, OsFile **pFd)
int sqlite3pager_open (Pager **ppPager, const char *zFilename, int nExtra, int flags)
void sqlite3pager_set_busyhandler (Pager *pPager, BusyHandler *pBusyHandler)
void sqlite3pager_set_destructor (Pager *pPager, void(*xDesc)(void *, int))
void sqlite3pager_set_reiniter (Pager *pPager, void(*xReinit)(void *, int))
int sqlite3pager_set_pagesize (Pager *pPager, int pageSize)
void sqlite3pager_read_fileheader (Pager *pPager, int N, unsigned char *pDest)
int sqlite3pager_pagecount (Pager *pPager)
static void clearHistory (PgHistory *pHist)
static int syncJournal (Pager *)
static void unlinkHashChain (Pager *pPager, PgHdr *pPg)
static void unlinkPage (PgHdr *pPg)
static void memoryTruncate (Pager *pPager)
static int pager_wait_on_lock (Pager *pPager, int locktype)
int sqlite3pager_truncate (Pager *pPager, Pgno nPage)
int sqlite3pager_close (Pager *pPager)
Pgno sqlite3pager_pagenumber (void *pData)
static void _page_ref (PgHdr *pPg)
int sqlite3pager_ref (void *pData)
static int pager_write_pagelist (PgHdr *pList)
static PgHdrpager_get_all_dirty_pages (Pager *pPager)
static int hasHotJournal (Pager *pPager)
static int pager_recycle (Pager *pPager, int syncOk, PgHdr **ppPg)
int sqlite3pager_get (Pager *pPager, Pgno pgno, void **ppPage)
int sqlite3pager_get2 (Pager *pPager, Pgno pgno, void **ppPage, unsigned char *pDataToFill)
voidsqlite3pager_lookup (Pager *pPager, Pgno pgno)
int sqlite3pager_unref (void *pData)
static int pager_open_journal (Pager *pPager)
int sqlite3pager_begin (void *pData, int exFlag)
static void makeDirty (PgHdr *pPg)
int sqlite3pager_write (void *pData)
int sqlite3pager_overwrite (Pager *pPager, Pgno pgno, void *pData)
void sqlite3pager_dont_write (Pager *pPager, Pgno pgno)
void sqlite3pager_dont_rollback (void *pData)
int sqlite3pager_commit (Pager *pPager)
int sqlite3pager_rollback (Pager *pPager)
int sqlite3pager_isreadonly (Pager *pPager)
intsqlite3pager_stats (Pager *pPager)
int sqlite3pager_stmt_begin (Pager *pPager)
int sqlite3pager_stmt_commit (Pager *pPager)
int sqlite3pager_stmt_rollback (Pager *pPager)
const char * sqlite3pager_filename (Pager *pPager)
const char * sqlite3pager_dirname (Pager *pPager)
const char * sqlite3pager_journalname (Pager *pPager)
int sqlite3pager_nosync (Pager *pPager)
void sqlite3pager_set_codec (Pager *pPager, void *(*xCodec)(void *, void *, Pgno, int), void *pCodecArg)
static int pager_incr_changecounter (Pager *pPager)
int sqlite3pager_sync (Pager *pPager, const char *zMaster, Pgno nTrunc)
int sqlite3pager_movepage (Pager *pPager, void *pData, Pgno pgno)
int sqlite3pager_loadall (Pager *pPager)
 Addition for Mozilla: This will attempt to populate the database cache with the first N bytes of the file, where N is the total size of the cache.

Variables

static const unsigned char aJournalMagic []
int sqlite3_opentemp_count = 0

Class Documentation

struct PgHdr

Definition at line 151 of file pager.c.

Collaboration diagram for PgHdr:
Class Members
u8 alwaysRollback
u8 dirty
u8 inJournal
u8 inStmt
u8 needSync
u32 notUsed
short int nRef
PgHdr * pDirty
Pgno pgno
PgHdr * pNextAll
PgHdr * pNextFree
PgHdr * pNextHash
PgHdr * pNextStmt
Pager * pPager
PgHdr * pPrevDirty
PgHdr * pPrevFree
PgHdr * pPrevHash
PgHdr * pPrevStmt
struct PgHistory

Definition at line 185 of file pager.c.

Class Members
u8 * pOrig
u8 * pStmt

Define Documentation

Definition at line 513 of file pager.c.

Definition at line 1772 of file pager.c.

#define CODEC1 (   P,
  D,
  N,
  X 
)    /* NO-OP */

Definition at line 197 of file pager.c.

#define CODEC2 (   P,
  D,
  N,
  X 
)    ((char*)D)

Definition at line 198 of file pager.c.

#define DATA_TO_PGHDR (   D)    (&((PgHdr*)(D))[-1])

Definition at line 206 of file pager.c.

Definition at line 1773 of file pager.c.

Definition at line 1774 of file pager.c.

#define FILEHANDLEID (   fd)    ((int)fd)

Definition at line 56 of file pager.c.

#define FORCE_ALIGNMENT (   X)    (((X)+7)&~7)

Definition at line 130 of file pager.c.

#define JOURNAL_HDR_SZ (   pPager)    (pPager->sectorSize)

Definition at line 336 of file pager.c.

#define JOURNAL_PG_SZ (   pPager)    ((pPager->pageSize) + 8)

Definition at line 329 of file pager.c.

#define MEMDB   pPager->memDb

Definition at line 347 of file pager.c.

#define page_ref (   P)    ((P)->nRef==0?_page_ref(P):(void)(P)->nRef++)

Definition at line 2156 of file pager.c.

#define PAGER_EXCLUSIVE   4 /* same as EXCLUSIVE_LOCK */

Definition at line 106 of file pager.c.

#define PAGER_MAX_PGNO   2147483647

Definition at line 368 of file pager.c.

#define PAGER_MJ_PGNO (   x)    ((PENDING_BYTE/((x)->pageSize))+1)

Definition at line 363 of file pager.c.

#define PAGER_RESERVED   2 /* same as RESERVED_LOCK */

Definition at line 105 of file pager.c.

Definition at line 353 of file pager.c.

#define PAGER_SHARED   1 /* same as SHARED_LOCK */

Definition at line 104 of file pager.c.

Definition at line 107 of file pager.c.

Definition at line 103 of file pager.c.

#define PAGERID (   p)    ((int)(p->fd))

Definition at line 55 of file pager.c.

#define PGHDR_TO_DATA (   P)    ((void*)(&(P)[1]))

Definition at line 205 of file pager.c.

#define PGHDR_TO_EXTRA (   G,
  P 
)    ((void*)&((char*)(&(G)[1]))[(P)->pageSize])

Definition at line 207 of file pager.c.

#define PGHDR_TO_HIST (   P,
  PGR 
)    ((PgHistory*)&((char*)(&(P)[1]))[(PGR)->pageSize+(PGR)->nExtra])

Definition at line 208 of file pager.c.

#define REFINFO (   X)

Definition at line 386 of file pager.c.

Definition at line 123 of file pager.c.

#define TEST_INCR (   x)

Definition at line 295 of file pager.c.

#define TRACE1 (   X)

Definition at line 40 of file pager.c.

#define TRACE2 (   X,
 
)

Definition at line 41 of file pager.c.

#define TRACE3 (   X,
  Y,
 
)

Definition at line 42 of file pager.c.

#define TRACE4 (   X,
  Y,
  Z,
  W 
)

Definition at line 43 of file pager.c.

#define TRACE5 (   X,
  Y,
  Z,
  W,
  V 
)

Definition at line 44 of file pager.c.


Typedef Documentation

typedef struct PgHdr

Definition at line 150 of file pager.c.

typedef struct PgHistory

Definition at line 184 of file pager.c.


Function Documentation

static void _page_ref ( PgHdr pPg) [static]

Definition at line 2123 of file pager.c.

                                 {
  if( pPg->nRef==0 ){
    /* The page is currently on the freelist.  Remove it. */
    if( pPg==pPg->pPager->pFirstSynced ){
      PgHdr *p = pPg->pNextFree;
      while( p && p->needSync ){ p = p->pNextFree; }
      pPg->pPager->pFirstSynced = p;
    }
    if( pPg->pPrevFree ){
      pPg->pPrevFree->pNextFree = pPg->pNextFree;
    }else{
      pPg->pPager->pFirst = pPg->pNextFree;
    }
    if( pPg->pNextFree ){
      pPg->pNextFree->pPrevFree = pPg->pPrevFree;
    }else{
      pPg->pPager->pLast = pPg->pPrevFree;
    }
    pPg->pPager->nRef++;
  }
  pPg->nRef++;
  REFINFO(pPg);
}
static void clearHistory ( PgHistory pHist) [static]

Definition at line 1836 of file pager.c.

                                          {
  sqliteFree(pHist->pOrig);
  sqliteFree(pHist->pStmt);
  pHist->pOrig = 0;
  pHist->pStmt = 0;
}

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static int hasHotJournal ( Pager pPager) [static]

Definition at line 2343 of file pager.c.

                                       {
  if( !pPager->useJournal ) return 0;
  if( !sqlite3OsFileExists(pPager->zJournal) ) return 0;
  if( sqlite3OsCheckReservedLock(pPager->fd) ) return 0;
  if( sqlite3pager_pagecount(pPager)==0 ){
    sqlite3OsDelete(pPager->zJournal);
    return 0;
  }else{
    return 1;
  }
}

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static void makeClean ( PgHdr pPg) [static]

Definition at line 3005 of file pager.c.

                                 {
  if( pPg->dirty ){
    pPg->dirty = 0;
    if( pPg->pDirty ){
      pPg->pDirty->pPrevDirty = pPg->pPrevDirty;
    }
    if( pPg->pPrevDirty ){
      pPg->pPrevDirty->pDirty = pPg->pDirty;
    }else{
      pPg->pPager->pDirty = pPg->pDirty;
    }
  }
}

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static void makeDirty ( PgHdr pPg) [static]

Definition at line 2988 of file pager.c.

                                 {
  if( pPg->dirty==0 ){
    Pager *pPager = pPg->pPager;
    pPg->dirty = 1;
    pPg->pDirty = pPager->pDirty;
    if( pPager->pDirty ){
      pPager->pDirty->pPrevDirty = pPg;
    }
    pPg->pPrevDirty = 0;
    pPager->pDirty = pPg;
  }
}

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static void memoryTruncate ( Pager pPager) [static]

Definition at line 1919 of file pager.c.

                                         {
  PgHdr *pPg;
  PgHdr **ppPg;
  int dbSize = pPager->dbSize;

  ppPg = &pPager->pAll;
  while( (pPg = *ppPg)!=0 ){
    if( pPg->pgno<=dbSize ){
      ppPg = &pPg->pNextAll;
    }else if( pPg->nRef>0 ){
      memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
      ppPg = &pPg->pNextAll;
    }else{
      *ppPg = pPg->pNextAll;
      unlinkPage(pPg);
      makeClean(pPg);
      sqliteFree(pPg);
      pPager->nPage--;
    }
  }
}

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static void page_add_to_stmt_list ( PgHdr pPg) [static]

Definition at line 800 of file pager.c.

                                             {
  Pager *pPager = pPg->pPager;
  if( pPg->inStmt ) return;
  assert( pPg->pPrevStmt==0 && pPg->pNextStmt==0 );
  pPg->pPrevStmt = 0;
  if( pPager->pStmt ){
    pPager->pStmt->pPrevStmt = pPg;
  }
  pPg->pNextStmt = pPager->pStmt;
  pPager->pStmt = pPg;
  pPg->inStmt = 1;
}

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static void page_remove_from_stmt_list ( PgHdr pPg) [static]

Definition at line 812 of file pager.c.

                                                  {
  if( !pPg->inStmt ) return;
  if( pPg->pPrevStmt ){
    assert( pPg->pPrevStmt->pNextStmt==pPg );
    pPg->pPrevStmt->pNextStmt = pPg->pNextStmt;
  }else{
    assert( pPg->pPager->pStmt==pPg );
    pPg->pPager->pStmt = pPg->pNextStmt;
  }
  if( pPg->pNextStmt ){
    assert( pPg->pNextStmt->pPrevStmt==pPg );
    pPg->pNextStmt->pPrevStmt = pPg->pPrevStmt;
  }
  pPg->pNextStmt = 0;
  pPg->pPrevStmt = 0;
  pPg->inStmt = 0;
}

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static u32 pager_cksum ( Pager pPager,
const u8 aData 
) [static]

Definition at line 947 of file pager.c.

                                                      {
  u32 cksum = pPager->cksumInit;
  int i = pPager->pageSize-200;
  while( i>0 ){
    cksum += aData[i];
    i -= 200;
  }
  return cksum;
}

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static int pager_delmaster ( const char *  zMaster) [static]

Definition at line 1074 of file pager.c.

                                               {
  int rc;
  int master_open = 0;
  OsFile *master = 0;
  char *zMasterJournal = 0; /* Contents of master journal file */
  i64 nMasterJournal;       /* Size of master journal file */

  /* Open the master journal file exclusively in case some other process
  ** is running this routine also. Not that it makes too much difference.
  */
  rc = sqlite3OsOpenReadOnly(zMaster, &master);
  if( rc!=SQLITE_OK ) goto delmaster_out;
  master_open = 1;
  rc = sqlite3OsFileSize(master, &nMasterJournal);
  if( rc!=SQLITE_OK ) goto delmaster_out;

  if( nMasterJournal>0 ){
    char *zJournal;
    char *zMasterPtr = 0;

    /* Load the entire master journal file into space obtained from
    ** sqliteMalloc() and pointed to by zMasterJournal. 
    */
    zMasterJournal = (char *)sqliteMalloc(nMasterJournal);
    if( !zMasterJournal ){
      rc = SQLITE_NOMEM;
      goto delmaster_out;
    }
    rc = sqlite3OsRead(master, zMasterJournal, nMasterJournal);
    if( rc!=SQLITE_OK ) goto delmaster_out;

    zJournal = zMasterJournal;
    while( (zJournal-zMasterJournal)<nMasterJournal ){
      if( sqlite3OsFileExists(zJournal) ){
        /* One of the journals pointed to by the master journal exists.
        ** Open it and check if it points at the master journal. If
        ** so, return without deleting the master journal file.
        */
        OsFile *journal = 0;
        int c;

        rc = sqlite3OsOpenReadOnly(zJournal, &journal);
        if( rc!=SQLITE_OK ){
          goto delmaster_out;
        }

        rc = readMasterJournal(journal, &zMasterPtr);
        sqlite3OsClose(&journal);
        if( rc!=SQLITE_OK ){
          goto delmaster_out;
        }

        c = zMasterPtr!=0 && strcmp(zMasterPtr, zMaster)==0;
        sqliteFree(zMasterPtr);
        if( c ){
          /* We have a match. Do not delete the master journal file. */
          goto delmaster_out;
        }
      }
      zJournal += (strlen(zJournal)+1);
    }
  }
  
  sqlite3OsDelete(zMaster);

delmaster_out:
  if( zMasterJournal ){
    sqliteFree(zMasterJournal);
  }  
  if( master_open ){
    sqlite3OsClose(&master);
  }
  return rc;
}

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static int pager_error ( Pager pPager,
int  rc 
) [static]

Definition at line 473 of file pager.c.

                                             {
  assert( pPager->errCode==SQLITE_FULL || pPager->errCode==SQLITE_OK );
  if( 
    rc==SQLITE_FULL ||
    rc==SQLITE_IOERR ||
    rc==SQLITE_CORRUPT ||
    rc==SQLITE_PROTOCOL
  ){
    pPager->errCode = rc;
  }
  return rc;
}

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static PgHdr* pager_get_all_dirty_pages ( Pager pPager) [static]

Definition at line 2331 of file pager.c.

                                                      {
  return pPager->pDirty;
}

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static int pager_incr_changecounter ( Pager pPager) [static]

Definition at line 3636 of file pager.c.

                                                  {
  void *pPage;
  PgHdr *pPgHdr;
  u32 change_counter;
  int rc;

  /* Open page 1 of the file for writing. */
  rc = sqlite3pager_get(pPager, 1, &pPage);
  if( rc!=SQLITE_OK ) return rc;
  rc = sqlite3pager_write(pPage);
  if( rc!=SQLITE_OK ) return rc;

  /* Read the current value at byte 24. */
  pPgHdr = DATA_TO_PGHDR(pPage);
  change_counter = retrieve32bits(pPgHdr, 24);

  /* Increment the value just read and write it back to byte 24. */
  change_counter++;
  put32bits(((char*)PGHDR_TO_DATA(pPgHdr))+24, change_counter);

  /* Release the page reference. */
  sqlite3pager_unref(pPage);
  return SQLITE_OK;
}

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static PgHdr* pager_lookup ( Pager pPager,
Pgno  pgno 
) [static]

Definition at line 834 of file pager.c.

                                                    {
  PgHdr *p;
  if( pPager->aHash==0 ) return 0;
  p = pPager->aHash[pgno & (pPager->nHash-1)];
  while( p && p->pgno!=pgno ){
    p = p->pNextHash;
  }
  return p;
}

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static int pager_open_journal ( Pager pPager) [static]

Definition at line 2860 of file pager.c.

                                            {
  int rc;
  assert( !MEMDB );
  assert( pPager->state>=PAGER_RESERVED );
  assert( pPager->journalOpen==0 );
  assert( pPager->useJournal );
  assert( pPager->aInJournal==0 );
  sqlite3pager_pagecount(pPager);
  pPager->aInJournal = sqliteMalloc( pPager->dbSize/8 + 1 );
  if( pPager->aInJournal==0 ){
    rc = SQLITE_NOMEM;
    goto failed_to_open_journal;
  }
  rc = sqlite3OsOpenExclusive(pPager->zJournal, &pPager->jfd,
                                 pPager->tempFile);
  pPager->journalOff = 0;
  pPager->setMaster = 0;
  pPager->journalHdr = 0;
  if( rc!=SQLITE_OK ){
    goto failed_to_open_journal;
  }
  sqlite3OsSetFullSync(pPager->jfd, pPager->full_fsync);
  sqlite3OsSetFullSync(pPager->fd, pPager->full_fsync);
  sqlite3OsOpenDirectory(pPager->jfd, pPager->zDirectory);
  pPager->journalOpen = 1;
  pPager->journalStarted = 0;
  pPager->needSync = 0;
  pPager->alwaysRollback = 0;
  pPager->nRec = 0;
  if( pPager->errCode ){
    rc = pPager->errCode;
    goto failed_to_open_journal;
  }
  pPager->origDbSize = pPager->dbSize;

  rc = writeJournalHdr(pPager);

  if( pPager->stmtAutoopen && rc==SQLITE_OK ){
    rc = sqlite3pager_stmt_begin(pPager);
  }
  if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM ){
    rc = pager_unwritelock(pPager);
    if( rc==SQLITE_OK ){
      rc = SQLITE_FULL;
    }
  }
  return rc;

failed_to_open_journal:
  sqliteFree(pPager->aInJournal);
  pPager->aInJournal = 0;
  if( rc==SQLITE_NOMEM ){
    /* If this was a malloc() failure, then we will not be closing the pager
    ** file. So delete any journal file we may have just created. Otherwise,
    ** the system will get confused, we have a read-lock on the file and a
    ** mysterious journal has appeared in the filesystem.
    */
    sqlite3OsDelete(pPager->zJournal);
  }else{
    sqlite3OsUnlock(pPager->fd, NO_LOCK);
    pPager->state = PAGER_UNLOCK;
  }
  return rc;
}

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static int pager_playback ( Pager pPager) [static]

Definition at line 1255 of file pager.c.

                                        {
  i64 szJ;                 /* Size of the journal file in bytes */
  u32 nRec;                /* Number of Records in the journal */
  int i;                   /* Loop counter */
  Pgno mxPg = 0;           /* Size of the original file in pages */
  int rc;                  /* Result code of a subroutine */
  char *zMaster = 0;       /* Name of master journal file if any */

  /* Figure out how many records are in the journal.  Abort early if
  ** the journal is empty.
  */
  assert( pPager->journalOpen );
  rc = sqlite3OsFileSize(pPager->jfd, &szJ);
  if( rc!=SQLITE_OK ){
    goto end_playback;
  }

  /* Read the master journal name from the journal, if it is present.
  ** If a master journal file name is specified, but the file is not
  ** present on disk, then the journal is not hot and does not need to be
  ** played back.
  */
  rc = readMasterJournal(pPager->jfd, &zMaster);
  assert( rc!=SQLITE_DONE );
  if( rc!=SQLITE_OK || (zMaster && !sqlite3OsFileExists(zMaster)) ){
    sqliteFree(zMaster);
    zMaster = 0;
    if( rc==SQLITE_DONE ) rc = SQLITE_OK;
    goto end_playback;
  }
  sqlite3OsSeek(pPager->jfd, 0);
  pPager->journalOff = 0;

  /* This loop terminates either when the readJournalHdr() call returns
  ** SQLITE_DONE or an IO error occurs. */
  while( 1 ){

    /* Read the next journal header from the journal file.  If there are
    ** not enough bytes left in the journal file for a complete header, or
    ** it is corrupted, then a process must of failed while writing it.
    ** This indicates nothing more needs to be rolled back.
    */
    rc = readJournalHdr(pPager, szJ, &nRec, &mxPg);
    if( rc!=SQLITE_OK ){ 
      if( rc==SQLITE_DONE ){
        rc = SQLITE_OK;
      }
      goto end_playback;
    }

    /* If nRec is 0xffffffff, then this journal was created by a process
    ** working in no-sync mode. This means that the rest of the journal
    ** file consists of pages, there are no more journal headers. Compute
    ** the value of nRec based on this assumption.
    */
    if( nRec==0xffffffff ){
      assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) );
      nRec = (szJ - JOURNAL_HDR_SZ(pPager))/JOURNAL_PG_SZ(pPager);
    }

    /* If this is the first header read from the journal, truncate the
    ** database file back to it's original size.
    */
    if( pPager->state>=PAGER_EXCLUSIVE && 
        pPager->journalOff==JOURNAL_HDR_SZ(pPager) ){
      assert( pPager->origDbSize==0 || pPager->origDbSize==mxPg );
      rc = pager_truncate(pPager, mxPg);
      if( rc!=SQLITE_OK ){
        goto end_playback;
      }
      pPager->dbSize = mxPg;
    }

    /* Copy original pages out of the journal and back into the database file.
    */
    for(i=0; i<nRec; i++){
      rc = pager_playback_one_page(pPager, pPager->jfd, 1);
      if( rc!=SQLITE_OK ){
        if( rc==SQLITE_DONE ){
          rc = SQLITE_OK;
          pPager->journalOff = szJ;
          break;
        }else{
          goto end_playback;
        }
      }
    }
  }
  /*NOTREACHED*/
  assert( 0 );

end_playback:
  if( rc==SQLITE_OK ){
    rc = pager_unwritelock(pPager);
  }
  if( zMaster ){
    /* If there was a master journal and this routine will return true,
    ** see if it is possible to delete the master journal.
    */
    if( rc==SQLITE_OK ){
      rc = pager_delmaster(zMaster);
    }
    sqliteFree(zMaster);
  }

  /* The Pager.sectorSize variable may have been updated while rolling
  ** back a journal created by a process with a different PAGER_SECTOR_SIZE
  ** value. Reset it to the correct value for this process.
  */
  pPager->sectorSize = PAGER_SECTOR_SIZE;
  return rc;
}

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static int pager_playback_one_page ( Pager pPager,
OsFile jfd,
int  useCksum 
) [static]

Definition at line 968 of file pager.c.

                                                                            {
  int rc;
  PgHdr *pPg;                   /* An existing page in the cache */
  Pgno pgno;                    /* The page number of a page in journal */
  u32 cksum;                    /* Checksum used for sanity checking */
  u8 aData[SQLITE_MAX_PAGE_SIZE];  /* Temp storage for a page */

  /* useCksum should be true for the main journal and false for
  ** statement journals.  Verify that this is always the case
  */
  assert( jfd == (useCksum ? pPager->jfd : pPager->stfd) );


  rc = read32bits(jfd, &pgno);
  if( rc!=SQLITE_OK ) return rc;
  rc = sqlite3OsRead(jfd, &aData, pPager->pageSize);
  if( rc!=SQLITE_OK ) return rc;
  pPager->journalOff += pPager->pageSize + 4;

  /* Sanity checking on the page.  This is more important that I originally
  ** thought.  If a power failure occurs while the journal is being written,
  ** it could cause invalid data to be written into the journal.  We need to
  ** detect this invalid data (with high probability) and ignore it.
  */
  if( pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
    return SQLITE_DONE;
  }
  if( pgno>(unsigned)pPager->dbSize ){
    return SQLITE_OK;
  }
  if( useCksum ){
    rc = read32bits(jfd, &cksum);
    if( rc ) return rc;
    pPager->journalOff += 4;
    if( pager_cksum(pPager, aData)!=cksum ){
      return SQLITE_DONE;
    }
  }

  assert( pPager->state==PAGER_RESERVED || pPager->state>=PAGER_EXCLUSIVE );

  /* If the pager is in RESERVED state, then there must be a copy of this
  ** page in the pager cache. In this case just update the pager cache,
  ** not the database file. The page is left marked dirty in this case.
  **
  ** If in EXCLUSIVE state, then we update the pager cache if it exists
  ** and the main file. The page is then marked not dirty.
  **
  ** Ticket #1171:  The statement journal might contain page content that is
  ** different from the page content at the start of the transaction.
  ** This occurs when a page is changed prior to the start of a statement
  ** then changed again within the statement.  When rolling back such a
  ** statement we must not write to the original database unless we know
  ** for certain that original page contents are in the main rollback
  ** journal.  Otherwise, if a full ROLLBACK occurs after the statement
  ** rollback the full ROLLBACK will not restore the page to its original
  ** content.  Two conditions must be met before writing to the database
  ** files. (1) the database must be locked.  (2) we know that the original
  ** page content is in the main journal either because the page is not in
  ** cache or else it is marked as needSync==0.
  */
  pPg = pager_lookup(pPager, pgno);
  assert( pPager->state>=PAGER_EXCLUSIVE || pPg!=0 );
  TRACE3("PLAYBACK %d page %d\n", PAGERID(pPager), pgno);
  if( pPager->state>=PAGER_EXCLUSIVE && (pPg==0 || pPg->needSync==0) ){
    rc = sqlite3OsSeek(pPager->fd, (pgno-1)*(i64)pPager->pageSize);
    if( rc==SQLITE_OK ){
      rc = sqlite3OsWrite(pPager->fd, aData, pPager->pageSize);
    }
    if( pPg ){
      makeClean(pPg);
    }
  }
  if( pPg ){
    /* No page should ever be explicitly rolled back that is in use, except
    ** for page 1 which is held in use in order to keep the lock on the
    ** database active. However such a page may be rolled back as a result
    ** of an internal error resulting in an automatic call to
    ** sqlite3pager_rollback().
    */
    void *pData;
    /* assert( pPg->nRef==0 || pPg->pgno==1 ); */
    pData = PGHDR_TO_DATA(pPg);
    memcpy(pData, aData, pPager->pageSize);
    if( pPager->xDestructor ){  /*** FIX ME:  Should this be xReinit? ***/
      pPager->xDestructor(pData, pPager->pageSize);
    }
#ifdef SQLITE_CHECK_PAGES
    pPg->pageHash = pager_pagehash(pPg);
#endif
    CODEC1(pPager, pData, pPg->pgno, 3);
  }
  return rc;
}

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static int pager_recycle ( Pager pPager,
int  syncOk,
PgHdr **  ppPg 
) [static]

Definition at line 2361 of file pager.c.

                                                                 {
  PgHdr *pPg;
  *ppPg = 0;

  /* Find a page to recycle.  Try to locate a page that does not
  ** require us to do an fsync() on the journal.
  */
  pPg = pPager->pFirstSynced;

  /* If we could not find a page that does not require an fsync()
  ** on the journal file then fsync the journal file.  This is a
  ** very slow operation, so we work hard to avoid it.  But sometimes
  ** it can't be helped.
  */
  if( pPg==0 && pPager->pFirst && syncOk && !MEMDB){
    int rc = syncJournal(pPager);
    if( rc!=0 ){
      return rc;
    }
    if( pPager->fullSync ){
      /* If in full-sync mode, write a new journal header into the
      ** journal file. This is done to avoid ever modifying a journal
      ** header that is involved in the rollback of pages that have
      ** already been written to the database (in case the header is
      ** trashed when the nRec field is updated).
      */
      pPager->nRec = 0;
      assert( pPager->journalOff > 0 );
      rc = writeJournalHdr(pPager);
      if( rc!=0 ){
        return rc;
      }
    }
    pPg = pPager->pFirst;
  }
  if( pPg==0 ){
    return SQLITE_OK;
  }

  assert( pPg->nRef==0 );

  /* Write the page to the database file if it is dirty.
  */
  if( pPg->dirty ){
    int rc;
    assert( pPg->needSync==0 );
    makeClean(pPg);
    pPg->dirty = 1;
    pPg->pDirty = 0;
    rc = pager_write_pagelist( pPg );
    if( rc!=SQLITE_OK ){
      return rc;
    }
  }
  assert( pPg->dirty==0 );

  /* If the page we are recycling is marked as alwaysRollback, then
  ** set the global alwaysRollback flag, thus disabling the
  ** sqlite_dont_rollback() optimization for the rest of this transaction.
  ** It is necessary to do this because the page marked alwaysRollback
  ** might be reloaded at a later time but at that point we won't remember
  ** that is was marked alwaysRollback.  This means that all pages must
  ** be marked as alwaysRollback from here on out.
  */
  if( pPg->alwaysRollback ){
    pPager->alwaysRollback = 1;
  }

  /* Unlink the old page from the free list and the hash table
  */
  unlinkPage(pPg);
  TEST_INCR(pPager->nOvfl);

  *ppPg = pPg;
  return SQLITE_OK;
}

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static int pager_reload_cache ( Pager pPager) [static]

Definition at line 1158 of file pager.c.

                                            {
  PgHdr *pPg;
  int rc = SQLITE_OK;
  for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
    char zBuf[SQLITE_MAX_PAGE_SIZE];
    if( !pPg->dirty ) continue;
    if( (int)pPg->pgno <= pPager->origDbSize ){
      rc = sqlite3OsSeek(pPager->fd, pPager->pageSize*(i64)(pPg->pgno-1));
      if( rc==SQLITE_OK ){
        rc = sqlite3OsRead(pPager->fd, zBuf, pPager->pageSize);
      }
      TRACE3("REFETCH %d page %d\n", PAGERID(pPager), pPg->pgno);
      if( rc ) break;
      CODEC1(pPager, zBuf, pPg->pgno, 2);
    }else{
      memset(zBuf, 0, pPager->pageSize);
    }
    if( pPg->nRef==0 || memcmp(zBuf, PGHDR_TO_DATA(pPg), pPager->pageSize) ){
      memcpy(PGHDR_TO_DATA(pPg), zBuf, pPager->pageSize);
      if( pPager->xReiniter ){
        pPager->xReiniter(PGHDR_TO_DATA(pPg), pPager->pageSize);
      }else{
        memset(PGHDR_TO_EXTRA(pPg, pPager), 0, pPager->nExtra);
      }
    }
    pPg->needSync = 0;
    pPg->dirty = 0;
#ifdef SQLITE_CHECK_PAGES
    pPg->pageHash = pager_pagehash(pPg);
#endif
  }
  pPager->pDirty = 0;
  return rc;
}

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static void pager_reset ( Pager pPager) [static]

Definition at line 850 of file pager.c.

                                      {
  PgHdr *pPg, *pNext;
  if( pPager->errCode ) return;
  for(pPg=pPager->pAll; pPg; pPg=pNext){
    pNext = pPg->pNextAll;
    sqliteFree(pPg);
  }
  pPager->pFirst = 0;
  pPager->pFirstSynced = 0;
  pPager->pLast = 0;
  pPager->pAll = 0;
  pPager->nHash = 0;
  sqliteFree(pPager->aHash);
  pPager->nPage = 0;
  pPager->aHash = 0;
  if( pPager->state>=PAGER_RESERVED ){
    sqlite3pager_rollback(pPager);
  }
  sqlite3OsUnlock(pPager->fd, NO_LOCK);
  pPager->state = PAGER_UNLOCK;
  pPager->dbSize = -1;
  pPager->nRef = 0;
  assert( pPager->journalOpen==0 );
}

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static void pager_resize_hash_table ( Pager pPager,
int  N 
) [static]

Definition at line 394 of file pager.c.

                                                         {
  PgHdr **aHash, *pPg;
  assert( N>0 && (N&(N-1))==0 );
  aHash = sqliteMalloc( sizeof(aHash[0])*N );
  if( aHash==0 ){
    /* Failure to rehash is not an error.  It is only a performance hit. */
    return;
  }
  sqliteFree(pPager->aHash);
  pPager->nHash = N;
  pPager->aHash = aHash;
  for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
    int h = pPg->pgno & (N-1);
    pPg->pNextHash = aHash[h];
    if( aHash[h] ){
      aHash[h]->pPrevHash = pPg;
    }
    aHash[h] = pPg;
    pPg->pPrevHash = 0;
  }
}

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static int pager_stmt_playback ( Pager pPager) [static]

Definition at line 1382 of file pager.c.

                                             {
  i64 szJ;                 /* Size of the full journal */
  i64 hdrOff;
  int nRec;                /* Number of Records */
  int i;                   /* Loop counter */
  int rc;

  szJ = pPager->journalOff;
#ifndef NDEBUG 
  {
    i64 os_szJ;
    rc = sqlite3OsFileSize(pPager->jfd, &os_szJ);
    if( rc!=SQLITE_OK ) return rc;
    assert( szJ==os_szJ );
  }
#endif

  /* Set hdrOff to be the offset to the first journal header written
  ** this statement transaction, or the end of the file if no journal
  ** header was written.
  */
  hdrOff = pPager->stmtHdrOff;
  assert( pPager->fullSync || !hdrOff );
  if( !hdrOff ){
    hdrOff = szJ;
  }
  
  /* Truncate the database back to its original size.
  */
  if( pPager->state>=PAGER_EXCLUSIVE ){
    rc = pager_truncate(pPager, pPager->stmtSize);
  }
  pPager->dbSize = pPager->stmtSize;

  /* Figure out how many records are in the statement journal.
  */
  assert( pPager->stmtInUse && pPager->journalOpen );
  sqlite3OsSeek(pPager->stfd, 0);
  nRec = pPager->stmtNRec;
  
  /* Copy original pages out of the statement journal and back into the
  ** database file.  Note that the statement journal omits checksums from
  ** each record since power-failure recovery is not important to statement
  ** journals.
  */
  for(i=nRec-1; i>=0; i--){
    rc = pager_playback_one_page(pPager, pPager->stfd, 0);
    assert( rc!=SQLITE_DONE );
    if( rc!=SQLITE_OK ) goto end_stmt_playback;
  }

  /* Now roll some pages back from the transaction journal. Pager.stmtJSize
  ** was the size of the journal file when this statement was started, so
  ** everything after that needs to be rolled back, either into the
  ** database, the memory cache, or both.
  **
  ** If it is not zero, then Pager.stmtHdrOff is the offset to the start
  ** of the first journal header written during this statement transaction.
  */
  rc = sqlite3OsSeek(pPager->jfd, pPager->stmtJSize);
  if( rc!=SQLITE_OK ){
    goto end_stmt_playback;
  }
  pPager->journalOff = pPager->stmtJSize;
  pPager->cksumInit = pPager->stmtCksum;
  assert( JOURNAL_HDR_SZ(pPager)<(pPager->pageSize+8) );
  while( pPager->journalOff <= (hdrOff-(pPager->pageSize+8)) ){
    rc = pager_playback_one_page(pPager, pPager->jfd, 1);
    assert( rc!=SQLITE_DONE );
    if( rc!=SQLITE_OK ) goto end_stmt_playback;
  }

  while( pPager->journalOff < szJ ){
    u32 nJRec;         /* Number of Journal Records */
    u32 dummy;
    rc = readJournalHdr(pPager, szJ, &nJRec, &dummy);
    if( rc!=SQLITE_OK ){
      assert( rc!=SQLITE_DONE );
      goto end_stmt_playback;
    }
    if( nJRec==0 ){
      nJRec = (szJ - pPager->journalOff) / (pPager->pageSize+8);
    }
    for(i=nJRec-1; i>=0 && pPager->journalOff < szJ; i--){
      rc = pager_playback_one_page(pPager, pPager->jfd, 1);
      assert( rc!=SQLITE_DONE );
      if( rc!=SQLITE_OK ) goto end_stmt_playback;
    }
  }

  pPager->journalOff = szJ;
  
end_stmt_playback:
  if( rc==SQLITE_OK) {
    pPager->journalOff = szJ;
    /* pager_reload_cache(pPager); */
  }
  return rc;
}

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static int pager_truncate ( Pager pPager,
int  nPage 
) [static]

Definition at line 1197 of file pager.c.

                                                   {
  assert( pPager->state>=PAGER_EXCLUSIVE );
  return sqlite3OsTruncate(pPager->fd, pPager->pageSize*(i64)nPage);
}

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static int pager_unwritelock ( Pager pPager) [static]

Definition at line 885 of file pager.c.

                                           {
  PgHdr *pPg;
  int rc;
  assert( !MEMDB );
  if( pPager->state<PAGER_RESERVED ){
    return SQLITE_OK;
  }
  sqlite3pager_stmt_commit(pPager);
  if( pPager->stmtOpen ){
    sqlite3OsClose(&pPager->stfd);
    pPager->stmtOpen = 0;
  }
  if( pPager->journalOpen ){
    sqlite3OsClose(&pPager->jfd);
    pPager->journalOpen = 0;
    sqlite3OsDelete(pPager->zJournal);
    sqliteFree( pPager->aInJournal );
    pPager->aInJournal = 0;
    for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
      pPg->inJournal = 0;
      pPg->dirty = 0;
      pPg->needSync = 0;
#ifdef SQLITE_CHECK_PAGES
      pPg->pageHash = pager_pagehash(pPg);
#endif
    }
    pPager->pDirty = 0;
    pPager->dirtyCache = 0;
    pPager->nRec = 0;
  }else{
    assert( pPager->aInJournal==0 );
    assert( pPager->dirtyCache==0 || pPager->useJournal==0 );
  }
  rc = sqlite3OsUnlock(pPager->fd, SHARED_LOCK);
  pPager->state = PAGER_SHARED;
  pPager->origDbSize = 0;
  pPager->setMaster = 0;
  pPager->needSync = 0;
  pPager->pFirstSynced = pPager->pFirst;
  return rc;
}

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static int pager_wait_on_lock ( Pager pPager,
int  locktype 
) [static]

Definition at line 1952 of file pager.c.

                                                          {
  int rc;
  assert( PAGER_SHARED==SHARED_LOCK );
  assert( PAGER_RESERVED==RESERVED_LOCK );
  assert( PAGER_EXCLUSIVE==EXCLUSIVE_LOCK );
  if( pPager->state>=locktype ){
    rc = SQLITE_OK;
  }else{
    do {
      rc = sqlite3OsLock(pPager->fd, locktype);
    }while( rc==SQLITE_BUSY && sqlite3InvokeBusyHandler(pPager->pBusyHandler) );
    if( rc==SQLITE_OK ){
      pPager->state = locktype;
    }
  }
  return rc;
}

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static int pager_write_pagelist ( PgHdr pList) [static]

Definition at line 2268 of file pager.c.

                                             {
  Pager *pPager;
  int rc;

  if( pList==0 ) return SQLITE_OK;
  pPager = pList->pPager;

  /* At this point there may be either a RESERVED or EXCLUSIVE lock on the
  ** database file. If there is already an EXCLUSIVE lock, the following
  ** calls to sqlite3OsLock() are no-ops.
  **
  ** Moving the lock from RESERVED to EXCLUSIVE actually involves going
  ** through an intermediate state PENDING.   A PENDING lock prevents new
  ** readers from attaching to the database but is unsufficient for us to
  ** write.  The idea of a PENDING lock is to prevent new readers from
  ** coming in while we wait for existing readers to clear.
  **
  ** While the pager is in the RESERVED state, the original database file
  ** is unchanged and we can rollback without having to playback the
  ** journal into the original database file.  Once we transition to
  ** EXCLUSIVE, it means the database file has been changed and any rollback
  ** will require a journal playback.
  */
  rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  while( pList ){
    assert( pList->dirty );
    rc = sqlite3OsSeek(pPager->fd, (pList->pgno-1)*(i64)pPager->pageSize);
    if( rc ) return rc;
    /* If there are dirty pages in the page cache with page numbers greater
    ** than Pager.dbSize, this means sqlite3pager_truncate() was called to
    ** make the file smaller (presumably by auto-vacuum code). Do not write
    ** any such pages to the file.
    */
    if( pList->pgno<=pPager->dbSize ){
      char *pData = CODEC2(pPager, PGHDR_TO_DATA(pList), pList->pgno, 6);
      TRACE3("STORE %d page %d\n", PAGERID(pPager), pList->pgno);
      rc = sqlite3OsWrite(pPager->fd, pData, pPager->pageSize);
      TEST_INCR(pPager->nWrite);
    }
#ifndef NDEBUG
    else{
      TRACE3("NOSTORE %d page %d\n", PAGERID(pPager), pList->pgno);
    }
#endif
    if( rc ) return rc;
    pList->dirty = 0;
#ifdef SQLITE_CHECK_PAGES
    pList->pageHash = pager_pagehash(pList);
#endif
    pList = pList->pDirty;
  }
  return SQLITE_OK;
}

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static void put32bits ( char *  ac,
u32  val 
) [static]

Definition at line 435 of file pager.c.

                                        {
  ac[0] = (val>>24) & 0xff;
  ac[1] = (val>>16) & 0xff;
  ac[2] = (val>>8) & 0xff;
  ac[3] = val & 0xff;
}

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static int read32bits ( OsFile fd,
u32 pRes 
) [static]

Definition at line 423 of file pager.c.

                                            {
  unsigned char ac[4];
  int rc = sqlite3OsRead(fd, ac, sizeof(ac));
  if( rc==SQLITE_OK ){
    *pRes = (ac[0]<<24) | (ac[1]<<16) | (ac[2]<<8) | ac[3];
  }
  return rc;
}

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static int readJournalHdr ( Pager pPager,
i64  journalSize,
u32 pNRec,
u32 pDbSize 
) [static]

Definition at line 686 of file pager.c.

 {
  int rc;
  unsigned char aMagic[8]; /* A buffer to hold the magic header */

  rc = seekJournalHdr(pPager);
  if( rc ) return rc;

  if( pPager->journalOff+JOURNAL_HDR_SZ(pPager) > journalSize ){
    return SQLITE_DONE;
  }

  rc = sqlite3OsRead(pPager->jfd, aMagic, sizeof(aMagic));
  if( rc ) return rc;

  if( memcmp(aMagic, aJournalMagic, sizeof(aMagic))!=0 ){
    return SQLITE_DONE;
  }

  rc = read32bits(pPager->jfd, pNRec);
  if( rc ) return rc;

  rc = read32bits(pPager->jfd, &pPager->cksumInit);
  if( rc ) return rc;

  rc = read32bits(pPager->jfd, pDbSize);
  if( rc ) return rc;

  /* Update the assumed sector-size to match the value used by 
  ** the process that created this journal. If this journal was
  ** created by a process other than this one, then this routine
  ** is being called from within pager_playback(). The local value
  ** of Pager.sectorSize is restored at the end of that routine.
  */
  rc = read32bits(pPager->jfd, (u32 *)&pPager->sectorSize);
  if( rc ) return rc;

  pPager->journalOff += JOURNAL_HDR_SZ(pPager);
  rc = sqlite3OsSeek(pPager->jfd, pPager->journalOff);
  return rc;
}

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static int readMasterJournal ( OsFile pJrnl,
char **  pzMaster 
) [static]

Definition at line 526 of file pager.c.

                                                            {
  int rc;
  u32 len;
  i64 szJ;
  u32 cksum;
  int i;
  unsigned char aMagic[8]; /* A buffer to hold the magic header */

  *pzMaster = 0;

  rc = sqlite3OsFileSize(pJrnl, &szJ);
  if( rc!=SQLITE_OK || szJ<16 ) return rc;

  rc = sqlite3OsSeek(pJrnl, szJ-16);
  if( rc!=SQLITE_OK ) return rc;
 
  rc = read32bits(pJrnl, &len);
  if( rc!=SQLITE_OK ) return rc;

  rc = read32bits(pJrnl, &cksum);
  if( rc!=SQLITE_OK ) return rc;

  rc = sqlite3OsRead(pJrnl, aMagic, 8);
  if( rc!=SQLITE_OK || memcmp(aMagic, aJournalMagic, 8) ) return rc;

  rc = sqlite3OsSeek(pJrnl, szJ-16-len);
  if( rc!=SQLITE_OK ) return rc;

  *pzMaster = (char *)sqliteMalloc(len+1);
  if( !*pzMaster ){
    return SQLITE_NOMEM;
  }
  rc = sqlite3OsRead(pJrnl, *pzMaster, len);
  if( rc!=SQLITE_OK ){
    sqliteFree(*pzMaster);
    *pzMaster = 0;
    return rc;
  }

  /* See if the checksum matches the master journal name */
  for(i=0; i<len; i++){
    cksum -= (*pzMaster)[i];
  }
  if( cksum ){
    /* If the checksum doesn't add up, then one or more of the disk sectors
    ** containing the master journal filename is corrupted. This means
    ** definitely roll back, so just return SQLITE_OK and report a (nul)
    ** master-journal filename.
    */
    sqliteFree(*pzMaster);
    *pzMaster = 0;
  }else{
    (*pzMaster)[len] = '\0';
  }
   
  return SQLITE_OK;
}

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static u32 retrieve32bits ( PgHdr p,
int  offset 
) [static]

Definition at line 456 of file pager.c.

                                               {
  unsigned char *ac;
  ac = &((unsigned char*)PGHDR_TO_DATA(p))[offset];
  return (ac[0]<<24) | (ac[1]<<16) | (ac[2]<<8) | ac[3];
}

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static int seekJournalHdr ( Pager pPager) [static]

Definition at line 599 of file pager.c.

                                        {
  i64 offset = 0;
  i64 c = pPager->journalOff;
  if( c ){
    offset = ((c-1)/JOURNAL_HDR_SZ(pPager) + 1) * JOURNAL_HDR_SZ(pPager);
  }
  assert( offset%JOURNAL_HDR_SZ(pPager)==0 );
  assert( offset>=c );
  assert( (offset-c)<JOURNAL_HDR_SZ(pPager) );
  pPager->journalOff = offset;
  return sqlite3OsSeek(pPager->jfd, pPager->journalOff);
}

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int sqlite3pager_begin ( void pData,
int  exFlag 
)

Definition at line 2952 of file pager.c.

                                               {
  PgHdr *pPg = DATA_TO_PGHDR(pData);
  Pager *pPager = pPg->pPager;
  int rc = SQLITE_OK;
  assert( pPg->nRef>0 );
  assert( pPager->state!=PAGER_UNLOCK );
  if( pPager->state==PAGER_SHARED ){
    assert( pPager->aInJournal==0 );
    if( MEMDB ){
      pPager->state = PAGER_EXCLUSIVE;
      pPager->origDbSize = pPager->dbSize;
    }else{
      rc = sqlite3OsLock(pPager->fd, RESERVED_LOCK);
      if( rc==SQLITE_OK ){
        pPager->state = PAGER_RESERVED;
        if( exFlag ){
          rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
        }
      }
      if( rc!=SQLITE_OK ){
        return rc;
      }
      pPager->dirtyCache = 0;
      TRACE2("TRANSACTION %d\n", PAGERID(pPager));
      if( pPager->useJournal && !pPager->tempFile ){
        rc = pager_open_journal(pPager);
      }
    }
  }
  return rc;
}

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int sqlite3pager_close ( Pager pPager)

Definition at line 2020 of file pager.c.

                                     {
  PgHdr *pPg, *pNext;
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  /* A malloc() cannot fail in sqlite3ThreadData() as one or more calls to 
  ** malloc() must have already been made by this thread before it gets
  ** to this point. This means the ThreadData must have been allocated already
  ** so that ThreadData.nAlloc can be set.
  */
  ThreadData *pTsd = sqlite3ThreadData();
  assert( pPager );
  assert( pTsd && pTsd->nAlloc );
#endif

  switch( pPager->state ){
    case PAGER_RESERVED:
    case PAGER_SYNCED: 
    case PAGER_EXCLUSIVE: {
      /* We ignore any IO errors that occur during the rollback
      ** operation. So disable IO error simulation so that testing
      ** works more easily.
      */
      disable_simulated_io_errors();
      sqlite3pager_rollback(pPager);
      enable_simulated_io_errors();
      if( !MEMDB ){
        sqlite3OsUnlock(pPager->fd, NO_LOCK);
      }
      assert( pPager->errCode || pPager->journalOpen==0 );
      break;
    }
    case PAGER_SHARED: {
      if( !MEMDB ){
        sqlite3OsUnlock(pPager->fd, NO_LOCK);
      }
      break;
    }
    default: {
      /* Do nothing */
      break;
    }
  }
  for(pPg=pPager->pAll; pPg; pPg=pNext){
#ifndef NDEBUG
    if( MEMDB ){
      PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
      assert( !pPg->alwaysRollback );
      assert( !pHist->pOrig );
      assert( !pHist->pStmt );
    }
#endif
    pNext = pPg->pNextAll;
    sqliteFree(pPg);
  }
  TRACE2("CLOSE %d\n", PAGERID(pPager));
  assert( pPager->errCode || (pPager->journalOpen==0 && pPager->stmtOpen==0) );
  if( pPager->journalOpen ){
    sqlite3OsClose(&pPager->jfd);
  }
  sqliteFree(pPager->aInJournal);
  if( pPager->stmtOpen ){
    sqlite3OsClose(&pPager->stfd);
  }
  sqlite3OsClose(&pPager->fd);
  /* Temp files are automatically deleted by the OS
  ** if( pPager->tempFile ){
  **   sqlite3OsDelete(pPager->zFilename);
  ** }
  */

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  /* Remove the pager from the linked list of pagers starting at 
  ** ThreadData.pPager if memory-management is enabled.
  */
  if( pPager==pTsd->pPager ){
    pTsd->pPager = pPager->pNext;
  }else{
    Pager *pTmp;
    for(pTmp = pTsd->pPager; pTmp->pNext!=pPager; pTmp=pTmp->pNext){}
    pTmp->pNext = pPager->pNext;
  }
#endif
  sqliteFree(pPager->aHash);
  sqliteFree(pPager);
  return SQLITE_OK;
}

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int sqlite3pager_commit ( Pager pPager)

Definition at line 3311 of file pager.c.

                                      {
  int rc;
  PgHdr *pPg;

  if( pPager->errCode ){
    return pPager->errCode;
  }
  if( pPager->state<PAGER_RESERVED ){
    return SQLITE_ERROR;
  }
  TRACE2("COMMIT %d\n", PAGERID(pPager));
  if( MEMDB ){
    pPg = pager_get_all_dirty_pages(pPager);
    while( pPg ){
      clearHistory(PGHDR_TO_HIST(pPg, pPager));
      pPg->dirty = 0;
      pPg->inJournal = 0;
      pPg->inStmt = 0;
      pPg->needSync = 0;
      pPg->pPrevStmt = pPg->pNextStmt = 0;
      pPg = pPg->pDirty;
    }
    pPager->pDirty = 0;
#ifndef NDEBUG
    for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
      PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
      assert( !pPg->alwaysRollback );
      assert( !pHist->pOrig );
      assert( !pHist->pStmt );
    }
#endif
    pPager->pStmt = 0;
    pPager->state = PAGER_SHARED;
    return SQLITE_OK;
  }
  if( pPager->dirtyCache==0 ){
    /* Exit early (without doing the time-consuming sqlite3OsSync() calls)
    ** if there have been no changes to the database file. */
    assert( pPager->needSync==0 );
    rc = pager_unwritelock(pPager);
    pPager->dbSize = -1;
    return rc;
  }
  assert( pPager->journalOpen );
  rc = sqlite3pager_sync(pPager, 0, 0);
  if( rc==SQLITE_OK ){
    rc = pager_unwritelock(pPager);
    pPager->dbSize = -1;
  }
  return rc;
}

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const char* sqlite3pager_dirname ( Pager pPager)

Definition at line 3601 of file pager.c.

                                               {
  return pPager->zDirectory;
}

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Definition at line 3279 of file pager.c.

                                            {
  PgHdr *pPg = DATA_TO_PGHDR(pData);
  Pager *pPager = pPg->pPager;

  if( pPager->state!=PAGER_EXCLUSIVE || pPager->journalOpen==0 ) return;
  if( pPg->alwaysRollback || pPager->alwaysRollback || MEMDB ) return;
  if( !pPg->inJournal && (int)pPg->pgno <= pPager->origDbSize ){
    assert( pPager->aInJournal!=0 );
    pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
    pPg->inJournal = 1;
    if( pPager->stmtInUse ){
      pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
      page_add_to_stmt_list(pPg);
    }
    TRACE3("DONT_ROLLBACK page %d of %d\n", pPg->pgno, PAGERID(pPager));
  }
  if( pPager->stmtInUse && !pPg->inStmt && (int)pPg->pgno<=pPager->stmtSize ){
    assert( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize );
    assert( pPager->aInStmt!=0 );
    pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
    page_add_to_stmt_list(pPg);
  }
}

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void sqlite3pager_dont_write ( Pager pPager,
Pgno  pgno 
)

Definition at line 3245 of file pager.c.

                                                      {
  PgHdr *pPg;

  if( MEMDB ) return;

  pPg = pager_lookup(pPager, pgno);
  assert( pPg!=0 );  /* We never call _dont_write unless the page is in mem */
  pPg->alwaysRollback = 1;
  if( pPg->dirty && !pPager->stmtInUse ){
    if( pPager->dbSize==(int)pPg->pgno && pPager->origDbSize<pPager->dbSize ){
      /* If this pages is the last page in the file and the file has grown
      ** during the current transaction, then do NOT mark the page as clean.
      ** When the database file grows, we must make sure that the last page
      ** gets written at least once so that the disk file will be the correct
      ** size. If you do not write this page and the size of the file
      ** on the disk ends up being too small, that can lead to database
      ** corruption during the next transaction.
      */
    }else{
      TRACE3("DONT_WRITE page %d of %d\n", pgno, PAGERID(pPager));
      makeClean(pPg);
#ifdef SQLITE_CHECK_PAGES
      pPg->pageHash = pager_pagehash(pPg);
#endif
    }
  }
}

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const char* sqlite3pager_filename ( Pager pPager)

Definition at line 3594 of file pager.c.

                                                {
  return pPager->zFilename;
}

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int sqlite3pager_get ( Pager pPager,
Pgno  pgno,
void **  ppPage 
)

Definition at line 2544 of file pager.c.

                                                             {
  /* This just passes through to our modified version with a NULL data pointer */
  return sqlite3pager_get2(pPager, pgno, ppPage, 0);
}

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int sqlite3pager_get2 ( Pager pPager,
Pgno  pgno,
void **  ppPage,
unsigned char *  pDataToFill 
)

Definition at line 2557 of file pager.c.

                                                  {
  PgHdr *pPg;
  int rc;

  /* The maximum page number is 2^31. Return SQLITE_CORRUPT if a page
  ** number greater than this, or zero, is requested.
  */
  if( pgno>PAGER_MAX_PGNO || pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
    return SQLITE_CORRUPT_BKPT;
  }

  /* Make sure we have not hit any critical errors.
  */ 
  assert( pPager!=0 );
  *ppPage = 0;
  if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
    return pPager->errCode;
  }

  /* If this is the first page accessed, then get a SHARED lock
  ** on the database file.
  */
  if( pPager->nRef==0 && !MEMDB ){
    if( !pPager->noReadlock ){
      rc = pager_wait_on_lock(pPager, SHARED_LOCK);
      if( rc!=SQLITE_OK ){
        return pager_error(pPager, rc);
      }
    }

    /* If a journal file exists, and there is no RESERVED lock on the
    ** database file, then it either needs to be played back or deleted.
    */
    if( hasHotJournal(pPager) ){
       /* Get an EXCLUSIVE lock on the database file. At this point it is
       ** important that a RESERVED lock is not obtained on the way to the
       ** EXCLUSIVE lock. If it were, another process might open the
       ** database file, detect the RESERVED lock, and conclude that the
       ** database is safe to read while this process is still rolling it 
       ** back.
       ** 
       ** Because the intermediate RESERVED lock is not requested, the
       ** second process will get to this point in the code and fail to
       ** obtain it's own EXCLUSIVE lock on the database file.
       */
       rc = sqlite3OsLock(pPager->fd, EXCLUSIVE_LOCK);
       if( rc!=SQLITE_OK ){
         sqlite3OsUnlock(pPager->fd, NO_LOCK);
         pPager->state = PAGER_UNLOCK;
         return pager_error(pPager, rc);
       }
       pPager->state = PAGER_EXCLUSIVE;

       /* Open the journal for reading only.  Return SQLITE_BUSY if
       ** we are unable to open the journal file. 
       **
       ** The journal file does not need to be locked itself.  The
       ** journal file is never open unless the main database file holds
       ** a write lock, so there is never any chance of two or more
       ** processes opening the journal at the same time.
       */
       rc = sqlite3OsOpenReadOnly(pPager->zJournal, &pPager->jfd);
       if( rc!=SQLITE_OK ){
         sqlite3OsUnlock(pPager->fd, NO_LOCK);
         pPager->state = PAGER_UNLOCK;
         return SQLITE_BUSY;
       }
       pPager->journalOpen = 1;
       pPager->journalStarted = 0;
       pPager->journalOff = 0;
       pPager->setMaster = 0;
       pPager->journalHdr = 0;

       /* Playback and delete the journal.  Drop the database write
       ** lock and reacquire the read lock.
       */
       rc = pager_playback(pPager);
       if( rc!=SQLITE_OK ){
         return pager_error(pPager, rc);
       }
    }
    pPg = 0;
  }else{
    /* Search for page in cache */
    pPg = pager_lookup(pPager, pgno);
    if( MEMDB && pPager->state==PAGER_UNLOCK ){
      pPager->state = PAGER_SHARED;
    }
  }
  if( pPg==0 ){
    /* The requested page is not in the page cache. */
    int h;
    TEST_INCR(pPager->nMiss);
    if( pPager->nPage<pPager->mxPage || pPager->pFirst==0 || MEMDB ){
      /* Create a new page */
      if( pPager->nPage>=pPager->nHash ){
        pager_resize_hash_table(pPager,
           pPager->nHash<256 ? 256 : pPager->nHash*2);
        if( pPager->nHash==0 ){
          return SQLITE_NOMEM;
        }
      }
      pPg = sqliteMallocRaw( sizeof(*pPg) + pPager->pageSize
                              + sizeof(u32) + pPager->nExtra
                              + MEMDB*sizeof(PgHistory) );
      if( pPg==0 ){
        return SQLITE_NOMEM;
      }
      memset(pPg, 0, sizeof(*pPg));
      if( MEMDB ){
        memset(PGHDR_TO_HIST(pPg, pPager), 0, sizeof(PgHistory));
      }
      pPg->pPager = pPager;
      pPg->pNextAll = pPager->pAll;
      pPager->pAll = pPg;
      pPager->nPage++;
      if( pPager->nPage>pPager->nMaxPage ){
        assert( pPager->nMaxPage==(pPager->nPage-1) );
        pPager->nMaxPage++;
      }
    }else{
      rc = pager_recycle(pPager, 1, &pPg);
      if( rc!=SQLITE_OK ){
        return rc;
      }
      assert(pPg) ;
    }
    pPg->pgno = pgno;
    if( pPager->aInJournal && (int)pgno<=pPager->origDbSize ){
      sqlite3CheckMemory(pPager->aInJournal, pgno/8);
      assert( pPager->journalOpen );
      pPg->inJournal = (pPager->aInJournal[pgno/8] & (1<<(pgno&7)))!=0;
      pPg->needSync = 0;
    }else{
      pPg->inJournal = 0;
      pPg->needSync = 0;
    }
    if( pPager->aInStmt && (int)pgno<=pPager->stmtSize
             && (pPager->aInStmt[pgno/8] & (1<<(pgno&7)))!=0 ){
      page_add_to_stmt_list(pPg);
    }else{
      page_remove_from_stmt_list(pPg);
    }
    makeClean(pPg);
    pPg->nRef = 1;
    REFINFO(pPg);

    pPager->nRef++;
    if( pPager->nExtra>0 ){
      memset(PGHDR_TO_EXTRA(pPg, pPager), 0, pPager->nExtra);
    }
    if( pPager->errCode ){
      sqlite3pager_unref(PGHDR_TO_DATA(pPg));
      rc = pPager->errCode;
      return rc;
    }

    /* Populate the page with data, either by reading from the database
    ** file, or by setting the entire page to zero.
    */
    if( sqlite3pager_pagecount(pPager)<(int)pgno || MEMDB ){
      memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
    }else{
      if (pDataToFill) {
        /* Just copy from the given memory */
        memcpy(PGHDR_TO_DATA(pPg), pDataToFill, pPager->pageSize);
        CODEC1(pPager, PGHDR_TO_DATA(pPg), pPg->pgno, 3);
      } else {
        /* Load from disk */
        assert( MEMDB==0 );
        rc = sqlite3OsSeek(pPager->fd, (pgno-1)*(i64)pPager->pageSize);
        if( rc==SQLITE_OK ){
          rc = sqlite3OsRead(pPager->fd, PGHDR_TO_DATA(pPg),
                                pPager->pageSize);
        }
        TRACE3("FETCH %d page %d\n", PAGERID(pPager), pPg->pgno);
        CODEC1(pPager, PGHDR_TO_DATA(pPg), pPg->pgno, 3);
        if( rc!=SQLITE_OK ){
          i64 fileSize;
          int rc2 = sqlite3OsFileSize(pPager->fd, &fileSize);
          if( rc2!=SQLITE_OK || fileSize>=pgno*pPager->pageSize ){
            /* An IO error occured in one of the the sqlite3OsSeek() or
            ** sqlite3OsRead() calls above. */
            pPg->pgno = 0;
            sqlite3pager_unref(PGHDR_TO_DATA(pPg));
            return rc;
          }else{
            clear_simulated_io_error();
            memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
          }
        }else{
          TEST_INCR(pPager->nRead);
        }
      }
    }

    /* Link the page into the page hash table */
    h = pgno & (pPager->nHash-1);
    pPg->pNextHash = pPager->aHash[h];
    pPager->aHash[h] = pPg;
    if( pPg->pNextHash ){
      assert( pPg->pNextHash->pPrevHash==0 );
      pPg->pNextHash->pPrevHash = pPg;
    }

#ifdef SQLITE_CHECK_PAGES
    pPg->pageHash = pager_pagehash(pPg);
#endif
  }else{
    /* The requested page is in the page cache. */
    TEST_INCR(pPager->nHit);
    page_ref(pPg);
  }
  *ppPage = PGHDR_TO_DATA(pPg);
  return SQLITE_OK;
}

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Definition at line 3449 of file pager.c.

                                          {
  return pPager->readOnly;
}

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const char* sqlite3pager_journalname ( Pager pPager)

Definition at line 3608 of file pager.c.

                                                   {
  return pPager->zJournal;
}

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Addition for Mozilla: This will attempt to populate the database cache with the first N bytes of the file, where N is the total size of the cache.

Because we can load this as one chunk from the disk, this is much faster than loading a subset of the pages one at a time in random order.

The pager must be initialized before this function is called. This means a statement must be open that has initialized the pager and is keeping the cache in memory.

Definition at line 3860 of file pager.c.

{
  int i;
  int rc;
  int loadSize;
  int loadPages;
  unsigned char* fileData;

  if (pPager->dbSize < 0 || pPager->pageSize < 0) {
    /* pager not initialized, this means a statement is not open */
    return SQLITE_MISUSE;
  }

  /* compute sizes */
  if (pPager->mxPage < pPager->dbSize)
    loadPages = pPager->mxPage;
  else
    loadPages = pPager->dbSize;
  loadSize = loadPages * pPager->pageSize;

  rc = sqlite3OsSeek(pPager->fd, 0);
  if (rc != SQLITE_OK)
    return rc;

  /* load the file as one chunk */
  fileData = sqliteMallocRaw(loadSize);
  if (! fileData)
    return SQLITE_NOMEM;
  rc = sqlite3OsRead(pPager->fd, fileData, loadSize);
  if (rc != SQLITE_OK) {
    sqliteFree(fileData);
    return rc;
  }

  /* Copy the data to each page. Note that the page numbers we pass to _get
   * are one-based, 0 is a marker for no page. We also need to check that we
   * haven't loaded more pages than the cache can hold total. There may have
   * already been a few pages loaded before, so we may fill the cache before
   * loading all of the pages we want to.
   */
  for (i = 1; i <= loadPages && pPager->nPage < pPager->mxPage; i ++) {
    void *pPage;
    rc = sqlite3pager_get2(pPager, 1, &pPage,
                           &fileData[(i-1)*(i64)pPager->pageSize]);
    if (rc != SQLITE_OK)
      break;
    sqlite3pager_unref(pPage);
  }
  sqliteFree(fileData);
  return SQLITE_OK;
}

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void* sqlite3pager_lookup ( Pager pPager,
Pgno  pgno 
)

Definition at line 2786 of file pager.c.

                                                   {
  PgHdr *pPg;

  assert( pPager!=0 );
  assert( pgno!=0 );
  if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
    return 0;
  }
  pPg = pager_lookup(pPager, pgno);
  if( pPg==0 ) return 0;
  page_ref(pPg);
  return PGHDR_TO_DATA(pPg);
}

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int sqlite3pager_movepage ( Pager pPager,
void pData,
Pgno  pgno 
)

Definition at line 3770 of file pager.c.

                                                                {
  PgHdr *pPg = DATA_TO_PGHDR(pData);
  PgHdr *pPgOld; 
  int h;
  Pgno needSyncPgno = 0;

  assert( pPg->nRef>0 );

  TRACE5("MOVE %d page %d (needSync=%d) moves to %d\n", 
      PAGERID(pPager), pPg->pgno, pPg->needSync, pgno);

  if( pPg->needSync ){
    needSyncPgno = pPg->pgno;
    assert( pPg->inJournal );
    assert( pPg->dirty );
    assert( pPager->needSync );
  }

  /* Unlink pPg from it's hash-chain */
  unlinkHashChain(pPager, pPg);

  /* If the cache contains a page with page-number pgno, remove it
  ** from it's hash chain. Also, if the PgHdr.needSync was set for 
  ** page pgno before the 'move' operation, it needs to be retained 
  ** for the page moved there.
  */
  pPgOld = pager_lookup(pPager, pgno);
  if( pPgOld ){
    assert( pPgOld->nRef==0 );
    unlinkHashChain(pPager, pPgOld);
    makeClean(pPgOld);
    if( pPgOld->needSync ){
      assert( pPgOld->inJournal );
      pPg->inJournal = 1;
      pPg->needSync = 1;
      assert( pPager->needSync );
    }
  }

  /* Change the page number for pPg and insert it into the new hash-chain. */
  pPg->pgno = pgno;
  h = pgno & (pPager->nHash-1);
  if( pPager->aHash[h] ){
    assert( pPager->aHash[h]->pPrevHash==0 );
    pPager->aHash[h]->pPrevHash = pPg;
  }
  pPg->pNextHash = pPager->aHash[h];
  pPager->aHash[h] = pPg;
  pPg->pPrevHash = 0;

  makeDirty(pPg);
  pPager->dirtyCache = 1;

  if( needSyncPgno ){
    /* If needSyncPgno is non-zero, then the journal file needs to be 
    ** sync()ed before any data is written to database file page needSyncPgno.
    ** Currently, no such page exists in the page-cache and the 
    ** Pager.aInJournal bit has been set. This needs to be remedied by loading
    ** the page into the pager-cache and setting the PgHdr.needSync flag.
    **
    ** The sqlite3pager_get() call may cause the journal to sync. So make
    ** sure the Pager.needSync flag is set too.
    */
    int rc;
    void *pNeedSync;
    assert( pPager->needSync );
    rc = sqlite3pager_get(pPager, needSyncPgno, &pNeedSync);
    if( rc!=SQLITE_OK ) return rc;
    pPager->needSync = 1;
    DATA_TO_PGHDR(pNeedSync)->needSync = 1;
    DATA_TO_PGHDR(pNeedSync)->inJournal = 1;
    makeDirty(DATA_TO_PGHDR(pNeedSync));
    sqlite3pager_unref(pNeedSync);
  }

  return SQLITE_OK;
}

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int sqlite3pager_nosync ( Pager pPager)

Definition at line 3616 of file pager.c.

                                      {
  return pPager->noSync;
}

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int sqlite3pager_open ( Pager **  ppPager,
const char *  zFilename,
int  nExtra,
int  flags 
)

Definition at line 1570 of file pager.c.

 {
  Pager *pPager = 0;
  char *zFullPathname = 0;
  int nameLen;  /* Compiler is wrong. This is always initialized before use */
  OsFile *fd;
  int rc = SQLITE_OK;
  int i;
  int tempFile = 0;
  int memDb = 0;
  int readOnly = 0;
  int useJournal = (flags & PAGER_OMIT_JOURNAL)==0;
  int noReadlock = (flags & PAGER_NO_READLOCK)!=0;
  char zTemp[SQLITE_TEMPNAME_SIZE];
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  /* A malloc() cannot fail in sqlite3ThreadData() as one or more calls to 
  ** malloc() must have already been made by this thread before it gets
  ** to this point. This means the ThreadData must have been allocated already
  ** so that ThreadData.nAlloc can be set. It would be nice to assert
  ** that ThreadData.nAlloc is non-zero, but alas this breaks test cases 
  ** written to invoke the pager directly.
  */
  ThreadData *pTsd = sqlite3ThreadData();
  assert( pTsd );
#endif

  /* If malloc() has already failed return SQLITE_NOMEM. Before even
  ** testing for this, set *ppPager to NULL so the caller knows the pager
  ** structure was never allocated. 
  */
  *ppPager = 0;
  if( sqlite3MallocFailed() ){
    return SQLITE_NOMEM;
  }
  memset(&fd, 0, sizeof(fd));

  /* Open the pager file and set zFullPathname to point at malloc()ed 
  ** memory containing the complete filename (i.e. including the directory).
  */
  if( zFilename && zFilename[0] ){
#ifndef SQLITE_OMIT_MEMORYDB
    if( strcmp(zFilename,":memory:")==0 ){
      memDb = 1;
      zFullPathname = sqliteStrDup("");
    }else
#endif
    {
      zFullPathname = sqlite3OsFullPathname(zFilename);
      if( zFullPathname ){
        rc = sqlite3OsOpenReadWrite(zFullPathname, &fd, &readOnly);
      }
    }
  }else{
    rc = sqlite3pager_opentemp(zTemp, &fd);
    zFilename = zTemp;
    zFullPathname = sqlite3OsFullPathname(zFilename);
    if( rc==SQLITE_OK ){
      tempFile = 1;
    }
  }

  /* Allocate the Pager structure. As part of the same allocation, allocate
  ** space for the full paths of the file, directory and journal 
  ** (Pager.zFilename, Pager.zDirectory and Pager.zJournal).
  */
  if( zFullPathname ){
    nameLen = strlen(zFullPathname);
    pPager = sqliteMalloc( sizeof(*pPager) + nameLen*3 + 30 );
  }

  /* If an error occured in either of the blocks above, free the memory 
  ** pointed to by zFullPathname, free the Pager structure and close the 
  ** file. Since the pager is not allocated there is no need to set 
  ** any Pager.errMask variables.
  */
  if( !pPager || !zFullPathname || rc!=SQLITE_OK ){
    sqlite3OsClose(&fd);
    sqliteFree(zFullPathname);
    sqliteFree(pPager);
    return ((rc==SQLITE_OK)?SQLITE_NOMEM:rc);
  }

  TRACE3("OPEN %d %s\n", FILEHANDLEID(fd), zFullPathname);
  pPager->zFilename = (char*)&pPager[1];
  pPager->zDirectory = &pPager->zFilename[nameLen+1];
  pPager->zJournal = &pPager->zDirectory[nameLen+1];
  strcpy(pPager->zFilename, zFullPathname);
  strcpy(pPager->zDirectory, zFullPathname);

  for(i=nameLen; i>0 && pPager->zDirectory[i-1]!='/'; i--){}
  if( i>0 ) pPager->zDirectory[i-1] = 0;
  strcpy(pPager->zJournal, zFullPathname);
  sqliteFree(zFullPathname);
  strcpy(&pPager->zJournal[nameLen], "-journal");
  pPager->fd = fd;
  /* pPager->journalOpen = 0; */
  pPager->useJournal = useJournal && !memDb;
  pPager->noReadlock = noReadlock && readOnly;
  /* pPager->stmtOpen = 0; */
  /* pPager->stmtInUse = 0; */
  /* pPager->nRef = 0; */
  pPager->dbSize = memDb-1;
  pPager->pageSize = SQLITE_DEFAULT_PAGE_SIZE;
  /* pPager->stmtSize = 0; */
  /* pPager->stmtJSize = 0; */
  /* pPager->nPage = 0; */
  /* pPager->nMaxPage = 0; */
  pPager->mxPage = 100;
  assert( PAGER_UNLOCK==0 );
  /* pPager->state = PAGER_UNLOCK; */
  /* pPager->errMask = 0; */
  pPager->tempFile = tempFile;
  pPager->memDb = memDb;
  pPager->readOnly = readOnly;
  /* pPager->needSync = 0; */
  pPager->noSync = pPager->tempFile || !useJournal;
  pPager->fullSync = (pPager->noSync?0:1);
  /* pPager->pFirst = 0; */
  /* pPager->pFirstSynced = 0; */
  /* pPager->pLast = 0; */
  pPager->nExtra = FORCE_ALIGNMENT(nExtra);
  pPager->sectorSize = PAGER_SECTOR_SIZE;
  /* pPager->pBusyHandler = 0; */
  /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
  *ppPager = pPager;
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  pPager->pNext = pTsd->pPager;
  pTsd->pPager = pPager;
#endif
  return SQLITE_OK;
}

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static int sqlite3pager_opentemp ( char *  zFile,
OsFile **  pFd 
) [static]

Definition at line 1544 of file pager.c.

                                                           {
  int cnt = 8;
  int rc;
  sqlite3_opentemp_count++;  /* Used for testing and analysis only */
  do{
    cnt--;
    sqlite3OsTempFileName(zFile);
    rc = sqlite3OsOpenExclusive(zFile, pFd, 1);
  }while( cnt>0 && rc!=SQLITE_OK && rc!=SQLITE_NOMEM );
  return rc;
}

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int sqlite3pager_overwrite ( Pager pPager,
Pgno  pgno,
void pData 
)

Definition at line 3205 of file pager.c.

                                                                 {
  void *pPage;
  int rc;

  rc = sqlite3pager_get(pPager, pgno, &pPage);
  if( rc==SQLITE_OK ){
    rc = sqlite3pager_write(pPage);
    if( rc==SQLITE_OK ){
      memcpy(pPage, pData, pPager->pageSize);
    }
    sqlite3pager_unref(pPage);
  }
  return rc;
}

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Definition at line 1806 of file pager.c.

                                         {
  i64 n;
  assert( pPager!=0 );
  if( pPager->dbSize>=0 ){
    n = pPager->dbSize;
  } else {
    if( sqlite3OsFileSize(pPager->fd, &n)!=SQLITE_OK ){
      pager_error(pPager, SQLITE_IOERR);
      return 0;
    }
    if( n>0 && n<pPager->pageSize ){
      n = 1;
    }else{
      n /= pPager->pageSize;
    }
    if( pPager->state!=PAGER_UNLOCK ){
      pPager->dbSize = n;
    }
  }
  if( n==(PENDING_BYTE/pPager->pageSize) ){
    n++;
  }
  return n;
}

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Definition at line 2109 of file pager.c.

                                         {
  PgHdr *p = DATA_TO_PGHDR(pData);
  return p->pgno;
}

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void sqlite3pager_read_fileheader ( Pager pPager,
int  N,
unsigned char *  pDest 
)

Definition at line 1787 of file pager.c.

                                                                             {
  memset(pDest, 0, N);
  if( MEMDB==0 ){
    disable_simulated_io_errors();
    sqlite3OsSeek(pPager->fd, 0);
    sqlite3OsRead(pPager->fd, pDest, N);
    enable_simulated_io_errors();
  }
}

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int sqlite3pager_ref ( void pData)

Definition at line 2163 of file pager.c.

                                 {
  PgHdr *pPg = DATA_TO_PGHDR(pData);
  page_ref(pPg);
  return SQLITE_OK;
}

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Definition at line 3375 of file pager.c.

                                        {
  int rc;
  TRACE2("ROLLBACK %d\n", PAGERID(pPager));
  if( MEMDB ){
    PgHdr *p;
    for(p=pPager->pAll; p; p=p->pNextAll){
      PgHistory *pHist;
      assert( !p->alwaysRollback );
      if( !p->dirty ){
        assert( !((PgHistory *)PGHDR_TO_HIST(p, pPager))->pOrig );
        assert( !((PgHistory *)PGHDR_TO_HIST(p, pPager))->pStmt );
        continue;
      }

      pHist = PGHDR_TO_HIST(p, pPager);
      if( pHist->pOrig ){
        memcpy(PGHDR_TO_DATA(p), pHist->pOrig, pPager->pageSize);
        TRACE3("ROLLBACK-PAGE %d of %d\n", p->pgno, PAGERID(pPager));
      }else{
        TRACE3("PAGE %d is clean on %d\n", p->pgno, PAGERID(pPager));
      }
      clearHistory(pHist);
      p->dirty = 0;
      p->inJournal = 0;
      p->inStmt = 0;
      p->pPrevStmt = p->pNextStmt = 0;
      if( pPager->xReiniter ){
        pPager->xReiniter(PGHDR_TO_DATA(p), pPager->pageSize);
      }
    }
    pPager->pDirty = 0;
    pPager->pStmt = 0;
    pPager->dbSize = pPager->origDbSize;
    memoryTruncate(pPager);
    pPager->stmtInUse = 0;
    pPager->state = PAGER_SHARED;
    return SQLITE_OK;
  }

  if( !pPager->dirtyCache || !pPager->journalOpen ){
    rc = pager_unwritelock(pPager);
    pPager->dbSize = -1;
    return rc;
  }

  if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
    if( pPager->state>=PAGER_EXCLUSIVE ){
      pager_playback(pPager);
    }
    return pPager->errCode;
  }
  if( pPager->state==PAGER_RESERVED ){
    int rc2;
    rc = pager_reload_cache(pPager);
    rc2 = pager_unwritelock(pPager);
    if( rc==SQLITE_OK ){
      rc = rc2;
    }
  }else{
    rc = pager_playback(pPager);
  }
  pPager->dbSize = -1;

  /* If an error occurs during a ROLLBACK, we can no longer trust the pager
  ** cache. So call pager_error() on the way out to make any error 
  ** persistent.
  */
  return pager_error(pPager, rc);
}

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void sqlite3pager_set_busyhandler ( Pager pPager,
BusyHandler pBusyHandler 
)

Definition at line 1709 of file pager.c.

                                                                           {
  pPager->pBusyHandler = pBusyHandler;
}

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void sqlite3pager_set_cachesize ( Pager pPager,
int  mxPage 
)

Definition at line 1485 of file pager.c.

                                                          {
  if( mxPage>10 ){
    pPager->mxPage = mxPage;
  }else{
    pPager->mxPage = 10;
  }
}

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void sqlite3pager_set_codec ( Pager pPager,
void *(*)(void *, void *, Pgno, int xCodec,
void pCodecArg 
)

Definition at line 3623 of file pager.c.

 {
  pPager->xCodec = xCodec;
  pPager->pCodecArg = pCodecArg;
}
void sqlite3pager_set_destructor ( Pager pPager,
void(*)(void *, int xDesc 
)

Definition at line 1721 of file pager.c.

                                                                         {
  pPager->xDestructor = xDesc;
}

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int sqlite3pager_set_pagesize ( Pager pPager,
int  pageSize 
)

Definition at line 1741 of file pager.c.

                                                          {
  assert( pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE );
  if( !pPager->memDb ){
    pPager->pageSize = pageSize;
  }
  return pPager->pageSize;
}

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void sqlite3pager_set_reiniter ( Pager pPager,
void(*)(void *, int xReinit 
)

Definition at line 1732 of file pager.c.

                                                                         {
  pPager->xReiniter = xReinit;
}

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void sqlite3pager_set_safety_level ( Pager pPager,
int  level,
int  full_fsync 
)

Definition at line 1520 of file pager.c.

                                                                            {
  pPager->noSync =  level==1 || pPager->tempFile;
  pPager->fullSync = level==3 && !pPager->tempFile;
  pPager->full_fsync = full_fsync;
  if( pPager->noSync ) pPager->needSync = 0;
}

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int* sqlite3pager_stats ( Pager pPager)

Definition at line 3456 of file pager.c.

                                      {
  static int a[11];
  a[0] = pPager->nRef;
  a[1] = pPager->nPage;
  a[2] = pPager->mxPage;
  a[3] = pPager->dbSize;
  a[4] = pPager->state;
  a[5] = pPager->errCode;
#ifdef SQLITE_TEST
  a[6] = pPager->nHit;
  a[7] = pPager->nMiss;
  a[8] = pPager->nOvfl;
  a[9] = pPager->nRead;
  a[10] = pPager->nWrite;
#endif
  return a;
}

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Definition at line 3481 of file pager.c.

                                          {
  int rc;
  char zTemp[SQLITE_TEMPNAME_SIZE];
  assert( !pPager->stmtInUse );
  assert( pPager->dbSize>=0 );
  TRACE2("STMT-BEGIN %d\n", PAGERID(pPager));
  if( MEMDB ){
    pPager->stmtInUse = 1;
    pPager->stmtSize = pPager->dbSize;
    return SQLITE_OK;
  }
  if( !pPager->journalOpen ){
    pPager->stmtAutoopen = 1;
    return SQLITE_OK;
  }
  assert( pPager->journalOpen );
  pPager->aInStmt = sqliteMalloc( pPager->dbSize/8 + 1 );
  if( pPager->aInStmt==0 ){
    /* sqlite3OsLock(pPager->fd, SHARED_LOCK); */
    return SQLITE_NOMEM;
  }
#ifndef NDEBUG
  rc = sqlite3OsFileSize(pPager->jfd, &pPager->stmtJSize);
  if( rc ) goto stmt_begin_failed;
  assert( pPager->stmtJSize == pPager->journalOff );
#endif
  pPager->stmtJSize = pPager->journalOff;
  pPager->stmtSize = pPager->dbSize;
  pPager->stmtHdrOff = 0;
  pPager->stmtCksum = pPager->cksumInit;
  if( !pPager->stmtOpen ){
    rc = sqlite3pager_opentemp(zTemp, &pPager->stfd);
    if( rc ) goto stmt_begin_failed;
    pPager->stmtOpen = 1;
    pPager->stmtNRec = 0;
  }
  pPager->stmtInUse = 1;
  return SQLITE_OK;
 
stmt_begin_failed:
  if( pPager->aInStmt ){
    sqliteFree(pPager->aInStmt);
    pPager->aInStmt = 0;
  }
  return rc;
}

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Definition at line 3531 of file pager.c.

                                           {
  if( pPager->stmtInUse ){
    PgHdr *pPg, *pNext;
    TRACE2("STMT-COMMIT %d\n", PAGERID(pPager));
    if( !MEMDB ){
      sqlite3OsSeek(pPager->stfd, 0);
      /* sqlite3OsTruncate(pPager->stfd, 0); */
      sqliteFree( pPager->aInStmt );
      pPager->aInStmt = 0;
    }
    for(pPg=pPager->pStmt; pPg; pPg=pNext){
      pNext = pPg->pNextStmt;
      assert( pPg->inStmt );
      pPg->inStmt = 0;
      pPg->pPrevStmt = pPg->pNextStmt = 0;
      if( MEMDB ){
        PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
        sqliteFree(pHist->pStmt);
        pHist->pStmt = 0;
      }
    }
    pPager->stmtNRec = 0;
    pPager->stmtInUse = 0;
    pPager->pStmt = 0;
  }
  pPager->stmtAutoopen = 0;
  return SQLITE_OK;
}

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Definition at line 3563 of file pager.c.

                                             {
  int rc;
  if( pPager->stmtInUse ){
    TRACE2("STMT-ROLLBACK %d\n", PAGERID(pPager));
    if( MEMDB ){
      PgHdr *pPg;
      for(pPg=pPager->pStmt; pPg; pPg=pPg->pNextStmt){
        PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
        if( pHist->pStmt ){
          memcpy(PGHDR_TO_DATA(pPg), pHist->pStmt, pPager->pageSize);
          sqliteFree(pHist->pStmt);
          pHist->pStmt = 0;
        }
      }
      pPager->dbSize = pPager->stmtSize;
      memoryTruncate(pPager);
      rc = SQLITE_OK;
    }else{
      rc = pager_stmt_playback(pPager);
    }
    sqlite3pager_stmt_commit(pPager);
  }else{
    rc = SQLITE_OK;
  }
  pPager->stmtAutoopen = 0;
  return rc;
}

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int sqlite3pager_sync ( Pager pPager,
const char *  zMaster,
Pgno  nTrunc 
)

Definition at line 3678 of file pager.c.

                                                                      {
  int rc = SQLITE_OK;

  TRACE4("DATABASE SYNC: File=%s zMaster=%s nTrunc=%d\n", 
      pPager->zFilename, zMaster, nTrunc);

  /* If this is an in-memory db, or no pages have been written to, or this
  ** function has already been called, it is a no-op.
  */
  if( pPager->state!=PAGER_SYNCED && !MEMDB && pPager->dirtyCache ){
    PgHdr *pPg;
    assert( pPager->journalOpen );

    /* If a master journal file name has already been written to the
    ** journal file, then no sync is required. This happens when it is
    ** written, then the process fails to upgrade from a RESERVED to an
    ** EXCLUSIVE lock. The next time the process tries to commit the
    ** transaction the m-j name will have already been written.
    */
    if( !pPager->setMaster ){
      rc = pager_incr_changecounter(pPager);
      if( rc!=SQLITE_OK ) goto sync_exit;
#ifndef SQLITE_OMIT_AUTOVACUUM
      if( nTrunc!=0 ){
        /* If this transaction has made the database smaller, then all pages
        ** being discarded by the truncation must be written to the journal
        ** file.
        */
        Pgno i;
        void *pPage;
        int iSkip = PAGER_MJ_PGNO(pPager);
        for( i=nTrunc+1; i<=pPager->origDbSize; i++ ){
          if( !(pPager->aInJournal[i/8] & (1<<(i&7))) && i!=iSkip ){
            rc = sqlite3pager_get(pPager, i, &pPage);
            if( rc!=SQLITE_OK ) goto sync_exit;
            rc = sqlite3pager_write(pPage);
            sqlite3pager_unref(pPage);
            if( rc!=SQLITE_OK ) goto sync_exit;
          }
        } 
      }
#endif
      rc = writeMasterJournal(pPager, zMaster);
      if( rc!=SQLITE_OK ) goto sync_exit;
      rc = syncJournal(pPager);
      if( rc!=SQLITE_OK ) goto sync_exit;
    }

#ifndef SQLITE_OMIT_AUTOVACUUM
    if( nTrunc!=0 ){
      rc = sqlite3pager_truncate(pPager, nTrunc);
      if( rc!=SQLITE_OK ) goto sync_exit;
    }
#endif

    /* Write all dirty pages to the database file */
    pPg = pager_get_all_dirty_pages(pPager);
    rc = pager_write_pagelist(pPg);
    if( rc!=SQLITE_OK ) goto sync_exit;

    /* Sync the database file. */
    if( !pPager->noSync ){
      rc = sqlite3OsSync(pPager->fd, 0);
    }

    pPager->state = PAGER_SYNCED;
  }else if( MEMDB && nTrunc!=0 ){
    rc = sqlite3pager_truncate(pPager, nTrunc);
  }

sync_exit:
  return rc;
}

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int sqlite3pager_truncate ( Pager pPager,
Pgno  nPage 
)

Definition at line 1973 of file pager.c.

                                                    {
  int rc;
  sqlite3pager_pagecount(pPager);
  if( pPager->errCode ){
    rc = pPager->errCode;
    return rc;
  }
  if( nPage>=(unsigned)pPager->dbSize ){
    return SQLITE_OK;
  }
  if( MEMDB ){
    pPager->dbSize = nPage;
    memoryTruncate(pPager);
    return SQLITE_OK;
  }
  rc = syncJournal(pPager);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  /* Get an exclusive lock on the database before truncating. */
  rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  rc = pager_truncate(pPager, nPage);
  if( rc==SQLITE_OK ){
    pPager->dbSize = nPage;
  }
  return rc;
}

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int sqlite3pager_unref ( void pData)

Definition at line 2808 of file pager.c.

                                   {
  PgHdr *pPg;

  /* Decrement the reference count for this page
  */
  pPg = DATA_TO_PGHDR(pData);
  assert( pPg->nRef>0 );
  pPg->nRef--;
  REFINFO(pPg);

  CHECK_PAGE(pPg);

  /* When the number of references to a page reach 0, call the
  ** destructor and add the page to the freelist.
  */
  if( pPg->nRef==0 ){
    Pager *pPager;
    pPager = pPg->pPager;
    pPg->pNextFree = 0;
    pPg->pPrevFree = pPager->pLast;
    pPager->pLast = pPg;
    if( pPg->pPrevFree ){
      pPg->pPrevFree->pNextFree = pPg;
    }else{
      pPager->pFirst = pPg;
    }
    if( pPg->needSync==0 && pPager->pFirstSynced==0 ){
      pPager->pFirstSynced = pPg;
    }
    if( pPager->xDestructor ){
      pPager->xDestructor(pData, pPager->pageSize);
    }
  
    /* When all pages reach the freelist, drop the read lock from
    ** the database file.
    */
    pPager->nRef--;
    assert( pPager->nRef>=0 );
    if( pPager->nRef==0 && !MEMDB ){
      pager_reset(pPager);
    }
  }
  return SQLITE_OK;
}

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int sqlite3pager_write ( void pData)

Definition at line 3037 of file pager.c.

                                   {
  PgHdr *pPg = DATA_TO_PGHDR(pData);
  Pager *pPager = pPg->pPager;
  int rc = SQLITE_OK;

  /* Check for errors
  */
  if( pPager->errCode ){ 
    return pPager->errCode;
  }
  if( pPager->readOnly ){
    return SQLITE_PERM;
  }

  assert( !pPager->setMaster );

  CHECK_PAGE(pPg);

  /* Mark the page as dirty.  If the page has already been written
  ** to the journal then we can return right away.
  */
  makeDirty(pPg);
  if( pPg->inJournal && (pPg->inStmt || pPager->stmtInUse==0) ){
    pPager->dirtyCache = 1;
  }else{

    /* If we get this far, it means that the page needs to be
    ** written to the transaction journal or the ckeckpoint journal
    ** or both.
    **
    ** First check to see that the transaction journal exists and
    ** create it if it does not.
    */
    assert( pPager->state!=PAGER_UNLOCK );
    rc = sqlite3pager_begin(pData, 0);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    assert( pPager->state>=PAGER_RESERVED );
    if( !pPager->journalOpen && pPager->useJournal ){
      rc = pager_open_journal(pPager);
      if( rc!=SQLITE_OK ) return rc;
    }
    assert( pPager->journalOpen || !pPager->useJournal );
    pPager->dirtyCache = 1;
  
    /* The transaction journal now exists and we have a RESERVED or an
    ** EXCLUSIVE lock on the main database file.  Write the current page to
    ** the transaction journal if it is not there already.
    */
    if( !pPg->inJournal && (pPager->useJournal || MEMDB) ){
      if( (int)pPg->pgno <= pPager->origDbSize ){
        int szPg;
        if( MEMDB ){
          PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
          TRACE3("JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
          assert( pHist->pOrig==0 );
          pHist->pOrig = sqliteMallocRaw( pPager->pageSize );
          if( pHist->pOrig ){
            memcpy(pHist->pOrig, PGHDR_TO_DATA(pPg), pPager->pageSize);
          }
        }else{
          u32 cksum, saved;
          char *pData2, *pEnd;
          /* We should never write to the journal file the page that
          ** contains the database locks.  The following assert verifies
          ** that we do not. */
          assert( pPg->pgno!=PAGER_MJ_PGNO(pPager) );
          pData2 = CODEC2(pPager, pData, pPg->pgno, 7);
          cksum = pager_cksum(pPager, (u8*)pData2);
          pEnd = pData2 + pPager->pageSize;
          pData2 -= 4;
          saved = *(u32*)pEnd;
          put32bits(pEnd, cksum);
          szPg = pPager->pageSize+8;
          put32bits(pData2, pPg->pgno);
          rc = sqlite3OsWrite(pPager->jfd, pData2, szPg);
          pPager->journalOff += szPg;
          TRACE4("JOURNAL %d page %d needSync=%d\n",
                  PAGERID(pPager), pPg->pgno, pPg->needSync);
          *(u32*)pEnd = saved;

         /* An error has occured writing to the journal file. The 
          ** transaction will be rolled back by the layer above.
          */
          if( rc!=SQLITE_OK ){
            return rc;
          }

          pPager->nRec++;
          assert( pPager->aInJournal!=0 );
          pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
          pPg->needSync = !pPager->noSync;
          if( pPager->stmtInUse ){
            pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
            page_add_to_stmt_list(pPg);
          }
        }
      }else{
        pPg->needSync = !pPager->journalStarted && !pPager->noSync;
        TRACE4("APPEND %d page %d needSync=%d\n",
                PAGERID(pPager), pPg->pgno, pPg->needSync);
      }
      if( pPg->needSync ){
        pPager->needSync = 1;
      }
      pPg->inJournal = 1;
    }
  
    /* If the statement journal is open and the page is not in it,
    ** then write the current page to the statement journal.  Note that
    ** the statement journal format differs from the standard journal format
    ** in that it omits the checksums and the header.
    */
    if( pPager->stmtInUse && !pPg->inStmt && (int)pPg->pgno<=pPager->stmtSize ){
      assert( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize );
      if( MEMDB ){
        PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
        assert( pHist->pStmt==0 );
        pHist->pStmt = sqliteMallocRaw( pPager->pageSize );
        if( pHist->pStmt ){
          memcpy(pHist->pStmt, PGHDR_TO_DATA(pPg), pPager->pageSize);
        }
        TRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
      }else{
        char *pData2 = CODEC2(pPager, pData, pPg->pgno, 7)-4;
        put32bits(pData2, pPg->pgno);
        rc = sqlite3OsWrite(pPager->stfd, pData2, pPager->pageSize+4);
        TRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
        if( rc!=SQLITE_OK ){
          return rc;
        }
        pPager->stmtNRec++;
        assert( pPager->aInStmt!=0 );
        pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
      }
      page_add_to_stmt_list(pPg);
    }
  }

  /* Update the database size and return.
  */
  if( pPager->dbSize<(int)pPg->pgno ){
    pPager->dbSize = pPg->pgno;
    if( !MEMDB && pPager->dbSize==PENDING_BYTE/pPager->pageSize ){
      pPager->dbSize++;
    }
  }
  return rc;
}

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static int syncJournal ( Pager pPager) [static]

Definition at line 2189 of file pager.c.

                                     {
  PgHdr *pPg;
  int rc = SQLITE_OK;

  /* Sync the journal before modifying the main database
  ** (assuming there is a journal and it needs to be synced.)
  */
  if( pPager->needSync ){
    if( !pPager->tempFile ){
      assert( pPager->journalOpen );
      /* assert( !pPager->noSync ); // noSync might be set if synchronous
      ** was turned off after the transaction was started.  Ticket #615 */
#ifndef NDEBUG
      {
        /* Make sure the pPager->nRec counter we are keeping agrees
        ** with the nRec computed from the size of the journal file.
        */
        i64 jSz;
        rc = sqlite3OsFileSize(pPager->jfd, &jSz);
        if( rc!=0 ) return rc;
        assert( pPager->journalOff==jSz );
      }
#endif
      {
        /* Write the nRec value into the journal file header. If in
        ** full-synchronous mode, sync the journal first. This ensures that
        ** all data has really hit the disk before nRec is updated to mark
        ** it as a candidate for rollback. 
        */
        if( pPager->fullSync ){
          TRACE2("SYNC journal of %d\n", PAGERID(pPager));
          rc = sqlite3OsSync(pPager->jfd, 0);
          if( rc!=0 ) return rc;
        }
        rc = sqlite3OsSeek(pPager->jfd,
                           pPager->journalHdr + sizeof(aJournalMagic));
        if( rc ) return rc;
        rc = write32bits(pPager->jfd, pPager->nRec);
        if( rc ) return rc;

        rc = sqlite3OsSeek(pPager->jfd, pPager->journalOff);
        if( rc ) return rc;
      }
      TRACE2("SYNC journal of %d\n", PAGERID(pPager));
      rc = sqlite3OsSync(pPager->jfd, pPager->full_fsync);
      if( rc!=0 ) return rc;
      pPager->journalStarted = 1;
    }
    pPager->needSync = 0;

    /* Erase the needSync flag from every page.
    */
    for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
      pPg->needSync = 0;
    }
    pPager->pFirstSynced = pPager->pFirst;
  }

#ifndef NDEBUG
  /* If the Pager.needSync flag is clear then the PgHdr.needSync
  ** flag must also be clear for all pages.  Verify that this
  ** invariant is true.
  */
  else{
    for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
      assert( pPg->needSync==0 );
    }
    assert( pPager->pFirstSynced==pPager->pFirst );
  }
#endif

  return rc;
}

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static void unlinkHashChain ( Pager pPager,
PgHdr pPg 
) [static]

Definition at line 1857 of file pager.c.

                                                      {
  if( pPg->pgno==0 ){
    /* If the page number is zero, then this page is not in any hash chain. */
    return;
  }
  if( pPg->pNextHash ){
    pPg->pNextHash->pPrevHash = pPg->pPrevHash;
  }
  if( pPg->pPrevHash ){
    assert( pPager->aHash[pPg->pgno & (pPager->nHash-1)]!=pPg );
    pPg->pPrevHash->pNextHash = pPg->pNextHash;
  }else{
    int h = pPg->pgno & (pPager->nHash-1);
    assert( pPager->aHash[h]==pPg );
    pPager->aHash[h] = pPg->pNextHash;
  }
  if( MEMDB ){
    clearHistory(PGHDR_TO_HIST(pPg, pPager));
  }
  pPg->pgno = 0;
  pPg->pNextHash = pPg->pPrevHash = 0;
}

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static void unlinkPage ( PgHdr pPg) [static]

Definition at line 1884 of file pager.c.

                                  {
  Pager *pPager = pPg->pPager;

  /* Keep the pFirstSynced pointer pointing at the first synchronized page */
  if( pPg==pPager->pFirstSynced ){
    PgHdr *p = pPg->pNextFree;
    while( p && p->needSync ){ p = p->pNextFree; }
    pPager->pFirstSynced = p;
  }

  /* Unlink from the freelist */
  if( pPg->pPrevFree ){
    pPg->pPrevFree->pNextFree = pPg->pNextFree;
  }else{
    assert( pPager->pFirst==pPg );
    pPager->pFirst = pPg->pNextFree;
  }
  if( pPg->pNextFree ){
    pPg->pNextFree->pPrevFree = pPg->pPrevFree;
  }else{
    assert( pPager->pLast==pPg );
    pPager->pLast = pPg->pPrevFree;
  }
  pPg->pNextFree = pPg->pPrevFree = 0;

  /* Unlink from the pgno hash table */
  unlinkHashChain(pPager, pPg);
}

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static int write32bits ( OsFile fd,
u32  val 
) [static]

Definition at line 446 of file pager.c.

                                           {
  char ac[4];
  put32bits(ac, val);
  return sqlite3OsWrite(fd, ac, 4);
}

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static int writeJournalHdr ( Pager pPager) [static]

Definition at line 626 of file pager.c.

                                         {
  char zHeader[sizeof(aJournalMagic)+16];

  int rc = seekJournalHdr(pPager);
  if( rc ) return rc;

  pPager->journalHdr = pPager->journalOff;
  if( pPager->stmtHdrOff==0 ){
    pPager->stmtHdrOff = pPager->journalHdr;
  }
  pPager->journalOff += JOURNAL_HDR_SZ(pPager);

  /* FIX ME: 
  **
  ** Possibly for a pager not in no-sync mode, the journal magic should not
  ** be written until nRec is filled in as part of next syncJournal(). 
  **
  ** Actually maybe the whole journal header should be delayed until that
  ** point. Think about this.
  */
  memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
  /* The nRec Field. 0xFFFFFFFF for no-sync journals. */
  put32bits(&zHeader[sizeof(aJournalMagic)], pPager->noSync ? 0xffffffff : 0);
  /* The random check-hash initialiser */ 
  sqlite3Randomness(sizeof(pPager->cksumInit), &pPager->cksumInit);
  put32bits(&zHeader[sizeof(aJournalMagic)+4], pPager->cksumInit);
  /* The initial database size */
  put32bits(&zHeader[sizeof(aJournalMagic)+8], pPager->dbSize);
  /* The assumed sector size for this process */
  put32bits(&zHeader[sizeof(aJournalMagic)+12], pPager->sectorSize);
  rc = sqlite3OsWrite(pPager->jfd, zHeader, sizeof(zHeader));

  /* The journal header has been written successfully. Seek the journal
  ** file descriptor to the end of the journal header sector.
  */
  if( rc==SQLITE_OK ){
    rc = sqlite3OsSeek(pPager->jfd, pPager->journalOff-1);
    if( rc==SQLITE_OK ){
      rc = sqlite3OsWrite(pPager->jfd, "\000", 1);
    }
  }
  return rc;
}

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static int writeMasterJournal ( Pager pPager,
const char *  zMaster 
) [static]

Definition at line 752 of file pager.c.

                                                                 {
  int rc;
  int len; 
  int i; 
  u32 cksum = 0;
  char zBuf[sizeof(aJournalMagic)+2*4];

  if( !zMaster || pPager->setMaster) return SQLITE_OK;
  pPager->setMaster = 1;

  len = strlen(zMaster);
  for(i=0; i<len; i++){
    cksum += zMaster[i];
  }

  /* If in full-sync mode, advance to the next disk sector before writing
  ** the master journal name. This is in case the previous page written to
  ** the journal has already been synced.
  */
  if( pPager->fullSync ){
    rc = seekJournalHdr(pPager);
    if( rc!=SQLITE_OK ) return rc;
  }
  pPager->journalOff += (len+20);

  rc = write32bits(pPager->jfd, PAGER_MJ_PGNO(pPager));
  if( rc!=SQLITE_OK ) return rc;

  rc = sqlite3OsWrite(pPager->jfd, zMaster, len);
  if( rc!=SQLITE_OK ) return rc;

  put32bits(zBuf, len);
  put32bits(&zBuf[4], cksum);
  memcpy(&zBuf[8], aJournalMagic, sizeof(aJournalMagic));
  rc = sqlite3OsWrite(pPager->jfd, zBuf, 8+sizeof(aJournalMagic));
  pPager->needSync = !pPager->noSync;
  return rc;
}

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Variable Documentation

const unsigned char aJournalMagic[] [static]
Initial value:
 {
  0xd9, 0xd5, 0x05, 0xf9, 0x20, 0xa1, 0x63, 0xd7,
}

Definition at line 321 of file pager.c.

Definition at line 1533 of file pager.c.